JP2568173Y2 - Liquid contact structure of pressure / differential pressure transmitter - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure / differential pressure transmitter used for measuring the pressure, flow rate and liquid level of a corrosive fluid.

[0002]

2. Description of the Related Art When measuring the pressure, flow rate, and liquid level of a corrosive fluid, a corrosion-resistant material such as tantalum or titanium is used as a material of a portion in contact with the fluid to be measured. However,
Since it is difficult to weld these materials to a commonly used material such as SUS316, it is necessary to use a corrosion-resistant material for members other than the liquid contact part. Since these corrosion resistant materials are expensive, pressure / differential pressure transmitters with corrosion resistant specifications generally have high costs.

[0003]

In the prior art, since a corrosion-resistant material must be used for members other than the liquid contact part, the cost of the pressure / differential pressure transmitter of the corrosion-resistant specification has been increased. Therefore, the present invention has an object of realizing a structure of a wetted part of a pressure / differential pressure transmitter which can reduce the cost of a corrosion resistant pressure / differential pressure transmitter by minimizing the use of corrosion resistant materials. I do.

[0004]

According to the present invention, the structure of the liquid contact portion of the pressure / differential pressure transmitter is a general specification (the liquid contact portion is made of, for example, SUS316 or the like and has a normal pressure). And a structure having a ring having a corrosion-resistant diaphragm outside the pressure-receiving diaphragm. To remove air bubbles existing between the two diaphragms and bring the two diaphragms into close contact with each other, the two rings are attached to the ring. In this configuration, a communication hole communicating with a gap between the diaphragms is provided, and a valve is attached to the atmosphere side of the communication hole.

[0005]

According to the structure of the pressure / differential pressure transmitter according to the present invention, the corrosive fluid to be measured comes into contact only with the corrosion-resistant material diaphragm. There is no danger of corrosion. In addition, at the time of installation, air bubbles remaining between the corrosion resistant diaphragm and the pressure receiving diaphragm are deaerated using a vacuum pump etc. through the communication hole of the ring, and the valve is closed to create a negative pressure between the two diaphragms. , And a temperature error due to expansion and contraction of the remaining air bubbles due to a change in ambient temperature can be eliminated.
Further, the transmitter body can be used with the general specifications as it is, and the corrosion-resistant material to be used can be minimized, so that the cost is reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIGS. 1 (a) and 1 (b) show a structure of a liquid contact part of a pressure / differential pressure transmitter according to an embodiment of the present invention. This embodiment shows the case of a pressure transmitter with a remote seal diaphragm. The corrosion-resistant diaphragm unit 6 shown in FIG.
Is inserted between the flange mounting pipe 1 and the pressure receiving portion 2 of the transmitter together with the packing 3 and the O-ring 7. As shown in FIG. 1 (b), the corrosion-resistant diaphragm unit 6 includes a corrosion-resistant material diaphragm 9 fixed to a ring 8 at a portion 12 by welding or bonding. The corrosion-resistant material diaphragm 9 includes a transmitter pressure receiving unit. The second pressure receiving diaphragm 4 is formed so as to substantially coincide with the corrugated surface.
Further, when the corrosion resistant diaphragm unit 6 is mounted on the pressure receiving portion 2, a communication hole communicating with a gap between the two diaphragms is formed in the ring 8 in order to remove bubbles existing between the pressure receiving diaphragm 4 and the corrosion resistant diaphragm 9. 10 are provided,
A valve 11 is mounted on the atmosphere side of the communication hole 10. The O-ring 7 is for keeping the space between both diaphragms airtight.

In the liquid-contacting part structure of the pressure / differential pressure transmitter according to one embodiment of the present invention, the corrosive fluid 14 to be measured is in contact with only the corrosion-resistant material diaphragm 9. Therefore, there is no possibility that the pressure receiving portion 2 of the general specification is corroded. At the time of installation, air bubbles remaining between the corrosion-resistant material diaphragm 9 and the pressure receiving diaphragm 4 are degassed by using a vacuum pump or the like through the communication hole 10 of the ring 8, and the valves 11 are closed to close both valves. Can be maintained in a negative pressure state, and the pressure receiving portion 2 is expanded by the expansion and contraction of the remaining air bubbles 13 (see FIG. 2) due to a change in ambient temperature.
, A pressure change occurs, and a temperature error of the transmitter caused by the pressure change can be eliminated.

According to the structure of the wetted part of the pressure / differential pressure transmitter according to one embodiment of the present invention, the anticorrosion diaphragm unit 6 is attached to the pressure receiving part 2 of the pressure transmitter of the general specification, and deaeration is performed. Since the pressure transmitter of the specification can be realized, the following effects can be obtained.

(A) The transmitter main body can be used for general use (standard specification) as it is, and the amount of corrosion-resistant material used can be reduced to a necessary minimum, so that the cost can be reduced.

(B) Corrosion-resistant specifications can be easily changed, and installation and replacement on site are easy.

(C) By preparing several types of corrosion resistant diaphragm units, the pressure of a plurality of corrosive fluids can be measured with one transmitter.

Next, another embodiment of the present invention shown in FIG. 3 will be described.

In this embodiment, communication holes 10, 10 'and valves 11, 11' are provided above and below the ring 8 of the corrosion-resistant diaphragm unit 6, respectively.
A liquid such as, for example, silicone oil can be sealed between the pressure receiving diaphragm 4 and the pressure receiving diaphragm 4. By filling the liquid from the lower communication hole 10, bubbles can be blown from the upper communication hole 10 ′, and the temperature error can be suppressed as in the case where a negative pressure is applied between both diaphragms.

[0015]

As described in detail above, according to the present invention, a corrosion-resistant diaphragm having a corrugated surface having substantially the same shape as the pressure-receiving diaphragm is provided outside the pressure-receiving diaphragm of the general-purpose pressure / differential pressure transmitter. The circumferential green is hermetically fixed to a ring, and the ring is provided with a communication hole communicating with a gap between the corrosion-resistant diaphragm and the pressure-receiving diaphragm, and a corrosion-resistant diaphragm unit having a valve attached to the atmosphere side of the communication hole is air-tight. By realizing the liquid contact part structure of the pressure / differential pressure transmitter, which is characterized by being attached, corrosive fluid comes into contact only with the corrosion resistant diaphragm, and the pressure receiving part of general specifications Will be completely prevented. Also, the transmitter body of general specifications can be used as it is,
A pressure / differential pressure transmitter having a corrosion resistant specification can be obtained only by attaching to the pressure receiving portion and deaeration, and the corrosion resistant material to be used can be minimized, so that the cost can be reduced. Further, the corrosion-resistant specification can be easily changed, and installation and replacement on site are easy. Therefore, by preparing several types of corrosion resistant diaphragm units, the pressure of a plurality of corrosive fluids can be measured with one transmitter.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing a structure of a liquid contact part of a pressure / differential pressure transmitter according to an embodiment of the present invention, FIG. 1 (a) is a cross-sectional view showing a state of being attached to a pressure receiving part, and FIG. It is sectional drawing which shows the structure of a diaphragm unit.

FIG. 2 is an enlarged sectional view of a communication hole and a valve enclosure of the corrosion-resistant diaphragm unit of FIG. 1 (b).

FIG. 3 is a cross-sectional view showing another embodiment of the liquid contact part structure of the pressure / differential pressure transmitter according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Flange installation piping 2 ... Pressure receiving part 4 ... Pressure receiving diaphragm 6 ... Corrosion resistant diaphragm unit 8 ... Ring 9 ... Corrosion resistant diaphragm 10 ... Communication hole 11 ... Valve

Claims (2)

(57) [Scope of request for utility model registration] The present invention relates to a pressure / differential pressure transmitter of a general specification, which is detachably attached to the outside of a pressure receiving diaphragm of a pressure receiving portion, wherein a corrosion resistant diaphragm having a corrugated surface having substantially the same shape as the pressure receiving diaphragm is provided. The corrosion-resistant diaphragm unit is hermetically fixed to the ring with its peripheral green, provided with a communication hole which communicates with a gap between the corrosion-resistant diaphragm and the pressure-receiving diaphragm, and a valve attached to the atmosphere side of the communication hole. Liquid / contact part structure of pressure / differential pressure transmitter characterized by being airtightly attached to the part. 2. The liquid contact part structure of a pressure / differential pressure transmitter according to claim 1, wherein a communication hole and a valve are provided at upper and lower portions of the ring which are separated from each other by approximately 180 °.