BACKGROUND AND SUMMARY OF THE INVENTION

Fluid flow regulators (controllers) provide a constant flow rate by means of a pressure differential regulating device that senses changes in upstream or downstream fluid pressure and compensates for the change. Conventional regulating devicesuse an impeller or a piston that is sensitive to a variable incoming fluid pressure, P.sub.1, and a downstream fluid pressure, P.sub.2. The piston reduces a valve opening when the differential pressure between P.sub.1 and P.sub.2 increases and enlargesthe valve opening when the pressure differential between P.sub.1 and P.sub.2 is reduced.

Examples of such regulators may be found in U.S. Pat. Nos. 5,931,191 issued Aug. 3, 1999, to Frank A. Taube, John D. Taube, and Peter H. Greverath for "Flow Control Valve for Passing Two Fluids in Opposite Directons"; U.S. Pat. No.5,913,328 issued Jun. 22, 1999 to John D. Taube, Peter H. Greverath and Eric Geile for "Flow Control Valve with One Piece Plug/Valve Tube Sleeve Assembly"; and U.S. Pat. No. 5,979,495, issued Nov. 9, 1999, to Frank A. Taube and Anthony J. Vizzini for"Adjustable Low Flow High Pressure Regulator". In each case the flow rate of the regulator is adjusted by an adjusting means, such as a needle valve, disposed in a fluid passage that connects incoming fluid pressure P.sub.1 on one side of the impeller,to the opposite side of the impeller which is at pressure P.sub.2.

The broad purpose of the present invention is to provide an improved fluid flow controller in which the flow rate adjusting valve is mounted on the controller body adjacent one end of the impeller chamber. The piston is balanced by the incomingpressure at P.sub.1 acting against one side of the piston, the adjusted fluid pressure P.sub.2 biasing the opposite side of the piston, and an impeller spring. The piston moves to either open or close a variable orifice or port connecting the impellerchamber to the outlet opening in response to changes in either the inlet fluid pressure or the outlet fluid pressure.

The preferred controller comprises a minimal number of components that can be easily manufactured.

Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS

The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which:

FIG. 1 is a longitudinal sectional view of a fluid flow controller illustrating the preferred embodiment of the invention;

FIG. 2 is a sectional view as seen along lines 2--2 of FIG. 1;

FIG. 3 is a sectional view as seen along lines 3--3 of FIG. 1;

FIG. 4 is a sectional view as seen along lines 4--4 of FIG. 1; and

FIG. 5 is a sectional view as seen along lines 5--5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, FIG. 1 illustrates a preferred fluid flow controller 10 which comprises a stainless steel body 12 having a cylindrical outer surface 14, and a flat top surface 16.

The controller body has a top cylindrical chamber 18 formed about an axis 20. The upper end of chamber 18, as viewed in FIG. 1, has an annular recess 22 for receiving an O-ring 24. The midsection of chamber 18 is reduced at 26 to form acylindrical bore 28. The lower part of bore 28 is threaded at 30, and then reduced in diameter to form a cylindrical chamber 32.

Controller body 12 has a lateral inlet opening 34 for receiving incoming fluid in the direction of arrow 35. The inner end of inlet opening 34 is fluidly connected to chamber 18. A longitudinal fluid passage 36 connects inlet opening 34 to ashort bottom passage 38 which, in turn, is fluidly connected to chamber 32. Chamber 18, bore 28 and chamber 32 are all formed along axis 20.

A bonnet 40 has an annular flange 42 seated on top surface 16 of the controller body to close the upper end of chamber 18. Bonnet 42 has an inner extension 44 that is slidably received into chamber 18. Bonnet flange 42 is seated on O-ring 24 toform a fluid-tight seal between the controller body and the bonnet flange.

Four socket-head cap screws 44 (only two shown) are each received through a respective opening 46 in the bonnet and a tapped opening 48 in the controller body to tightly fasten the bonnet to the body. The bonnet has internally threaded opening50 supported along axis 20.

An adjusting needle valve 52 is threadably mounted in threaded opening 50. The unthreaded mid-section of the needle valve has an annular groove 54 receiving an O-ring 56 to form a fluid tight seal between the needle valve and the bonnet. Thelower end of the needle valve has a tapered end 58 supported along axis 20 in chamber 18.

The controller body also has a lateral outlet opening 60, which extends into bore 28.

A valve cylinder 62 is removably disposed in bore 28. The lower end of the valve cylinder is threaded at 64 and threadably engaged with threaded bore 30. The valve cylinder has an annular groove 66 which cooperates with cylindrical surface 68of bore 28 to form an annular passage 70 that is aligned with outlet opening 60.

The upper end of the valve cylinder, as viewed in FIG. 1, has a hexagonal configuration 72 for mating with a socket wrench (not shown) for tightening the valve cylinder in the controller body. The valve cylinder also has a pair of annulargrooves 74 and 76 disposed on opposite sides of passage 70 for supporting a pair of O-rings 78 and 80. The O-rings form a fluid tight seal between the controller body and the valve cylinder on opposite sides of passage 70.

The valve cylinder is sized so that it can be passed through chamber 18 for either removal from or insertion into the controller body.

The valve cylinder has an upper internal threaded bore 82, and a smaller cylindrical impeller chamber 84. A pressure-sensitive metal piston 86 is slidably mounted in impeller chamber 84 for motion toward a lower position in which the pistonabuts an annular retaining spring 88. The piston has an internal axial bore 90 with a lower blind end for seating the lower end of a compression spring 92.

An orifice plug 94 is threadably mounted in threaded bore 82 of the valve cylinder. The orifice plug has an inner recess 96 seating the upper end of the compression spring. Plug 94 has a central orifice 98 sized to receive tapered end 58 of theneedle valve. The tapered end of the needle valve is adjusted with respect to orifice 98 by inserting a tool (not shown) into valve slot 100 to precisely adjust the size of the fluid passage through orifice 98, thereby adjusting the rate of fluid flowfrom chamber 18 into impeller chamber 84, between the fixed orifice plug and the movable piston.

Three lateral port means 102 in the valve cylinder fluidly connect impeller chamber 84 to annular passage 70. The piston is chosen with a length such that when it is raised from its seated position on spring 88, it partially obstructs ports 102to form three variable sized orifice openings.

OPERATION

In operation, fluid at pressure P.sub.1 enters inlet opening 34 from a conduit and a suitable fitting, not shown. The fluid passes downwardly through passage 36, through passage 38 into chamber 32. The incoming fluid also passes into chamber 18at pressure P.sub.1, through the fixed, adjusted orifice passage defined between the needle valve and orifice 98 into impeller chamber 84, reduced to pressure P.sub.2.

Thus, piston 86 is exposed to a pressure differential between fluid pressure P.sub.2 in the low pressure side of the piston, and pressure P.sub.1 on the high-pressure side of the piston. The fluid pressure is then reduced as it passes throughport means 102 to outlet pressure P.sub.3. The location of the piston in the impeller chamber is a function of the differential pressure on the high P.sub.1 and low P.sub.2 pressure sides of the piston and the bias of spring 92.

The controller does not, however, operate independently of varying outlet pressures P.sub.3 that may exist downstream of port means 102. Flow through the impeller chamber is a function of differential pressure. If pressure P.sub.3 increases,the flow rate through ports 102 decreases, thereby increasing pressure P.sub.2 and creating an imbalance on the piston. The piston moves downwardly, increasing the size of ports 102, and increasing flow through orifice 98, and returning stability to theflow rate.

If inlet pressure P.sub.1 acting on the high pressure side of the piston in chamber 32 increases, the piston rises against the compression spring to change the flow rate through ports 102 to maintain the fluid flow according to the adjusted sizeof the flow passage through orifice 98. If incoming fluid at pressure P.sub.1 is reduced, the piston moves downwardly under the bias of compression spring 92 thereby opening port means 102 a sufficient amount to restore the outlet flow rate.

When the piston is in a stable condition, pressure P.sub.2 plus the bias of spring 92 equals pressure P.sub.1. Any change in pressures P.sub.1 or P.sub.3 causes a change in the pressure differential thereby causing the piston to automaticallymove to a position returning stability and a constant flow rate through the controller.

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