general discription of press filter

how to use vlookup with multiple conditions

I will in this article demonstrate how to use the VLOOKUP function with multiple conditions. The function was not built for these circumstances, however, I will demonstrate a few workarounds and also explain how they work.

The image above shows a data set in cell range B2:F12, the VLOOKUP function in cell D16 looks for both a value in column B and another value in column C. If both values match a third value on the same row is retrieved from column D and shown in cell D17.

IF({FALSE; FALSE; FALSE; FALSE; TRUE; FALSE; FALSE; FALSE; FALSE; TRUE},{"A","Australia","Atlantic Corporation","Birdie","Schneider"; "B","North America","Uplink Corporation","Amshula","Canty"; "C","Asia","Omni Consumer Products","Jaycee","Martin"; "D","Europe","Galaxy Corp","Tracy","Tuck"; "A","South America","The New Firm","Tory","Byrnes"; "B","Australia","ZiffCorp","Santos","Cowart"; "C","North America","Minuteman Cafe","Gen","Lindgren"; "D","Asia","Demo Company","Edwin","Shinn"; "E","Europe","Western Gas & Electric","Allayna","Egan"; "F","South America","Trans United Airways","Ervin","Hennessey"}, "")

{"","","","","";"","","","","";"","","","","";"","","","","";"A","South America","The New Firm","Tory","Byrnes";"","","","","";"","","","","";"","","","","";"","","","","";"F","South America","Trans United Airways","Ervin","Hennessey"}

This array has commas and semicolons as delimiting characters, the picture below shows the array in cell range B3:F12. It is now obvious that the IF function has filtered records containing ony the condition.

VLOOKUP(D14, {"", "", "", "", ""; "", "", "", "", ""; "", "", "", "", ""; "", "", "", "", ""; "A", "South America", "The New Firm", "Tory", "Byrnes"; "", "", "", "", ""; "", "", "", "", ""; "", "", "", "", ""; "", "", "", "", ""; "F", "South America", "Trans United Airways", "Ervin", "Hennessey"}, 3, FALSE)

The first condition is specified in cell D14, to compare that value with the values in cell range B3:B14 I use the equal sign. It is a logical operator that returns TRUE or FALSE after the evaluations is made.

The COUNTIF function counts values that equal a condition, however, it can also count multiple conditions but we must enter this formula as an array formula in order to calculate multiple values in one cell.

This array has as many values as there are values in cell range B3:B12, the values also corresponds to B3:B12. 0 (zero) indicates that the value is not equal to "C" or "D" and 1 shows that the value is equal to "C" or "D".

The lookup values are found in row 5,6,9 and 10 but only the corresponding values from row 5 and 6 are returned, that is how the VLOOKUP function is supposed to work. If you need to extract multiple values based on a condition read this: 5 easy ways to VLOOKUP and return multiple values

The image above demonstrates an array formula in cell D17 that returns a value from column D (Company Name) if the corresponding value on the same row in column B or C matches the specified value in cell D17.

In this case B3:C12, this is fine as long as you enter the formula as an array formula. The formula performs multiple calcualtions in one cell, the result is an array containing boolean values, TRUE or FALSE.

No, you can't concatenate multiple return values from a VLOOKUP function. It will only return one instance. This example shows how to concatenate multiple values using multiple conditions using the TEXTJOIN, IF and COUNTIF functions.

IF({0; 0; 1; 1; 0; 0; 0; 1; 0; 0}, {"Atlantic Corporation"; "Uplink Corporation"; "Omni Consumer Products"; "Galaxy Corp"; "The New Firm"; "ZiffCorp"; "Minuteman Cafe"; "Demo Company"; "Western Gas & Electric"; "Trans United Airways"}, "")

{"","","","",""; "B",40910,"Uplink Corporation","Amshula","Canty"; "C",40911,"Omni Consumer Products","Jaycee","Martin"; "D",40912,"Galaxy Corp","Tracy","Tuck"; "A",40913,"The New Firm","Tory","Byrnes"; "B",40914,"ZiffCorp","Santos","Cowart"; "C",40915,"Minuteman Cafe","Gen","Lindgren"; "","","","",""; "","","","",""; "","","","",""}.

VLOOKUP(C2,IF({0;1;1;1;1;1;1;0;0;0},{"A", 40909, "Atlantic Corporation", "Birdie", "Schneider";"B", 40910, "Uplink Corporation", "Amshula", "Canty";"C", 40911, "Omni Consumer Products", "Jaycee", "Martin";"D", 40912, "Galaxy Corp", "Tracy", "Tuck";"A", 40913, "The New Firm", "Tory", "Byrnes";"B", 40914, "ZiffCorp", "Santos", "Cowart";"C", 40915, "Minuteman Cafe", "Gen", "Lindgren";"D", 40916, "Demo Company", "Edwin", "Shinn";"E", 40917, "Western Gas & Electric", "Allayna", "Egan";"F", 40918, "Trans United Airways", "Ervin", "Hennessey"},""),3,FALSE)

=VLOOKUP("A",{"","","","","";"B",40910,"Uplink Corporation","Amshula","Canty";"C",40911,"Omni Consumer Products","Jaycee","Martin";"D",40912,"Galaxy Corp","Tracy","Tuck";"A",40913,"The New Firm","Tory","Byrnes";"B",40914,"ZiffCorp","Santos","Cowart";"C",40915,"Minuteman Cafe","Gen","Lindgren";"","","","","";"","","","","";"","","","",""},3,FALSE)

The INDEX and MATCH function is more versatile than VLOOKUP and it is easier to apply more conditions if needed, however, it still can only return one value even if there are more records that match. The INDEX, SMALL and IF function can return multiple values, read this article: 5 easy ways to VLOOKUP and return multiple values

I am having a problem getting vlookup to work when asking it to check two different tables based on what data is percent in specific cells. Basically I want it to check one table if a persons gender is male, and another table if the gender is female. Any idea how I can accomplish this? I would really appreciate any help I could get. Thank you very much.

I want to search for value by using two criteria. ex: vlookup with invoice number and serial number search for the discription in other sheet or other related information. Each invoice number has multiple serial numbers or items.Ex. invoice number 1 has 1to 5 items, I need search for all 5 items from database to the main sheet.

I am trying to keep track of components for manufacturing purposes. I have one table where i keep my manufacturing data (product, quantity and date) each of my products require a unique valve and i want to have another table where i can look up the item and if it falls in a particular month indicate the total quantity.

Hi Oscar, Please how do I handle this case... An excel column has up to a thousand entries and each entry is to be looked up in another column. The aim is to find out if their is any entry among the up to one thousand entries which is in the other column or not. Since the number of entries to be looked up for is large, I want to avoid doing this one at a time.

Hi I'm trying to do a vlookup from detail related to a person ID. However, the ID has two records. One record is "Completed" and another record is "Pending Update". How do I formulate it such that the vlookup will pick up the "Pending Update" line instead of the "Completed"

I have a vlookup table that retrieves an employee list. What I need is when I select an employee from the lookup. When I move to the next row I only want to be able to select an employee that has not been previously selected.

Oscar, I know this is an older thread, but I am trying to use a version of the VLOOKUP and two conditions (date range)formula, but my table is on another tab and instead of matching my Id's from tab1 to the Ids in table 1,(C2 in the actual formula), it's providing the actual value in my table matching the cell reference from tab 1. So it's giving me the ID in cell A129 instead of trying to find a match for that ID in the table. I am not sure what I am doing wrong. Can you provide assistance?

Need Help: I have an file with Column B having entries and i need to match these with my entries in column A. However the column B may have multiple relevant values in column B. How do i do it? Also if i enter any values of column B it has to give me an output of the values i have in column A.

Good Day to you, I have a question. I need a Vlookup or should it be sumif formulas for 2 sheets, base on two criteria on sheet2. First the date (A1)in sheet 2, then the Item code (B1)in sheet 2, to get the total amount at sheet1 for a certain item. its kinda like your first graph here, first find the Item, then Region, to get the answer. but my answer is quantity and need to add up.

Thank you for the examples. I needed a way to look up workers' compensation class code premium rates by state. I had a table of about 200 class codes, in each of 3 states. Being able to find a class code rate based on the state required this 2 column lookup. The IF inside of the VLOOKUP did the trick perfectly!

How to add a formula to your comment Insert your formula here. Convert less than and larger than signs Use html character entities instead of less than and larger than signs. < becomes < and > becomes >

qvc phone number | call now & skip the wait

This is QVC's best phone number, the real-time current wait on hold and tools for skipping right through those phone lines to get right to a QVC agent. This phone number is QVC's Best Phone Number because 32,184 customers like you used this contact information over the last 18 months and gave us feedback. Common problems addressed by the customer care unit that answers calls to 800-367-9444 include Cancel or change order, Refunds and returns, Account issue, Billing issue, Order issue and other customer service issues. The QVC call center that you call into has employees from Texas, Virginia and is open 24 hours, 7 days according to customers. In total, QVC has 2 phone numbers. It's not always clear what is the best way to talk to QVC representatives, so we started compiling this information built from suggestions from the customer community. Please keep sharing your experiences so we can continue to improve this free resource.

While 800-367-9444 is QVC's best toll-free number, there are 3 total ways to get in touch with them. The next best way to talk to their customer support team , according to other QVC customers, is by calling their 800-345-1515 phone number for their Purchasing department. Besides calling, the next favorite option for customers looking for help is via 800-345-1515 for Purchasing. If you think this information is inaccurate or know of other ways to contact QVC please let us know so we can share with other customers.And you can click here if you want to compare all the contact information we've gathered for QVC.

In short, the two companies are not related. GetHuman builds free tools and shares information amongst customers of companies like QVC. For large companies that includes tools such as our GetHuman Phone, which allows you to call a company but skip the part where you wait on the line listening to their call technology music. We've created these shortcuts and apps to try to help customers like you (and ourselves!) navigate the messy phone menus, hold times, and confusion with customer service, especially with larger companies. And as long as you keep sharing it with your friends and loved ones, we'll keep doing it.

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mysql - laravel join with 3 tables - stack overflow

I didn't realize you were using DB:: queries and not models. So I'm fixing the answer and providing a lot more clarity. I suggest you use models, it's a lot easier for those beginning with the framework and specially SQL.

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filter presses for sludge treatment

Filtration is the most widely used method in the treatment of sludge produced by wastewater treatment. It can consist just in dreinage though sand beds or it can be mechanical under vacuum middle or high pressure conditions which require more sophisticated equipment. Filter presses operate applying very high pressures to the cake (from 5 to 15 bars and sometimes even more).

A filter comprises a set of vertical, juxtaposed recessed plates, presses against each other by hydraulic jacks at one end of the set. The pressure applied to the joint face of each filtering plate must withstand the chamber internal pressure developed by the sludge pumping system. This vertical plate layout forms watertight filtration chambers allowing easy mechanisation for the discharge of cakes. Filter chlotes finely or tightly meshed are applied to the two groowed surfaces in these plates. Orifices feed the sludge to be filtered under pressure in the filtration chamber. They are usually placed in the center of the plates allowing a proper distribution of flow, right pressure and better drainage of sludge within the chamber. Solids sludge gradually accumulates in the filtration chamber until the final compacted cake is formed. The filtrate is collected at the back of the filtration support and carried away by internal ducts.

2- Filling: During this short phase chamber are filled with sludge for filtration. Filling time depends on the flow of the feed pump. For sludge having good filterability it is best to fill the filter very quickly so as to avoid the formation of a cake in the first chamber before the last ones have been filled.

3- Filtration: Once the chamber have been filled continuous arrival of sludge to be dewatered provokes a rise in pressure due to the formation of an increasingly thick layer of filter sludge on the cloths. This filtration phase can be stopped manually, by a timer or more convenientely by a filtrate flow indicator which issues a stop alarm when the end of filtration rate has been reached. When the filtration pump has stopped, the filtrate circuits and central duct, which is still filled with liquid sludge, are purged by compressed air.

3- Filter opening: The moving head is drawn back to disengage the first filtration chamber. The cake falls has a result of his own weight. A mechanised system pulles out the plates one by one. The speed of plate separation can be adjusted to account to the cake texture.

4- Washing: Whasing of clothes should be carried out every 15-30 processing oprations. For mid- or large units this take place on press using water sprayers at very high pressure (80-100 bar). Whasing is sincronized with separation of plates.

The production capacity of a filter press is somewhere between 1.5 and 10 kg of solid per m2 of filtering surface. For every the filter press model the chamber volume and the filtering surface depend on the number of plates in the filer.

One of the advantages of the filer press is that it can accept sludge with average filterability. It is always advantageous to optimally thicken sludge before filter press operations. Although sludge presenting a high filterability enables better production capacities, a filter press still accepts sludge with low conditioning precision. This tolerance means that the device offers greater owerall operational safety.

what is a filter press and how does it work? - micronics, inc

Micronics is the world-wide authority on filter presses and advanced liquid filtration technology. Here, well explore the question how does a filter press work? We will also examinethe applications where they are most frequently utilized, and some of Micronics standard and custom filter press solutions.

A filter press is a piece of equipment used in liquid/solid separation. Specifically, the filter press separates the liquids and solids using pressure filtration, wherein a slurry is pumped into the filter press and is dewatered under pressure. Basically, each filter press is designed based on the volume and type of slurry that needs to be dewatered. Micronics, Inc. is a trusted expert in liquid/solid separation and offers a wide range of filter press types and capacities to suit specific application needs for trouble-free, economical dewatering. These include configurations such as sidebar automatic, manual overhead, automatic dual overhead beam, stainless steel clad, explosion-proof filter presses, vacuum filter presses, and hand filter presses.

The working principle of filter presses is that slurry is pumped into the machine such that solids are distributed evenly during the fill cycle. Solids build up on the filter cloth, forming the filter cake; the filtrate exits the filter plates through the corner ports into the manifold, yielding clean filtered water.

Filter presses are a pressure filtration method and as such, as the filter press feed pump builds pressure, solids build within the chambers until they are completely chock-full of solids, forming the cake. Once the chambers are full, the cycle is complete and the filter cakes are ready to be released. In many higher capacity filter presses, fast action automatic plate shifters are employed, speeding cycle time. Some filter presses are specifically designed for fully automatic, 24-hour operation in a harsh environment such as mines or chemical manufacturing plants.

Filter presses can be built in a wide range of sizes, from small, lab-scale 150 mm presses, to those with much larger capacities, such as those with 1500 and 2000 mm filter plates. Filter presses are used for liquid/solid separation in an extensive range of industries and applications including:

The industry, application and operational considerations will guide specifics such as the overall design, filtration capacity, number of chambers, filter plate size, materials of construction, as well as additional features/systems such as automatic plate shifters, cloth washing system, drip trays, cake shields and safety light curtains. Design of a filter press depends on a host of factors such as filtration cycle time, cake dryness required, cloth life, whether manual or automated plate shifting is desired, and many other factors.

If youre interested in learning more about how a filter press could be customized for your specific application, contact Micronics, Inc. today. Or we may have just the right standard or used filter press in-stock to meet your needs today. Contact Micronics, Inc. today and benefit from our engineered filtration experience.

Micronics Is Your Trusted Partner for Total Engineered Filtration Solutions. We offer end-to-end solutions from Filter Media to Industry-Leading Equipment to Spare Parts & Accessories to On-Site and Remote Services. Whether for Your Filter Press operation or your Baghouse, you can count on Micronics deep industry and applications knowledge for the right engineered filtration solution to meet your needs. We look forward to working with your team.

pressure filter - an overview | sciencedirect topics

Pressure filters are similar in bed construction to rapid gravity filters, except that they are contained in a steel pressure vessel. Perforated pipes or a steel plate with nozzles are used for collecting the filtered water and for distribution of the washwater and air scour. The steel pressure vessel is cylindrical, arranged horizontally (Fig. 8.4) or vertically. With a pipe lateral underdrain system the bottom of the vessel is usually filled with concrete so as to obtain a flat base. In the plenum floor design a steel plate into which nozzles are screwed, is used. In a horizontal vessel, sometimes vertical plates are welded inside to give a rectangular shaped sand bed within the cylinder so that the bed may be washed evenly and there are no dead areas beneath which air scour and water pipes cannot be placed. More commonly media is placed in the entire vessel such that the depth is equally distributed about the horizontal diameter of the filter. The whole of the cylinder is kept filled with water under pressure and at the highest point an air release valve is inserted for the release of trapped air. To avoid having to employ special transportation procedures for large loads the maximum diameter of filters is limited to 34 m and the length/height is limited to about 12 m.

The backwashing of such filters is very similar to that of an open rapid gravity filter. A bellmouth and pipe can be used for the removal of dirty washwater in a vertical filter; for most horizontal filters a single vertical plate located near to one of the dished ends facilitates washwater removal, but for the larger filters, a central washout channel formed by two vertical plates is necessary.

The advantage of pressure filters is that excess raw water pressure is not lost when the filtration process takes place, as is the case with an open rapid gravity filter system. About 3 m head may be lost in friction through the sand bed and the inlet and outlet fittings. This includes an allowance for dirt loss of about 1.51.8 m. This combined head loss is between the common inlet and outlet bus mains serving a battery of filters. Pressure filters may be interposed on a pumped or gavity pipeline without a large loss of pressure on the supply. Air binding, hence negative head, should not occur in pressure filters if the pressure in the media is always above that at the points upstream where air could have got into solution.

Pressure filters suffer from the disadvantage that the state of the bed under backwashing conditions and when the plant is working cannot be directly observed. It is of vital importance, therefore, that every pressure filter is fitted with an open box or dish in the front of it, into which the washwater is turned so that at least any washing out of the sand may be observed and the backwash rate immediately reduced.

When coagulation or other chemical treatment is required chemicals are injected and mixed under pressure and flocculation must be hydraulically carried out in pressure vessels fitted with baffles. The same applies when a contact tank is needed on the downstream side for disinfection.

Pressure filter installations are often not provided with any form of individual flow control. The result is that each operates as a declining rate filter for at least part of its filtration cycle and flow is concentrated through the clean, newly washed filters. An orifice plate may be installed in the outlet to restrict flow. However, a better option is to modulate the outlet valve using signals from a flowmeter on each filter so that flow equals the total flow divided by the number of filters in service. As the head loss through the filter increases the outlet valve opens to maintain the average flow. When employing flow controllers head loss can be monitored on individual filters; the filter run can be terminated either on headloss, length of filter run or turbidity breakthrough.

The equipment required for air scouring pressure filters and for valve control is similar to that used for rapid gravity filters. The filtered water usually has enough pressure for backwashing and this is often used so avoiding the need for backwash tanks of pumps. For a filter washed by separate air and water the required rate of application of water is about four times as great as the rate of filtration which is about 56 m/h. Thus in a large filter battery of about 15 filters, groups of five filters can be taken out of service at a time and the combined filtrate from four of the filters can be used to wash the fifth filter, and so on, until all filters in the group are washed. In large pressure filter plants arrangements are usually made to wash filters in groups at a specific time each day. Monitoring of individual filters for loss of head is seldom done except when outlet flow control is used. In fact, because a large battery of filters is usually supplied by a common inlet bus main and the outlets from filters also connect to a common outlet bus main, it is only meaningful to measure the headloss across the battery of filters. Individual filtrates could usefully be monitored for turbidity.

Pressure filters come under special procedures for pressure vessel design and fabrication. Condensation on the outside of the tanks is a continual nuisance as it causes corrosion of the steel shell and staining of the floor below. The pressure applied to steel pressure filters is not usually in excess of 80 m head of water. This should normally be adequate for most distribution systems. Above this pressure the thickness of plates used for the steel shell may be so great that cost rises rapidly. Due to the limitations on throughput and pre-treatment by clarification their application in preference to rapid gravity filters is restricted to small plants which are required to be installed into a system without breaking the hydraulic gradient, for iron and manganese removal primarily in ground waters, treating stored water by direct filtration or as GAC adsorbers for organics removal.

Pressure filters are similar in concept to rapid gravity filters, except that they are contained in a steel pressure vessel. Perforated pipes or a steel plate with nozzles are used for collecting the filtered water and for distribution of the washwater and air scour. The steel pressure vessel is cylindrical, arranged either horizontally (Fig. 9.5) or vertically. With a pipe lateral underdrain system the bottom of the vessel is usually filled with concrete so as to obtain a flat base. In the plenum floor design a steel plate is used, into which nozzles are screwed. In a horizontal vessel, vertical plates are sometimes welded inside to give a rectangular shaped sand bed within the cylinder so that the bed may be washed evenly and there are no dead areas beneath which air scour and water pipes cannot be placed. More commonly, media is placed in the entire vessel such that the depth is equally distributed above and below the centreline of the filter. The whole of the cylinder is kept filled with water under pressure and an air release valve is provided at the highest point for the release of trapped air. To avoid the requirement for special transportation procedures for large loads the maximum diameter of filters is limited to 34m and the length/height is limited to about 12m.

The backwashing of such filters is very similar to that of an open rapid gravity filter. A bellmouth and pipe can be used for the removal of dirty washwater in a vertical filter; for most horizontal filters a single vertical plate located near to one of the dished ends facilitates washwater removal, but for the larger filters, a central washout channel formed by two vertical plates is necessary.

The advantage of pressure filters is that excess raw water pressure is not lost when the filtration process takes place, as is the case with an open rapid gravity filter system. About 3m head may be lost in friction through the sand bed and the inlet and outlet fittings. This includes an allowance for dirt loss of about 1.51.8m. This combined headloss is between the common inlet and outlet bus mains serving a battery of filters. Pressure filters may be installed in a pumped or gravity pipeline without a large loss of pressure on the supply. Air binding, hence negative head, should not occur in pressure filters if the pressure in the media is always greater than that at the points upstream where air could have gone into solution.

Pressure filters suffer from the disadvantage that the state of the bed under backwashing conditions and when the plant is working cannot be directly observed. It is of vital importance, therefore, that every pressure filter is fitted with an open box or dish in the front of it, into which the washwater is turned so that at least any washing out of the sand may be observed and the backwash rate immediately reduced.

When coagulation or other chemical treatment is required chemicals are injected and mixed under pressure and flocculation must be hydraulically carried out in pressure vessels fitted with baffles. The same applies when a contact tank is needed on the downstream side for disinfection. Pressure filter installations are often not provided with any form of individual flow control. The result is that each operates as a declining rate filter for at least part of its filtration cycle and flow is concentrated through the clean, newly washed filters. An orifice plate may be installed in the outlet to restrict flow. However, a better option is to modulate the outlet valve using signals from a flow meter on each filter so that the flow equals the total flow divided by the number of filters in service. As the headloss through a filter increases the outlet valve opens to maintain this average flow. When employing flow controllers headloss can be monitored on individual filters; the filter run can be terminated on any of headloss, length of filter run or turbidity breakthrough. Care is needed when providing this form of control on pumped systems to minimize the pumping head required.

The equipment required for air scouring pressure filters and for valve control is similar to that used for rapid gravity filters. The filtered water usually has enough pressure for backwashing and this is often used so avoiding the need for backwash tanks or pumps. For a filter washed by separate air and water the required rate of application of water is about four times as great as the rate of filtration which is about 56m3/h.m2. Thus in a large filter battery of about 15 filters, groups of five filters can be taken out of service at a time and the combined filtrate from four of the filters can be used to wash the fifth filter, and so on, until all filters in the group are washed. In large pressure filter plants, arrangements are usually made to wash filters in groups at a specific time each day. Monitoring of individual filters for loss of head is seldom done except when outlet flow control is used. In fact, because a large battery of filters is usually supplied by a common inlet bus main and the outlets from filters also connect to a common outlet bus main, it is only meaningful to measure the headloss across the battery of filters. Individual filtrates could usefully be monitored for turbidity.

Specific regulations apply to the design, fabrication and testing of pressure vessels. In the UK, BS PD 5500 (2012) is followed. Condensation on the outside of the tanks is a continual nuisance as it causes corrosion of the steel shell and staining of the floor below. The pressure applied to steel pressure filters is not usually in excess of 80m head of water, which should be adequate for most distribution systems. Above this pressure, the thickness of plates used for the steel shell is likely to cause costs to rise rapidly. The use of pressure filters in place of rapid gravity filters is limited by the common requirement for upstream treatment by clarification processes operating at atmospheric pressure and practical considerations limiting their suitability for high throughputs. For these reasons, pressure filtration is usually restricted to small plants where it is undesirable to break the hydraulic gradient, iron and manganese removal (primarily in groundwaters), treatment of stored water by direct filtration or organics removal in GAC adsorbers.

The rotary pressure filter is a continuously operating unit for pressure filtration, cake washing, and drying of slurries up to 50% solids. The filter houses a rotating drum with cell inserts fitted within the filter media. Filtration is conducted via pressure of up to 6bar. Positive displacement washing or countercurrent washing follows filtration. Multiple washing steps as well as solvent exchanges, steaming, and extraction are accomplished. Finally, the cake is dried by means of blowing hot or ambient gas.

This filter has a uniquely designed discharge system providing for atmospheric discharge from pressure filtration. After automatic cake discharge, the filter cloth is washed; the clean filter cloth then re-enters the feeding/filtration zone thereby continuing the process. All solvent and gas streams can be recovered separately and reused in the process to minimize consumption. The rotary pressure filter is used for applications requiring maximum washing efficiency and containment. The overall cycle time for filtration, cake washing, and drying is <2min.

A medium-pressure filter tester using visual casting bed was adopted (see Fig. 6.6). This device evaluates the filtrate reduction property of the system by calculating the depth of invasion of drilling fluids into the casting bed, and measures the depth of invasion of the amphiphilic polymer reservoir protecting agent LCM-8 and other kinds of film-forming agents, as shown in Fig. 6.8. It is obvious that the depth of invasion of LCM-8 is lower than that in the samples compared, illustrating that LCM-8 forms a more compact and tough membranoid substance on the casting bed (Fig. 6.7).

Multi-element pressure filters usually comprise a cylindrical vessel inside which a number of horizontal or vertical porous elements covered by filter cloths are placed (see also Section 1.4.2.2). Either flat elements, in the form of square, circular or rectangular leaves, or tubular candles are used and these are spaced sufficiently far apart to avoid the possibility of cakes touching on adjacent elements. During a typical cycle the feed suspension is pumped into the vessel to induce variable pressure filtration and thus cake formation on the outer surfaces of the cloths (see Figure 6.2). In filters with horizontal elements, cake formation is restricted to the upper surfaces of leaves only. Washing and gas deliquoring phases at constant pressure often occur in a cycle and these operations are readily arranged in all filter variants. Filter leaves can be automatically extracted for cake discharge if adequate floor/height provisions are made. When more frequent cake discharge is required, solids are generally removed with the filter leaves in situ either by vibration, rotating blades, centrifugal force (horizontal elements only) or liquid resluicing to give a wet discharge. It is noted that cake formation in a filter fitted with candles can take place either at variable pressure, in a manner similar to the multi-element leaf filter, or at constant pressure.

The simplest batch pressure filter is the plate filter where the slurry is placed between two vertical plates clamped together by an externally operated screw system or hydraulic ram (Figure15.3). A series of hollow frames separate the plates which are placed side by side and hung from two parallel rails on either side of the plates. The filtering medium is placed against the sides of the plates and the slurry is pumped between them. The slurry pressure presses the pulp against the medium forcing the liquid through the cloth and leaving the solids as a cake, on both surfaces of the frame.

The plates are usually square shaped with ribbed or studded surfaces. Circular plates are also available in industry. The size of plates varies from about 450 450mm to 2000 2000mm and frames from 10mm to 202mm in thickness. They are usually made of steel to withstand pressures in excess of 1800kPa.

In operation, feed in the form of slurry is pumped in through a common channel entering the filters through individual ports. This ensures uniform distribution of feed in each chamber. The feed can be charged either through top or bottom ports in the frame. The filtrate leaves the individual filter beds through ports to a common discharge channel. In some installations the discharge from individual filters can be controlled. This introduces the flexibility of accepting or rejecting the product from a particular plate which can be suspected to be faulty and probably discharging unclear or turbid filtrate into the main product stream. Production of turbid and unclear filtrate often occurs due to a tear or bursting of the filter medium and needs to be isolated. The normal and often used medium is woven cotton or plastics which permits filtering rates ranging between 0.1 and 0.6m3/h/m2. Non-woven plastics with various apertures are also used.

Steam is used in some cases to assist in drying the filter cake. The Larox RT Filters have provision for multistage washing, vibration and hot air drying of cakes [3]. Merrill Filters working on these principles have been used in the gold industry for filtering gold cyanide solutions and zinc dust precipitates.

In a belt press filter, pressure can be achieved up to 12 bars. It consists of two endless belts and several rolls. The slurry is first flocculated before dewatering. The filter cake from a rotary vacuum filter can be further reduced by 5%6% moisture in the belt press filter (Bragg, 1983). Belt press filters are used for dewatering coal tailings thickener under flow. Belt presses utilise pressure filtration with the assistance of shear through the differential travelling velocity of the two belts wrapping around rollers. High flocculant dosage is required, particularly for ultrafine tailings containing clays so that the slurry drains by gravity after the wedge zone, and is viscous enough not to ooze out between the filter belts. Belt press filters have lower installation costs compared to other pressure filters, while their operating costs depend considerably on the high flocculant consumption (Bickert, 2013).

The makers of atmospheric pressure filter-press electrolysers guarantee a purity of 99.7% for oxygen and 99.9% for hydrogen. A check is normally kept on the gas purities by drawing off samples into measuring burettes. In the case of oxygen the sample is then passed over copper, which combines with the oxygen and leaves the hydrogen impurity as residue; while in the case of hydrogen, a platinum spiral electrically heated to redness in the gas causes the oxygen impurity to be removed by a combination with twice its volume of hydrogen to form water, leaving the main bulk of hydrogen as residue.

A computer controlled a pressure filter. It circulated the liquor through the filter for two hours. As more solid was deposited on the filter, the pressure drop increased. To measure the pressure drop, the computer counted the number of times that the pressure of the air in the filter needed to be topped up in 15 minutes. It had been told that if fewer than five top-ups were needed, filtration was complete, and it could move on to the next phase: smoothing the filter cake. If more than five top-ups were needed, the liquor was circulated for an additional two hours.

There was a leak of compressed air into the filter, which misled the computer into calculating that filtration was complete. The computer signaled completion to the operator, who opened the filter door; the entire batchliquid and solidwas spilled.

To be fair to the computer, or rather to the programmer, the computer had detected that something was wrongthere was no increase in power consumption during smoothingand had signaled this finding by stopping the operation, but the operator ignored this warning sign or did not appreciate its significance [3].

Again, a Hazop would probably have disclosed the weakness in the system for detecting the pressure drop through the cake, and changes could have been made. In particular, the filter should have been fitted with a device to prevent the operator from opening it more than a crack while it was full of liquid. Many accidents have occurred because operators opened up autoclaves or other pressure vessels while they were up to pressure (see Sections 13.5 and 17.1). Opening up a vessel while it is full of liquid is not as dangerous but, nevertheless, dangerous enough.

One particular design of pressure filter is the filter cartridge, typified by the Metafilter which employs a filter bed deposited on a base of rings mounted on a fluted rod, and is extensively used for clarifying liquids containing small quantities of very fine suspended solids. The rings are accurately pressed from sheet metal of very uniform thickness and are made in a large number of corrosion-resistant metals, though stainless steels are usually employed. The standard rings are 22 mm in external diameter, 16 mm in internal diameter and 0.8 mm thick, and are scalloped on one side, as shown in Figure 7.13, so that the edges of the discs are separated by a distance of 0.025-0.25 mm according to requirements. The pack is formed by mounting the rings, all the same way up, on the drainage rod and tightening them together by a nut at one end against a boss at the other as shown in Figure 7.14. The packs are mounted in the body of the filter which operates under either positive or reduced pressure.

The bed is formed by feeding a dilute suspension of material, to the filter usually a form of kieselguhr, which is strained by the packs to form a bed about 3 mm thick. Kieselguhr is available in a number of grades and forms a bed of loose structure which is capable of trapping particles much smaller than the channels. During filtration, the solids build up mainly on the surface and do not generally penetrate more than 0.5 mm into the bed. The filtrate passes between the discs and leaves through the fluted drainage rod, and operation is continued until the resistance becomes too high. The filter is then cleaned by back-flushing, which causes the filter cake to crack and peel away. In some cases the cleaning may be incomplete as a result of channelling. If for any reason the spaces between the rings become blocked, the rings may be quickly removed and washed.

The Metafilter is widely used for filtering domestic water, beer, organic solvents and oils. The filtration characteristics of clay-like materials can often be improved by the continuous introduction of a small quantity of filter aid to the slurry as it enters the filter. On the other hand, when the suspended solid is relatively coarse, the Metafilter will operate successfully as a strainer, without the use of a filter bed.

The Metafilter is very robust and is economical in use because there is no filter cloth and the bed is easily replaced and hence labour charges are low. Mono pumps or diaphragm pumps are most commonly used for feeding the filter. These are discussed in Volume 1, Chapter 8.

50 filters of wordpress: an introduction to filters

WordPress is an amazing platform and the most popular content management system in the world. The reason for this title is because of its extensibility.In this series, we're going to learn about filters - one of the best ways we can extend WordPress.

There areliterallyhundreds of WordPress filters in the core and these 50 examples will be only a part of them (about 10%), so there might be an addendum if you like the series and suggest new examples about new filters.

So, in essence, filters are functions doing stuff to your website's data before WordPress outputs it. A filter is one of the two kinds of hooks in WordPress the other one is called actions which is the subject for another series of articles.

Even though it looks a complicated topic, filters (and actions) are really easy to understand. I was also intimidated when I first came across with them, but after seeing how simple they are, I got to know hundreds of filters and actions just by checking the Codex or digging the core code.

Using WordPress filters is, as I said, pretty easy. There are just some basic functions to get to know and you need to learn about what each filter does. (To be honest, the hardest part is learning all the filters but as you can imagine, you can't learn every single filter at once you learn them when you need them.)

Let's say that we're building a plugin to remove the vowels in post titles. Instead of saying "remove the vowels in my post titles", you say "hook this function (which removes the vowels) to the filter of my post titles".

There's also another function called remove_all_filters() which has only two parameters ($tag and $priority) where you set the name of the filter and set the priority. As its name suggests, it removes all functions hooked to the filter.

Wonder how these filters are created? There's a special function called apply_filters() which is all around the core code to create hundreds of filters. Of course, it can be used outside the core which means we can create filters inside our plugins and themes, too.

If you need additional info on this topic, you should check out a great tutorial by Pippin Williamson on Tuts+ Code: "Writing Extensible Plugins With Actions and Filters". In this tutorial, you can learn how to create filters and actions for your plugin or your theme.

The more you work on them, the more fun you have with filters. There are hundreds of them and learning each one gets you one step closer to being a WordPress guru. In the next part of this series, we're going to learn about 10 WordPress filters:

I'm really excited about this series and I hope you'll enjoy it as much as I do. If you think you can help me with the tutorials by suggesting more filters and asking for more examples, don't hesitate to tell me and share your thoughts by commenting below.

filtration definition and processes (chemistry)

Filtration is a process used to separate solids from liquids or gases using a filter medium that allows the fluid to pass through but not the solid. The term "filtration" applies whether the filter is mechanical, biological, or physical. The fluid that passes through the filter is called the filtrate. The filter medium may be a surface filter, which is a solid that traps solid particles, or a depth filter, which is a bed of material that traps the solid.

Filtration is typically an imperfect process. Some fluid remains on the feed side of the filter or embedded in the filter media and some small solid particulates find their way through the filter. As a chemistry and engineering technique, there is always some lost product, whether it's the liquid or solid being collected.

Sometimes filter aids are used to improve flow through a filter. Examples of filter aids are silica, diatomaceous earth, perlite, and cellulose. Filter aids may be placed on the filter prior to filtration or mixed with the liquid. The aids can help prevent the filter from clogging and can increase the porosity of the "cake" or feed into the filter.

A related separation technique is sieving. Sieving refers to use of a single mesh or perforated layer to retain large particles while allowing the passage of smaller ones. In contrast, during filtration, the filter is a lattice or has multiple layers. Fluids follow channels in the medium to pass through a filter.

There are more effective separation methods than filtration for some applications. For example, for very small samples in which it's important to collect the filtrate, the filter medium may soak up too much of the fluid. In other cases, too much of the solid can become trapped in the filter medium.

Two other processes that can be used to separate solids from fluids are decantation and centrifugation. Centrifugation involves spinning a sample, which forces the heavier solid to the bottom of a container. In decantation, the fluid is siphoned or poured off of the solid after it has fallen out of solution. Decantation can be used following centrifugation or on its own.

filtration | definition, examples, & processes | britannica

Filtration, the process in which solid particles in a liquid or gaseous fluid are removed by the use of a filter medium that permits the fluid to pass through but retains the solid particles. Either the clarified fluid or the solid particles removed from the fluid may be the desired product. In some processes used in the production of chemicals, both the fluid filtrate and the solid filter cake are recovered. Other media, such as electricity, light, and sound, also can be filtered.

The art of filtration was known to early humans, who obtained clear water from a muddy river by scooping a hole in the sand on a river bank to a depth below the river water level. Clear water filtered by the sand would trickle into the hole. The same process on a larger scale and with refinements is commonly used to purify water for cities.

The basic requirements for filtration are: (1) a filter medium; (2) a fluid with suspended solids; (3) a driving force such as a pressure difference to cause fluid to flow; and (4) a mechanical device (the filter) that holds the filter medium, contains the fluid, and permits the application of force. The filter may have special provisions for removal of the filter cake or other solid particles, for washing the cake, and possibly for drying the cake. The various methods used for treating and removing the cake, for removing the clarified filtrate, and for creating the driving force on the fluid have been combined in various ways to produce a great variety of filter equipment.

Filter media may be divided into two general classes: (1) thin barriers, exemplified by a filter cloth, filter screen, or common laboratory filter paper; (2) thick or en masse barriers, such as sand beds, coke beds, porous ceramics, porous metal, and the precoat of filter aid which is often used in the industrial filtration of fluids that contain gelatinous precipitates.

A thin filter medium offers a single barrier in which the openings are smaller than the particles to be removed from the fluid. A single thin filter medium usually is satisfactory if the layers of solid particles that accumulate on the medium produce a porous cake that is permeable to the fluid. If the filter cake is gelatinous or the particles are soft and compressible, rather than firm, the filter cake may blind; that is, the pores in the cake may close and stop filtration. If this happens, a filter aid or a thick filter medium such as the sand bed may be used.

Contrary to the situation with the thin medium, the pores in a thick filter medium such as a sand bed may be appreciably larger than the particles to be removed. The particles may travel for some distance along the tortuous path of the fluid through the medium but sooner or later will be entrapped in the finer interstices between the particles that constitute the filter bed. In this way the soft particles removed are distributed over a volume of filter medium that is sufficient to prevent blinding and stoppage of filtration. After solids accumulate the beds may be backwashed with clear fluid to clean the bed.

The fluid to be filtered will pass through the filter medium only if some driving force is applied. This force may be caused by gravity, centrifugation, application of pressure on the fluid above the filter, or application of vacuum below the filter or by a combination of such forces. Gravitational force alone may be used in large sand-bed filters and in simple laboratory filtrations. Centrifuges containing a bowl with a porous filter medium may be considered as filters in which gravitational force is replaced by centrifugal force many times greater than gravity. If a laboratory filtration is difficult a partial vacuum is usually applied to the container below the filter medium to increase the rate of filtration. Most industrial filtration processes involve the use of pressure or vacuum, depending upon the type of filter used, to increase the rate of filtration and also to decrease the size of the equipment required.

3 ways to use a french press or cafetiere - wikihow

wikiHow is a wiki, similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 42 people, some anonymous, worked to edit and improve it over time. There are 19 references cited in this article, which can be found at the bottom of the page. wikiHow marks an article as reader-approved once it receives enough positive feedback. This article received 13 testimonials and 98% of readers who voted found it helpful, earning it our reader-approved status. This article has been viewed 831,583 times. Learn more...

Automatic coffeemakers may be quick and convenient, but nothing beats the French press for flavor intensity, as well as style. By allowing the coffee grounds to mingle with the water, it creates a stronger, thicker and more piquant cup of coffee, retaining essential oils and sediments that would otherwise get caught up in drip coffee maker's filters. If you've got one languishing in your cupboard, dig it out, clean it and follow these easy steps for a fresh new cup of coffee.

If you want to use a French press, or cafetiere, grind fresh coffee beans and bring a pot of water to a boil. Place the coffee grounds into the bottom of the French press and pour in the water. Lift up the plunger and stir the grounds to help extract the coffee. Allow the coffee to steep with the plunger up for 3-4 minutes, then slowly press down the plunger to separate the grounds from the water. Pour the coffee into a mug and enjoy! If you like, you can also brew loose-leaf tea in your French press. If you want to learn the right size for grinding your coffee beans, keep reading the article! Did this summary help you?YesNo