Hydraulic filter assembly with priority valve

• US 20040026332A1
• Filed: 08/08/2002
• Published: 02/12/2004
• Est. Priority Date: 08/08/2002
• Status: Active Grant

• Current Assignee: PTI Technologies, Inc. (ESCO Technologies, Inc.)
• Original Assignee: PTI Technologies, Inc. (ESCO Technologies, Inc.)
• Inventors: Mouhebaty, Bijan, Moscaritolo, Daniel K.
• Granted Patent: US 6,908,545 B2
• Time in Patent Office: Days
• US Class Current: 210/739
• CPC Class Codes: B01D 2201/188 Multiple filtering elements having filtering areas of different size
• CPC Class Codes: B01D 29/21 with corrugated, folded or wound sheets
• CPC Class Codes: B01D 29/56 in series connection
• CPC Class Codes: B01D 35/143 Filter condition indicators
• CPC Class Codes: B01D 35/157 Flow control valves: Damping or calibrated passages
• CPC Class Codes: B01D 35/1573 Flow control valves
• CPC Class Codes: B01D 35/1576 Calibrated passages
• CPC Class Codes: B01D 35/30 Filter housing constructions
• CPC Class Codes: F15B 13/022 Flow-dividers; Priority valves
• CPC Class Codes: F15B 21/041 Removal or measurement of solid or liquid contamination, e.g. filtering
• CPC Class Codes: Y10T 137/2592 Carried choke

Abstract

A filter module assembly utilizes a priority valve installed in a manifold to allow for continuous filtration of hydraulic fluid up to a predetermined flow value and diverts occasional high flow to a secondary circuit. This arrangement provides both a low pressure drop at a high flow condition and structural integrity (1,000,000 impulse cycles from 0 to 6000 psi) while at the same time may reduce the weight by as much as 50% from a conventional design approach.

Claims

1. A filter module assembly for removing particles from a fluid, the filter module assembly comprising:

a parallel combination of a first filtering element and a second filtering element, each having a porous filter medium, a mean pore diameter of the porous filter medium of the second filtering element being greater than a mean pore diameter of the porous filter medium of the first filtering element; and

a fluid flow rate responsive valve arranged in communication with a fluid inlet, the first filtering element, and the second filtering element, the valve directing at least a portion of the fluid from the fluid inlet around the first filtering element through the parallel second filtering element in response to a predetermined fluid flow rate.

3. The filter module assembly of claim 1 wherein the filter medium of at least one of the filtering elements has a hollow, generally cylindrical configuration.

4. The filter assembly of claim 1 wherein the filter module assembly includes a high pressure relief valve.

5. The filter assembly of claim 1 wherein the filter module assembly includes a bypass valve.

6. The filter assembly of claim 1 wherein the filter module assembly includes a device to measure pressure, temperature, and flow.

2. The filter module assembly of claim I wherein the filter medium of at least one of the filtering elements is pleated.

7. A filter module assembly comprising:

a manifold having an inlet for receiving a fluid, an outlet for expelling the fluid, and fluid flow paths therebetween;

a primary filtering element and a secondary filtering element positioned in parallel to define a primary circuit fluid flow path and a secondary circuit fluid flow path, the primary filtering element being contained within a filter bowl, the secondary filtering element being contained within the manifold, each filtering element including a porous filter medium, a mean pore diameter of the porous filter medium of the primary filtering element being smaller than a mean pore diameter of the porous filter medium of the secondary filtering element; and

a fluid flow rate responsive valve for directing at least a portion of the fluid around the primary filtering element and through the parallel secondary filtering element when the flow rate of the fluid is greater than a predetermined fluid flow rate.

8. The filter module assembly of claim 7 wherein the primary filtering element has a hollow, generally cylindrical configuration, and the secondary filter element is a metal screen filter element, wherein the fluid flow rate responsive valve communicates between the inlet, the primary filtering element, and the secondary filtering element.

9. The filter module assembly of claim 7 wherein the primary filtering element includes a perforated core and the porous filter medium is pleated, the pleated porous filter medium being disposed about the perforated core.

10. A fluid flow rate responsive valve comprising:

a piston including a plurality of circular apertures;

a spring;

a spring guide;

a valve body coaxial with the piston and of larger diameter than the piston so as to form an annular passage between the piston and the valve body, the valve body including a plurality of first circular apertures and a plurality of second circular apertures, the plurality of second circular apertures are in constant communication with the annular passage and the plurality of circular apertures of the piston to form a primary circuit fluid flow path;

wherein the piston is slidably mounted within the valve body, the spring being biased in a first shape in contact with the spring guide urging the piston into a first position within the valve body to close the piston over the plurality of first circular apertures of the valve body when the flow rate of the fluid is below a predetermined fluid flow rate, and the spring being biased in a plurality of shapes in contact with the spring guide allowing the piston to move away from the first position to allow the piston to expose the plurality of first circular apertures of the valve body when the flow rate of the fluid is above a predetermined fluid flow rate, the plurality of first circular apertures of the valve body then being in communication with a first passage to form a secondary circuit fluid flow path, the plurality of spring shapes and the amount of exposure of the plurality of first circular apertures of the valve body being proportional to the flow rate of the fluid.

11. The fluid flow rate responsive valve of claim 11, wherein the piston includes a first larger diameter cylindrical portion and a second smaller diameter cylindrical portion, the first larger diameter cylindrical portion of the piston is in a first position within the valve body to close the piston over the plurality of first circular apertures of the valve body when the flow rate of the fluid is below a predetermined fluid flow rate, the second cylindrical portion containing the plurality of circular apertures.

12. A process for filtering a fluid comprising:

sensing a fluid flow rate of a fluid;

passing the entire fluid flow through a first porous filter medium when the flow rate of the fluid is less than a predetermined fluid flow rate; and

directing at least a portion of the fluid to bypass the first porous filter medium through a parallel second porous filter medium when the flow rate of the fluid is greater than the predetermined fluid flow rate, wherein a mean pore diameter of the second porous filter medium is greater than a mean pore diameter of the first porous filter medium.

13. The filtering process of claim 13, wherein sensing the fluid flow rate and directing a portion of the fluid includes using a fluid flow rate responsive valve.