JPS6213613B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure transmitter with a displacement device, and in particular, provides a calibration means that can calibrate the zero point and measured pressure and detect abnormalities in the diaphragm while the pressure transmitter is installed in a plant. This invention relates to a pressure transmitter equipped with a displacement device.

Pressure transmitters, differential pressure transmitters, etc. for liquid metal sodium used as coolant in fast breeder reactors are
Once installed in a plant, removal is extremely difficult. In the pressure transmitter equipped with a displacement device, which is the object of the present invention, the displacement device is also used as the primary pressure transmission medium.
In order to encapsulate NaK, the pressure transmitter must be welded to the plant. During periodic inspections, the pressure transmitter is disconnected and removed from the plant, and after completing prescribed tests such as zero point and measurement pressure calibration, it is reinstalled by welding. It required a lot of effort.

The object of the present invention is to solve the above-mentioned difficulties and provide a pressure transmitter with a displacement device that can calibrate the zero point and measured pressure and check the diaphragm while being installed in the plant. In the present invention, a calibration means is provided in the middle of the secondary pressure transmission medium pipeline that transmits the measured pressure to the pressure transmitter through the displacement part, and the plant pressure is measured, zero point calibration is performed, and the measured pressure is adjusted by operating the valve. The intended purpose was achieved by switching between calibration and diaphragm checks.

Embodiments of the present invention will be described below with reference to the drawings. The figure is a cross-sectional view showing the configuration of an embodiment of the present invention, in which a pressure receiving diaphragm 3 is provided in a pressure receiving part 1 horizontally with the inner bottom of a pressure receiving port 2 provided laterally, and a pressure receiving chamber 4 and NaK7 are connected to each other. It is separated into a primary pressure transmission medium chamber 5 which is enclosed. The displacement section 8 is separated by a displacement diaphragm 9 into a primary pressure transmission medium chamber 10 and a secondary pressure transmission medium chamber 11 . Opposing surfaces 12 and 13 facing the displacement diaphragm 9 are each formed on a back-up plate in order to prevent excessive displacement of the displacement diaphragm 9. Then, the pressure receiving part 1 and the replacement part 8
Both primary pressure transmission medium chambers 5 and 10 are connected by a pressure guiding pipe 6 and are filled with NaK7.

14 is a pressure transmitter that outputs an electric signal proportional to the introduced pressure, and is connected to the secondary pressure transmission medium chamber 11 of the displacement section 8 through a capillary tube 15, and is connected to a secondary pressure transmission medium such as silicone oil. 16 are included. The pressure receiving section 1, the pressure guiding tube 6, the displacement section 8, and the capillary tube 15 constitute a displacement device.

A first valve 17 is provided in the middle of the capillary tube 15. Further, a pressure conduit 1 branched and connected at an intermediate point between this first valve 17 and the pressure transmitter 14
8 and a second valve 19 on the pipe. 20
1 is a calibration pressure introduction section, which is separated by a diaphragm 21 into a pressure receiving chamber 23 having a pressure receiving port 22 and a secondary pressure transmission medium chamber 24. The diaphragm 21
Opposed surfaces 25 and 26 are respectively formed on the back-up plate to prevent excessive displacement of the diaphragm 21. The secondary pressure transmission medium chamber 24 is connected to a pressure conduit 18 having a second valve 19 in the middle thereof, and is filled with a secondary pressure transmission medium 16 such as silicone oil. The first valve 17, the pressure conduit 18, and the calibration pressure introducing section 20 constitute a calibration means 27.

Next, a description will be given of the plant pressure measurement state of the pressure transmitter with displacement device configured as described above. 1st
The first valve 17 is opened and the second valve 19 is closed. Measurement pressure Pa of high temperature metallic sodium from pressure receiving port 2
is applied, this pressure Pa is applied to the pressure receiving diaphragm 3
and is transmitted to the silicone oil 16 via the displacement diaphragm 9 of the displacement section 8.
And silicone oil 1 in the capillary tube 15
6 to a pressure transmitter 14, which outputs an electrical signal proportional to the pressure Pa.
At this time, the pressure receiving part 1 is heated to several hundred degrees due to the high temperature metal sodium, but the pressure tube 6 and the displacement part 8 dissipate the heat and the temperature drops, and the temperature of the silicone oil 16 in the pressure transmitter 14 is about room temperature. is maintained.

Next, we will explain how to calibrate the device when it is installed in a plant. First, a pressure Pb that is approximately equal to the plant pressure Pa is applied from the pressure receiving port 22 of the calibration pressure introduction part 20.
After adding , the second valve 19 is opened and the first valve 17 is closed. The plant pressure Pa is now shut off.
Therefore, when Pb is set to zero, no pressure is applied to the pressure transmitter 14, and zero point calibration can be performed. With the above operation, the pressure Pb is approximately equal to Pa
The reason why the valve is operated by adding is to prevent silicone oil and NaK from moving and deforming the pressure receiving diaphragm 3, displacement diaphragm 9, and diaphragm 21 of the calibration pressure introduction part due to sudden pressure changes. .

To calibrate the measured pressure Pa of the plant, record the pressure value output from the pressure transmitter 14 when Pa is applied, and then input the pressure connected to the pressure standard from the pressure receiving port 22 of the calibration pressure introduction part 20. In addition, the output pressure value of the pressure transmitter 14 is made equal to the recorded value. Since the pressure indicated by the pressure standard at this time indicates the true measured pressure Pa of the plant, the output of the pressure transmitter 14 can be calibrated by this.

To shift from the above calibration operation to normal plant pressure measurement operation, open the first valve 17 to increase the plant pressure Pa while applying a pressure approximately equal to the plant pressure Pa from the calibration pressure introduction section 20. After applying to the pressure transmitter 14, the second valve 19 is closed;
Thereafter, the pressure applied to the calibration pressure introducing section 20 may be reduced to zero.

Next, a method for checking the diaphragm will be explained. First, the zero point is measured using the zero point calibration method described above. At this time, the first valve 17 is closed, and the second valve 1
9 is in the open state. A pressure several hundred mmH ₂ O higher than the diaphragm check measurement pressure Pa is applied from the pressure receiving port 22 of the calibration pressure introduction part 20, the first valve 17 is opened, and after leaving it for several minutes, the first valve 17 is closed. If the pressure receiving diaphragm 3 and the displacement diaphragm 9 do not have holes, the first valve 17 is closed and the pressure conduit changes due to the deflection of the pressure receiving diaphragm 3 and the displacement diaphragm 9 when diaphragm check pressure is applied. The absolute amount of secondary pressure transmission medium present in 18 and in the capillary tube 15 from the first valve 17 to the pressure transmitter 14 remains unchanged. In other words, the state of the pressure transmitter 14 when the diaphragm check pressure is applied is held as is. Next, reduce the pressure applied from the calibration pressure introduction part to zero and measure the zero point. At this time, the diaphragm of the pressure sensitive element of the pressure transmitter 14 undergoes a displacement in the opposite direction equal to the amount of deflection when the diaphragm check pressure is applied, and returns to the state of zero deflection. Therefore, the zero point after this check operation is equal to the zero point before this operation, indicating that there is no abnormality in the pressure receiving diaphragm 3 and the displacement diaphragm 9. In the above operation, the measured pressure Pa
Applying a pressure several hundred mmH ₂ O higher means a pressure that does not deform the diaphragm. When the pressure receiving diaphragm 3 and displacement diaphragm 9 have holes, the enclosed primary pressure transmission medium (NaK) and secondary pressure transmission medium (silicone oil) migrate through the holes. The absolute amount of secondary pressure transmission medium present in the pressure conduit 18 and in the capillary tube 15 from the first valve 17 to the pressure transmitter 14 will be reduced. And the first
By closing the valve 17, the above state is held. Thereafter, when the diaphragm check pressure is returned to zero, the diaphragm of the pressure sensitive element of the pressure transmitter 14 returns to the negative side beyond the zero deflection state due to the decrease in the absolute amount of the secondary pressure transmission medium. The zero point changes to the negative side. This change in the zero point indicates that an abnormality has occurred in the diaphragm. The transition from the diaphragm check operation to the normal plant pressure measurement operation may be performed in exactly the same manner as the transition from the calibration operation described above.

The valve operations in each of the above calibration and diaphragm check operations are easy and there is no risk of making a mistake.
In the unlikely event that the valve is operated incorrectly, for example, the calibration pressure introduction part 20
Even if the second valve 19 is opened without closing the first valve 17 when the calibration pressure is zero, the displacement diaphragm 9 of the displacement section 8 and the calibration pressure introducing section 2
Each of the diaphragms 22 of 0 has its opposite surface 1
Since excessive displacement is prevented by the backup plates formed at 3 and 25, abnormal deformation of the diaphragm does not occur, and therefore measurement accuracy can be maintained.

As described in detail above, according to the present invention, by providing a pressure transmitter with a displacement device with a calibration means, it is possible to perform calibration and check the diaphragm with simple operations while the pressure transmitter is installed in a plant. Since the normal plant pressure measurement operation can be started immediately, the calibration and diaphragm check operations are facilitated and labor-saving, and the measurement accuracy is improved.

In addition, although the above-mentioned embodiment explained the case where it was applied to a pressure transmitter, it can be implemented in exactly the same way to a differential pressure transmitter.

[Brief explanation of the drawing]

The figure is a sectional view showing the configuration of a pressure transmitter with a displacement device according to an embodiment of the present invention. 1...Pressure receiving part, 3...Pressure receiving diaphragm, 6...
... Impulse tube, 7 ... Primary pressure transmission medium, 8 ... Replacement part, 9 ... Replacement diaphragm, 14 ... Pressure transmitter, 15 ... Capillary tube, 16 ... Secondary pressure transmission medium, 17...first valve, 18...
Pressure conduit, 19...second valve, 20...calibration pressure introduction section, 21...diaphragm, 23...pressure receiving chamber, 24...secondary pressure transmission medium chamber.

Claims (1)

[Scope of Claims] 1. A pressure receiving diaphragm provided in the pressure receiving part and receiving the measured pressure, and a replacement part provided in the replacement part and receiving the measured pressure received by the diaphragm via a pressure impulse pipe in which a primary pressure transmission medium is sealed. diaphragm and
A pressure transmitter receives the measured pressure received by the diaphragm via a capillary tube containing a secondary pressure transmission medium and outputs a signal proportional to the measured pressure. It is branched and there is a second branch on the way.
a pressure conduit having a valve and containing a secondary pressure transmission medium; a calibration pressure introducing section connected to the pressure conduit and separated by a diaphragm into a secondary pressure transmission medium chamber and a pressure receiving chamber; The pressure transmitter is provided at an intermediate position between the replacement part of the pillar tube and the pressure conduit branch point and holds the pressure receiving state of the pressure transmitter when a diaphragm check pressure exceeding the measurement pressure is applied from the calibration pressure introduction part. A pressure transmitter with a displacement device, characterized in that it is equipped with a first valve that performs a function and a calibration means. 2. The pressure transmitter with a displacement device according to claim 1, wherein the opposing surfaces of the displacement diaphragm and the diaphragm of the calibration pressure introduction section are formed in a backup plate.