CA2077280C - Valve controlled in dependence on differential pressure with desired-value setting facility - Google Patents
Valve controlled in dependence on differential pressure with desired-value setting facilityInfo
- Publication number
- CA2077280C CA2077280C CA002077280A CA2077280A CA2077280C CA 2077280 C CA2077280 C CA 2077280C CA 002077280 A CA002077280 A CA 002077280A CA 2077280 A CA2077280 A CA 2077280A CA 2077280 C CA2077280 C CA 2077280C
- Authority
- CA
- Canada
- Prior art keywords
- diaphragm
- valve
- spring
- housing
- valve according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000008878 coupling Effects 0.000 claims abstract description 28
- 238000010168 coupling process Methods 0.000 claims abstract description 28
- 238000005859 coupling reaction Methods 0.000 claims abstract description 28
- 238000007789 sealing Methods 0.000 claims description 10
- 230000006835 compression Effects 0.000 claims description 3
- 238000007906 compression Methods 0.000 claims description 3
- 230000001627 detrimental effect Effects 0.000 abstract description 2
- 238000010276 construction Methods 0.000 description 4
- 238000002788 crimping Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000002349 favourable effect Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 210000004907 gland Anatomy 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 210000002105 tongue Anatomy 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D16/00—Control of fluid pressure
- G05D16/14—Control of fluid pressure with auxiliary non-electric power
- G05D16/16—Control of fluid pressure with auxiliary non-electric power derived from the controlled fluid
- G05D16/163—Control of fluid pressure with auxiliary non-electric power derived from the controlled fluid using membranes within the main valve
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D16/00—Control of fluid pressure
- G05D16/028—Controlling a pressure difference
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Power Engineering (AREA)
- Control Of Fluid Pressure (AREA)
- Safety Valves (AREA)
Abstract
A valve controlled in dependence on differential pressure with a set-point setting facility, comprises a valve housing (4), a diaphragm housing (16), and a setting device (3) which is removable as a unit from the diaphragm housing (16). A pin (36) connected to the diaphragm (23) projects in a sealed manner from the diaphragm housing (16). The set-point spring (50) extends between an adjustable supporting plate (51) and a spring plate (52). The forces of the set-point spring (50) are transferred by way of a releasable coupling (64) to the pin (36). The coupling (64) is in particular designed to transfer tensile forces. In this manner, the set-point spring can be adjusted or exchanged at any time. In addition, detrimental transverse forces originating in the set-point spring are prevented from being transferred to the valve rod. The valve is therefore accessible and of low friction.
Description
The invention relates to a valve controlled in dependence on differential pressure with a set-point reference setting facility, having a valve housing, which comprises a valve seat and a closure member provided with a valve rod, with a diaphragm housing, which is mounted on the valve housing and is divided by a diaphragm acting on the valve rod into two pressure chambers, and with a setting device, which is mounted on the diaphragm housing and comprises a set-point spring acting on the diaphragm and an adjusting means for the set-point spring.
In the case of a known valve of this kind (EP-OS 354 427), in which the diaphragm housing is arranged between the valve housing and the setting device, use is made of a continuous valve rod, which at one end carries the closure member, in the middle is connected to the diaphragm, and at the other end is loaded by the set-point spring.
The set-point spring bears at one end against the diaphragm housing and at the other against a spring plate, which is arranged to screw onto the valve rod. After removal of a cover, the springs can also be exchanged.
In the known construction, manipulation of the set-point spring (adjusting and exchanging it) poses problems because the space receiving the spring is connected to the system by way of the pressure chamber remote from the valve and is therefore accessible only after additional precautions have been taken in the system. Because the valve rod is long and is mounted with one free end close to the closure member in a guide means of the valve housing, there is a danger that it will buckle under the influence of the axial forces Icd:sg t and/or transverse forces that are caused, for example, by unsymmetrical spring forces (skewed state). That would lead to increased friction at all sealed points, to a corresponding hysteresis of the valve movement, and to wear and tear at the sealing points.
For that reason, the valve rod is of very thick construction. It is therefore heavy and expensive, in particular when it consists of stainless steel or another expensive material in order to be compatible with the medium to be controlled.
The invention is based on the problem of providing a valve of the kind mentioned in the introduction that is controlled in dependence on differential pressure and in which the set-point spring can be adjusted or exchanged at any time.
Generally speaking, the present invention may be considered as providing a valve controlled in dependence on differential pressure with a set-point reference setting facility, comprising: a valve housing having a valve seat and a closure member provided with a valve rod; a diaphragm housing mounted on the valve housing and divided by a diaphragm acting on the valve rod into two pressure chambers, from which chambers a pin connected to the diaphragm projects in a sealed manner; a setting device mounted on the diaphragm housing; the setting device being removable as a unit from the diaphragm housing; a set-point spring acting on the diaphragm and arranged between a supporting plate and a spring plate; adjusting means for the set-point spring;
and a releasable coupling transferring the spring forces to the pin.
Because the pin is guided in a sealed manner out of the diaphragm housing, no further sealing is required in the setting device. The set-point spring is located in the atmosphere and can be adjusted at any time. Because the setting device is removable as a Icd:sg A~
~ 2077280 unit, exchange of the springs can also be effected in a simple manner.
There is no continuous valve rod. On the contrary, the coupling effects a separation between the spring plate loaded by the spring force and the pin transferring the forces to the diaphragm and the closure member. This coupling must be releasable, so that the setting device can be removed as a unit. A releasable coupling has so much play that skewed positions or lateral displacements caused by skewed springs are compensated in that the pin passing through its seal is not subjected to any detrimental transverse forces. If desired, this can be further assisted by suitable design of the coupling, for example as a flexible coupling. Because the pin is virtually free from transverse forces, it, and the entire valve rod, can be manufactured with a smaller cross-section and therefore at a lower cost. The smaller the cross-section, the greater also is the independence from the static pressure in the system.
Valves of this kind controlled in dependence on differential pressure are used, for example, in hot water heating systems, in order to guarantee a given pressure difference between the supply pressure and the return pressure in the heating circuit. In this and in other cases, the pressure chamber remote from the valve carries the higher pressure and the pressure chamber closer to the valve carries the lower pressure. For this application therefore, care has to be taken that the coupling is designed to transfer tensile forces. The set-point spring must be effective against the diaphragm loading.
In a preferred embodiment, the set-point spring is a helical compression spring, the end of which close to the diaphragm is engaged by the supporting plate and the end of which remote from the diaphragm is engaged by the spring plate. Because it is not the spring plate Icd:~
_q .A ~' . 4 .
that is adjustable relative to the valve rod but the supporting plate that is adjustable relative to a stationary part of the setting device, a stable construction is created.
The coupling is preferably arranged at the end of the setting device close to the diaphragm. The lever arm acting on the pin between the coupling and the seal is small, so that for this reason too, any stress on the seal is negligible.
The releasable coupling is especially advantageously a snap-fit coupling. The coupling is automatically brought into its effective position as the setting device is placed on the diaphragm housing or on brief depression of the spring plate.
It is recommended for the snap-fit coupling to be formed by a head on the pin and by a holder comprising at least two resilient arms engaging behind the head. By opening out the arms, the snap-fit coupling can also be released again.
In a preferred embodiment, provision is made for the spring plate to have a tubular extension running towards the diaphragm; at its free end, the extension carries the holder and to form the resilient arms is provided with slots. Because of the extension, the slots are comparatively long. Small forces are therefore sufficient to open out the arms.
It is especially favourable if the head has sloping faces at its end remote from the diaphragm and/or if the holder has sloping faces on its side close to the diaphragm in order to facilitate the snap-fit action. The sloping faces facilitate automatic snapping-on.
The spring plate is preferably connected by way of a conical wall tapering towards the diaphragm with the tubular extension, and the Icd:sg ~q}
~ !~
~ 2077280 . 5 .
slots extend right into the conical wall. If a tool is pressed onto the conical wall, the arms open out.
Moreover, it is favourable for the pin to pass through a sealing housing secured to the diaphragm housing and provided on its periphery with profilings, and for an annular base of the setting means to be arranged to be pushed onto the sealing housing and be secured to it by means of at least one screw engaging behind the profilings. In this manner the setting device can be secured releasably yet securely to the diaphragm housing.
In further development of the invention, provision is made for the supporting plate to be held so that it cannot rotate and to have an external thread which engages with an internal thread of a rotary knob concentrically surrounding the set-point spring, and for the rotary knob to be held so that it is able to rotate yet is axially fixed on a base of the setting device. This is an especially simple construction for adjusting the set-point spring.
An index ring, which engages by means of at least one radial pointer through an axial slot in the rotary knob, is preferably located rotatably on the supporting plate. A scale can be mounted at this axial slot. An indication of the desired value that has been set can be obtained in a simple manner.
The invention is explained in detail hereinafter with reference to a preferred embodiment illustrated in the drawing. The single Figure shows a longitudinal section through a valve according to the invention.
The valve illustrated consists of three parts fastened to one another, namely, a valve unit 1, a fit-on diaphragm unit 2 and a setting device 3.
Icd:s8 ~ 2077280 . 6 .
The valve unit 1 comprises a valve housing 4 with a valve seat 5. The latter co-operates with a closure member 6 which is connected to a valve rod 7. The closure member is arranged to be ~crewed onto a threaded portion 8 of the valve rod 7 and clamps the base of a cup 9 drawn from sheet metal fixedly to a step in the valve rod 7. An insert lo in the housing 4 forming a passage-way has a guide section 11 for the valve rod 7 and a seal 12 for the cup 9.
This creates a compensation chamber 13 which is connected by way of a system of ducts 14 in the closure member 6 and in the valve rod 7 to the inlet chamber 15 of the valve housing 4. Static pressure compensation at the closure member is obtained in this way.
The fit-on diaphragm unit 2 has a diaphragm housing 16 with a lower shell 17 and an upper shell 18 connected to the lower shell by crimping. A fixing ring 19, which can be fastened to the valve housing 4 by means of a union nut 20, is secured to the lower shell 17 by crimping. A sealing housing 21 acting as a packing gland is secured to the upper shell 18 by crimping and has a profiling 22 in the form of a circumferential annular groove with conical side walls.
A diaphragm 23 is clamped peripherally between the shells 17 and 18 and is covered on both sides by supporting plates 24 and 25. An insert 26 has a circumferential wall 27 which passes through a central opening in the supporting plates 24, 25 and is fixed there by crimping. At its upper end the valve rod 7 carries a contact face 28 formed by a plate, which is pressed with the aid of a valve spring 29 against the insert 26.
The diaphragm 23 divides the diaphragm housing 16 into a pressure chamber 30 close to the valve and a pressure chamber 31 remote from the valve. The pressure chamber 30 is connected by way of Icd:~g A ;-~ 2077280 . 7 .
a bore 32 to the compensation chamber 13, and thus to the inletchamber 15 of the valve housing 4. The pressure chamber 31 has a connection 33 for a pulse line, by which a system pressure to be monitored, which is generally higher than the pressure in the pressure chamber 30, can be supplied. In the pressure chamber 30 there is a diaphragm spring 34 which urges the diaphragm 23 upwards, and in the pressure chamber 31 there is a diaphragm spring 35 which urges the diaphragm 23 downwards. A guided pin 36 is connected at its lower end by way of an articulation 37 to the insert 26. The pin projects lo through the sealing housing 21 to the outside. The articulation 37 comprises a hemispherical head 38, which is connected to the pin 36 by a neck 39, and an articulation socket 40, which engages behind the articulation head 38. The articulation socket is formed by a transverse bore 41, the axis of which is at right angles to the plane of the drawing and adjoining the upper side of which is a slot 42 running in the same direction for the passage of the neck 39. On assembly, the articulation head 38 is pushed from the side into the transverse bore 41 and is held in the middle of the bore by a pushed-on cap 43 so that it is able to perform a limited swivel movement in all directions.
A relief valve 44 is provided in the insert 26 and comprises a valve ball 45 which is pressed by a spring 46 against the free end of an axial bore 47 connected to the transverse bore 41.
The setting device 3 comprises an annular base 48, which is arranged to be pushed onto the sealing housing 21 and is to be fastened to the diaphragm housing 16 by means of screws 49 that engage with conical points in the annular groove 22. A set-point spring 50 in the form of a helical compression spring extends coaxially with the Icd:s~s ...
A~
~ 2077280 pin 36 between a supporting plate 51 close to the diaphragm and a spring plate 52 remote from the diaphragm. The supporting plate 51 is prevented from rotating by a guide member 53 and has an external thread 54 which engages with a corresponding internal thread on the circumferential wall 55 of a rotary knob 56. At its lower end, the rotary knob 56 has resilient tongues 57 which engage by means of projections 58 beneath a step of the base 48. The rotary knob 56 is therefore capable of rotation, but is axially fixed. Mounted on the supporting plate 51 is an index ring 59 which has radial pointers 60 lo that project through two axial slots 61 in the knob 56 and cooperate with markings on the outside of the knob.
The spring plate 52 is joined by way of a conical wall 62 to a tubular extension 63 which extends as far as the vicinity of the fit-on diaphragm unit 2 and there forms with the pin 36 a coupling 64, in particular a snap-fit coupling. For that purpose, the pin 36 has a head 65 which is provided at its top end with a sloping face 66.
This co-operates with a holder 67, which likewise has sloping faces 68, engaging behind it. The holder is constructed on resilient arms 69 which are created by axially parallel slots 70 in the tubular extension 63. The slots 70 extend into the conical wall 62 so that, by introducing a tool through an end opening 71 in the rotary knob 56, the spring arms 69 can be spread apart at the transition from the extension 63 to the conical wall 62, and the coupling 64 can thereby be released.
Assuming that the illustrated valve is intended to keep the pressure drop constant in a system, for instance in a hot water heating system, then the valve is arranged at the exit of the system, that is to say, in the return line, and the connection 33 is connected Icd:sg ~ 2077280 . 9 .
to the supply line. The lower pressure chamber 30 then carries the return pressure and the upper pressure chamber 31 carries the supply pressure. This produces a force acting in the closing direction.
counteracting this is the force of the set-point spring 50 which is effective to apply a tensile force in the region of the articulation 37 and the coupling 64. In the usual manner, a state of equilibrium is established, in which the pressure drop in the system has the desired value.
The set-point spring can be adjusted at any time by rotating the rotary knob 56. If it is desired to use a different spring assembly, the setting device 3 can simply be exchanged as a unit.
Using a tool which has a smaller angle of taper than the conical wall 62, the spring arms 69 are opened out so that the coupling 64 is released. On renewed assembly, the coupling 64 snaps on automatically by virtue of the sloping faces 66 and 68. Should the force of the set-point spring 50 be too great, it is sufficient to press the spring plate 52 downwards somewhat; that can be effected without difficulty through the opening 71.
The play and the articulation mobility of the coupling 64 prevents transverse forces, which may occur on account of asymmetry of the set-point spring 50 on the spring plate 52, from being transferred to the pin 36 to an intrusive degree. The same applies in respect of the articulation 37 too, if the diaphragm 23 should be positioned askew. The pin 36 can therefore be guided with low friction, and so that it is easily movable, right through the sealing housing 21.
Transverse forces cannot be transmitted from the diaphragm to the valve rod 7 either, because the valve rod 7 is separated from the insert 26, and only compressive forces can be transmitted. As a Icd:sg ~_t . 10 .
consequence, there is no need to fear undesirable friction at the seal 12, Which would obstruct the mobility of the valve and cause undesirable wear and tear.
In heating systems, it may happen that by shutting off all loads the return pressure will drop in the pressure chamber 30 on account of cooling of the water and the contraction associated therewith, while the supply pressure in the pressure chamber 31 corresponds to the normal system pressure, for example 5 bar. So that thick and sluggish diaphragms do not have to be used, the relief valve 44 is provided, which opens under the said circumstances and effects a partial pressure equalization between the two pressure chambers 30 and 31.
t~d:sg A
In the case of a known valve of this kind (EP-OS 354 427), in which the diaphragm housing is arranged between the valve housing and the setting device, use is made of a continuous valve rod, which at one end carries the closure member, in the middle is connected to the diaphragm, and at the other end is loaded by the set-point spring.
The set-point spring bears at one end against the diaphragm housing and at the other against a spring plate, which is arranged to screw onto the valve rod. After removal of a cover, the springs can also be exchanged.
In the known construction, manipulation of the set-point spring (adjusting and exchanging it) poses problems because the space receiving the spring is connected to the system by way of the pressure chamber remote from the valve and is therefore accessible only after additional precautions have been taken in the system. Because the valve rod is long and is mounted with one free end close to the closure member in a guide means of the valve housing, there is a danger that it will buckle under the influence of the axial forces Icd:sg t and/or transverse forces that are caused, for example, by unsymmetrical spring forces (skewed state). That would lead to increased friction at all sealed points, to a corresponding hysteresis of the valve movement, and to wear and tear at the sealing points.
For that reason, the valve rod is of very thick construction. It is therefore heavy and expensive, in particular when it consists of stainless steel or another expensive material in order to be compatible with the medium to be controlled.
The invention is based on the problem of providing a valve of the kind mentioned in the introduction that is controlled in dependence on differential pressure and in which the set-point spring can be adjusted or exchanged at any time.
Generally speaking, the present invention may be considered as providing a valve controlled in dependence on differential pressure with a set-point reference setting facility, comprising: a valve housing having a valve seat and a closure member provided with a valve rod; a diaphragm housing mounted on the valve housing and divided by a diaphragm acting on the valve rod into two pressure chambers, from which chambers a pin connected to the diaphragm projects in a sealed manner; a setting device mounted on the diaphragm housing; the setting device being removable as a unit from the diaphragm housing; a set-point spring acting on the diaphragm and arranged between a supporting plate and a spring plate; adjusting means for the set-point spring;
and a releasable coupling transferring the spring forces to the pin.
Because the pin is guided in a sealed manner out of the diaphragm housing, no further sealing is required in the setting device. The set-point spring is located in the atmosphere and can be adjusted at any time. Because the setting device is removable as a Icd:sg A~
~ 2077280 unit, exchange of the springs can also be effected in a simple manner.
There is no continuous valve rod. On the contrary, the coupling effects a separation between the spring plate loaded by the spring force and the pin transferring the forces to the diaphragm and the closure member. This coupling must be releasable, so that the setting device can be removed as a unit. A releasable coupling has so much play that skewed positions or lateral displacements caused by skewed springs are compensated in that the pin passing through its seal is not subjected to any detrimental transverse forces. If desired, this can be further assisted by suitable design of the coupling, for example as a flexible coupling. Because the pin is virtually free from transverse forces, it, and the entire valve rod, can be manufactured with a smaller cross-section and therefore at a lower cost. The smaller the cross-section, the greater also is the independence from the static pressure in the system.
Valves of this kind controlled in dependence on differential pressure are used, for example, in hot water heating systems, in order to guarantee a given pressure difference between the supply pressure and the return pressure in the heating circuit. In this and in other cases, the pressure chamber remote from the valve carries the higher pressure and the pressure chamber closer to the valve carries the lower pressure. For this application therefore, care has to be taken that the coupling is designed to transfer tensile forces. The set-point spring must be effective against the diaphragm loading.
In a preferred embodiment, the set-point spring is a helical compression spring, the end of which close to the diaphragm is engaged by the supporting plate and the end of which remote from the diaphragm is engaged by the spring plate. Because it is not the spring plate Icd:~
_q .A ~' . 4 .
that is adjustable relative to the valve rod but the supporting plate that is adjustable relative to a stationary part of the setting device, a stable construction is created.
The coupling is preferably arranged at the end of the setting device close to the diaphragm. The lever arm acting on the pin between the coupling and the seal is small, so that for this reason too, any stress on the seal is negligible.
The releasable coupling is especially advantageously a snap-fit coupling. The coupling is automatically brought into its effective position as the setting device is placed on the diaphragm housing or on brief depression of the spring plate.
It is recommended for the snap-fit coupling to be formed by a head on the pin and by a holder comprising at least two resilient arms engaging behind the head. By opening out the arms, the snap-fit coupling can also be released again.
In a preferred embodiment, provision is made for the spring plate to have a tubular extension running towards the diaphragm; at its free end, the extension carries the holder and to form the resilient arms is provided with slots. Because of the extension, the slots are comparatively long. Small forces are therefore sufficient to open out the arms.
It is especially favourable if the head has sloping faces at its end remote from the diaphragm and/or if the holder has sloping faces on its side close to the diaphragm in order to facilitate the snap-fit action. The sloping faces facilitate automatic snapping-on.
The spring plate is preferably connected by way of a conical wall tapering towards the diaphragm with the tubular extension, and the Icd:sg ~q}
~ !~
~ 2077280 . 5 .
slots extend right into the conical wall. If a tool is pressed onto the conical wall, the arms open out.
Moreover, it is favourable for the pin to pass through a sealing housing secured to the diaphragm housing and provided on its periphery with profilings, and for an annular base of the setting means to be arranged to be pushed onto the sealing housing and be secured to it by means of at least one screw engaging behind the profilings. In this manner the setting device can be secured releasably yet securely to the diaphragm housing.
In further development of the invention, provision is made for the supporting plate to be held so that it cannot rotate and to have an external thread which engages with an internal thread of a rotary knob concentrically surrounding the set-point spring, and for the rotary knob to be held so that it is able to rotate yet is axially fixed on a base of the setting device. This is an especially simple construction for adjusting the set-point spring.
An index ring, which engages by means of at least one radial pointer through an axial slot in the rotary knob, is preferably located rotatably on the supporting plate. A scale can be mounted at this axial slot. An indication of the desired value that has been set can be obtained in a simple manner.
The invention is explained in detail hereinafter with reference to a preferred embodiment illustrated in the drawing. The single Figure shows a longitudinal section through a valve according to the invention.
The valve illustrated consists of three parts fastened to one another, namely, a valve unit 1, a fit-on diaphragm unit 2 and a setting device 3.
Icd:s8 ~ 2077280 . 6 .
The valve unit 1 comprises a valve housing 4 with a valve seat 5. The latter co-operates with a closure member 6 which is connected to a valve rod 7. The closure member is arranged to be ~crewed onto a threaded portion 8 of the valve rod 7 and clamps the base of a cup 9 drawn from sheet metal fixedly to a step in the valve rod 7. An insert lo in the housing 4 forming a passage-way has a guide section 11 for the valve rod 7 and a seal 12 for the cup 9.
This creates a compensation chamber 13 which is connected by way of a system of ducts 14 in the closure member 6 and in the valve rod 7 to the inlet chamber 15 of the valve housing 4. Static pressure compensation at the closure member is obtained in this way.
The fit-on diaphragm unit 2 has a diaphragm housing 16 with a lower shell 17 and an upper shell 18 connected to the lower shell by crimping. A fixing ring 19, which can be fastened to the valve housing 4 by means of a union nut 20, is secured to the lower shell 17 by crimping. A sealing housing 21 acting as a packing gland is secured to the upper shell 18 by crimping and has a profiling 22 in the form of a circumferential annular groove with conical side walls.
A diaphragm 23 is clamped peripherally between the shells 17 and 18 and is covered on both sides by supporting plates 24 and 25. An insert 26 has a circumferential wall 27 which passes through a central opening in the supporting plates 24, 25 and is fixed there by crimping. At its upper end the valve rod 7 carries a contact face 28 formed by a plate, which is pressed with the aid of a valve spring 29 against the insert 26.
The diaphragm 23 divides the diaphragm housing 16 into a pressure chamber 30 close to the valve and a pressure chamber 31 remote from the valve. The pressure chamber 30 is connected by way of Icd:~g A ;-~ 2077280 . 7 .
a bore 32 to the compensation chamber 13, and thus to the inletchamber 15 of the valve housing 4. The pressure chamber 31 has a connection 33 for a pulse line, by which a system pressure to be monitored, which is generally higher than the pressure in the pressure chamber 30, can be supplied. In the pressure chamber 30 there is a diaphragm spring 34 which urges the diaphragm 23 upwards, and in the pressure chamber 31 there is a diaphragm spring 35 which urges the diaphragm 23 downwards. A guided pin 36 is connected at its lower end by way of an articulation 37 to the insert 26. The pin projects lo through the sealing housing 21 to the outside. The articulation 37 comprises a hemispherical head 38, which is connected to the pin 36 by a neck 39, and an articulation socket 40, which engages behind the articulation head 38. The articulation socket is formed by a transverse bore 41, the axis of which is at right angles to the plane of the drawing and adjoining the upper side of which is a slot 42 running in the same direction for the passage of the neck 39. On assembly, the articulation head 38 is pushed from the side into the transverse bore 41 and is held in the middle of the bore by a pushed-on cap 43 so that it is able to perform a limited swivel movement in all directions.
A relief valve 44 is provided in the insert 26 and comprises a valve ball 45 which is pressed by a spring 46 against the free end of an axial bore 47 connected to the transverse bore 41.
The setting device 3 comprises an annular base 48, which is arranged to be pushed onto the sealing housing 21 and is to be fastened to the diaphragm housing 16 by means of screws 49 that engage with conical points in the annular groove 22. A set-point spring 50 in the form of a helical compression spring extends coaxially with the Icd:s~s ...
A~
~ 2077280 pin 36 between a supporting plate 51 close to the diaphragm and a spring plate 52 remote from the diaphragm. The supporting plate 51 is prevented from rotating by a guide member 53 and has an external thread 54 which engages with a corresponding internal thread on the circumferential wall 55 of a rotary knob 56. At its lower end, the rotary knob 56 has resilient tongues 57 which engage by means of projections 58 beneath a step of the base 48. The rotary knob 56 is therefore capable of rotation, but is axially fixed. Mounted on the supporting plate 51 is an index ring 59 which has radial pointers 60 lo that project through two axial slots 61 in the knob 56 and cooperate with markings on the outside of the knob.
The spring plate 52 is joined by way of a conical wall 62 to a tubular extension 63 which extends as far as the vicinity of the fit-on diaphragm unit 2 and there forms with the pin 36 a coupling 64, in particular a snap-fit coupling. For that purpose, the pin 36 has a head 65 which is provided at its top end with a sloping face 66.
This co-operates with a holder 67, which likewise has sloping faces 68, engaging behind it. The holder is constructed on resilient arms 69 which are created by axially parallel slots 70 in the tubular extension 63. The slots 70 extend into the conical wall 62 so that, by introducing a tool through an end opening 71 in the rotary knob 56, the spring arms 69 can be spread apart at the transition from the extension 63 to the conical wall 62, and the coupling 64 can thereby be released.
Assuming that the illustrated valve is intended to keep the pressure drop constant in a system, for instance in a hot water heating system, then the valve is arranged at the exit of the system, that is to say, in the return line, and the connection 33 is connected Icd:sg ~ 2077280 . 9 .
to the supply line. The lower pressure chamber 30 then carries the return pressure and the upper pressure chamber 31 carries the supply pressure. This produces a force acting in the closing direction.
counteracting this is the force of the set-point spring 50 which is effective to apply a tensile force in the region of the articulation 37 and the coupling 64. In the usual manner, a state of equilibrium is established, in which the pressure drop in the system has the desired value.
The set-point spring can be adjusted at any time by rotating the rotary knob 56. If it is desired to use a different spring assembly, the setting device 3 can simply be exchanged as a unit.
Using a tool which has a smaller angle of taper than the conical wall 62, the spring arms 69 are opened out so that the coupling 64 is released. On renewed assembly, the coupling 64 snaps on automatically by virtue of the sloping faces 66 and 68. Should the force of the set-point spring 50 be too great, it is sufficient to press the spring plate 52 downwards somewhat; that can be effected without difficulty through the opening 71.
The play and the articulation mobility of the coupling 64 prevents transverse forces, which may occur on account of asymmetry of the set-point spring 50 on the spring plate 52, from being transferred to the pin 36 to an intrusive degree. The same applies in respect of the articulation 37 too, if the diaphragm 23 should be positioned askew. The pin 36 can therefore be guided with low friction, and so that it is easily movable, right through the sealing housing 21.
Transverse forces cannot be transmitted from the diaphragm to the valve rod 7 either, because the valve rod 7 is separated from the insert 26, and only compressive forces can be transmitted. As a Icd:sg ~_t . 10 .
consequence, there is no need to fear undesirable friction at the seal 12, Which would obstruct the mobility of the valve and cause undesirable wear and tear.
In heating systems, it may happen that by shutting off all loads the return pressure will drop in the pressure chamber 30 on account of cooling of the water and the contraction associated therewith, while the supply pressure in the pressure chamber 31 corresponds to the normal system pressure, for example 5 bar. So that thick and sluggish diaphragms do not have to be used, the relief valve 44 is provided, which opens under the said circumstances and effects a partial pressure equalization between the two pressure chambers 30 and 31.
t~d:sg A
Claims (12)
1. A valve controlled in dependence on differential pressure with a set-point reference setting facility, comprising: a valve housing having a valve seat and a closure member provided with a valve rod; a diaphragm housing mounted on the valve housing and divided by a diaphragm acting on the valve rod into two pressure chambers, from which chambers a pin connected to the diaphragm projects in a sealed manner; a setting device mounted on the diaphragm housing; said setting device being removable as a unit from the diaphragm housing; a set-point spring acting on the diaphragm and arranged between a supporting plate and a spring plate; adjusting means for the set-point spring; and a releasable coupling transferring the spring forces to said pin.
2. A valve according to claim 1, wherein said releasable coupling is designed to transfer tensile forces.
3. A valve according to claim 1 or 2, wherein said set-point spring is a helical compression spring, the end of which close to the diaphragm is engaged by the supporting plate and the end of which remote from the diaphragm is engaged by the spring plate.
4. A valve according to one of claims 1 to 3, wherein said releasable coupling is arranged at the end of the setting device close to the diaphragm.
5. A valve according to one of claims 1 to 4, wherein said releasable coupling is a snap-fit coupling.
6. A valve according to claim 5, wherein said snap-fit coupling is formed by a head on said pin and by a holder comprising at least two resilient arms engaging behind said head.
7. A valve according to claim 6, wherein said spring plate has a tubular extension running towards the diaphragm, which extension, at its free end, carries said holder and is provided with slots to form said resilient arms.
8. A valve according to one of claims 5 to 7, wherein said head has sloping faces at its end remote from the diaphragm and/or said holder has sloping faces on its side close to the diaphragm in order to facilitate the snap-fit action.
9. A valve according to claim 8, wherein said spring plate is connected to the tubular extension by way of a conical wall tapering towards the diaphragm, and the slots extend right into the conical wall.
10. A valve according to one of claims 1 to 9, wherein said pin passes through a sealing housing secured to said diaphragm housing and provided on its periphery with profilings and an annular base of said setting device is arranged to be pushed onto said sealing housing and to be secured to it by means of at least one screw engaging behind the profilings.
11. A valve according to one of claims 1 to 10, wherein said supporting plate is held so that it cannot rotate and has an external thread which engages with an internal thread of a rotary knob concentrically surrounding the set-point spring, and the rotary knob is held so that it is able to rotate yet is axially fixed on a base of said setting device.
12. A valve according to one of claims 1 to 11, wherein an index ring, which engages by means of at least one radial pointer through an axial slot in the rotary knob, is located rotatably on said supporting plate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4131708A DE4131708C1 (en) | 1991-09-24 | 1991-09-24 | Valve controlled by differential pressure - has loading controlled by helical compression spring fitted in easily removable unit. |
| DEP4131708.4 | 1991-09-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2077280A1 CA2077280A1 (en) | 1993-03-25 |
| CA2077280C true CA2077280C (en) | 1998-05-19 |
Family
ID=6441326
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002077280A Expired - Fee Related CA2077280C (en) | 1991-09-24 | 1992-09-01 | Valve controlled in dependence on differential pressure with desired-value setting facility |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA2077280C (en) |
| DE (1) | DE4131708C1 (en) |
| DK (1) | DK174166B1 (en) |
| PL (1) | PL169644B1 (en) |
| RU (1) | RU2090794C1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10256021B4 (en) * | 2002-11-30 | 2010-02-04 | Danfoss A/S | Heat exchanger valve arrangement, in particular radiator valve arrangement |
| CN100410601C (en) * | 2002-12-05 | 2008-08-13 | 周纪昌 | Air conditioner pressure regulating unloading valve |
| DE102014119387B4 (en) | 2014-12-22 | 2017-03-16 | Samson Ag | Membrane drive for a control valve |
| DK178871B1 (en) * | 2015-11-05 | 2017-04-10 | Danfoss As | Valve with detachable regulation unit |
| EP3193056A1 (en) * | 2016-01-15 | 2017-07-19 | Danfoss A/S | Valve arrangement |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3235274C2 (en) * | 1982-09-23 | 1986-07-31 | Samson Ag, 6000 Frankfurt | Safety device for control devices, such as pressure reducers |
-
1991
- 1991-09-24 DE DE4131708A patent/DE4131708C1/en not_active Expired - Lifetime
-
1992
- 1992-09-01 CA CA002077280A patent/CA2077280C/en not_active Expired - Fee Related
- 1992-09-23 RU SU925052693A patent/RU2090794C1/en active
- 1992-09-24 PL PL92296033A patent/PL169644B1/en unknown
- 1992-09-24 DK DK199201183A patent/DK174166B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DK174166B1 (en) | 2002-08-05 |
| DK118392A (en) | 1993-03-25 |
| PL169644B1 (en) | 1996-08-30 |
| CA2077280A1 (en) | 1993-03-25 |
| DE4131708C1 (en) | 1993-04-29 |
| DK118392D0 (en) | 1992-09-24 |
| PL296033A1 (en) | 1993-05-17 |
| RU2090794C1 (en) | 1997-09-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |