Filtration system and method
10300411 ยท 2019-05-28
Assignee
Inventors
Cpc classification
B01D29/688
PERFORMING OPERATIONS; TRANSPORTING
B01D2201/087
PERFORMING OPERATIONS; TRANSPORTING
B01D29/54
PERFORMING OPERATIONS; TRANSPORTING
B01D29/68
PERFORMING OPERATIONS; TRANSPORTING
B01D29/50
PERFORMING OPERATIONS; TRANSPORTING
B01D36/001
PERFORMING OPERATIONS; TRANSPORTING
International classification
B01D29/50
PERFORMING OPERATIONS; TRANSPORTING
B01D29/60
PERFORMING OPERATIONS; TRANSPORTING
B01D29/66
PERFORMING OPERATIONS; TRANSPORTING
B01D29/54
PERFORMING OPERATIONS; TRANSPORTING
B01D29/11
PERFORMING OPERATIONS; TRANSPORTING
B01D36/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Method and apparatus are provided for treating and removing particulate matter from fluid or treating and removing fluid from a recoverable particulate matter from fluid circulating into, through and out of an industrial operation, and for washing a disposable cartridge filter used therein. The influent fluid is maintained at a flow rate such that the differential pressure across the cartridge filter is no greater than 10 psi to prevent the buildup of non-porous filter cake. A pressure detecting mechanism and method is also provided to detect the amount of deposited particulate matter inside the cartridge filter, so that an operator can determine whether the cartridge filter should be taken out to remove or recycle the deposited particulate matter.
Claims
1. A method for removing particulate matter in a fluid to be filtered, said particulate matter being deposited in a filter housing, comprising the steps of: a) feeding the fluid to be filtered containing particulate matter into the filter housing with at least one first filter in the upper portion of the housing at a controlled flow rate maintained such that a differential pressure across the first filter is no greater than 10 psi that will not form a substantially non-porous filter cake on the filter in the upper portion, wherein the differential pressure is continuously monitored in order to adjust the controlled flow rate; b) continuing to feed the fluid to be filtered containing particulate matter into the filter housing at the controlled flow rate, allowing the particulate matter to fall by gravity into a second filter in the lower portion of the housing; c) discontinuing the feed of fluid to be filtered; d) cleaning the first filter in the upper portion of the filter housing by introducing a pressurized gas into the filter housing to dislodge the particulate matter deposited on the first filter; and e) collecting dislodged particulate matter accumulated within the second filter in the lower portion of the filter housing.
2. The method of claim 1, wherein the method further comprising: e) removing the accumulated particulate matter from the second filter.
3. The method of claim 1, wherein the amount of particulate matter in the second filter in the lower portion of the filter housing is measured by the steps of e) introducing a predetermined volume of gas into a means for measuring pressure change within a hollow core of the second filter in the lower portion of the filter housing as it fills with particulate matter; and f) measuring the rate of pressure change within the hollow core of the second filter in the lower portion of the filter housing.
4. The method of claim 1, wherein the differential pressure across the first filter is no greater than 2 psi and no less than 0.1 psi.
5. The method of claim 1, wherein the flow rate of the fluid to be filtered is 1.5 gallon/minute.
6. The method of claim 1, wherein the flow rate of the fluid to be filtered is 2 gallon/minute.
7. The method of claim 1, wherein the flow rate of the fluid to be filtered is 2.5 gallon/minute.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(8) The disclosure provides novel system and method for reducing and removing the particulate matter deposited on the surface of cartridge filters within a filter housing. In one aspect of the invention, a method for removing particulate matter in a fluid to be filtered is provided, where particulate matter is deposited in a filter housing. The method comprises the steps of: a) feeding the fluid to be filtered containing particulate matter into the filter housing with at least one first filter in the upper portion of the housing at a flow rate and pressure that will not form a non-porous filter cake on the filter in the upper portion; b) continuing to feed the fluid to be filtered containing particulate matter into the filter housing at the predetermined flow rate and pressure allowing the particulate matter to fall by gravity into a second filter in the lower portion of the housing; c) cleaning the first filter in the upper portion of the filter housing by introducing a pressurized gas into the filter housing to dislodge the particulate matter deposited on the first filter; and d) collecting dislodged particulate matter accumulated within the second filter in the lower portion of the filter housing.
(9) In another aspect of this invention, a system of removing particulate matter in a fluid to be filtered is provided. The system comprises: a) a generally cylindrical filter housing with an inlet for introducing a fluid to be filtered that contains particulate matter, a clean fluid outlet, a first gas inlet, an exterior-to-interior filter in an upper chamber of the filter housing above an interior-to-exterior filter in a lower chamber of the filter housing; b) the inlet for introducing the fluid to be filtered located on the housing between the exterior-to-interior filter on the upper chamber and the interior-to-exterior filter in the lower chamber extending at an angle inside the housing to direct the fluid flow in a circular flow around the inside of the filter housing; c) the exterior-to-interior filter on the upper chamber having a hollow core in communication with the clean fluid outlet; d) the interior-to-exterior filter in the lower chamber having a hollow core in communication with the bottom portion of the upper chamber; and e) a gas diffuser in communication with said first gas inlet and located within the hollow core of the exterior-to-interior filter in the upper chamber of the filter housing.
(10) In one embodiment, the method further comprising the step of removing the accumulated particulate matter from the second filter.
(11) In another embodiment, the method further comprises a step for measuring the amount of particulate matter in the second filter, wherein the measuring step is carried out by first introducing a predetermined volume of gas into a means for measuring pressure change within a hollow core of the second filter in the lower portion of the filter housing as it fills with particulate matter; and measuring the rate of pressure change within the hollow core of the second filter in the lower portion of the filter housing.
(12) In one embodiment, the flow rate of the fluid to be filtered is maintained such that the differential pressure across the first filter is no greater than 10 psi, and preferably no greater than 2 psi and no less than 0.1 psi. In another embodiment, the flow rate is 1.5 gallon/minute, and preferably 2.0 gallon/minute, and more preferably 2.5 gallon/minute.
(13) In one embodiment, the exterior-to-interior filter comprises a filter media having a pore size of less than 5 micrometers, and preferably having a pore size of 2 micrometers.
(14) In one embodiment, the system further comprises an annular spacer in the housing between the upper chamber and the lower chamber, wherein the interior surface of the annular spacer is sloped to form an interior angled connection between the upper chamber and the lower chamber. The system may further comprise a solids funnel ring under the annular spacer within the filter housing. The solids funnel ring is preferably sloped at an angle between 20 and 30. In another embodiment, the interior surface of the annular spacer is sloped at an angle between 80 and 90
(15) With reference to
(16) A spacer plate 104 is placed between the upper and lower chambers and has ports 105, 106 extending therethrough. The port 105 is the fluid inlet for introducing the fluid to be filtered, and port 106 with valve 106a outside the spacer plate 104 is an air inlet line that is connected to an air distribution ring 107 located inside the bottom of upper chamber 102 below the exterior-to-interior cartridge filter 119a. An interior to exterior filter 119b extends from the bottom of spacer plate 104 inside lower chamber. An air release line 108 introduces air from the air flow volume detector 121 (shown later in
(17) Also referring to
(18) Also shown in
(19) An air and pressure vent 116, as shown in
(20) Referring back to
(21) At the bottom of the lower chamber 103 is a purge fluid outlet 123 and contains a valve (not shown) of known construction, which is selectively movable between open and closed positions. An air inlet purge line 125 with valve 126 is located on the lower chamber. Both of the purge fluid outlet 123 and the air inlet purge line 125 are in fluid communication with the purge fluid in the lower chamber 103. By purge fluid it means the fluid filtered by the interior-to-exterior cartridge filter 119b, which will exit the filter housing lower chamber 103 through the purge fluid outlet 123.
(22) As shown in
(23) During filtration process, air can be brought into the filtration system by pump cavitation, leaks on suction piping or just air or gas being relieved due to pressure changes. This air will move to the top of the vessel and needs to be relieved to keep the cartridge filter fully submerged for the best efficiency in operation. The air and pressure vent 116 and the control valve 116a thereon, which is selectively movable between open and closed positions, control the venting of air during the filtering operation to maintain the fluid level above the exterior-to-interior flow disposable cartridge filter 119a.
(24) In order to avoid the formation of a substantially non-porous particulate filter cake around the exterior surface of the exterior-to-interior cartridge filter 119a, the flow rate at the influent fluid inlet 105 is controlled by the valve 110 to achieve optimal flow rate by incorporation of a conventional flow meter of known design, which may be affixed to the influent fluid inlet 105. Or, alternatively, the clean fluid outlet 113 and the valve 110 and 118 can be controlled to maintain the proper flow rate.
(25) The controlled flow rate is not limited, depending on different influent to be filtered, the nature of the particulate matter, and the size and number of cartridge filters used, so long as the empirical data shows that it is less likely to build up the non-porous filter cake at such flow rate for such fluid. In one embodiment, the flow rate is 1.5 gallon per minute. In another embodiment, the flow rate is 2 gallons per minute. In another embodiment, the flow rate is 2.5 gallons per minute. The goal is to maintain the differential pressure across the filter at a relatively low range. The differential pressure is measured by a pressure transducer and continuously monitored throughout the operation. Taking the clean fluid inside the inner hollow core as the baseline pressure, preventing particulate buildup can be achieved when the differential pressure outside the cartridge filter 119a is no more than about 10 psi greater than the baseline pressure. In a preferred embodiment, the differential pressure between the outside and inside of the cartridge filter is 0-2 psi, and more preferably 1.5 psi. The viscosity of the fluid to be filtered may vary, but the range of differential pressure is similar for different fluids.
(26) Additionally, the pore size of the cartridge filter 119a may also contribute to the fact that non-porous particulate layer is less likely to form. With a filter having a filter media with pore size less than 5 micrometers, and more preferably 2 micrometers, the particulate matter does not enter the pores, and therefore stays on the outside surface of the cartridge filter 119a.
(27) When it is desired to clean the exterior-to-interior flow cartridge filter 119a, a pressurized air or gas scrubbing action may be necessary to dislodge the porous particulate filter cake around the exterior of the exterior-to-interior cartridge filter 119a. The influent fluid inlet 105 is closed off with valve 110, the air vent 116 and pressure relief valve 116a at the uppermost end of the upper chamber 102 is opened for relieving pressure and allowing scrubbing air to escape. With reference to
(28) The pressurized air or gas need only have sufficient pressure to effect the scrubbing. The range of the pressure can be easily chosen by a person skilled in the art to be both effective and energy efficient. In one embodiment, the pressurized air or gas has a pressure less than about 50 psi. In a preferred embodiment, the pressurized air or gas has a pressure not higher than about 20 psi.
(29) Now, with reference to
(30) Now with reference to
(31) When the particulate matter accumulated as slurry and will form a solid cake in the inner hollow core 151 of the cartridge filter 119b, the perforation(s) in tube 122 are surrounded (and possibly partially or fully plugged) by the slurry, which will inhibit air passing out of the perforations. The more perforations being plugged, the slower it is for the air to escape, hence the slower pressure decrease as measured by the pressure transducer 131. To initiate the measuring process, air (or other suitable gas) is released from the air flow volume detector 121 by fully opening valve 130, allowing the air to flow through the discharge line 132 to the inlet 108 to the perforated tube 122. The air pressure in the perforated tube 122 is measured by the pressure gauge 129 and simultaneously by the pressure transducer 131 for more accurate readings. These readings provide the air or gas pressure reduction in relation to time by predetermined schedule as to the volume of contaminate or recoverable particulate matter contained within the interior-to-exterior flow disposable cartridge 119b. In other words, the slower the pressure reduction, the more accumulated particulate matter within the interior-to-exterior flow disposable cartridge filter 119b, because more perforations have been blocked by the slurry. By comparing the pressure reduction rate to a chart obtained through previous testing, an operator can determine the level of accumulated particulate matter inside the filter 119b. Once particulate matter has filled filter 119b, it should be removed and either replaced or cleaned and replaced in order to continue the filtration process.
(32) Upon completion of the cleaning of the exterior-to-interior cartridge 119a and the measuring process to determine the contaminate or recoverable particulate matter volume in the interior-to-exterior flow disposable cartridge 119b, the operator then determines whether the system has remaining capacity for further filtration process or the cartridge filter needs to be changed. In the former situation the recovery system may be put back into filtration mode by reversing the procedure used to prepare for filter cleaning. In the latter case, the operator shuts down the filtration system and replaces the full cartridge filter with a new one.
(33) Additional filtering and cleaning procedures along with the measuring the collection of the particulate in filter 119b described above may be repeated as desired. This filtering method and apparatus can prolong the life of disposable filter cartridges, because the lack of particulate build-up and cleaning steps allow re-use of the cartridges. A disposable filter cartridge can be re-used until filter flow is inhibited. Both filters 119a and 119b can be used until the fluid cannot pass at an adequate flow rate.
(34) With reference to
(35) At this time the purge fluid outlet valve 124 is opened while continuing the flow of air or gas from the air or gas inlet valve 117 to the air diffuser 115, and the air or gas inlet valve 106a to the air distribution ring 107. As shown in
(36) With reference to both
(37) Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this illustration only and the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention such as a manual operation or a fully automated system.