WO1999015817A1

WO1999015817A1 - A fluid control valve

Info

Publication number: WO1999015817A1
Application number: PCT/DK1997/000402
Authority: WO
Inventors: Holger Tychsen
Original assignee: York International AS
Current assignee: York International AS
Priority date: 1997-09-24
Filing date: 1997-09-24
Publication date: 1999-04-01
Anticipated expiration: 2000-03-24
Also published as: AU4295797A

Abstract

A fluid control valve comprises a valve housing, a closure element (4) and a valve spindle, the valve housing being provided with a valve seat and with an axial, cylindrical, valve guide bore (7). The closure element is provided with a valve cone (9) and with a valve stem (10), slidably received inside the valve guide bore. According to the invention the valve stem comprises exterior bearing surfaces adapted for sliding engagement with the valve guide bore, and a groove or planar facet, whereas the valve guide bore comprises a key (16) for sliding engagement with the groove or planar facet in order to guide the closure element in non-rotatable engagement with the valve housing.

Description

A Fluid Control Valve

The present invention relates to a fluid control valve and more particularly to a fluid control valve wherein a closure element may be displaced axially between an open and a closed position and vice versa by the operation of a rotating shaft.

The invention still more particularly relates to a fluid control valve for use in refrigerant loops, subject to high pressures, high differential pressures __n either direction and a wide range of temperatures.

Norwegian allowed application No. 120 771 teaches a fluid control valve comprising a valve housing, a closure element and a rotatable valve spindle, wherein the the closure element comprises a hexagonal stem portion received m sliding engagement in a hexagonal bore m the valve housing and wherein stem portion comprises a countersunk bore with an internal thread m threaded engagement with a thread of the valve spindle. The closure element is displaced by rotation of the spindle, the hexagonal parts providing sliding non-rotational guidance of the closure element. This valve is designed for use as a tap for water.

German published application No. DE 37 16 072 Al discloses a fluid control valve comprising a valve housing defining a cylindrical bore and a closure element received in sliding engagement m the bore, the closure element comprising sections shaped as a polygon with rounded corners, which corners are m sliding engagement with the inside of the cylindrical bore. The purpose of the polygon shape is to provide fluid passages along the axial direction of the cylinder bore. The publication is silent regarding controlling rotation of the closure element, which is operated to axial displacement by the action of a solenoid.

The inventor has tested a design for a fluid control valve comprising a valve housing, a closure element and a valve spindle, wherein the valve housing is provided with a hexagonal bore which slidingly receives a hexagonal stem of the closure element and wherein the closure element is displaced by the rotation of a spindle m threaded engagement with a thread m a countersunk bore m the stem. The inventor has found that this design achieves a satisfactory performance, but only at the cost of a relatively complicated manufacturing procedure. In particular, the provision of the mating pair of hexagonal surfaces and especially the shaping of the female part requires a complicated manufacturing procedure.

The invention provides a fluid control valve as recited in claim 1.

This fluid control valve uses a plain cylindrical bore for guiding the valve stem. A cylindrical bore can be manufactured more readily and to a greater precision than is the case with a hexagonal socket.

The valve stem is provided with mating exterior bearing surfaces, i.e. surfaces shaped substantially as parts of a cylindrical surface centered at the stem axis. These surfaces may also be manufactured by simple equipment and using simple procedures, e.g. turning, and to a very accurate result. In order to provide non-rotating, axially slidable guidance of the valve stem, the valve stem comprises a groove or a planar facet which cooperates with a key in the cylindrical bore. The groove or planar facet does not require high precision machining since it takes no part in guiding the valve stem, except for preventing rotation. Some play between the groove or planar facet and the key is acceptable, as it will have no consequences other than permitting a small twist of the closure element on reversing the direction of rotating the spindle.

In the valve according to the invention the spindle may be secured in rotating and non-displaceable engagement with the valve housing while the closure element is axially displaceable relative to the spindle, e.g. by mating threads, or the spindle may be secured in rotating and non-displaceable engagement with the valve closure element to be displaced axially together with the valve closure element by cooperating threads of the spindle and the valve housing.

According to a particular preferred embodiment, the spindle is provided with a double set of threads of different or opposite pitch, one thread engaging a respective mating thread of the closure element and the other thread engaging a respective mating thread of the valve housing. This embodiment provides a very sturdy control of the closure element displacement, capable of operating properly, also when subjected to substantial fluid pressures in either direction.

The key may comprise a pad or some other solid element secured inside the cylindrical guide bore.

According to a preferred embodiment the key comprises essentially a rivet of which the shaft is received in a radial bore of the wall defining the cylindrical valve guide and of which the head provides the surface adapted for sliding engagement with the groove or planar facet of the valve stem. According to a preferred embodiment the valve stem exterior contour has the shape of a regular polygon with rounded corners. In this case any of the planar sections may provide the planar facet for sliding engagement with the key.

According to a preferred embodiment the stem has the shape of a square with rounded corners.

Further features and advantages of the invention will appear from the appended description of preferred embodiments given with reference to the drawings wherein

Fig. 1 shows a valve according to the invention m axial section,

Fig. 2 shows parts of the valve of Fig. 1 in another axial section, and

Fig. 3 shows the parts of Fig. 2 in a section perpendicular to the axis.

All figures are schematic and not necessarily to scale and illustrate only those parts which are essential in order to enable those skilled in the art to understand and practise the invention whereas other parts are omitted from the drawings for the sake of clarity. Throughout the drawings identical references have been used to designate identical or similar features.

Reference is first made to Fig. 1 for a description of the valve according to the invention.

The valve 1 basically comprises a valve housing 3 assembled from a valve chamber 21 and a valve cover 22. The valve housing receives a closure element 4 which is axially displaceable within the valve housing in order to permit a valve cone 9 to sealingly engage a valve seat 6 or selectively to lift off the valve seat. In this way a fluid conduit 2 defined by the valve housing 3 may be selectively opened or blocked to fluid passage, in a way which is generally known in the art.

The closure element 4, which will be explained in more detail later, basically comprises a valve cone 9 adapted for permitting sealing engagement with the valve seat 6 and supported by a valve stem 10 which is received in a valve guide bore 7. The sliding engagement between the valve stem and the valve guide bore provides accurate guidance of the closure element 4 to be displaceable along an axis 11 of the valve in order that the valve cone 9 will engage the seat 6 properly.

A spindle 5 basically comprises a spindle shaft 25 fitted with a spindle handle 28 by which the shaft may be rotated. The shaft 25 is received in the valve cover bore 23 which may be provided with seals or the like as known in the art. The spindle shaft extends through the valve cover bore 23 and axially through and projecting slightly beyond the guide bore 7 in the position illustrated in Fig. 1. The valve seat 6, the valve guide bore 7 and the valve cover bore 23 are all generally defined by rotational surfaces centered along the valve axis 11.

The spindle shaft 25, adjacent the end proximal to the valve seat comprises a male thread 26, referred to as the proximal spindle thread.

The spindle shaft at a position spaced from and distally from the valve seat further comprises a second male thread 27 referred to as the distal spindle thread which atingly engages a thread 24 in the valve cover. Reference is now made to Figs 2 and 3 for a description of further details of the valve. Figs 2 and 3 basically illustrate again the closure element and the component providing the valve cover whereas the valve chamber and all components associated with the spindle have been removed from these figures for the purposes of illustration. Fig. 3 illustrates a section with the line A-A of Fig. 2 whereas Fig. 2 illustrates a section with the line B-B of Fig. 3. It may at this point be noted that the axial section of Fig. 2 differs from the axial section illustrated in Fig. 1 by an angle of close to 45° about the valve axis.

Figs 2 and 3 illustrate a protuberant guide wall 8, which is integral with the valve cover, and which delimits the valve guide bore 7. The guide wall 8 has been provided with a smaller radial bore 20 wherein a rivet 16 has been inserted. The rivet 16 comprises a rivet shank 19 received in the radial bore 20 and a rivet head 17, located inside the guide bore.

Fig. 3 illustrates how the top surface 18 of the rivet head slidingly engages one' of the flat surfaces or facets 15 of the valve stem 10 which is shaped as a square with rounded corners.

The rivet 16 is easily assembled with the valve cover by means of inserting the rivet shaft from the interior of the valve guide bore 7 before introducing the valve stem. Once the valve stem has been introduced, the rivet is firmly secured with no possibility of coming out.

As referred to above, the closure element 4 comprises the valve cone 9 supported by the valve stem 10. As may be seen in fig 3, the stem section has the outer contour of a square with rounded corners. According to the invention, the rounded corners are shaped as parts of a cylinder sized for closely guided, sliding engagement inside the valve guide bore 7 along the valve axis 11.

The angular extent of the cylindrical sectors, also referred to as stem bearing surfaces 12, vis a vis the angular extent of the planar facets may be varied within a wide range as appropriate to suit different sizes of rivet heads. It is also possible to use one size of rivet head for a wide range of guide bore diameters by appropriate sizing of the angular extent of the facets.

As may be seen from figs 2 and 3, the stem comprises a circular, countersunk bore 13, with a female thread 14 adjacent the end distally from the valve cone. This thread 14 is adapted for mating engagement with the spindle proximal thread.

The proximal and the distal spindle threads as well as the respective mating threads are oppositely pitched, in order that the spindle on rotation is displaced axially in the same direction as the closure element, but with half the excursion.

Although various components have been explained in particular detail above, it should be remembered that this explanation has the sole purpose of exemplifying how the invention might be practised, but is in no way intended to limit the scope of the invention which is defined exclusively by the appended patent claims.

Claims

PATENT CLAIMS

1. A fluid control valve comprising a valve housing, a closure element and a valve spindle, the valve housing being provided with a valve seat and with an axial, cylindrical, valve guide bore and the closure element being provided with a valve cone and with a valve stem, slidably received inside the valve guide bore for guiding the closure element in axial displacement between a position, where the valve cone is in sealing engagement with the valve seat and a position, where the valve cone is spaced from the valve seat, said valve stem comprising exterior bearing surfaces adapted for sliding engagement with the valve guide bore, and a groove or planar facet, said valve guide bore comprising a key for sliding engagement with the groove or planar facet in order to guide the closure element in non-rotatable engagement with the valve housing, the valve housing and the spindle being provided with means for guiding the spindle in rotatable engagement with the valve housing and for controlling spindle axial displacement, the spindle and the closure element being provided with means for guiding the closure element in rotatable engagement with the spindle and for controlling mutual axial displacement, the spindle and at least one of the valve housing or the closure element being provided with means for mutually cooperating threaded engagement in order to displace the closure element axially relative to the valve housing upon rotation of the spindle.

2. The valve according to claim 1, w h e r e i n the valve stem exterior contour as seen in a section perpendicular to the stem axis has the shape of a regular polygon with rounded corners, the rounded corners being substantially shaped as sections of a cylindric surface, centered at the stem axis and providing said exterior bearing surfaces.

3. The valve according to claim 2, w h e r e i n said contour has the shape of a square with rounded corners.

4. The valve according to claim 1, w h e r e i n the key comprises a peg received in a radial bore in a wall of said valve guide bore.

5. The valve according to claim 4, w h e r e i n the key comprises a rivet with a rivet head and a rivet shaft, of which the rivet shaft is received inside the radial bore, while the rivet head provides a surface adapted for sliding engagement with the groove or planar facet of the valve stem.

6. The valve according to claim 1, w h e r e i n the valve stem comprises a countersunk, threaded bore, while the spindle comprises an external, mating thread, located at a position proximal to the valve seat.

7. The valve according to claim 1, w h e r e i n the valve housing comprises an internal, axial, threaded bore, while the spindle comprises an external, mating thread, located at a position distal from the valve seat.

8. The valve according to claim 1, w h e r e i n the spindle comprises a first, external thread at its end proximal to the valve seat and a second, external thread, spaced from the first one and pitched opposite the first one, in that the valve stem comprises a countersunk bore with an internal thread adapted for mating cooperation with said first thread, and in that the valve housing comprises an axial bore with an internal thread adapted for mating cooperation with said second thread.