JPS6039522Y2 - pressure transmitter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure transmitter, and more particularly to a pressure transmitter in which a center plate is provided in the center of a pressure receiving diaphragm.

The pressure receiving part of a conventional pressure or differential pressure transmitter consists of a single pressure receiving diaphragm with a center plate, and the pressure receiving diaphragm receives input from pressure or differential pressure and feedback force applied to the pressure receiving diaphragm via a rod. pressure is applied.

It is preferable to maintain the input point where the input is applied and the reaction force point where the reaction force is applied at the same point, but in reality this is difficult due to mechanical errors and they differ to some extent.

As a result, a moment is generated to rotate the pressure receiving diaphragm, which causes abnormal deformation and unstable characteristics of the pressure receiving diaphragm, resulting in deterioration of the accuracy of the pressure or differential pressure transmitter.

Fig. 1 is a configuration diagram showing a conventional example of a non-liquid ring type pneumatic differential pressure transmitter, where 200 is the transmitter body, and the low pressure is the low pressure inlet 5.
1, the high pressure is introduced from the high pressure inlet 52, respectively.

The introduced pressure difference between the high pressure and the low pressure acts on the pressure receiving diaphragm 11 having the center plate 53 to generate a force Fi.

Due to the force Fi, the pressure receiving diaphragm is displaced to the low pressure side,
The displacement is transmitted to the connecting plate 12 connected to the center plate 53.

The connecting plate 12 is connected to one end of the lower rod 13, and the other end of the lower rod 13 is connected to the upper rod 1 through a seal diaphragm 14 that seals the high pressure chamber 53 from the outside air.
It is connected to one end of 5.

The other end of the upper rod 15 is connected to one end of a range rod 16 by a guide plate 31, a restoring bellows 18 is connected to the other end of the range rod 16, and a movable range nut 17 is installed in the middle. The range rod 16 is configured to move using the range nut 17 as a fulcrum.

On the other hand, a flapper operating rod 19 is attached to the guide plate 31 for moving a flapper 20 having a spring action, which has one end fixed to a part of the main body 200 and the other end facing the nozzle 21 fixed to the main body 200.

Therefore, when the center plate 53 and the connecting plate 12 move to the right, the lower rod 13 and the upper rod 15 move toward the seal diaphragm 1.
The flapper operating rod 1 rotates counterclockwise using 4 as a fulcrum.
9 moves the flapper 20 toward the nozzle 21 side.

Therefore, the distance between the flapper 20 and the nozzle 21 becomes narrower, and the nozzle back pressure increases. This is amplified by the pilot valve 22, and the outlet pressure EPO becomes an output signal and is applied to the restoring bellows 21 to create a pressure is converted into force and acts as a feedback force to rotate the range rod 16 clockwise around the range nut 17, and the force Fi generated by the measured differential pressure and the feedback force Fi due to the output pressure Po are When balanced, the range rod 16 comes to rest.

Since the output Po at this time is proportional to the measured differential pressure, the differential pressure can be measured.

FIG. 2 is an enlarged view of the pressure receiving part consisting of the pressure receiving diaphragm 11 and the center plate 53 in FIG.
1, a force Fi acts on the center plate 53 to displace the center plate 53 to the right, and a force Fi acts on the center plate 53 to try to pull back the center plate 53 due to the output pressure Po.

There is no problem if the input point where the force Fi acts and the reaction force point where the force Ff acts coincide on the center plate 53, but generally they often do not coincide due to machine manufacturing errors, resulting in a deviation δ1.

This deviation δ1 generates a moment Mi that tends to rotate the center plate 53, in other words, the pressure receiving diaphragm 11, which causes abnormal deformation of the pressure receiving diaphragm 11, causing deterioration of accuracy and instability of characteristics.

Therefore, there is a drawback that a highly accurate and reliable non-liquid ring type differential pressure transmitter cannot be provided.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a highly accurate and reliable pressure or differential pressure transmitter.

For this reason, the present invention provides a pressure transmitter main body, a pressure receiving diaphragm provided on the pressure transmitter main body, a center plate provided at the center of the pressure receiving diaphragm, a rod having a sealing mechanism connected to the center plate, and the above-mentioned. A device comprising a means for extracting a signal according to displacement of a pressure receiving diaphragm, wherein a support diaphragm having a first communicating hole in the center is provided substantially parallel to the pressure receiving diaphragm, and a connection connecting the support diaphragm and the center plate. A member is provided, and the connecting member is provided with a second communication hole that communicates the space formed by the pressure receiving diaphragm and the support diaphragm with the first communication hole.

The present invention will be described in detail below with reference to embodiments.

FIG. 3 shows the components of an embodiment of the non-liquid sealed pneumatic differential pressure transmitter according to the present invention, and FIG. 4 shows the components of the pressure receiving section, which is the main point of the present invention.

Figure 3 shows the pressure receiving diaphragm 111 and the support diaphragm 1.
12, the center plate 53, and the connecting member 301, the configuration is exactly the same as in FIG. 1, so only the pressure receiving section will be described.

Support diaphragm 112 with central communication hole 116
It is sufficient that L (L>0, 1720 or more of the diameter of a normal diaphragm is larger than the pressure receiving diaphragm 111).

) are mounted parallel to the distance.

Further, the center plate 53 and the support diaphragm 112 are connected by a connecting member 301 having a communication hole 113, and the space 114 formed by the pressure receiving diaphragm 111 and the support diaphragm 112 is connected to the communication hole 113.
It communicates with the low pressure inlet 51 via.

Therefore, the second moment of inertia of the pressure receiving portion made up of the pressure receiving diaphragm 111, the support diaphragm 112, the center plate 53, and the connecting member 301 is increased.

Therefore, differential pressure acts on the pressure receiving diaphragm 111,
The input point at which force Fi acts to displace center plate 53 to the right side and the reaction force point at which force Ff acts to pull back center plate 53 due to output pressure Po do not coincide on center plate 53, resulting in a deviation δ1. Even if a moment Mi is generated that tries to rotate the center plate 53, in other words, the pressure receiving diaphragm 111, the center plate 53 is also connected to the support diaphragm via the connecting member 301, so that the center plate 53 Rotation can be prevented.

Therefore, abnormal deformation of the pressure receiving diaphragm 111 does not occur, and instability of characteristics does not occur.

In other words, a highly accurate and reliable non-liquid ring type differential pressure transmitter can be provided.

As described above, the present invention merely provides a support diaphragm connected to the pressure receiving diaphragm via a connecting member, so that rotation of the center plate can be prevented without causing a large increase in mass of the movable system centered on the pressure receiving diaphragm. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a conventional non-liquid ring pneumatic differential pressure transmitter, Fig. 2 is an enlarged view of the pressure receiving part in Fig. 1, and Fig. 3 is a non-liquid ring type showing an embodiment of the present invention. FIG. 4 is an enlarged view of the pressure receiving section of FIG. 3 showing the main points of the present invention. 12... Connection plate, 13... Lower rod, 14... Seal diaphragm, 15...
... Upper rod, 53 ... Center plate, 111 ...
...Pressure diaphragm, 112... Support diaphragm, 113, 116... Communication hole, 20
1... Transmitter body, 301... Connection member.

Claims (1)

[Scope of utility model registration request] A pressure transmitter main body, a pressure receiving diaphragm provided in the pressure transmitter main body, a center plate provided at the center of the pressure receiving diaphragm, a rod having a sealing mechanism connected to the center plate, and a pressure receiving diaphragm provided in the pressure transmitter main body, a rod having a sealing mechanism connected to the center plate, and a pressure receiving diaphragm provided in the pressure transmitter main body. A support diaphragm having a first communication hole in the center is provided substantially parallel to the pressure receiving diaphragm, and a connecting member is provided to connect the support diaphragm and the center plate. A pressure transmitter, characterized in that the member is provided with a second communication hole that communicates the space formed by the pressure receiving diaphragm and the support diaphragm with the first communication hole.