US 6,395,186 B1Granted

Pressure liquid filtration with ultrasonic bridging prevention

AssigneeDelaware Capital Formation, Inc.

InventorsAllen De Kock, Christopher Rau

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Abstract

Methods and apparatus for increasing the continuous filtering flow rate through a pressure liquid filter unit of liquid-to-be-filtered having (1) a carrier liquid, (2) coalescing solids particles which tend to adhere and bridge filter element gaps sized substantially larger than said particles and (3) larger impurity elements to be filtered out of the liquid-to-be-filtered and sized larger than such filter element gap. A pressure liquid filter unit contains a filter element having gaps, a given gap being sized to reliably pass the carrier liquid and coalescing solids particles at a first relatively low liquid flow rate, but blocking coalescing solids particles passage therethrough due to bridging of said gaps by the coalescing solids particles at a relatively high liquid flow rate. The coalescing solids particles adjacent said gap are agitated at an ultrasonic frequency, thereby passing the carrier liquid and coalescing solids particles through the gap at the relatively high flow rate without bridging and blinding of the gap by the coalescing solids particles.

Claims32

Dependent claims

A method for increasing flow rate, through a liquid pressure filter unit, of liquid-to-be-filtered having (1) a carrier liquid, (2) coalescing solids particles which tend to stick together to bridge and thus blind a filter element gap sized substantially larger than the size of an average said coalescing solids particle, and (3) larger, impurity elements to be filtered out of said liquid-to-be-filtered and sized larger than such filter element gaps, comprising the steps:

providing a liquid pressure filter unit having a housing including an inlet and an outlet and a filter element having gaps substantially larger than said particles but smaller than said larger impurity elements, said filter element having a relatively low through flow rate in which said carrier liquid and coalescing solids particles pass reliably through said gap, said filter element having a relatively higher through flow rate at which said coalescing solids particles rapidly coalesce and bridge and blind said gaps and thus substantially immediately render said filter unit substantially inoperative;
fixing at least one ultrasonic transducer on said housing for contact with liquid-to-be-filtered in said housing;
admitting liquid-to-be-filtered under pressure through said filter unit inlet and into contact with said filter element while energizing said ultrasonic transducer;
transmitting said ultrasonic vibrations through said liquid-to-be-filtered and thereby agitating, at an ultrasonic frequency, coalescing solids particles adjacent said gaps, thereby facilitating passage of said carrier liquid and coalescing solids particles through said gaps and preventing said coalescing solids particles from coalescing and thus bridging and blinding said gaps while continuing said through flow at said relatively higher through flow rate.

1 more element

Method of preventing bridging, and thereby stopping of filter flow, through a liquid pressure filter unit, of liquid-to-be-filtered, of a kind having (1) a carrier liquid, (2) coalescing solids particles which tend to stick together to bridge and thus blind a filter element gap sized larger than the width of said particles, and (3) larger impurity elements to be filtered out of said liquid to be filtered and sized larger than such a filter element gap, comprising the steps of:

I. providing a liquid pressure filter unit comprising
(A) a housing having a housing wall and an inlet and an outlet which open through said wall,
(B) a filter element fixed in said housing and having an inlet side communicating with said inlet, and outlet side communicating with said outlet and a rigid, self-supporting filtering wall of the kind including
(1) spaced, side-by-side face wires communicating with said inlet and defining said inlet side,
(2) spaced, side-by-side support wires extending generally at right angles to said face wires, fixedly locating said face wires, and defining said outlet side, and
(3) gaps, wherein a given said gap is bounded by an adjacent pair of said face wires and an adjacent pair of said support wires,
(C) at least one ultrasonic transducer (1) located outside said housing, (2) fixed to said housing, (3) extending through said housing wall, and (4) having an active inner face in direct contact with liquid-to-be-filtered within said housing, without need to occupy space within said housing or interfere with flow in said housing;
II. continuously, and simultaneously ultrasonically enhancing, filtering by:
(A) from a process liquid system, flowing liquid-to-be-filtered under pressure through said inlet to said inlet side of said filter element, said liquid to be filtered being of the kind including clay slurries and white mineral slurries and having (1) a carrier liquid, (2) coalescing solids particles which tend to stick together to bridge and thus blind a filter element gap sized larger than the width of said particles and (3) impurity elements to be filtered out of said liquid-to-be-filtered and sized larger than such a filter element gap and coalescing solids particles,
(B) passing through said filter element wall gaps said carrier liquid and coalescing solids particles but blocking passage through said gaps of said larger impurity elements by means of said wires, said coalescing solids particles having a relatively slow flow rate at which they flow easily and in sequence through a said filter element wall gap and having a relatively faster rate at which they tend to stick together and to bridge and blind said filter element wall gap,
(C) setting said flow at said relatively faster rate while continuously electrically energizing said ultrasonic transducer and therewith (1) continuously applying ultrasonic energy from said ultrasonic transducer directly to said liquid-to-be-filtered in contact with said inlet side of said filter element wall, continuously agitatingly moving said coalescing solids particles adjacent a said filter element wall gap at an ultrasonic frequency and therewith (1) interfering with coagulating of said coalescing solids particles at said gap, (2) preventing bridging and blinding of said gap by said coalescing solids particles, and (3) allowing said coalescing particles to pass through said gap at said relatively faster rate,
(D) directing said carrier liquid and coalescing solids particles from said outlet side of said filter element through said outlet to a process liquid system;
whereby flow of said coalescing solids particles through said filter element wall gaps continues at said relatively faster rate without risk of bridging and blinding thereby of said filter element wall gaps.

10 more elements

Apparatus for preventing bridging, and thereby stopping of filter flow, through a liquid pressure filter unit supplied with liquid-to-be-filtered of a kind having (1) carrier liquid, (2) coalescing solids particles which tend to stick together to bridge and thus blind a filter element gap sized larger than the width of the particles, and (3) larger impurity elements to be filtered out of the liquid-to-be-filtered and sized larger than such a filter element gap, the apparatus comprising:

a housing having a housing wall, and an inlet and an outlet which open through said wall;
at least one filter element fixed in said housing and having an inlet side communicating with said inlet, an outlet side communicating with said outlet, and a rigid self-supporting filtering wall of a kind including elements fixed together to bound filtering gaps;
at least one ultrasonic transducer (1) located outside said housing, (2) fixed to said housing, (3) extending through said housing wall, and (4) having an active inner portion in direct contact with liquid within said housing;
control means for continuously
(A) holding open said inlet and outlet to flow through said filter element of liquid-to-be-filtered under pressure of a kind having (1) a carrier liquid, (2) coalescing solids particles which tend to stick together to bridge and thus blind a filter element gap sized larger than the width of said particles and (3) impurity elements to be filtered out of said liquid-to-be-filtered and sized larger than a filter element gap and coalescing solids particles, and
(B) simultaneously applying ultrasonic energy from said transducer to at least said carrier liquid and coalescing solids particles and thus avoiding bridging and blinding of a filter element gap by such coalescing solids particles;
whereby flow of said coalescing solids particles through said filter element wall gap continues at the faster rate than in the absence of said ultrasonic transducer.

4 more elements

Dependencies are inferred from the claim text.