US3613719A

US3613719A - Compressor valve arrangement

Info

Publication number: US3613719A
Application number: US864392A
Authority: US
Inventors: Friedrich Bauer
Original assignee: Hoerbiger Ventilwerke GmbH and Co KG
Current assignee: Hoerbiger Ventilwerke GmbH and Co KG
Priority date: 1968-10-16
Filing date: 1969-10-07
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19
Also published as: DE1948491A1; GB1242153A; DK121567B; NL6914885A; FR2020833A1; AT277434B

Abstract

A compressor valve arrangement having a device for regulating delivery quantities and wherein a valve plate can be raised from a valve seat against a closing force by means of control pistons displaceable in cylinder bores in the valve seat.

Description

United States Patent lnventor Friedrich Bauer Vienna, Austria Appl. No. 864,392 1 Filed Oct. 7, 1969 Patented Oct. 19, 1971 Assignee Hoerbiger Ventilwerke Aktiengesellschaft Priority Oct. 16, 1968 Austria A10l29/68 COMPRESSOR VALVE ARRANGEMENT 5 Claims, 3 Drawing Figs.

US. Cl 137/522, 251/63.4, 417/446 Int. Cl F16k 15/00 Field of Search 417/297,

References Cited UNITED STATES PATENTS McCarroll Holland Sahle Hirsch Mikina Hackbart."

Ott et a1 FOREIGN PATENTS 4/1955 ltaly 1.

Primary Examiner Laverne D. Geiger Assistant ExaminerDavid J. Zobkiw Att0mey--Watson, Cole, Grindle & Watson 251/58 X 251/58 X 417/298 X 417/298 137/522 X 417/446 137/522X ABSTRACT: A compressor valve arrangement having a device for regulating delivery quantities and wherein a valve plate can be raised from a valve seat against a closing force by means of control pistons displaceable in cylinder bores in the valve seat.

COMPRESSOR VALVE ARRANGEMENT BACKGROUND OF THE INVENTION It is known for valves of piston type compressors to be provided with devices which make it possible to raise the valve plate from the valve seat and keep it open, in order to permit starting up of the compressor under no-load conditions, and possibly also regulation of the delivery quantity during operation. The induction valves are generally kept open by these devices so that the medium drawn in is again forced back into the induction line during the pressure stroke of the compres sor piston. In the same way, it is also possible to bring about regulation of the delivery quantity by raising the pressure valve plates, the compressed gas thus flowing back into the cylinder and preventing opening of the induction valve.

In known types of valve having control pistons acted upon by a pneumatic or hydraulic medium for raising the valve plate, the control pistons are disposed in cylinder bores the axes of which are perpendicular to the plane of the valve plate to be raised. The control pistons are thus displaceable in the direction of movement of the valve plate and act upon the latter either directly or by means of lifting pins fastened on pistons.

In the other known constructional types, in which the valve plate is raised by springs acting upon it via lifting pins and the pressure medium actuated control pistons serve to pull back the spring-loaded lifting pins from the valve plate, the cylinder bores of the control pistons are also disposed in the lifting direction. Since, as a result of the small stroke of the valve plate, which is of the order of magnitude of about 1 mm., the adjusting path of the control pistons is equally small, it is necessary, for the purpose of achieving sufficiently great lifting forces at a specific control pressure to provide either a plurality of control pistons or relatively large control pistons. In many cases, the space necessary for this purpose is not available in the valve seat itself, so that bulky designs, with lifting pins disposed on the control pistons, are required. In addition, in the event of the regulating device requiring too much room, there is a disadvantageous restriction of the valve cross section available for the passage of the medium delivered.

The invention has the aim of improving compressor valves with a regulating device of the type, mentioned particularly in respect of the space requirement of the regulation device.

SUMMARY OF THE INVENTION According to the invention, a compressor valve arrangement is provided, comprising a valve seat having flow channels therein controlled by a valve plate, spring means arranged to press the valve plate on to the valve seat and lifting means arranged to raise the valve plate from the valve seat against closing forces acting upon the valve plate, wherein the lifting means comprises control pistons displaceable in cylinder bores in the valve seat, the cylinder bores being disposed in the valve seat with their axes inclined in relation to the direction of movement of the valve plate, and the control pistons each have a control face inclined to the axis of the piston and in driving connection with the valve plate, preferably with the interposition of a lifting piece.

As a result of this arrangement of the cylinder bores, the spatial accommodation of the regulating device in the valve seat is more easily possible, because the cylinder bores with the control pistons do not have to be disposed precisely below the valve plate with axes extending in the direction of movement of the latter. Furthermore, a ratio between the lifting movements of the control pistons and the valve plate may be achieved, in which the path covered by the piston during the lifting process may be considerably greater than the stroke of the valve plate. As a result, sufficiently great lifting forces can be achieved, even with a smaller number of control pistons or with the aid of pistons having a smaller diameter, so that compared with known valves the space requirement of the entire regulating device can be substantially reduced while the lifting forces remain the same, or conversely, substantially greater lifting forces can be achieved with the same use ofspace.

In a preferred embodiment of the invention, the axes of the cylinder bores are arranged perpendicularly to the direction of movement of the valve plate, and the control pistons each have, at one end, a conical control surface on which the associated lifting piece is supported. This form of construction can be easily manufactured, because the cylinder bores can be provided radially in the peripheral face of the valve seat, and is distinguished by a particularly low space requirement, only a slight structural height being necessary for the valve seat. In addition, the radial arrangement of the cylinder bores simpli fies the supplying of the pressure medium. A desired transmission ratio may easily be established by selecting the inclination of the conical control faces at the ends of the control pistons. The lifting pieces advantageously consist of balls, which can be obtained cheaply and which cause only relatively low-frictional forces during the lifting movement.

The control pistons may be of hollow construction and may each contain in their interior a return spring by which they are restored to their original position after the control pressure has been cut off. In many cases, however, the closing forces acting upon the valve plate may alone be sufficient for returning control pistons. The return springs may be seated in blind bores at the end face of the control pistons which is opposite the end of the piston which is acted upon by the pressure. The return spring may conveniently be supported at one end against the inside of the pressure-loaded end wall of the hollow control piston, and at the other end against a pressure pin which projects from the control piston and is continuous with the base of the cylinder bore containing the piston. In this case, the control pistons are expediently constructed in two parts, and each consist of a hollow cylinder, which is sealed at one end, and a cap which is fitted on to the open end of the said cylinder and is preferably provided with the inclined control face. The control pistons then form, together with their return spring, a self-contained component and which can be inserted and removed easily and quickly.

BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention are now described by way of example with reference to the accompanying drawings, which show, in FIG. 1, a compressor valve according to the invention in axial cross section, in FIG. 2, an enlarged detail of the valve and, in FIG. 3, a partially diagrammatic detail of another form of valve arrangement.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows the upper part of a compressor having a cylinder sleeve 1 and a piston 2. On a flangelike edge of the cylinder sleeve 1 is fitted an annular induction valve 3, which, together with the cylinder sleeve 1 is fastened in a suspended manner on the compressor casing 5 by means of screws 4. Disposed concentrically inside the annular induction valve 3 is a pressure valve 6 which is only shown in section and is pressed on to its seating surface, formed by the induction valve 3, via a pressure part 7 and by means of a spring 8 which is braced against a cover 9. The induction valve 3 has a valve seat 10, with flow channels 11 controlled by a valve plate 12 consisting of a single ring, and also has a catcher l3 and, braced against the latter, more annular plates 14, particularly one or more spring plates, which press the valve plate 12 on to the valve seat 10.

In the valve seat 10 and distributed over the periphery thereof, there are provided a plurality of cylinder bores 15, for example eight in number, which start at the outer surface of the valve seat 10 and extend in the radial direction so that their axes are inclined at a right angle to the direction of movement of the valve plate 12. In the cylinder bores 15 are disposed control pistons 16 which, at their inner end, have a conical control face 17, on each of which a ball 18, which serves as a lifting piece, is guided. The balls 18 lie below the valve plate 12 and form a driving connection between the control piston 16 and the valve plate 12. A channel 19 is formed in the compressor casing 5 for supplying a pneumatic or hydraulic pressure medium to the cylinder bores 15, and opens into a sealed-off annular groove 20 which is left between the induction valve 3 and the compressor casing 5 and which surrounds the valve seat 10, thus providing a supply of pressure medium to the cylinder bores 15.

In use, pressure medium supplied through the channel 19 and the annular groove 20 acts upon the control pistons 16 and displaces them radially inward. During this process, the balls 18 slide along the conical control faces and are lifted by the latter against the valve plate 12 so that this is raised from the valve seat 10. The induction valve is thereby held open until the pressure acting upon the control pistons 16 is reduced, whereupon the latter return to their original position, either due partly to the closing forces acting on the valve plate 12 or with the aid of return springs of their own. Depending upon the inclination of the conical control face 17 relative to the axis of the control piston 16, the ratio between the adjusting movement of the control piston and the lifting movement executed by the ball 18 is determined.

The control piston 16 illustrated in FIG. 2 is of hollow construction and is provided with a return spring 21. In this case, the control piston consists of a hollow cylinder 22, which is closed at one end, and a cap 23 which is fitted on to the open end of the said cylinder and is bevelled to form the conical control face 17. The return spring 21 is braced at one end against the inside of the end wall of the hollow cylinder 22 and at the other end, against a pressure pin 24 which passes through the cap 23 and is continuous, at its outer end, with the base of the cylinder bore 15. There is thus formed a compact structural unit which consists of the control piston and return spring and is distinguished by simple manipulation and a low space requirement.

FIG, 3 shows a form of embodiment in which the cylinder bore is inclined at an acute angle in relation to the direction of movement of the valve plate 12. In addition, the control piston 16' in this case acts directly, without the interposition of a lifting piece, upon the valve plate 12, the control face 17 sliding on the underside of the valve plate 12 during the adjusting movement. This embodiment, too, is distinguished by a low space requirement, while, in the example illustrated, the cylinder bore 15 intersects with the flow channel 11 in the valve seat 10 so that, because of the arrangement of the control pistons 16', there is practically no loss of flow cross section in the valve. Furthermore, as with the exemplified embodiment in FIG. 1, an advantageous ratio between the adjusting movement of the control piston 16 and the lifting movement of the valve plate 12 is achieved, the size of which can be determined according to choice by selecting the angle of inclination of the cylinder bore 15.

The devices for regulating delivery quantities shown in the exemplified embodiments may be applied with equal advantage both to induction valves and to pressure valves.

I claim:

1. A compressor valve arrangement comprising a valve seat having flow channels therein controlled by a valve plate, spring means arranged to press the valve plate on to the valve seat and lifting means arranged to raise the valve plate from the valve seat against a closing force acting upon the valve plate, wherein the lifting means comprises control pistons displaceable in cylinder bores in the valve seat, each of said con trol pistons being of hollow construction having a control face inclined in relation to the piston axis in driving connection with the valve plate and further having a pressure-loaded end wall spaced from said control face, a pressure pin within each piston and projecting outwardly therefrom in contact with the base of each respective cylinder bore, a return spring within each piston, one end of the return spring bearing against said pressure pin and the other end of said return spring bearing against the inner surface of said pressure-loaded end wall, and the cylinder bores being disposed in the valve seat with their axes inclined to the direction of movement of the valve plate.

2. An arrangement as claimed in claim 1 wherein a lifting piece is interposed between said face of each piston and the valve plate. I

3. An arrangement as claimed in claim 2 wherein the axes of the cylinder bores are perpendicular to the direction of movement of the valve plate, and the face of each of the control pistons is a conical control surface on which the corresponding lifting piece is supported.

4. An arrangement as claimed in claim 2 wherein the lifting pieces consist of balls.

5. An arrangement as claimed in claim 1 wherein each control piston consists of a hollow cylinder sealed at one end, a cap fitted on the open end of the said cylinder, said inclined control face being defined by said cap, and said pressure pin projecting through said cap.

Claims

1. A compressor valve arrangement comprising a valve seat having flow channels therein controlled by a valve plate, spring means arranged to press the valve plate on to the valve seat and lifting means arranged to raise the valve plate from the valve seat against a closing force acting upon the valve plate, wherein the lifting means comprises control pistons displaceable in cylinder bores in the valve seat, each of said control pistons being of hollow construction having a control face inclined in relation to the piston axis in driving connection with the valve plate and further having a pressure-loaded end wall spaced from said control face, a pressure pin within each piston and projecting outwardly therefrom in contact with the base of each respective cylinder bore, a return spring within each piston, one end of the return spring bearing against said pressure pin and the other end of said return spring bearing against the inner surface of said pressure-loaded end wall, and the cylinder bores being disposed in the valve seat with their axes inclined to the direction of movement of the valve plate.

2. An arrangement as claimed in claim 1 wherein a lifting piece is interposed between said face of each piston and the valve plate.