WO1999010669A1

WO1999010669A1 - Weir valve with fins in outlet chamber to improve flow and reduce head loss

Info

Publication number: WO1999010669A1
Application number: PCT/AU1998/000684
Authority: WO
Inventors: Douglas Harold Emmins
Original assignee: Douglas Harold Emmins
Priority date: 1997-08-26
Filing date: 1998-08-26
Publication date: 1999-03-04
Also published as: AUPO877697A0

Abstract

A valve such as diaphragm valve has a valve chamber with an inlet (2) and an outlet (3) and an inlet and outlet flow path, a valve arrangement adapted to enter the valve chamber to prevent flow through the valve. The valve has at least two flow directors (21 to 23) in the outlet flow path to improve the flow through the valve and to reduce head loss. There may be two to five flow directors which may be angled at between 8° to 20° to an adjacent flow director or a notional centre line of the valve. Flow is improved by creating a venturi effect and/or laminar flow and/or reducing cavitation or turbulence.

Description

WEIR VALVE WITH FINS IN OUTLET CHAMBER TO IMPROVE FLOW AND REDUCE HEAD LOSS

FIELD OF INVENTION

This invention relates to valves for controlling the flow of fluids and more particularly to improving flow through such valves.

BACKGROUND AND PRIOR ART

A valve is used in a fluid flow line to stop flow in that line. This generally requires some form of obstruction in the fluid flow line to stop flow. When flow is required it is desirable to move the flow restricting obstruction as much out of a valve chamber as possible so that it and the valve chamber give as little flow obstruction as possible. It is inevitable, however, that in a vaive a certain loss in pressure or head loss across the valve occurs owing to the constructional features of the valve.

A significant loss occurs due to turbulence forming in a vaive chamber and this turbulence can be carried downstream of the vaive chamber into a valve outlet flow path.

It is an object of this invention to provide an improvement in flow through a valve or a reduction in pressure head loss across such a valve.

The invention will be discussed generally in relation to a diaphragm valve but the principle therein may be applicable to a wide range of valves.

BRIEF DESCRIPTION OF INVENTION

In one form therefore the invention is said to reside in a valve of a type having a valve chamber, an inlet, an outlet, an inlet flow path, an outlet flow path and a valve member adapted to enter the valve chamber to prevent flow through the valve, the valve being characterised by at least two flow directors in the outlet fiow path whereby to improve the fiow through the vaive and to reduce head loss across the vaive.

In an alternative form the invention is said to reside in a diaphragm valve of a type having a valve chamber, an iniεt, an outlet, an inlet fiow path and an outlet fiow path and a diaphragm arrangement including a diaphragm adapted to enter the vaive chamber to prevent flow through the diaphragm valve, the diaphragm valve being characterised by at least two flow directors in the outlet flow path whereby to improve flow through the valve and to reduce head loss across the valve.

In a preferred embodiment of either of these forms of the invention there may be two to five flow directors in the outlet flow path.

Preferably, the flow directors comprise plates extending aiong the flow path.

In a preferred embodiment, the flow directors may be angled to the direction of flow of the fluid in the valve so that the cross sectional area between adjacent flow directors reduces towards the outlet from the valve chamber.

The angle between a longitudinal line through the valve and the direction of longitudinal extent of the or each flow director on each side of a notional centre line of the valve or from an adjacent flow director may be in the range of from 8° to 20°.

Where there are two flow directors the angle between a notional centre line of the valve and the fiow director on each side of it may be about 10°.

Where there are three flow directors the angle between a centre fiow director and the flow director on each side of it may be about 10°.

Where there are four flow directors the angle between a notional centre line of the valve and the first flow director on each side of it may be about 10° and the angle between the first flow director on each side and the second flow director on each side of it may be about 10°.

Where there are five flow directors the angle between a centre flow director and the first flow director on each side of it may be about 10° and the angle between the first flow director on each side and the second flow director on each side of it may be about 10°.

Preferably the diaphragm valve body and the fiow directors are made as a single casting or moulding from plastics material, brass or cast iron. The vaive may further include at least one flow director on the inlet flow path.

Generally the valve chamber region of a valve is of a larger volume than the flow path into and out of a vaive and the directors assist in returning flow from the valve chamber into the outlet flow path.

In the case of a diaphragm valve it is known to piace single diaphragm support arrangements into one or both of the inlet flow path and outlet flow path with the primary aim of providing support for the diaphragm when it is in the closed position to prevent buckling of the diaphragm with potential leaking and damage problems. These siπgie plates can assist with flow direction but it has been found that the addition of one or more further flow directors in the outlet of the valve particularly if they provide a slightly tapered flow path towards the outlet of the valve do substantially reduce pressure head loss across the valve.

Although the mechanism involved which actually assists in reducing the head loss or improving the flow through the vaive with the flow directors of the present invention is not fully understood it is believed that the improvement may be a result of three factors. The applicant does not wish to be held to these explanations but they may assist in understanding of the nature of the improvement.

A first factor may be that the fiow directors act to straighten out the turbulence merely by being placed in the outlet flow from the valve.

A second explanation may be that the flow directors in tapering the fiow path to the outlet may provide a venturi effect which actually increases the flow rate at the outlet thereby drawing fluid out of the vaive to improve the flow.

A third factor may be that the plates prevent or reduce cavitation in the fluid as it flows over the valve seat associated with the valve arrangement and thereby reduces friction and hence allows less head loss across the valve.

The number of flow directors used in the valve may be to some extent dependent upon the size of the valve. For instance, in a 50mm diaphragm vaive there may be two flow directors which are angled towards each other towards the outlet of the valve. In a larger valve such as an 80mm or 150mm diaphragm valve there may be three or five fiow directors in the outlet.

Preferably the flow director plates extend back into the vaive to the extent that they provide a support surface for the diaphragm on the downstream side of the valve.

BRIEF DESCRIPTION OF THE DRAWINGS

This then generally describes the invention but to assist in understanding reference will now be made to the accompanying drawings which show a preferred embodiment of the invention.

FIG 1 shows one embodiment of a diaphragm vaive according to the invention in side view;

FIG 2 shows a cross-sectional view of the valve shown in FIG 1 with the valve closed;

FIG 3 shows a cross-sectional view of the valve shown in FIG 1 with the vaive open;

FIG 4 shows a plan view of the body of a diaphragm valve according to one embodiment of the invention;

FIG 5 shows an end view from the outlet end of the body of a diaphragm valve according to the embodiment of the invention shown in Fig 4;

FIG 6 shows a perspective view from the inlet end of the embodiment of the invention shown in Fig 4;

FIG 7 shows a perspective view from the outlet end of the embodiment of the invention shown in Fig 4;

FIG 8 shows a plan view of the body of a diaphragm valve according to an alternative embodiment of the invention;

FIG 9 shows a plan view of the body of a diaphragm valve according to another embodiment of the invention; and

FIG 10 shows a plan view of the body of a diaphragm valve according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Now looking more closely at the drawings and in particular FIGS 1 to 7, it can be seen that the valve of this embodiment comprises a valve body 1 with an inlet end 2 and outlet end 3. The valve body 1 has a pianar upper surface 5 as best can be seen in FIGS 6 and 7 onto which is fitted a vaive cap 6 with a diaphragm 8 sandwiched between the valve cap 6 and the valve body 1. Bolts 9 hold the valve cap to the valve body and act to retain the diaphragm around its periphery.

In the flow prevention state as can be seen in FIG 2 spring 10 holds the diaphragm 8 so that its central portion 11 rests onto valve seat 12. The valve is held closed by water pressure through pipe 13 which takes a fluid pressure tapping from the inlet end 2 as can be seen in FIG 1 when valve 15 in the tube 13 is opened.

When valve 15 is closed liquid pressure in the diaphragm chamber 16 is allowed to bleed out to waste (by means not shown) and liquid pressure in the valve inlet flow path 2 against the diaphragm 8 causes the diaphragm 8 to lift up against the spring 10 so that flow can occur through the valve as shown by arrow 17 in FIG 3.

A diaphragm support plate 20 is provided in the inlet flow path and a combination flow director and diaphragm support plate 21 is provided in the outlet flow path.

Also provided in the outlet fiow path 3 are two further flow director plates 22 and 23 as can be seen in FIGS 4 to 7. These additional flow director plates 22 and 23 have a curved leading edge which is substantially the shape of the diaphragm when it is in its closed position so they will also assist with support of the diaphragm when it is in the closed position. The plates 23 and 22 are angled to the general direction of fiow through the valve so that the cross sectional area of the flow path between them and between them and the sides of the valve chamber reduces in the direction of flow. This can be particularly seen in FIGS 4 and 5.

As can be seen in FIG 4 the angle α between the notional centre line of the valve shown by dotted line 25 and the the direction of longitudinal extent of the flow director 23 as shown by dotted line 26 can be in the range of from 8° to 20° and is preferably about 10°.

FIG 8 shows an alternative embodiment of a diaphragm valve body according to the invention. In this embodiment the valve body has 40 has a flange connection 41 at the inlet end 42 and a flange connection 43 at the inlet end 44. In the valve chamber 46 there is a valve seat 48 upon which the diaphragm (not shown) engages to prevent flow through the valve. On the inlet side of the valve seat 48 there is a single flange 50 which provides support for the diaphragm when it is in the closed position. On the outlet side of the valve seat 48 there are a set of five flow director flanges 51 , 52, 53, 54 and 55 which act to smooth flow through the valve when the valve is opened. The central flange 53 is substantially parallel to the direction of flow through the valve and the flanges 51 , 52, 54 and 55 are angled to the central flange 53 so that the space between them reduces in cross sectional area towards the outlet 44. A diaphragm vaive with five fiow directors in the outlet flow path is particularly useful for valves adapted to be connected to pipes with diameters of 150mm or above.

FIG 9 shows an another embodiment of a diaphragm valve body according to the invention. In this embodiment the valve body has 60 has a screw threaded connection 61 at the inlet end 62 and a screw threaded connection 63 at the inlet end 64. In the vaive chamber 66 there is a valve seat 68 upon which the diaphragm (not shown) engages to prevent flow through the valve. On the outlet side of the valve seat 48 there are a set of two flow director flanges 71 , and 72 which act to smooth flow through the valve when the valve is opened. There is no central flange but the flanges 71 and 72 are angled to each other so that the space between them reduces in cross sectional area towards the outlet 64. A diaphragm valve with only two flow directors in the outlet flow path is particularly useful for valves adapted to be connected to pipes with diameters of 50mm or less. Such a valve body may be manufactured from plastics material by processes such as injection moulding. As can be seen in FIG 9 the angle β between the notional centre line of the valve shown by dotted line 73 and the the direction of longitudinal extent of the flow director 71 as shown by dotted line 74 can be in the range of from 8° to 20° and is preferably about 10°.

FIG 10 shows an another embodiment of a diaphragm valve body according to the invention. In this embodiment the valve body has 80 has a drop in type connection 81 at the inlet end 82 and the other part of the drop in connection 83 at the inlet end 84. In the valve chamber 86 there is a valve seat 88 upon which the diaphragm (not shown) engages to prevent flow through the valve. On the inlet side of the valve seat 88 there is a siπgie flange 90 which provides support for the diaphragm when it is in the closed position. On the outlet side of the valve seat 88 there are a set of four flow director flanges 91 , 92, 93 and 94 which act to smooth fiow through the valve when the valve is opened. There is no central flange but the flanges 91 and 92 on one side of the centre line are angled to each other and the flanges 93 and 94 on the other side of the centre line are angled to each other so that the space between them reduces in cross sectional area towards the outlet 84. A diaphragm valve with four flow directors in the outlet flow path may be particularly useful for valves adapted to be connected to pipes with diameters of 100mm to 150mm.

The diaphragm valve body according to this invention including the flow directors may be made as a single casting or moulding from plastics material, brass or cast iron or may be fabricated by known methods.

Preferably the flow directors are moulded or cast into the valve bodies at the time of formation.

Throughout this specification various indications have been given to the scope of this invention but the invention is not limited to any one of these but may reside in one or more of these combined together. The examples and preferred embodiments are given for illustration only and not for limitation.

Throughout this specification and the claims that follow unless the context requires otherwise the terms 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A valve of a type having a valve chamber, an inlet, an outlet, an inlet flow path, an outlet flow path and a valve member adapted to enter the valve chamber to prevent flow through the valve, the valve being characterised by at least two flow directors in the outlet flow path whereby to improve the flow through the valve and to reduce head loss across the valve.

2. A valve as in Claim 1 wherein there are two to five flow directors in the outlet flow path.

3. A valve as in Claim 1 wherein the flow directors comprise plates extending longitudinally in the outlet flow path.

4. A valve as in Claim 1 wherein the flow directors are angled to the direction of flow of the fluid in the valve so that the cross sectional area between adjacent flow directors reduces towards the outlet from the valve chamber.

5. A valve as in Claim 4 wherein the angle between a longitudinal line through the valve and the direction of longitudinal extent of the or each flow director on each side of a notional centre line of the valve or from an adjacent flow director is from 8┬░ to 20┬░.

6. A valve as in Claim 5 wherein there are two flow directors and the angle between a notional centre line of the valve and the flow director on each side of it is about 10┬░.

7. A valve as in Claim 5 wherein there are three flow directors and the angle between a centre flow director and the flow director on each side of it is about 10┬░.

8. A valve as in Claim 5 wherein there are four flow directors and the angle between a notional centre line of the valve and the first flow director on each side of it is about 10┬░ and the angle between the first flow director on each side and the second flow director on each side of it is about 10┬░.

9. A valve as in Claim 5 wherein there are five flow directors and the angle between a centre flow director and the first flow director on each side of it is about 10┬░ and the angle between the first flow director on each side and the second flow director on each side of it is about 10┬░.

10. A diaphragm valve of a type having a valve chamber, an inlet, an outlet, an inlet flow path and an outlet flow path and a diaphragm arrangement including a diaphragm adapted to enter the valve chamber to prevent flow through the diaphragm valve, the diaphragm valve being characterised by at least two flow directors in the outlet flow path whereby to improve flow through the valve and to reduce head loss across the valve.

11. A diaphragm valve as in Claim 10 wherein there are two to five flow directors in the outlet flow path.

12. A diaphragm valve as in Claim 10 wherein the flow directors comprise plates extending longitudinally in the outlet flow path.

13. A diaphragm valve as in Claim 10 wherein the flow directors are angled to the direction of flow of the fluid in the valve so that the cross sectional area between adjacent flow directors reduces towards the outlet from the valve chamber.

14. A diaphragm valve as in Claim 10 wherein diaphragm valve body and the flow directors are made as a single casting or moulding from plastics material, brass or cast iron.

15. A valve as in Claim 13 wherein the angle between a longitudinal line through the valve and the direction of longitudinal extent of the or each flow director on each side of a notional centre line of the valve or from an adjacent flow director is from 8┬░ to 20┬░.

16. A diaphragm valve as in Claim 10 wherein there are two flow directors and the angle between a notional centre line of the valve and the flow director on each side of it is about 10┬░.

17. A diaphragm valve as in Claim 10 wherein there are three flow directors and the angle between a centre flow director and the flow director on each side of it is about 10┬░.

18. A diaphragm valve as in Claim 10 wherein there are four flow directors and the angle between a notional centre line of the valve and the first flow director on each side of it is about 10┬░ and the angle between the first flow director on each side and the second flow director on each side of it is about 10┬░.

19. A valve as in Claim 10 wherein there are five flow directors and the angle between a centre flow director and the first flow director on each side of it is about 10┬░ and the angle between the first flow director on each side and the second flow director on each side of it is about 10┬░.

20. A diaphragm valve as in Claim 10 further including at least one flow director on the inlet flow path.