WO2001071289A1

WO2001071289A1 - Control valve

Info

Publication number: WO2001071289A1
Application number: PCT/DK2001/000176
Authority: WO
Inventors: Mads Lildholdt
Original assignee: Broen Armatur A/S
Priority date: 2000-03-21
Filing date: 2001-03-16
Publication date: 2001-09-27
Also published as: AU2001242306A1

Abstract

The invention concerns a control valve (1) with an insert (9), for example a venturi (37), and a fine adjustment mechanism ensuring that the flow through the valve (1) can be measured exactly and controlled precisely. The fine adjustment mechanism comprises a regulating member (24) which is provided adjustably displaceable in a passage (25) in a ball body (6), where displacement of the regulating member (24) results in reduction of the cross-section of the through-going duct (7) in the ball body (6).

Description

Control Valve

The present invention concerns a control valve as indicated in the preamble of claim 1.

Different kinds of shutoff and control valves are used in connection with conducting water in piping systems such as heating facilities. The water flow through the different branches in the piping is to be suitably adjusted for achieving a satisfactory heat transport system. Therefore, it is necessary to measure the flow through the single branches and valves. For this purpose, a number of measuring units are connected at the single branches.

N typical measuring method for determining the flow through a pipe branch is to measure the differential pressure around a constriction in this branch. For this purpose, specially shaped constrictions, such as apertures or so-called Venturis, are provided inside the pipe. Due to the flow of the liquid, the pressure before the constriction will be different from the pressure in the constriction and immediately after the constriction. By measuring the pressure differential, the rate of flow may be determined. Different measuring gates are thus provided in the pipes around these constrictions, and when the pressure is to be measured, measuring probes are disposed in these gates for reading pressure and temperature after which the flow rate may be determined and possibly regulated by means of valves.

N measurement pipe installation with constriction, measuring gates and control valve is usually a unit with many components as they comprise several sealings and joints. Furthermore, the installation is relatively long as a certain length, typically corresponding to at least five pipe diameters, are required between the constriction and the valve.

In order to reduce this length and to reduce the amount of work by installation, there is disclosed a ball valve in US patent 5 533 549 in which a venturi and two measuring gates are built into the valve. However, this valve has a great disadvantage as the flow may only be regulated by turning the ball body in the valve whereby it is no longer possible to perform a fine adjustment of the flow through the valve.

The purpose of the invention is to indicate a valve ensuring both an exact measure- ment of the flow and a precise regulation of the flow while at the same time the control valve is a compact unit.

This purpose is achieved with a control valve of the kind mentioned in the introduction, having the peculiar features as stated in the characterising part of claim 1.

According to the invention, a method known per se for exact measurement of the flow through a conduit with a valve is combined with a precise adjustment of the flow while at the same time the control valve being compact so that constriction, measuring gates, ball body as well as the fine adjustment mechanism are all contained in the valve housing. The number of component to be mounted by the plumber are thereby minimised, simultaneously facilitating installation together with savings of work time and materials during mounting.

In a further embodiment of the invention, the regulating member is largely cylindric with a screw thread on a part of the regulating member and is disposed in a boring in the spindle. The screw thread engages a corresponding thread at the inner side of the boring so that turning of the regulating member about its longitudinal axis provides the displacement of the regulating member.

In a further embodiment of the invention, the valve comprises a spindle handle for turning the spindle about its longitudinal axis, where the spindle handle is provided with a through-going hole, thus forming access to the outermost part of the regulating member. Preferably, the regulating member will be provided with a specially shaped hole, e.g. a hexagonal hole, in which a suitable tool may be placed for turning the regulating member. However, it may also be possible that the regulating member is provided with its own fine adjustment handle extending through the spindle handle and being accessible outside the spindle handle. In a further embodiment of the invention, the valve comprises a revolution counter with digit display showing how many revolutions the regulating member has been turned from a reference position. The revolution counter is of great help for the user when fine adjustment is to be made and provides the possibility of adjusting the valve to a predetermined value of the flow in advance. In particular, this is an advantage if the adjustment is to be changed between different settings, e.g. a day setting and a night setting. In a preferred embodiment, the revolution counter is provided as a mechanical apparatus but may alternatively be an electronic revolution counter with digital display.

In a further embodiment of the invention, the revolution counter comprises a first gear wheel fastened to the regulating member and which is provided with ten digits at its upper side and a second gear wheel provided with ten digits at its upper side. These two gear wheel engage each other, the second gear wheel having a gear ratio of 1 : 10 to the first gear wheel. Each time the first gear wheel has rotated one revolution, the second gear wheel is turned 1/10 revolution.

In a still further embodiment of the invention, the revolution counter is built into the spindle handle, and the spindle handle is provided with two windows at its upper side for showing one digit from the first gear wheel and one digit from the second gear wheel. The interval between the digits in the first window correspond to 1/10 revolution of the regulating member, and the interval between the digits in the second window corresponds to a full revolution of the regulating member. When the regulating member is rotated, the first gear wheel is also rotated therewith. Nt the upper side of the first gear wheel, the digits from 0 to 9 are printed with the same mutual angular distance. If this gear wheel is turned 1/10 revolution, in the first window may be seen a shift from one digit to a succeeding digit. When the first gear wheel is turned a whole revolution, the second gear wheel is rotated 1/10 revolution, whereby a shift from one digit to a succeeding digit can be seen in the second window. Alternatively, the gear wheels may be substituted by cylinders in mutual engagement. In a still further embodiment of the invention, the constriction is provided as an insert comprising an orifice plate, a flow-nozzle or a venturi. The orifice plate fits closely to the inner side of the valve housing in the through flow passage and is provided with a central hole. The surfaces of the plate are preferably flat and parallel. A flow-nozzle is usually formed as a continual constriction succeeded by a cylindric part. A venturi is usually shaped as a continual constriction succeeded by an outlet with increasing cross-section.

In a further embodiment according to the invention, the insert comprises an inlet sec- tion and an outlet section and is provided with a first transverse passage through the insert downstream of the constriction and where the first transverse passage is connected with the first measuring gate via the first readout duct.

In a further embodiment of the invention, the insert also has a second transverse pas- sage provided in the insert and offset relative to the second aperture in the valve housing. Furthermore, an annular duct is provided, connecting the second transverse passage with the second aperture and the second readout duct.

The transverse passage in the inlet section is provided as two mutually opposed holes. If the valve and the insert in the valve are oriented so that one of the holes are located at the bottom of the through flow passage of the valve, it is possible that this hole eventually will be clogged by particles carried with the flow in the liquid and deposited upstream of the constriction of the insert due to the force of gravity and the flow. Due to the opposite hole in the insert, however, it is always ensured that one of the holes is not clogged, whereby an exact measurement is ensured, also in the case of long time intervals between the measurements.

The annular duct may be provided as a groove at the outer side of the inlet section of the insert. This embodiment has the advantage that it is only the insert which has to be machined for providing the annular duct. However, it is preferred that the annular duct is provided as a groove in the valve housing so that it is covered by the inlet section of insert. In that case, the valve housing is to be machined for making the annular duct. Thereby the inlet section of the venturi may be formed with the largest possible internal cross-section whereby the difference between the cross-section of the inlet section and the cross-section of the constriction is the greatest possible, something which favourable with regard to the accuracy of the pressure differential measurements.

It is the intention of the invention that insert as well as regulating member form parts of a control valve as the purpose is to provide an exact adjusting and reading of the regulation in the valve. However, it is only possible to utilise a part of the invention, namely the insert with the specially shaped inlet section for improving existing valves.

The invention will be explained in more detail below with reference to the drawing in which:

Fig. 1 shows a section through a first embodiment of the control valve according to the invention and as seen perpendicularly to the direction of flow,

Fig. 2 shows a cross-section of the venturi according to the invention, Fig. 3 shows a section through the second measuring gate where the section is parallel with the flow,

Fig. 4 shows the control valve as seen from above, i.e. in parallel with the axis of rotation of the spindle handle,

Fig. 5 shows a section through a second embodiment of the control valve according to the invention where the insert comprises an orifice plate, and

Fig. 6 shows a section through a third embodiment of the control valve according to the invention where the insert comprises a flow-nozzle.

Fig. 1 shows a vertical section in parallel with the direction of flow through the valve 1 according to the invention. The valve 1 comprises a valve housing 2 with central through flow passage 3 from a supply pipe 4 to a discharge pipe 5. A ball body 6 with through-going duct 7 is disposed in the valve housing 2, where the ball body 6 is sus- pended rotatably in the through flow passage 3 for controlling the flow through the valve 1. For shutting off the liquid flow through the valve 1, the ball body 6 in the valve housing is turned by means of a spindle handle 40 connected to the body 6 via a spindle 8.

A venturi 37 is provided as insert 9 in the through flow passage 3 in the valve housing 2. The venturi 37 has an inlet section 10, a constriction 1 1 and an outlet section 12, where a first transverse passage 13 is disposed immediately after, or downstream, of the constriction 11. As liquid flows through the valve 1 , the constriction 11 in the venturi 37 causes different pressure conditions in the inlet section 10, the constriction

1 1 and the outlet section 12, respectively, of the venturi 37. By measuring the pressure at the inlet section 10 and the constriction 11 , the flow speed and hence the flow rate through the valve 1 may be determined from the pressure differential.

For measuring the pressure at the inlet section 10 of the venturi 37 and at the constriction 11 , the valve 1 is provided with a first measuring gate 15 and a second measuring gate 14 provided in the valve housing 2. The second measuring gate 14 is connected with a second transverse passage 17 in the inlet section 10 via a second readout duct and an annular duct 16. The second transverse passage 17 is provided in the venturi 37 as two mutually opposed holes 18 in the inlet section 10 of the venturi 37. The annular duct 16 is provided as a groove in the valve housing 2 and is covered by the inlet section 10 of the venturi 37. The venturi 37 is shown enlarged and in greater detail on Fig. 2.

The pressure at the inlet section 10 is transmitted through the second transverse passage 17 and into the annular duct 16 and further on via the second aperture and the second readout duct (not shown) into the second measuring gate 14 where the pressure may be read by a suitable measuring probe. If the valve 1 and the venturi 37 are oriented so that one of the holes 18 is at the bottom of the through flow passage 3 of the valve, it is possible that this hole 18 eventually will be clogged by particles brought with the flow in the liquid and which due to the gravity and flow are deposited before, or upstream, of the constriction 11 of the venturi 37. Due to the opposite hole 18 in the inlet section 10 of the venturi, however, it will always be safeguarded that at least one of the holes 18 are not clogged whereby an accurate measurement is ensured, also by long time intervals between the measurements. The venturi 37 is disposed in the valve housing 2 in such a way that the holes in the transverse passage 17 is offset relative to the apertures for the readout ducts.

Fig. 3 shows a section through the first measuring gate 15 and perpendicular to the direction of flow. The first measuring gate 15 is connected with a transverse passage 13 downstream of the constriction 11.

The venturi 37 insert 9 is shown in greater detail on Fig. 2. The venturi is provided with an external groove 23 at the outer side of the venturi 37. The pressure at the constriction 11 is transmitted through the first transverse passage 13 and into the outer groove 23 and further on through the first aperture 36 into the first readout duct 22. Using the first measuring gate 15, the pressure may be measured by means of a suitable probe.

Preferably, the transverse passage 13 downstream of the constriction 11 of the venturi 37, analogous with the second transverse passage 17 in the inlet section 10 of the venturi 37, will be 90° offset relative to the apertures of the readout ducts. If one of the holes 21 from the transverse passage 13 in the venturi 37 is located right at this aperture 36, there is the risk that the readout duct 22 is clogged when the valve 1 is mounted so that the hole 21 and the access are directed downwardly. The shown orientation on Fig. 3 of the transverse duct 20 of the venturi 37 relative to the first aperture 36 will therefore not be preferred in practice.

In order to regulate the flow through the control valve 1, the valve has a fine adjustment mechanism comprising a regulating member 24 disposed adjustably displaceable in a passage 25 in the ball body 6 where a displacement of the regulating member 24 results in a reduction of the cross-section of the through-going duct 7 in the ball 6, see

Fig. 1. The regulating member 24 is provided in a boring in the spindle 8 and is largely cylin- dric. The regulating member 24 is provided with a thread 26 on a part 27 of the regulating member 24, and the thread 26 engages a corresponding thread 28 at the inner side of the boring so that turning of the regulating member 24 about its longitudinal axis causes a displacement of the regulating member 24. The turning may be performed with a tool (not shown) which is put through the hole 20 in the spindle handle 40 and in a coupling piece 29 of the regulating member. The coupling piece 29 is preferably shaped as a polygonal hole with six or twelve edges so that a hexagonal wrench may be inserted into the hole and used for turning the regulating member 24. However, there is also the possibility of other shapes of the coupling piece and the corresponding tool. Alternatively, it is possible that an extension is provided permanently on the regulating member 24, extending through the handle 40 and accessible outside the spindle handle 40.

Fig. 4 shows the control valve 1 in direction in parallel with the axis of rotation of the spindle handle 40. The spindle handle 40 is provided with a revolution counter 30 with digit display, where the revolution counter 30 shows how many revolutions the regulating member 24 has been turned from a reference position.

In the embodiment shown on Fig. 1, the revolution counter 30 comprises a first gear wheel 31 , which is fixedly connected to the regulating member 24, and a second gear wheel 32 engaging the other wheel 31 through a gear transmission 33, however in such a way that the gear ratio for the second gear wheel relative to the first gear wheel is 1 :10, i.e. the second gear wheel 32 turns ten times slower than the first gear wheel 31.

As depicted on Fig. 4, the revolution counter is integrated in the spindle handle 40 which is provided with two windows 33,34 at its upper side for displaying one digit from the first gear wheel 31 and one digit from the second gear wheel 32. The interval between the digits in the first window corresponds to 1/10 revolution of the regulating member 24 and the interval between the digits in the second window corresponds to a complete revolution of the regulating member 24. Fig. 5 shows a second embodiment of the valve, provided with an insert with an orifice plate 38 with a central hole 41. The insert 9 furthermore has a cylindric outlet 12 provided with a transverse passage 13.

Fig. 6 shows a third embodiment of the valve, provided with an insert with a flow- nozzle 39, where the constriction 1 1 and the inlet section 10 bear great similarity with the venturi 37 but where the outlet section 12 with a transverse passage 13 is cylindric.

Numbering of parts

1. valve

2. valve housing 3. through flow passage

4. supply pipe

5. discharge pipe

6. ball body

7. through-going hole in ball body 8. spindle

9. insert

10. inlet section

1 1. constriction

12. outlet section 13. second transverse passage disposed after the constriction

14. second measuring gate

15. first measuring gate

16. annular duct

17. second transverse passage provided in inlet section 18. holes in inlet section

19. second readout duct

20. hole through the spindle handle

21. holes in constriction

22. readout duct in the constriction (first readout duct) 23. external groove in venturi

24. regulating member

25. passage in ball body

26. screw thread on regulating member

27. part of regulating member with thread 28. corresponding screw thread on spindle

29. coupling piece

30. revolution counter 31. first gear wheel

32. second gear wheel

33. gear transmission

34. first window 35. second window

36. first aperture in valve housing for first readout duct

37. venturi

38. orifice plate

39. flow-nozzle 40. spindle handle

41. central hole in orifice plate

Claims

1. A control valve (1) comprising:

- a valve housing (2) with through flow passage (3) from an inlet pipe (4) to an outlet pipe (5),

- a ball body (6) with a through-going duct (7), the ball body (6) being disposed ro- tatably in the through flow passage (3) of the valve housing (2) for controlling the flow through the valve (1),

- a spindle (8) for turning the ball body (6), - an insert (9) with a constriction (1 1) provided in the valve housing (2)

- a first measuring gate (15) and a second measuring gate (14) provided in the valve housing (2),

- a first readout duct (22) and a second readout duct, where the first readout duct connects the first measuring gate (15) with a first aperture in the valve housing (2) down- stream of the constriction (11), and where the second readout duct connects the second measuring gate (14) with a second aperture in the valve housing (2) upstream of the constriction (11), characterised in that

- the valve (1) has a fine adjustment mechanism including a regulating member (24) which is arranged adjustably displaceable in a passage (25) in the ball body (6) so that displacement of the regulating member (24) results in a reduction of the cross-section of the through-going duct (7).

2. A valve according to claim 1 , characterised in that the regulating member (24) is largely cylindric with a screw thread (26) on a part (27) of the regulating member (24) and is disposed in a boring in the spindle (8), that the screw thread (26) engages a corresponding thread (28) at the inner side of the boring, and that turning of the regulating member (24) about its longitudinal axis provides the displacement of the regulating member (24),

3. A valve according to claim 1 or 2, characterised in that the valve (1) comprises a spindle handle (40) for turning the spindle (8) about its longitudinal axis, where the spindle handle (40) is provided with a through-going hole (20), thus forming access to the outermost part of the regulating member (24).

4. A valve according to any of claim 1 - 3, characterised in that the valve (1) com- prises a revolution counter (30) with digit display showing how many revolutions the regulating member (24) has been turned from a reference position.

5. A valve according to claim 4, characterised in that the revolution counter (39) comprises a first gear wheel (31 ) fastened to the regulating member (24) and which is provided with ten digits at its upper side, that the revolution counter (30) comprises a second gear wheel (32) provided with ten digits at its upper side and engaging the first gear wheel (31 ), the second gear wheel (32) having a gear ratio of 1 : 10 to the first gear wheel (31).

6. A valve according to claim 4 or 5, characterised in that the revolution counter (30) is integrated in the spindle handle (40), and that the spindle handle (40) is provided with two windows (33,34) at its upper side for showing one digit from the first gear wheel (31) and one digit from the second gear wheel (32), where the interval between the digits in the first window (33) correspond to 1/10 revolution of the regulating member (24), and where the interval between the digits in the second window (34) corresponds to a full revolution of the regulating member (24).

7. A valve according to claim 1 - 6, characterised in that the constriction (1 1) is provided as an insert (9) comprising an orifice plate (38), a flow-nozzle (39) or a ven- turi (37).

8. A valve (1) according to claim 7, characterised in that the insert (9) comprises an inlet section (10) and an outlet section (12) and is provided with a first transverse passage (13) through the insert (9) after the constriction (11) and where the first trans- verse passage (13) is connected with the first measuring gate (15) via the first readout duct (22).

9. A valve device according to claim 7 or 8, characterised in that the insert (9) has also a second transverse passage (17) which is provided in the insert (10) and offset relative to the second aperture, and that an annular duct (16) is provided, connecting the second transverse passage (17) with the second readout duct.

10. Fine adjustment mechanism for a valve according to any preceding claim.