JPS601394Y2 - pressure transmitter - Google Patents

Description

[Detailed description of the invention] This invention is a pressure transmitter that responds to fluid pressure and generates signals such as electric signals corresponding to the pressure. The present invention relates to a pressure transmitter that has a relatively long distance between the two and is suitable for special situations such as when the fluid to be measured is at a high temperature or contains radioactivity.

When the pressure-receiving element that receives the pressure of the fluid to be measured and the transmitter body that generates signals such as electrical signals corresponding to that pressure are separated, the pressure transmitter was conventionally configured as shown in Figure 1. was.

A fluid to be measured 11 is housed in, for example, a tank 12, a pressure receiving part 13 is fitted into a hole provided in a part of the tank 12, and a pressure receiving element, for example a diaphragm 14, is in contact with the fluid to be measured in the pressure receiving part 13. It is provided.

The pressure receiving part 13 is connected to the transmitter main body 15 by a pressure impulse pipe 16, and the pressure impulse pipe 16 is filled with an incompressible sealed liquid 17.

The diaphragm 14, which is a pressure receiving element, is displaced in response to the pressure of the fluid 11 to be measured, and this is transmitted within the sealed liquid 17 to the pressure receiving diaphragm 18 within the transmitter body 15.

In the transmitter main body 15, the diaphragm 18 is connected to the fluid to be measured 11.
It is displaced according to the pressure of the air, and this is converted into an air signal or an electric signal.

In such a pressure transmitter, when the temperature of the fluid 11 to be measured is high, such as 120° C. or higher, the sealed liquid 17 must also be one for high temperatures.

Otherwise, bubbles will be generated from the filled liquid 17 and the pressure receiving element 1
The pressure received at 4 is not properly transmitted to the pressure receiving element 18 of the transmitter body.

On the other hand, the viscosity of the filling liquid for high temperatures is generally high, and this is comparable to the viscosity of the filling liquid used at room temperature, for example, Honzuke.

Therefore, there is a time delay between the pressure change in the pressure receiving element 14 and the pressure change received by the pressure receiving element 18 of the transmitter body on the waist.

In other words, the time constant of pressure transmission becomes large, especially in the impulse pipe 16.
If the length of is long, the response will be delayed considerably, which is undesirable.

From this point of view, in the past, for example, a space is formed within the wall 19 of the containment vessel in which the tank 12 is stored, and the space is divided into two rooms by the pressure transmitting element 21, and one of the rooms 22 and 22 are connected to each other. The element 14 is connected to the element 14 by a pressure impulse pipe 16, and the inside thereof is filled with a sealing liquid 17.

Further, a pressure guiding pipe 24 is connected between the other chamber 23 separated by the pressure transmitting element 21 and the pressure receiving element 18 of the transmitter main body, and the inside thereof is filled with a sealed liquid 25.

The sealed liquid 25 has low fluid viscosity and can easily transmit pressure.

Therefore, even if the length of the impulse pipe 24 is relatively long, the transmission element 2
The pressure displacement experienced by the pressure element 1 is relatively quickly transmitted to the pressure receiving element 18.

If the sliding is arranged in this manner, the temperature of the liquid to be measured 11 is high and a liquid with high viscosity can be used as the sealed liquid 17.

For example, when the measured fluid 11 is high temperature, contains radioactivity, and is dangerous, such as temporary cooling water in nuclear power generation, the container 19 serves as a barrier to block radioactivity. Therefore, the transmitter main body 15 cannot be provided inside the container 19, that is, on the tank 12 side.

According to the structure shown in FIG. 2, the distance between the pressure receiving element 14 and the transmitter body 15 can be made considerably long.

However, in such a structure, if either the pressure receiving element 14 or the transmitter main body 15 breaks down, the entire structure becomes unusable.

Therefore, in order to ensure safety, it is necessary to have a pressure transmitter identical to this pressure transmitter as a spare, which increases costs.

The purpose of this invention is to allow a relatively long distance between the pressure receiving element and the transmitter body, and also to be able to measure, for example, the pressure of a high-temperature fluid to be measured without a large delay. It is an object of the present invention to provide a pressure transmitter in which countermeasures against failure of one of the transmitter bodies can be constructed at relatively low cost.

According to this invention, the pressure of the pressure receiving element is transmitted to the first pressure transmitting element by the sealed liquid in the pressure conduit, and the second transmitting element is detachably attached to the first pressure transmitting element. An incompressible liquid is sealed between the second pressure transmitting elements, and the second pressure transmitting element and the transmitter main body are connected by a pressure conduit, and the incompressible sealed liquid is placed inside the second pressure transmitting element and the transmitter main body.

In this way, if the pressure transmitter main body breaks down, the second
The pressure transmitting element can be easily removed and another pressure transmitter body can be attached.

In addition, if the pressure receiving element, the first pressure transmitting element, the impulse pipe connecting these elements, and their sealed liquid are prepared in advance as a spare, it is possible to connect the transmitter body to the spare first pressure transmitting element in the event of a failure of the pressure receiving element. do it.

For example, in FIG. 3, parts corresponding to those in FIG.

That is, the open surface of a cup-shaped holder 27, which has a short cylindrical shaft with one end closed, is closed with a diaphragm 21 as a pressure transmitting element, and this holder 27 is buried in the concrete wall constituting the container 19. inserted and screwed down as necessary.

The pressure pipe 16 is connected to the inside of the holder 27 through a hole made in the container 19 .

A filling liquid 17 is sealed inside this.

A pressure transmission element 28 is detachably attached to the pressure transmission element 21 .

In the figure, like the pressure transmitting element 21, the open side of a cylindrical holding body 29 whose short end of the shaft is closed is closed with a diaphragm 28 as a pressure transmitting element.

A flange portion of the pressure holding body 29 is brought into contact with a flange portion of the holding body 27 and is tightened with, for example, a screw 31.

An incompressible liquid 32 is filled between the pressure transmitting elements 21,28.

In order to fill this sealed liquid 32, the pressure receiving elements 21, 28 are slightly retracted from the flange facing surface of the holder 27, 29, and the sealed liquid 32 is filled between these pressure receiving elements.

For its filling, small holes 33.34 are drilled in the holding body 29, through which the outside is connected to the space between the pressure transmitting elements 21.28.

One of these small holes is used as an inlet for incompressible liquid, and the other is used as an exhaust hole for air that has been inside.

After filling the filling liquid 32, these small holes 33, 34 are closed.

For example, an O-ring 35 is used to maintain airtightness of the contact surfaces of the holders 27 and 29.

A pressure guiding pipe 24 is connected between the pressure transmitting element 28 and the pressure receiving element 18 of the transmitter body 15.

That is, a hole is made in the closing plate of the holder 29 that holds the pressure transmitting element 28, and one end of the pressure guiding pipe 24 is connected to the hole.

The pressure conduit 24 is filled with a sealed liquid 25 . In this case, the filling liquid 25 used is, for example, one with relatively low viscosity.

As a backup, a pressure receiving element 14a in contact with the pressure of the fluid to be measured is provided in the tank 12 as a holder 13, and a pressure transmitting element 21a is provided in the container 19 on the same side as the pressure transmitting element 21 and relatively close thereto. It is provided.

A blind flange 37 is screwed onto the holder 27a using, for example, screws 31a to cover the holder 27a.

The pressure transmitting element 21a and the pressure receiving element 14a are the pressure guiding pipe 16a.
The impulse pipe 16a is filled with an incompressible liquid 17a.

Because of this configuration, for example, when the fluid to be measured 11 is at a high temperature, such as the primary cooling water of a nuclear power plant, the filled liquid 17 is made of a fluid with relatively high viscosity that can withstand high temperatures.

However, the length within this impulse tube 16 can be shortened.

If the length of the impulse tube 24 is increased and a liquid with low viscosity is used as the sealed liquid 25, the measured fluid 1
A pressure transmitter having a relatively fast response speed to one pressure change is obtained.

In addition, when the primary cooling water mentioned above contains radioactivity, the pressure transmission element 21.2 also blocks the radioactivity.
This can be sufficiently achieved by forming 8 into a double structure.

Further, for example, if the transmitter body 15 fails, the pressure transmitting element 2
8 from the pressure transmitting element 21, and attaching another normal transmitter main body and the other pressure transmitting element to the pressure transmitting element 21 with a pressure guiding pipe.

If the pressure receiving element 14 is out of order, the pressure transmitting element 21a
The blind flange 37 may be removed, and the pressure transmitting element 2B that has been operating well up to that point may be removed and connected to the pressure transmitting element 21a side.

Therefore, it is not necessary to configure the transmitter main body, the pressure transmitting element, and the pressure receiving element all as a pressure transmitter as a backup.

When one part of the current system fails, the other parts can be used.

Incidentally, an incompressible liquid 38 may be filled between the pressure transmitting element 21a on the side used as a reserve and the flange 37 to prevent the pressure transmitting element 21a from being damaged.

In addition, the third method is used not only when the fluid to be measured is at a high temperature, but also when used as a shield in cases where it contains radioactivity, as mentioned above, in order to shut it off in dangerous cases.
The structure shown in the figure can be used, in which case the filled liquid 1
There is no need to use one for high temperature as 7.

These filling liquids are selected depending on the purpose of use.

For the pressure receiving element, the pressure transmitting element, etc., not only a diaphragm but also other elements such as a bellows can be used.

Further, the transmitter main body 15 can be configured to detect various pressures such as so-called gauge pressure based on atmospheric pressure, absolute pressure based on vacuum, or differential pressure with other pressures.

As mentioned above, the construction of the pressure transmitter according to this invention is relatively simple, and it is possible to use the conventional pressure-receiving element as the transmitter body, for example, with the structure shown in Figure 1. In other words, what is shown in FIG. 1 can be detachably attached to the pressure transmitting element 21 in FIG. You can design it accordingly.

Furthermore, the transmitter main body can be replaced, and the one provided as a spare has a simple structure, and the construction thereof is also easy, and the overall cost can be reduced.

[Brief explanation of the drawing]

Figure 1 is a route diagram showing a conventional pressure transmitter with a diaphragm, Figure 2 is a route diagram showing a conventional pressure transmitter in which pressure transmitting elements are relayed, and Figure 3 is an example of a pressure transmitter based on this invention. FIG. 11: Fluid to be measured, 14: Pressure receiving element, 16: Impulse tube, 15°25°32: Incompressible sealed liquid, 1°21a. 28: Pressure transmission element.

Claims (1)

[Scope of utility model registration request] a pressure receiving element that contacts a fluid to be measured and responds to its pressure; a first pressure transmitting element that responds to liquid pressure; a first pressure guiding pipe connected between the first pressure transmitting element and the pressure receiving element; an incompressible first sealed liquid filled inside the first pressure impulse pipe; a second pressure transmitting element that is detachably attached to the first pressure transmitting element and responsive to liquid pressure;
an incompressible second sealed liquid interposed between the pressure transmitting element and the second pressure transmitting element to transmit the pressure receiving state of the first pressure transmitting element to the second pressure transmitting element; a small hole for communicating between the two pressure transmitting elements and the outside and for allowing the second sealed liquid to flow in; and an electric signal in response to pressure;
A pressure transmitter body that generates a signal such as an air signal, a second impulse pipe connecting the pressure receiving side of the pressure transmitter body and the second pressure transmitting element, and a non-compressible compressor filled in the second impulse pipe. a preliminary pressure receiving element that is provided near the pressure receiving element and responds to the pressure in contact with the fluid to be measured; and a preliminary pressure receiving element that is provided near the first pressure transmitting element and responds to the liquid pressure. A first pressure transmitting element for backup that responds, a pressure impulse pipe continuous between the first pressure transmission element for backup and the first pressure receiving element for backup, and an incompressible sealed liquid filled inside the pressure impulse pipe. and a blind flange removably attached to cover the surface of the first reserve pressure transmission element opposite to the impulse pipe, and the blind flange and the first reserve pressure transmitting element.
an incompressible liquid sealed between the pressure transmitting element and the second pressure transmitting element, the second pressure transmitting element is removed from the first pressure transmitting element, and the spare first pressure transmitting element is replaced in place of the blind flange. A pressure transmitter that is configured so that it can be installed on.