CN209370577U

CN209370577U - Process valve with sensor function

Info

Publication number: CN209370577U
Application number: CN201821775396.7U
Authority: CN
Inventors: S·科尔本施拉格
Original assignee: Samson AG
Current assignee: Samson AG
Priority date: 2017-10-30
Filing date: 2018-10-30
Publication date: 2019-09-10
Anticipated expiration: 2028-10-30
Also published as: DE102017125459B4; DE102017125459A1

Abstract

The utility model relates to a kind of process valves with sensor function, wherein throttling body elasticity is connected to valve rod.It is additionally provided with the transmission lever for being rigidly connected to throttling body and equipped with the sender unit in transmission lever and the sensor on valve rod (130).Sensor coordinates the relative displacement in sender unit with quantitative measurment transmission lever relative to valve rod (130).The process valve being designed in this way, which allows to accommodate in pressure chamber to act in the pressure of throttling body and the protected field outside valve chest, measures caused stroke.Temperature sensitive, pressure-sensitive and vibration sensing part such as precise sensors or analysis electronic device are protected.Due to directly measuring the power on throttling body, therefore avoids measurement and be distorted because of friction.It even can determine that the power as caused by sealing is lost.

Description

Process valve with sensor function

Technical Field

The utility model relates to a process valve with sensor function. It allows determining the force acting on the valve throttle body. Process valves are used in the process industry. They are used in particular for throttling of fluid flows.

Knowing the force acting on the valve throttle body of a process valve is desirable for many purposes: the flow rate can thus be determined without additional complex technology when the valve is open. Furthermore, if it is determined that the force exerted by the valve drive mechanism (or drive pressure in the case of a pneumatic or hydraulic drive mechanism) is known, the loss caused by the drive mechanism itself or the seal can be determined. The course of the loss change over a longer period of time is of interest, since the state of the valve or of the seal can be derived therefrom.

Background

It is known to the person skilled in the art, for example, to determine the force acting on the throttle body in a process valve by means of a force transmitter between the drive rod and the valve stem. It is disadvantageous here that the friction of the seal between the valve spindle and the valve housing is transferred into the force measurement. Therefore, the friction force cannot be independently determined. The measurement system directly on the throttle body also encounters the working fluid and must endure high temperatures and severe wear.

It is also known to determine the force applied by a valve drive mechanism. However, the friction losses also distort the result in this case. In particular, the loss cannot be determined in a simple manner. If the drive mechanism is pneumatic, this method has the additional disadvantage that a possibly rapid pressure peak cannot be detected because of the compressibility of the air.

A device for measuring the force acting on a valve stem is disclosed in EP3049702a 1. It is mounted between the valve stem and the drive mechanism. The friction losses cannot be taken into account in a simple manner in this device either.

Publication DE102010036711a1 shows a similar force measuring device. But it is mounted between the valve stem and the throttle body. It is particularly disadvantageous in this arrangement that the most sensitive parts are located in the valve housing, where they are subjected to high thermal loads, for example.

In the publication DE19601023a1, a valve is disclosed, which has a hollow piston. At the end of the hollow interior of the piston remote from the bung, there is a piezoelectric pressure sensor that can measure the fluid pressure as it increases within the piston. Such a valve structure is for example not suitable for aggressive fluids or for fluids with high or low temperatures. Since a complete valve seal is difficult and furthermore the sensor is unprotected and in direct contact with the fluid.

EP3084381a1 discloses a solid "sensor body", which is provided centrally on its side facing the fluid with an area in which an electromechanical transducer for pressure measurement is located behind the membrane. The sensor body can be clamped for mounting in its outer region. Are not specified for use in process valves as chokes.

A safety valve triggered by a bending pin is disclosed in US6,155,284. It has a pressure measuring piston in the closure part, which is connected by means of a rod to a bending pin, which triggers and releases the closure part, i.e. the valve opens, when a predetermined pressure is exceeded. This seems to be an irreversible process. I.e. such a mechanism is not meaningful within a process valve. Furthermore, no narrowly defined measurement is specified, but merely a determination is made that a predetermined threshold value is exceeded.

SUMMERY OF THE UTILITY MODEL

The object of the invention is to provide a device and a method which allow the determination of the force acting on a throttle body of a process valve, while avoiding or minimizing the disadvantages of the prior art.

The use of the singular should not exclude the plural and vice-versa unless otherwise indicated.

A process valve is proposed, which has a valve housing, a valve seat, a throttle body, a valve spindle and a drive unit acting on the valve spindle. The drive unit presses the throttle body into the valve seat by means of the valve rod to close the process valve and pulls it out of the valve seat to open the process valve. According to the utility model discloses, throttle body elastic connection is to the valve rod. A transmission rod is rigidly connected to the throttle body, and a signal transmitter is provided on the transmission rod and a sensor is provided on the valve stem. The transfer rod is preferably arranged parallel to the valve stem. The sensor is coordinated with the signal transmitter to quantitatively measure the relative displacement of the transfer rod with respect to the valve stem.

The connection of the throttle body to the valve rod is designed such that it always remains in the elastic region. In this way it is ensured that the relative displacement to be measured of the transmission rod relative to the valve stem is proportional to the force acting on the throttle body (or the connection of the throttle body to the valve stem). For this purpose, it can also be approximately proportional to the pressure difference below and above the throttle body. As the connecting mechanism between the throttle body and the valve stem, any deformable body may be employed as long as it is elastically deformed as specified.

A process valve designed in this way allows the pressure acting on the throttle body to be accommodated in the pressure chamber and the resulting stroke to be tapped off in a protected region outside the valve housing. Temperature-sensitive, pressure-sensitive and vibration-sensitive components such as precision sensors or analytical electronics are therefore protected against the adverse effects of the fluid medium. Since the force is measured directly on the throttle body, measurement distortions due to e.g. friction at the sleeve or other sealing means are avoided and even the force losses due to such a seal can be determined.

It is particularly advantageous if the valve stem of the process valve is hollow and the transmission rod is arranged in the hollow valve stem. The measuring device is thus protected on the one hand and on the other hand allows the force loss occurring at the seal of the through-passage of the valve spindle through the valve housing to be determined, since said force loss acts on the valve spindle but not on the transmission rod.

Since the connection between the valve spindle and the throttle body has a sealed interior space with respect to the medium whose flow can be regulated by the process valve, it is achieved in particular that the sensor is protected against potentially aggressive media. This is advantageous for a long service life of the sensor or for the first time allows the use of sensitive sensors.

In an extremely simple and durable embodiment of the process valve, the valve spindle and the throttle body are connected elastically by means of a spring element.

When the spring element is a spring element in the form of a bladder, one obtains a good seal against the medium whose flow can be regulated by the process valve. This has the advantage that the seal is slightly frictional.

The measurement accuracy is increased when at least one guide is provided in the valve spindle, wherein the guide guides the transmission rod in the valve spindle in such a way that the transmission rod is prevented from falling over. The guide is preferably designed in the form of a ball or bead and has extremely low friction.

Furthermore, the measuring accuracy is advantageously influenced when the maximum displacement of the transmission rod relative to the valve spindle is one tenth of the maximum stroke of the valve spindle relative to the valve housing. The maximum displacement of the transmission rod relative to the valve stem is preferably 5 mm, particularly preferably 1 mm, and very particularly preferably 0.2 mm.

It is also advantageous for the measurement accuracy that the sensor operates in a non-contact manner. For example, magnetoresistive sensors, hall sensors, capacitive sensors, inductive sensors or potentiometric sensors can be used. Thereby avoiding losses in the sensor itself.

For the case where the fluid temperature differs from the ambient temperature, the measurement accuracy can be further improved when the process valve has at least one temperature sensor. The influence of the temperature difference on the length of, for example, the valve stem and/or the transfer rod can then be taken into account. The at least one temperature sensor is preferably arranged either in the valve spindle or on the spring element or on or in the throttle body.

Some of the process steps are detailed below. These steps do not necessarily have to be performed in the order illustrated and the proposed method may have other steps not mentioned.

To accomplish this task, a method of measuring lost force in a process valve having a construction as further described above is also proposed, wherein the valve stem is sealed with respect to the valve housing by a sealing means, such as a plug sleeve with a packing. Here, the force of the drive unit acting on the valve stem is predetermined. The following steps are carried out: the spring force acting on the spring connection between the valve spindle and the throttle body is determined by means of a sensor, and the difference between the driving force and the spring force is determined and defined as the loss force.

The loss force is preferably repeatedly measured as described above at predetermined time intervals. The wear of the sealing device can then be inferred from the change in the loss force over time. This allows, for example, to plan maintenance measures and perhaps maintenance intervals in order to always replace the sealing device in good time before a leak occurs.

The absolute position of the throttle body can also be determined from the relative displacement of the transmission rod with respect to the valve stem and the predetermined position of the drive unit acting on the valve stem. This allows a more accurate knowledge of the opening state of the process valve, i.e. the momentary size of the flow-through opening.

Advantageously, the flow through the process valve is determined from the absolute position of the throttle body and the force acting on the elastic connection between the valve spindle and the throttle body. It is sufficient here to use that the force acting on the throttle body is proportional to the fluid pressure acting on it.

Further details and features emerge from the following description of preferred embodiments in conjunction with the dependent claims. In this case, the respective features may be implemented by themselves or in combination with one another. The possible ways of accomplishing the task are not limited to the described embodiments. Thus, for example, a range recital always includes all non-claimed intermediate values and all conceivable subranges.

Drawings

One embodiment is schematically illustrated. Specifically speaking:

fig. 1 shows a schematic cross-sectional view of a process valve of the present invention.

Reference numerals

100 process valves;

105 a valve housing;

110 on the inflow side;

115 a drainage side;

120 a throttle body;

125 a valve seat;

130 a valve stem;

135 engaging grooves;

140 a plug sleeve;

145 bladder spring member;

150 a transfer rod;

155 a signal transmitter;

160 a sensor;

165 guide member.

Detailed Description

Fig. 1 shows a process valve 100 having a valve housing 105 according to the present invention. Between the inlet side 110 and the outlet side 115, there is a throttle body 120 that is forced into a valve seat 125 to throttle the fluid flow. For this purpose, a valve stem 130 is used, on the upper end of which there can be an engagement groove 135, which makes it possible to connect any usual valve drive mechanism (e.g. pneumatic, electric or hydraulic). The valve stem is sealed through the valve housing by a sleeve 140. Alternatively, other types of sealing means are possible.

The valve rod 130 is connected to the throttle body 120 by an elastic element, preferably a spring element, particularly preferably a spring element 145 in the form of a bladder. The connection is designed to be sealed, even preferably airtight. The tightness can be obtained, for example, by welding the capsule together with the valve stem and the throttle body.

The valve stem 130 is preferably hollow. Preferably, there is a transfer rod 150 rigidly connected to the throttle body 120 in its interior. A signal transmitter 155 is mounted on the transfer bar 150, typically at or near its upper end. Here, it may be, for example, a metal tooth structure or a permanent magnet. A sensor 160 is associated with the signal transmitter 155, which sensor can be mounted immovably on the valve rod 130 in the corresponding position. That is, the sensor allows for accurate, preferably non-contact, measurement of the displacement of the transfer rod 150 (and thus the throttle body 120) relative to the valve stem 130. Such displacement is proportional to the force acting on the throttle body 120 due to the resilient connection.

At least one guide 165 is generally mounted on the transfer rod 150 in an upper region to prevent the transfer rod 150 from tipping relative to the valve stem 130. The component is designed in particular to be low in friction. It may be, for example, a spherical or bead-shaped thickening of the transfer rod 150, which is coated with, for example, PTFE (teflon), POM or PEEK, or it may be a bronze or brass sleeve with a graphite coating (the latter being used in particular for high-temperature applications).

The bellows spring element 145 has a defined spring stiffness and is designed such that it always operates in the elastic range. Thus, a relative movement occurs between the throttle body 120 and the valve stem 130, which is directly proportional to the pressure on the throttle body 120 by the spring stiffness of the sac spring member 145. This relative movement is transmitted outwardly within the valve stem 130, i.e., out of the valve housing 105, by the transmission rod 150. To this end, the transfer rod 150 is fixedly connected at its lower end to the throttle body 120. At the upper end of the transfer rod 150 is a sensor transmitter 155. The corresponding sensor chip 160 is rigidly connected to the valve stem 130 so that it can measure relative movement in a non-contact manner.

The guide 165 on the transfer rod 150 in the region between the capsule and the sender magnet 155 eliminates radial movement of the sender 155 and thus helps minimize hysteresis. The guide 165 is preferably spherical or bead-shaped and designed for extremely low friction.

The capsule seal is at the same time a spring element for force measurement. In this way, friction of the seal can be eliminated. The spring travel of the bladder is designed for maximum throttling force. The travel of the bladder is typically a maximum of 5 mm. The approximately frictionless measuring system combines the advantages of, on the one hand, the direct application of the throttling forces in the highly loaded pressure chambers and, on the other hand, the measurement of the stroke outside the valve housing 105 in a considerably protected region.

The bellows-type spring element 145 can be replaced by any deformable body which permits an air-tight connection between the throttle body 120 and the valve spindle 130, which encloses the transmission rod 150 and can be elastically deformed in a defined manner under a force in the longitudinal direction. It should be possible to inhibit radial deflection and tilting of the throttle body 120 and to allow axial deformation by a corresponding design.

The sensor magnet or sensor transmitter 155 may be used simultaneously for stroke measurement on the valve stem 130. In this case, a second sensor chip (not shown) is used, which measures the movement of the sensor means 155 relative to the valve housing 105.

To measure the relative movement between the throttle body 120 or the transfer rod 120 and the valve stem 130, a magnetoresistive position sensor, a Hall-type position sensor, a capacitive position sensor, an inductive position sensor, a potentiometric position sensor, or any other known type of position sensor may be used. Non-contact operating sensors are preferred.

The temperature drop between the valve seat 125 and the sensor chip 160 can be measured and taken into account for temperature error compensation measures by one or more temperature sensing devices (e.g., PT100, not shown).

If one combines the travel measurement of the throttle body 120 with the measurement of the travel of the valve stem 130 relative to the valve housing 105 as is common in conventional valve positioners, one obtains an accurate position of the throttle body 120. In this way, it is possible to accurately determine whether the throttle body 120 is seated on the valve seat 125 of the valve 100 and what force the throttle body 120 in the closed position experiences. The lost force between the drive mechanism and the throttle body 120 can be determined by comparison with the driving force. For each of the other throttle body positions, the efficiency of the adjustment force may also be determined. The efficiency is primarily determined by the penetration of the stem through the seal 140. The efficiency may be considered for fault diagnosis purposes. The course of the efficiency over time indicates wear of the seal 140 seal. One of the causes may also be incrustation of the valve due to deposits, for example, when the deposits interfere with the valve stem 130 and/or the throttle body 120.

Glossary

Bag type spring element

Here, it is a preferred one-piece combination of spring element and sealing element.

Throttle body

This component is also often referred to as a valve cone because it is generally designed to be conical. The throttle body is used in the process valve to adjust the size of the flow opening. For closing, the throttle body is generally pressed into the valve seat by the drive mechanism by means of a valve spindle and is withdrawn from the valve seat for opening. By forming the conical shape precisely, it is possible to obtain different flow cross sections with different positioning by means of the drive.

Process valve

Process valves, also known as regulator or control valves, are used to throttle or control fluid flow. For this purpose, the throttle body is moved in the flow opening of the valve seat by means of a drive mechanism. Thereby, the size of the through-flow opening can be changed, whereby the through-flow is changed until the through-flow opening is closed. Generally, a pneumatic drive or an electric drive is used for this purpose.

Valve housing

It means the valve part which, together with the valve seat and the throttle body, encloses the flow-through opening. The valve seat generally surrounds the flow opening of the valve.

Valve seat

In a process valve, the valve seat forms a counterpart of the throttle body and is adapted to the throttle body with respect to its shape. This achieves that, on the one hand, the valve is tightly closed and, on the other hand, it has the desired relationship of the flow cross section and the positioning of the throttle body. Typically, the valve seat and the throttle body can be replaced together to achieve different flow characteristics of the valve.

Valve rod

The valve stem is a common connection between the throttle body of the valve and the drive mechanism. It is generally designed to be rigid, but may also have flexible elements.

Citation of documents, citation of patent documents: EP3049702a 1; DE102010036711a 1; DE19601023a 1; EP3084381a 1; US6,155,284.

Claims

1. A process valve (100) having a valve housing (105), a valve seat (125), a throttle body (120), a valve stem (130) and a drive unit acting on the valve stem, characterized in that,

wherein the drive unit forces the throttle body (120) into the valve seat (125) with the valve stem (130) to close the process valve (100) and pulls the throttle body out of the valve seat (125) to open the process valve (100);

wherein the throttle body (120) is resiliently connected to the valve stem (130); and is

-a transfer rod (150) is provided, rigidly coupled to the throttle body (120);

a signal transmitter (155) provided on the transfer lever (150); and

a sensor (160) on the valve stem (130); wherein,

the sensor (160) is coordinated with the signal transmitter (155) to quantitatively measure the relative displacement of the transfer rod (150) with respect to the valve stem (130).

2. The process valve (100) of claim 1, wherein the valve stem (130) is hollow and the transfer rod (150) is disposed within the hollow valve stem (130).

3. The process valve (100) according to one of the preceding claims, wherein the connection between the valve stem (130) and the throttle body (120) has an inner chamber which is sealed off from a medium, the flow of which can be regulated by the process valve (100).

4. The process valve (100) of claim 1, wherein the valve stem (130) and the throttle body (120) are resiliently coupled by a spring member.

5. The process valve (100) of claim 4, wherein the spring member is a bladder spring member (145).

6. The process valve (100) of claim 2,

at least one guide (165) is provided,

the guide is arranged in the valve stem (130), wherein,

the guide (165) guides the transfer rod (150) within the valve stem (130) to prevent the transfer rod (150) from tipping.

7. The process valve (100) of claim 1, wherein the maximum displacement of the transfer rod (150) relative to the valve stem (130) is one-tenth of the maximum travel of the valve stem (130) relative to the valve housing (105).

8. The process valve (100) of claim 1, wherein the maximum displacement of the transfer rod (150) relative to the valve stem (130) is 5 millimeters.

9. The process valve (100) of claim 1, wherein the sensor (160) operates in a non-contact manner.

10. The process valve (100) of claim 4, wherein at least one temperature sensor is provided.

11. The process valve (100) of claim 10, wherein the at least one temperature sensor is disposed

Within the valve stem (130), or

On said spring element, or

On or in the throttle body (120).

12. The process valve (100) of claim 8, wherein the maximum displacement of the transfer rod (150) relative to the valve stem (130) is 1 millimeter.

13. The process valve (100) of claim 8, wherein the maximum displacement of the transfer rod (150) relative to the valve stem (130) is 0.2 millimeters.