GB2358454A - A gas valve housing - Google Patents

Abstract

A gas valve housing comprises a metallic first part (main body in preferred embodiment), a non-metallic second part 10 and a retaining member 12 arranged such that if the second part 10 is removed, fractured, or destroyed gas leakage would be substantially avoided. The retainer 12 may be fixed and held in a fixed position relative to the first part, possibly by bolts or screws 68. The valve 4 may be controlled by the rotation of a spindle 8, passing through the non-metallic part 10. The non-metallic part may also act as a guide or bearing for the spindle 8. The retaining member 12 may also let the spindle 8 through it and can be a flat sheet or plate.

Description

1 2358454 GAS HOUSING This invention relates to gas housings such as gas

valve housings at least partly made from a non-metallic material or materials, and in particular to such valves used to control domestic and commercial gas bumers.

Valves for controlling gas flow rate often have intricate parts that are relatively expensive to manufacture from metallic materials, but can more easily and more economically be manufactured from non-metallic materials such as plastics which can be made to better tolerances. However such materials generally have less mechanical integrity than metallic housing components and so there is a greater likelihood of failure due to fracture or combustion for example. Consequently Gas Industry standards (e.g. BS EN 126: 1995 - Multifunctional controls for gas burning appliances) state that "upon removal or fracture of this non-metallic part under all circumstances not more than 30 dM3 /h of gas can escape at the maximum working pressure". This regulation has in general prevented the use of non-metallic components for gas valve housings as the gas valve supply industry has been unable to meet the necessary safety standards using such materials.

An object of this invention is to provide a gas housing particularly for a control valve made partly of non-metallic material or materials such that in the event of mechanical failure, the housing can meet the safety standard set by BS EN 126: 1995.

In one aspect the invention provides a gas housing comprising a first metallic part, a second non-metallic part and a retaining member associated with, within or in contact with the second non-metallic part such that in the event of removal, fracture or destruction of the second non-metallic part, leakage of gas is substantially avoided.

2 Preferably, the retaining member is operably secured to the first part. The fixing a be permanent but the retaining member is Preferably removable or at least mova relative to the first part, such as by a hinge.

The retaining member may take the form of a substantially flat sheet or plah Preferably, the retaining member is bolted or screwed to the first part and has a recs through which a spindle passes such as for a valve. Preferably, the housing compri,e a valve which is activated by rotation of a spindle and the spindle passes through recess in the second nonmetallic part.

Preferably, the second non-metallic part acts as a guide or bearing for the spindle, an' also as a retainer whilst it is present.

Another aspect of the invention provides a gas housing, such as a plug valve housit'L comprising a first metallic body part and a second nonmetallic body part whic. operably co-operates to prevent accidental leakage of gas from the gas housing, th gas housing further comprises a safety component associated with the secon non-metallic body part which safety component acts to inhibit gas leakage from th gas housing in the event of failure of the second non-metallic body part.

Preferably the second non-metallic body part comprises of plastics material andl i therefore relatively inexpensive to manufacture and would enable manufacture t better tolerances. Also, the gas housing can comprise a third part which can b movable such as for use in a valve. Beneficially the safety component probably act:si t retain the third part in the gas housing in the event of failure of the see( 1 1 non-metallic part. In one form, the third part comprises rotary or plug val,v components such as a valve barrel and spindle, and the second non- metallic part a 1 as a spindle guide member. Beneficially the safety components can comprise mequ to retain the valve barrel and spindle in the event of failure of the second non-metalli part. In one form the safety component comprises an aperture in which the vil-v 3 spindle is operably journaled. Beneficially, the safety component can comprise metallic material or material which would not undergo combustion below 500 degrees Celsius. Moreover, the safety component is preferably attached to the first metallic body part by metallic fixings such as screws, or other forms of attachment which never the less would retain the safety component in a fixed relative position with the first metallic body part even in the presence of an ambient temperature in the order of 500 degrees Celsius.

An embodiment of the invention will now be described by reference to the following diagrammatic drawings, in which:

Figure I is an exploded side view, showing selected features of a valve of the invention, Figure 2 is an end view of the main body of Figure 1, Figure 3 is an end view of the inner face of the spindle guide member of Figure 1, Figure 4 is an end view of the outer face of the spindle guide member of Figure I and, Figure 5 is an end view of the spindle retainer of Figure 1.

Referring to Figure I there is shown a plug valve according to the invention which comprises six main components namely the main body 2, rotatable valve barrel or plug 4, spring 6, spindle 8, spindle guide member 10 and spindle retainer or safety component 12.

The main body 2 is formed from a metallic material such as aluminium and has on its first side face a gas inlet port 14 comprising a threaded portion 16, inwardly tapering portion 18 and cylindrical portion 20. Threaded portion 16 can accept a standard male 4 i threaded union fitting (not shown). The second side face of the main body ha.,; frustroconical recess 22 for housing the frustroconical section 42 of the valve barrel (described later) and also a pair of threaded holes 32 (see also Figure 2). The vt barrel 4 and inlet port 14 are positioned co-axially within the main body 2. The ooe j end of recess 22 has a short cylindrical section 24 and a thin annular rim 26 th extends to the second end face of the main body. The upper part of the main bod has a flange portion 34 with two threaded holes 36 used to secure the flange to a appliance etc. The flange 34 houses near its centre an outlet port fitting 30 used!, 1 connect the valve to a gas outlet channel (not shown). The fitting 30 is made o metallic material, for example brass and is sealed within an outlet bore 38 in the flat'[ portion 34 of the main body 2 by a squat sealing tube 40 made of flexible resiliei material such as rubber. Bore 3 8 extends from the upper face of flange 34 downwal'.!l. through the main body 2 and connects with a smaller diameter gas outlet channel,12 that provides fluid communication between port fitting 30 and the upper surface of ti. frustroconical recess 22. Hence, when the valve barrel is appropriately positio, c within recess 22 (see later) gas can flow in direction A through the inlet port 14 of tt, main body 2, through the valve barrel 4 and up through channel 28 to outlet port 3d, j direction B. Valve barrel 4 comprises a frustroconical portion 42 and a cylindrical portion 44, l cylindrical portion having a cylindrical bore 46 and a rectangular slot 48 extendin i an axial direction and having an open end that can accept a cross spindle 64 (see lat.' 1 The frustroconical portion 42 has a gas passage or channel 50 having at least pr outlet on the external face.of the conical surface of portion 42. Preferably, there at,e plurality of outlets connected to a single inlet channel each outlet being located i different radial direction and being of different diameter. This arrangement allowst, gas flow rate through the valve to be continuously varied as the valve barrel 4r rotated within the frustroconical recess 22.

Spindle 8 is made of metallic material, preferably brass and comprises a main shank portion 60 with a circular cross section, a chamfered end section 62 with a segmented circular cross section, a cross spindle 64 and an axial recess 66 of relatively short length dimensioned to accept the first end of a spring 6. The second end of spring 6 engages bore 46 in the valve barrel 4. The chamfered portion 62 of the spindle 8 is dimensioned to allow engagement with the stem of a control knob or like device (not shown).

The spindle guide member 10 (see Figures 3 and 4) provides a housing and bearing in which the spindle 8 may rotate and also limits the rotation of the spindle 8 as required in order for the valve barrel 4 to control gas flow through the main body 2. The invention allows the spindle guide member 10 to be made of a non-metallic material and yet still meet the safety standards mentioned above. Its inner face (Figure 3) comprises an annular rim 70 and a central recess 80 in which the main shank 60 of spindle 8 is operably journalled. Between central recess 80 and annular rim 70 there is an inner annular shelf 102 which is continuous with slot 92 (see latter). Between the inner annular shelf 102 and annular rim 70 there is a spiral-like section comprising a first inclined arcuate portion 94, arcuate slot 98 and a second inclined arcuate portion 96; portion 98 is followed (in a clockwise direction as illustrated in Figure 3) by a arcuate step 90 and a slot 92. When spindle 8 is located within the spindle guide member 10 the cross spindle 64 locates either in slot 92 or within the spiral like section 94,96,98. The arcuate step 90 acts as an end stop and so as the spindle 8 is rotated clockwise within guide member 10, cross spindle 64 abuts face 100 so preventing its further rotation. Likewise when rotated in an anticlockwise direction the cross spindle 64 abuts against face 104 and rests in slot 92. Thus, the rotation of the spindle 8 is limited to less than a full circle, in this case to an angular rotation of about 240 degrees. Arcuate slot 98 provides an intermediate setting corresponding to rotation of the spindle in a clockwise direction by about 90 degrees from end stop 104. The arcuate shape of the slot or recess 98 ensures that the spindle can easily be rotated 6 in either direction out of the slot in order to further open or close the valve, wi spring 6 ensures that cross spindle 64 can be retained in slot 98 if desired.

The outer face of guide member 10 (Figure 4) comprises a raised annular rirn which surrounds recess 80 and a generally annular shaped recess 88 which extend$ its upper and lower ends to portions of the guide number 10 containing pin holes 8, The annular recess 88 is formed by the combination of annular rim 78 and raised eo walls 84 and 86. A spindle retainer 12 (see figure 5) is dimensioned to fit witj annular recess 88 and around pin holes 82. The spindle retainer is preferably maul i metallic material. Thus, the retainer 12 has a central recess 74 to accommodate 1 spindle and upper and lower holes 76 to accommodate securing pins 68.

When the valve is assembled valve barrel 4 is housed within frustroconical recess spring 6 is located under compression between bore 46 and axial recess 66, with;t, cylindrical end of spindle 8 within bore 46 and cross spindle 64 within slot 48. '1] spindle guide member is then fitted over the spindle via recess 80 so that annular vii 70 engages annular recess 26. The spindle guide 10 is held flush against the secon end face of the main body by spindle retainer 12 fitting over annular recess 88 on, L outer face of the spindle guide 10 and by pins 68 that pass through holes 76 of spin01 retainer 12, and holes 82 of spindle guide member 10 to engage threaded bore holes 3 within the main body 2.

Spindle retainer 12 serves a vital function. In the event of spindle guide memberll mechanically failing, for example through fracture or combustion of this non-metal li component, the retainer 12 ensures that the spindle 8 is retained within bore 46 of ib valve barrel and the spring being in compression ensures thereby that the barrel 4 slay located within the frustroconical recess 22, thus preserving the sealing integrity of b valve, sufficiently at least to minimise any significant gas leakage. In the event l c failure of spindle guide number 10 such as through destruction in combusti..i Spindle retainer 12 remains secured to the main body 2 by pins 68 and cross spinol 7 64 continue to abut the inner face of the spindle retainer thus preventing outward movement of the spindle 8, spring 6 and valve barrel 4. In other forms the retainer or safety component can for example be formed within spindle guide member 10 or similar second non-metallic component of a gas housing.

Claims (11)

1. A gas housing comprising a first metallic part, a second non- metallic part and; retaining member associated with, within or in contact with the second non-metallit part such that in the event of removal, fracture or destruction of the non-metallic p4tib leakage of gas is substantially avoided.

2. A gas flow control valve according to Claim I wherein the retaining member, 1)1: operably secured to the first part.

3. A gas flow control valve according to any preceding claim wherein retaining member is held in a fixed position relative to the first part.

4. A gas flow control valve according to any preceding claim wherein th retaining member is bolted or screwed to the first part.

5. A gas flow control valve according to any preceding claim wherein the valvej activated by rotation of a spindle.

6. A gas flow control valve according to Claim 5 wherein the spindle pas, 4e, through a recess in the second non-metallic part.

7. A gas flow control valve according to Claim 5 or 6 wherein the seco non-metallic part acts as a guide or bearing for the spindle.

8. A gas flow control valve according Claim 5,6 or 7 wherein the retaini member has a recess through which the spindle passes.

9. A gas flow control valve according to any preceding claim wherein h retaining member is a substantially flat sheet or plate.

10. A gas housing, such as a plug valve housing, comprising a first metallic body part and a second non-metallic body part which operably cooperates to prevent accidental leakage of gas from the gas housing, the gas housing further comprises a safety component associated with the second non-metallic body part which safety component acts to inhibit gas leakage from the gas housing in the event of failure of the second nonmetallic body part.

11. A gas flow control valve substantially as herein before described by reference to Figures 1-5.