GB2060823A - Manufacturing water fittings - Google Patents

Abstract

3 DIVIDED 4" (22 mm) and 1 DIVIDED 2" (15 mm) water fittings are made using the same size valve assembly for each fitting. The through-flow bore (24a) in the fixed valve seat (24) of the 3 DIVIDED 4" fitting has an internal diameter in the range 11 to 13.5 mm and a depth of 2 mm to 3 mm, and a chamfer (25) underneath the fixed valve seat, so that the flow rate meets the British Standard for 3 DIVIDED 4" fittings. <IMAGE>

Description

SPECIFICATION Manufacturing water fittings This invention relates to water fittings, particularly but not exclusively domestic taps.

It is current practice in the UK to make domestic taps of two different sizes, a larger i" tap suitable for for example a bath with a shank adapted to be connected to a " (22 mm) supply line, and a wash basin or sink tap of smaller size adapted to be connected to a < " (15 mm) supply line. In the larger tap the internal flow passages and valve assembly are correspondingly larger than those of the < " tap.

British Standard 541 2 lays down various criteria which a 21' and 4" water fitting shall meet in order to satisfy the British Standard and one of these criteria concerns the minimum flow rate through the fitting. There are two different flow rates for the two different sizes of fitting.

We have discovered that we can considerably simplify the manufacture of water fittings by using the same (smaller) valve assembly for both > " and 9" fittings and modifying the valve seat of the larger fitting and thereby still achieve the minimum flow rate laid down by the above British Standard.

According to the present invention there is provided a method of manufacturing two water fittings, the first fitting having a larger body and water through-flow passage and being adapted for connection to a larger diameter supply pipe and the second fitting having a smaller body and smaller water through-flow passage and being adapted for connection to a smaller diameter supply pipe, the method comprising providing each fitting with respective fixed valve seats having through-flow bores of substantially the same diameter and adapted to co-operate with respective valve closure members of the same size for closing off the respective through-flow passage, providing the underside rim of the through-flow bore of the larger fitting with a chamfer so as to significantly reduce the length of the bore by means of the chamfer, and providing each fitting with respective valve control assemblies formed as units of the same size which are fitted in fluid-tight manner into respective apertures in the housings.

According to a further aspect of the present invention there is provided a 4" (22 mm) water fitting comprising a body, a shank adapted for connection to a 9" (22 mm) supply pipe for supplying water to the fitting, a fixed valve seat at the inner end of the shank and having an internal through-flow bore of diameter in the range 11 to 1 3.5 mm, a valve assembly formed as a unit and screwed into a hole in the body opposite the valve seat, the valve assembly carrying a valve closure member and sealing member having a size and shape designed to close against the valve seat and not exceeding 1 9 mm in diameter, the underside of the valve seat having a chamfer, the depth of the through-flow bore being in the range 2 to 3 mm, excluding the chamfer.

In order that the invention can be more clearly understood reference will now be made to the accompanying drawings in which: Figure 1 is a cross section through a conventional i" (22 mm) bath tap which we currently manufacture, Figure 2 is a cross section through a 9" (22 mm) bath tap modified according to an embodiment of the present invention and Figure 3 is a cross section through a (15 mm) wash basin tap which we currently manufacture.

Referring to Fig. 1 of the drawings there is shown a cross section through a zit bath tap which we currently manufacture. An exter nally-threaded shank 1 is adapted at its end 2 to receive a 43fl1 (22 rnrn) supply pipe (not shown). The internal diameter 3 of the shank 1 corresponds substantially to the internal diameter of the supply pipe. The supply pipe is connected to the end 2 by a conventional tap connector (not shown) and the end 2 has an enlarged bore 2a to receive the spigot of the tap connector and the bottom rim 2b of the shank 1 will seal against a circular gasket of the tap connector.

At the other end of the shank 1 is a fixed valve seat 4 of substantially the same diameter as the shank. The tap has a body 5 and the through-flow passage of the body extends up the shank, through the valve, through the body and out through the spout outlet 6 which includes a flow straightener 7.

The valve seat is closed by a sealing member 8 carried by a washer plate 9 and held in place on the washer plate by a nut 1 0. The washer plate is held captive in but free to rotate with respect to a spindle 11 which carries a handle 1 2 rotational fast therewith by means of insert i 3 and a clip 14. An index 1 5 indicates whether the tap is connected to hot or cold supply.

The body 5 has an internally-threaded hole 1 6 into which is screwed the valve head 1 7.

The head 1 7 is sealed to the body 5 by a washer 1 8 and the spindle 11 has a thread 11 a which mates with the corresponding internal thread in the head 1 7. Thus rotation of the spindle 11 causes it to raise or fall depending on the direction of rotation to thus open and close respectively the valve.

In order to seal the spindle against water leakage a gland screw 1 9 is screwed into the top of the head 1 7 and compresses packing 20.

A shield 21 covers the top part of the head within the hollow interior of the handle and is held in position by a spring 22. A sleeve 23 conceals the tap head from view as the handle rises and falls with the spindle.

In this tap the sealing member has an outside diameter of 1 9 mm.

Referring now to Fig. 2 there is shown partly in cross section a 431' bath tap modified to receive a smaller valve assembly than the top illustrated in Fig. 1 and in which the fixed valve seat has been modified to improve the flow rate through the tap. It is pointed out that although the tap body shown in Fig. 2 is a slightly difference shape to that shown in Fig. 1, this difference is not thought to be material to the present invention.

Referring in detail to Fig. 2 the tap has a threaded shank 33 having the same internal and external diameters as the shank 1 of Fig.

1. However the top of the shank 33 has a valve seat 24 of modified construction. The through-flow bore 24a of the valve seat has an internal diameter of 11.7 mm but could be in the range 11 mm to 13.5 mm and because the underside rim of the valve seat 24 has a chamfer at 25, the internal bore 24a has been significantly reduced in length to approximately half what it would have been without the chamfer. The body, indicated by reference numeral 26, and shank 23 are made of brass which is die-cast with a sand core and the casting, prior to machining, will leave the bore with a depth of approximately 5 or 6 mm.

However one part of the machining process includes the formation of the chamfer 25 which is a 45, chamfer and has a depth of about 3 mm. This leaves the bore through the fixed valve seat with a depth of 2 mm but could be in the range 2 mm to 3- mm. The machining tolerance is + 0.2 mm.

The valve assembly 27 is the same as the one we currently use on our Ill taps (described with reference to Fig. 3) and is of the non-rising type. The body 26 has a hole 28 into which the valve assembly is screwed. A sealing washer 29 seals the valve assembly to the body. The assembly is not shown in section as the internal working is not thought to be material to an understanding of the present invention.

The valve assembly carries a movable valve member 30 carrying valve sealing member 31 and the sealing member 31 is partially enclosed in a recess in the member 30.

The outside diameter of the sealing member 31 is 16 mm. The longest size both for the valve member 30 and the washer 31 is limited by the size of the hole 28 through which the valve member and sealing member are introduced. Currently this hole has a 21' BSP thread limiting the size of valve member and sealing member to an outside diameter of 1 9 mm.

The tap shown in Fig. 2 achieves a flow rate of 0.32 litres per second at a pressure of 0.1 bar which satisifies the flow requirement of the aforementioned British Standard specification. The flow rate of the tap shown in Fig.

1 is only a little in excess of this, being 0.35 litres per second. The flow rate achieved by the tap shown in Fig. 2 is surprising in view of the small size of the valve sealing member and valve seat and bore. We believe the main contributor to this flow rate improvement is the chamfer 25 which reduces the length of the bore of the valve seat significantly.

Referring now to Fig. 3 of the drawings there is shown partly in cross section a 3111 basin tap utilising exactly the same valve assembly as the tap shown in Fig. 2. Corresponding parts have been given corresponding reference numerals and although the underside rim of the seat of Fig. 3 is shown with a chamfer this is not essential.

The internal diameter of the shank of the 1 11 2 1 tap is approximately 3111 (1 5 mm) and the diameter of the bore of the fixed valve seat is the same as that of the tap of Fig. 2 and of course the sealing member is the same size as that of Fig. 2, since as stated above the two taps have exactly similar valve assemblies.

Figs. 2 and 3 are substantially to scale in relation to one another and it can be seen that the body of the tap of Fig. 3 is slightly smaller than that of Fig. 2 but of generally the same shape. The shank is adapted to be connected to a 21 supply pipe whereas the shank of the tap of Fig. 2 is adapted to be connected to a 311 41' supply pipe, both in the manner described in relation to the tap shown in Fig. 1. Both shanks carry the conventional back nut and washer.

Both the conventional and modified 31' taps have a flow straightener (anti-splash device) at the end of the spout. In the 41' taps described herein the flow straighteners 7 and 34 both have an internal diameter of 1 9.2 mm. In our exper ments we found that the presence of an anti-splash device has an adverse affect on the flow rate. We used two different sizes, one 8 mm long and the other 6 mm long and in general the 6 mm one gave the better flow rate. The straightener 34 is 6 mm long.

In our experiments we firstly attempted to increase the diameter of the bore of the valve seat from 11. 7 mm to 13.5 mm but discovered that this had less beneficial effect on flow rate than did the machined chamfer on the underside of the valve seat to reduce the length of the bore.

Claims (10)

1. A method of manufacturing two water fittings, the first fitting having a larger body and water through-flow passage and being adapted for connection to a larger diameter supply pipe and the second fitting having a smaller body and smaller water through-flow passage and being adapted for connection to a smaller diameter supply pipe, the method comprising providing each fitting with respective fixed valve seats having through-flow bores of substantially the same diameter and adapted to co-operate with respective valve closure members of the same size for closing off the respective through-flow passage, providing the underside rim of the through-flow bore of the larger fitting with a chamfer so as to significantly reduce the length of the bore by means of the chamfer, and providing each fitting with respective valve control assemblies formed as units of the same size which are fitted in fluid-tight manner into respective apertures in the housings.

2. A method as claimed in claim 1 wherein the body of the larger tap is made by die-casting and the chamfer is produced by subsequent machining.

3. A method as claimed in claim 1 or claim 2, wherein the depth of the bore of the valve seat of the larger fitting is in the range 2 mm to 3 mm.

4. A method as claimed in claim 2 or claim 3 wherein the depth of the chamfer is 3 mm.

5. A method as claimed in claim 3 or 4 wherein the diameter of the bore of the larger fitting is in the range 11 mm to 1 2 mm.

6. A method as claimed in claim 5, wherein the valve closure member of each fitting carries a resilient sealing member, the outside diameter of each resilient sealing member being in the range 1 5 to 1 6 mm.

7. A method of manufacturing two water fittings substantially as hereinbefore described with reference to Figs. 2 and 3 of the accompanying drawings.

8. Two fittings manufactured by a method according to any of claims 1 to 6.

9. A l1 (22 mm) water fitting comprising a body, a shank adapted for connection to a 4311 (22 mm) supply pipe for supplying water to the fitting, a fixed valve seat at the inner end of the shank and having an internal through-flow bore of diameter in the range 11 to 1 3.5 mm, a valve assembly formed as a unit and screwed into a hole in the body opposite the valve seat, the valve assembly carrying a valve closure member and sealing member having a size and shape designed to close against the valve seat and not exceeding 1 9 mm in diameter, the underside of the valve seat having a chamfer, the depth of the through-flow bore being in the range 2 to 3 mm, excluding the chamfer.

10. A " (22 mm) water fitting substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.