GB2198501A

GB2198501A - A valve for a pressurized flowing medium

Info

Publication number: GB2198501A
Application number: GB08629369A
Authority: GB
Inventors: Erkki Niskanen
Original assignee: NISKANEN ERKKI Oy; ERKKI NISKANEN Oy
Current assignee: NISKANEN ERKKI Oy; ERKKI NISKANEN Oy
Priority date: 1986-12-09
Filing date: 1986-12-09
Publication date: 1988-06-15
Also published as: DE3642264A1; GB8629369D0

Abstract

A valve for a pressurized flowing medium, comprises a body (1) defining a valve chamber (2) and at least two connections (3, 4) thereto. A stationary counter piece (5) is arranged within the valve chamber on a support (6) so as to be coaxial with one connection (3). A closing element (9) surrounds axially slidably the counter piece and is fastened to a spindle (7) mounted in the counter piece. In order to make the body as hermetically closed as possible, a cylinder space (12) is provided in the counter piece, and a piston (13) is fastened to the spindle displaceably within the cylinder space. The cylinder space and the piston form an actuator (14) for displacing of the closing element, which actuator is wholly positioned within the valve body. The cylinder space is connectable to an external pressure medium source by means of pressure medium conduits (15, 16). The actuator (14) may include a spring positioned in the spindle-end chamber of the cylinder space (12), to replace the pressure supply via conduit (16). <IMAGE>

Description

A spindle valve for a pressurized flowing medium This invention relates to a spindle valve for a pressurized flowing medium, comprising - a body comprising at least two connections and a valve housing separating the connections from each other, - a spindle mounted axially slidably with respect to the body and provided with a closing element positioned within the valve housing, - a stationary counter piece supported by the body within the valve housing and surrounded by the closing element in a liquid-tight manner, and - an actuator for axial displacement of the spindle for pressing the closing element against one connection to a closed position and respectively for lifting the closing element from said connection to an open position.

In many practical cases there is a risk that pressure impacts are created within a pipe system, which pressure impacts may be many times greater than the normal medium pressure prevailing within the pipe system. In food production industries, e.g., it is absolutely necessary that the closing element does not open unintentionally due to such instantaneous pressure impacts.

International Patent Application WO 84/03344 discloses a spindle valve in which a counter piece supported by the body is mounted in the valve housing to be positioned on the axial extension of the inlet connection.

The area of the counter piece in a plane transverse with respect to the direction of movement of the spindle essentially corresponds to the cross-sectional area of the inlet connection. The closing element is cup-shaped and surrounds the counter piece inamedium-tight manner.

By virtue of such a structure, the opening effect of the medium pressure and the forces caused by a possible pressure impact do not affect the closing element to any greater degree, because the stationary counter piece receives all these strains.

In the valve according to said International Patent Application, the spindle displacing the closing element extends from the valve housing through the bod of the valve into an external actuator, e.g. a solenoid, by means of which the spindle can be drawn axially outwards for the opening of the valve. A compression spring returns the spindle to a closed position. However, sealing problems arise due to the fact that the moving element, in this case the spindle, extends through the bod to the outside of the valve housing, because there is the danger trat the sealinos get worn or fail for some other reason under the influence of the movement of the spindle, so that some medium leaks outside the body.An untight connection from outside the valve into the valve housing is formed in a similar way. This is extremely disadvantageous n tne ood industries in particular.

The object of the present invention is to provide a spindle valve which avoids the above disadvantages and which can ho closed essentials sits hermetically even tnough the spindle is displaced b means of an actuator.

this object is achieved b means of a spindle valve according to the invention, which is characterized in that the counter niece of the valve housing and the spindle of the closing eletnent for a pressure-medium- operated actuator for displacing the closing element.

The invention is based on the idea that the actuator is wholly positioned within the valve body in no valve housing, so that only the medium conduit(s) required for the operatic of the actuator pass through the body. The conduits are easy to seal to the body in a itO liquid-rrocf m r.-,er by means of stationary connec- tors. In this way t is ensured tnat no undesired medium connection from the valve housing tothe of the valve can be formed. Nevertheless, the valve is still balanced against pressure impacts.

The invention will be described in more detail in the following with reference to the attached drawing, wherein Figures 1 and 2 are axial sectional views of a spindle valve according to one preferred embodiment of the invention when the closing element is in a closed position and in an open position respectively.

The spindle valve shown in the drawing comprises a body 1 provided with a valve housing 2 and two connections 3, 4 communicating therewith. A cylindrical counter piece 5 projecting into the valve housing is stationarily supported on the body by means of a support 6 in such a manner that the counter piece is concentric with one connection.

The valve further comprises a spindle 7 which is mounted axially slidably in a bottom plate 8 cf the counter piece concentrically therewith. The projecting end of the spindle is provided with a sleeve-like closing element 9 which surrounds the counter piece. The cylindrical inner surface 9a of the closing element forms a slide surface which is concentric with a cylindrical outer srae 5a of the counter piece. The diameter of said inner surface is of such a size that a ring seal 10 in the counter piece is pressed slidably but in a mediumtight manner against the slide surface of the closing element.The end edge of the closing element on the-connection side forms a seal edge 9b, Figure 2, which is pressable against a seal surface 3a of the connection 3 in a tightly closing manner.

The outer diameter cf the counter piece is essentially equal to the inner diameter of the connection 3.

The bottom plate cf the closing element is provided with openings 11, so that the outer surface of the bottom plate of the counter piece, too, is exposed to the pressure prevailing in the valve housing. By virtue of this structure the counter piece receives the pressure impacts possible occuring in the pipe system when the closing element is in the closed position. When the closing element is in the open position, the counter piece is exposed to an equal pressure on both sides.

According to the invention a cylinder space 12 is formed within the counter piece, and a piston 13 axially displaceable within the cylinder is attached to the inner end of the spindle, so that the cylinder space and the piston form an actuator 14 for the valve. Both chambers of the cylinder space are connected by means of pressure medium conduits 15, 16 to connectors l, which are mounted ir one valve bfldy end by means of which the cylinder space can oe connected to an external pressure medium source throuch a control valve. The closing element can be displaced alternatel to closed and open position by pressurizing either chamber of the cylinder space.

It is noted that the actuator is wholly positioned within the counter piece and that the connectors 17 for the pressure medium are the only means required by the actuator passing from the valve housing to the outside of the body Tnese connectors are easy to mount in an abso- -. tely m gnt manne on the body. The eve nousing can thus be closed quite hermetically with the exception of the connections 3 and 4.

The drawing and the description related thereto are only intended to illustrate the idea of the invention.

; its details, the spindle valve according to the invention may vary within the scope of the claims. Accordingly, the valve can be easily modified to form a three-way valve, and the closing element can be such that when one connection is open, another, axially opposite connection closed by the closing element. It is likewise possible to operate the actuator by means cf pressure medium in one onamoer onlv and to arrange a compression spring returning the piston in the other chamber of the cylinder space.

Claims

Claims:

1. A spindle valve for a pressurized flowing medium, comprising - a body (1) comprising at least two connections (3,4) and a valve housing (2) separating the connections from each other, - a spindle (7) mounted axially slidably with respect to the body and provided with a closing element (9) positioned within the valve housing, - a stationary counter piece (5) supported by the body within the valve housing and surrounded by the closing element in a liquid-tight manner, and - an actuator (14)for axial displacement of the spindle for pressing the closing element against one connection to a closed position and respectively for lifting the closing element from said connection to an open position, c h a r a c t e r i z e d in that the counter piece (5) of the valve housing (2) and the spindle (7) of the closing element (9) form a pressure-medium-operated actuator (14) for displacing the closing element.

2. A valve according to claim 1, c h a r a c t e r i z e d in that a cylinder space (12) is formed in the counter piece (5) and that the spindle (7) is axially slidably mounted in the counter piece and provided with a piston (13) displaceable in the cylinder space.

3. A valve according to claim 2, c h a r a c t e r i z e d in that both chambers of the cylinder space (12) of the counter piece (5) are connected to a pressure medium conduit (15,16) communicating with an external pressure medium source.

4. A valve according to claim 2, c h a r a c t e r i z ed in that one chamber of the cylinder space (12) of the counter piece is connected to a pressure medium conduit (15) communicating with an external pressure medium source, and the other chamber is provided with a compression spring positioned between an end wall (8) of the cylinder space and the piston (13).

5. A valve according to claim 2 or 3, c h a r a c t e r i z e d in that the counter piece (5) is fastened to the connection (3) by means of a support (6) so that the cylinder space (12) of the counter piece is concentric with the connection.

6. A valve according to claim 1 or 2, c h a r a c t e r i z e d in that an area of the counter piece (5) in a plane transverse with respect to the direction of movement of the spindle (7) corresponds essentially to a cross-sectional area of the connection (3) closed by the closing element.

7. A valve according to claim 1 or 2, c h a r a c t e r i z e a in that the closing element (s) is sleeve- like and arranged to slice axially and in a pressure mezium-tic= manner (1C) on tne counter piece (5).

8. A spindle valve constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.