US3521662A - Throttle valve - Google Patents

Description

July 28, 1970 H. BACHE 3,521,662

THROTTLE VALVE Filed Aug. 8. 1967 Inventar".

n U.S. Cl. 137-269 United States Patent O M' 3,521,662 THRO'ITLE VALVE Hermann Bache, Eutingen, Germany, assignor to Stahlwerke Bruninghaus G.m.b.H., Westhofen, Westphalia, Germany Filed Aug. 8, 1967, Ser. No. 659,204 Claims priority, application Germany, Aug. 17, 1966, St 25,767 Int. Cl. F16k 15/14, 17/18 10 Claims ABSTRACT OF THE DISCLOSURE The body of a reversible throttle valve accomodates an axially reciprocable tubular piston and two adjustable diaphragms each adjacent to one axial end of the piston to define therewith an annular orifice. The piston is displaced by inflowing liquid to reduce the size of one orilice and the diaphragm which is located in the path of fluid issuing from the piston yields in response to increasing fluid pressure to increase the size of the respective orifice. The piston consists of a material whose thermal expansion coeilicient is higher than that of the material of the valve body so that the size of that orifice which throttles the flow of iluid decreases in responseV to a rise in lluid temperature.

BACKGROUND OF THE INVENTION The present invention relates to throttle valves in general, and more particularly to improvements in valves which are utilized for automatic regulation of hydraulic fluids.

Conventional pressure-responsive throttle valves for hydraulic adjusting or driving systems are not entirely satisfactory. Such valves can produce satisfactory throttling action in response to substantial changes in fluid pressure but are less sensitive when the fluid pressure fluctuates within a narrow range. This is due to the fact that the amount q of fluid passing through the throttling orifice is proportional to the root of the pressure p, whereas the throttling action of the valve varies in accordance with the ratio p/q.

SUMMARY OF THE INVENTION yIt is an object of my invention to provide a simple, compact, rugged and relatively inexpensive throttle valve which is more sensitive than the aforementioned conventional valves.

Another object of the invention is to provide a throttle valve whose throttling action varies with changes in fluid pressure within a wide range.

A further object of the invention is to provide a reversible throttle valve of the just outlined character.

An additional object of the invention is to provide a throttle valve whose ilow restricting action can vary as a function of changes in the pressure and/or temperature of conveyed lluid.

A concomitant object of the invention is to provide a valve whose throttling action can be regulated independently of changes in temperature and/r pressure of the lluid.

Still another object of my invention is to provide a selfcleaning piston-type throttle valve which is capable of responding to changes in one or more characteristics of conveyed fluid.

An ancillary object of the invention is to provide a novel valve body, a novel valve member and a novel mounting for adjustable flow restricting elements of the improved thottle valve.

-Brieily outlined, one feature of my invention resides in the provision of a throttle valve which is particularly 3,521,662 Patented July 28, 1970 ICS' suited for regulating the flow of hydraulic iluids. The valve comprises a preferably adjustable flow restricting deformable diaphragm and fluid conveying means defining with the diaphragm a fluid ilow restricting orilice and having a passage for directing the fluid toward the diaphragm. The diaphragm bounds a portion of the orifice and is yieldable in response to increasing fluid pressure to thereby enlarge the orifice so that the latters size varies as a function of fluid pressure.

The fluid conveying means preferably includes a valve body having a fluid-admitting inlet opening and an outlet opening which receives fluid from the orifice, and an axially reciprocable piston-like tubular valve member installed in the valve body to dene the passage and to direct fluid issuing from one of its axial ends against the diaphragm. The valve body preferably accommodates a second diaphragm at the other axial end of the valve member so that the valve can convey fluid in two directions.

The valve member may consist of a material whose thermal expansion coefficient is higher than that of the valve body so that the valve member can change the size of the orilice in response to changes in fluid temperature.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved throttle valve itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single gure of the drawing is an axial sectional view of a throttle valve which embodies my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improved throttle valve comprises a fluid conveying unit composed of a valve body or housing 1 and an axially reciprocable tubular valve member or piston 3. The valve body 1 has a radially extending inlet opening 5, a radially extending outlet opening 5a, two internal chambers 4, 4a which respectively'communicate with the openings 5 and 5a, and an axial bore 2 which receives the piston 3. The axial bore 12 of the piston 3 constitutes a passage in which the fluid flows in a direction from the inlet opening 5 to the outlet opening 5a.

'Ihe valve further comprises two adjustable diaphragms 10, 10a which are respectively installed in the chambers 4 and 4a. The conduits which convey uid to the inlet opening 5 and from the outlet opening 5a are not shown in the drawing. The outer ends of the chambers 4, 4a receive externally threaded sockets 6, 6a which mesh with the valve body 1 and accommodate threaded plugs 7, 7a forming part of adjusting means for the diaphragms 10, 10a. Sealing rings 8 and 8a are employed to prevent leakage between the valve body 1 and sockets 6, 6a on the one hand and between the sockets 6, 6a and plugs 7, 7a on the other hand.

The inner end portions 9, 9a of the plugs 7, 7a constitute holders for the diaphragms 10, 10a. These holders are received in the chambers 4, 4a and clampingly engage the marginal portions of the respective diaphragms, i.e., the central portions of the diaphragms are not supported so that each thereof can yield to fluid pressure by undergoing deformation in a direction away from the respective axial end of the piston 3. The intake and discharge ends of the passage or bore 12 in the piston 3 are respectively shown at 11 and 11a. The holders 9, 9a are provided with compartments 13, 13a which communicate with the chambers 4, 4a through radial ports 14, 14a. Thus, fluid entering the chamber 4 via inlet opening 5 can fiow through the port 14 to fill the compartment 13 and to insure that both sides of the diaphragm 10 are subjected to identical pressure. Fluid entering the chamber 4a through the discharge end 11a of the passage or bore 12 can fiow through the port 14a to fill the compartment 13a.

The end portions 15, 15a of the piston 3 form fianges and are respectively received in chambers 4, 4a. These flanges limit the extent of axial movement of the piston 3 with reference to the valve body 1. The drawing shows the ange 15 in abutment with an internal stop face 16 at one axial end of the bore 2 in the valve body 1. The face B of the flange 15a is spaced from the stop face 16a at the other axial end of the bore 2. The valve of my invention comprises two mirror symmetrical halves (the symmetry plane extends at the right angles to and midway between the axial ends of the bore 2) which is of advantage because the direction of fiuid fiow can be reversed, i.e., the opening 5a can serve as an inlet opening.

The axial length of the piston 3 is a multiple of its diameter. This piston is made of a material having a high thermal expansion coefficient, for example, of brass. The valve body 1 consists of a material having a relatively low thermal expansion coefficient. For example, the valve body may be made of cast iron or an alloy containing 64 percent iron and 36 percent nickel.

The operation is as follows:

A supply conduit admits pressurized hydraulic fluid in the direction indicated by arrow P. Such fluid enters the chamber 4 through the inlet opening 5 and fills the compartment 13 behind the diaphragm 10. The fluid acts against the exposed end face of the flange 15 and shifts the piston 3 axially until the collar 15 reaches the stop shoulder 16. Such axial movement of the piston 3 causes an enlargement of the annular orifice or gap S between the flange 15 and diaphragm 10. At the same time, the effective area of the annular orifice r gap Sa between the fiange 15a and diaphragm 10a is reduced to its normal value for the average pressure of fluid which leaves the chamber 4a via outlet opening 5a (see the arrow Pa). The fiow of fluid through the orifice S is throttled very little or not at al, i.e., the throttling action is furnished by the flange 15a of the piston 3 and diaphragm 10a.

If the temperature of the conveyed fluid rises, the axial length of the piston 3 increases, i.e., the flange 15a moves nearer to the diaphragm 10a and effects a reduction in the rate of fluid flow if the fluid temperature rises. The area of the orifice Sa increases in response to a drop in iiuid temperature,

In the illustrated embodiment, the diaphragm 10a extends across the path of the jet of unthrottled fluid which issues at the discharge end 11a of the passage or bore 12 in the piston 3. The outer side of the diaphragm 10a is 'subjected to lesser pressure (of Huid in the compartment 13a). Therefore, the diaphragm 10a yields to the extent which is proportional to fiuid pressure in the chamber 4a (or to the pressure differential between the chamber 4a and compartment 13a). In other words, the effective cross-sectional area of the orifice Sa will change as a function of fluid pressure (it will increase with increasing fluid pressure). This insures that the throughput of the valve varies as a function of changes in fluid pressure. The ratio of the effective cross-sectional area of the orifice Sa to the fluid pressure remains constant or nearly constant, at least within a certain pressure range which is contemplated by the designer of the system employing the improved valve.

If the direction of fluid flow is reversed, i.e., if the fiuid pressure at the inlet opening drops below the pressure at the outlet opening 5a, the fluid enters the chamber 4a first and shifts the piston 3 axially to place the face B of the flange 15a into abutment with the stop face 16a. The end 11 is then the discharge end of the passage or bore 12 and the ange 15 cooperates with the diaphragm to define a flow restricting orifice which admits fluid to the chamber 4 whence the fiuid ows through the opening 5. The cross-secti0nal area of the orifice Sa increases to equal that of the orifice S in the drawing.

The plug 7 and/or 7a will be turned relative to the socket 6 or 6a if the operator wishes to adjust the size of the orifice S and Sa independently of changes in fiuid temperature or pressure.

An important advantage of my improved valve is that it is of the self-cleaning type. Thus, and if the direction of fluid fiow is reversed, eventual deposits of foreign matter in the clearance between the piston 3 and valve body 1 are Aloosened to be flushed out by the fluid. Such foreign matter can enter the valve through the opening 5 or 5a or is constituted by fragments removed from the piston 3 and/or valve body 1 in response to reciprocation of the piston.

It is clear that the improved valve is susceptible of many additional modifications without departing from the spirit of my invention. For example, and if no compensation for changes in fluid temperature is desired or needed, the expansion coefficient of the material of the piston 3 can be the same as that of the material of the valve body 1. Also, the diaphragm 10 and/or 10a can be replaced by a part of the valve body 1 if the rate of fluid fiow should be regulated solely as a function of temperature changes but not as a function of changes in fluid pressure. The diaphragm 10 or 10a can be omitted if the Valve is used for conveying of fluid in a single direction.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

What is claimed is:

1. In a throttle valve, particularly in a valve for regulating the flow of hydraulic fluids, a combination cornprising a diaphragm; fiuid conveying means including a passage for directing fiuid towards said diaphragm', and means cooperating with said diaphragm and said fiuid conveying means for permanently maintaining an end of said passage facing said diaphragm spaced from the latter so as to define between said end of said passage and said diaphragm a fluid flow restricting gap, said diaphragm being yieldable in response to increasing fluid pressure to thereby enlarge the size of said gap, so that such size varies as a function of changes in fiuid pressure.

2. A combination as defined in claim 1, wherein said fiuid conveying means defines a chamber which receives fluid via said gap, said diaphragm having a first side facing said gap and a second side facing a compartment communicating with said chamber.

3. A combination as defined in claim 1, wherein said fluid conveying means comprises a movable piston having an end face bounding a portion of said gap, said passage including a channel extending through said piston and having a discharge end providing in said end face and facing said diaphragm.

l4. A combination as defined in claim 3, wherein said fiuid conveying means further comprises a body receiving said piston for axial movement toward and away from said diaphragm, said piston having a second face on which the fiuid acts upstream of said channel to move the piston axially toward said diaphragm.

5. A combination as defined in claim 4, wherein said second face is constituted by a second end face of said piston and wherein said channel extends axially of said piston and has an intake end in said second end face.

6. A combination as defined in claim 5, further comprising a second diaphragm adjacent to and defining with said second end face a second gap.

7. A combination as dened in claim 6, further comprising adjusting means for changing the position of at least one of said diaphragms with reference to said piston to thus select the size of the respective gap independently of changes in fluid pressure.

8. A combination as defined in claim 7, wherein said adjusting means comprises a pair of adjusting devices each arranged to change the position of one of said diaphragms in the axial direction of said piston.

9. A combination as dened in claim 7, further comprising a pair of chambers provided in said body and each accommodating one of said diaphragrns and each communicating with the respective gap, one of said chambers having a fluid-admitting inlet opening and the other chamber having a uid-evacuating outlet opening.

10. A combination as defined in claim 1, further comprising adjusting means for changing the position of said diaphragm with reference to said end of said passage to 6 thereby adjust the size of said gap independently of changes in uid pressure.

References Cited UNITED STATES PATENTS M. CARY NELSON, Primary Examiner R. J. MILLER, Assistant Examiner U.S. C1. X.R. 137-4939, 468

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