JPS6239307Y2 - - Google Patents

Description

[Detailed Description of the Invention] 1. Technical Field of the Invention The present invention relates to a pressure transmitter that converts pressure into an electrical signal and transmits it, and particularly relates to a gauge pressure transmitter based on atmospheric pressure.

2. Prior Art and its Problems This type of pressure transmitter is constructed as shown in FIG. That is, 1 is a cylindrical main body casing, 2 is a pressure introducing cover attached to one end of this casing 1, 3 is a semiconductor pressure sensitive element arranged in the casing 1 so as to partition the cylindrical part, and 4 is a A liquid diaphragm partitions the fluid to be measured and the pressure transmission medium 5, 6 is a lead for taking out the output signal of the pressure sensitive element, 7 is a signal processing circuit section, 8 is a connection terminal for transmitting an electric signal to the outside, and 9 is a lead for taking out the output signal of the pressure sensitive element. This is a hole that communicates with the outside air.

This pressure transmitter converts pressure into an electrical signal as follows. That is, the pressure of the fluid to be measured introduced into the pressure introduction cover 2 is transmitted to the pressure transmission medium 5 via the liquid separation diaphragm 4, and further transmitted to one surface of the pressure sensitive element 5.
The other surface of the pressure sensitive element 5 is open toward the signal processing circuit section 7 and communicates with the atmosphere through an outside air communication hole 9. Therefore, a pressure difference between the pressure of the fluid to be measured and atmospheric pressure (i.e., gauge pressure) is applied to the pressure-sensitive element 5, and the pressure difference formed within the pressure-sensitive element corresponds to this pressure. The resistance value of the resistance layer changes and is converted into an electrical signal. The electrical signal is further amplified by a signal processing circuit 7 and transmitted.

This pressure transmitter has a hole 9 in the casing 1 for communicating the atmospheric pressure in order to use the atmospheric pressure as a reference, but moisture, corrosive atmosphere, and in the worst case, rainwater can enter through this hole. There is a possibility that
These may corrode the electronic components, substrates, etc. of the signal processing circuit section 7, which may impede its functionality.

A pressure transmitter having a structure as shown in FIG. 2 is known as a pressure transmitter that compensates for these drawbacks. That is, 11 is a cylindrical body casing, 12 is a pressure introduction cover attached to one end of the casing 11, 13 is an outside air introduction cover attached to the other end of the casing 11, and 14 is a pressure introduction cover attached to the other end of the casing 11. A semiconductor pressure-sensitive element arranged to partition the cylindrical part,
15, 15' are the casing 11 and each cover 12,
A liquid separation diaphragm 16, 16' is attached between the diaphragms 15, 15' and the semiconductor pressure-sensitive element 14, and a pressure transmission medium is sealed in the space formed by the diaphragm 15, 15' and the semiconductor pressure-sensitive element 14, respectively.
17 is a lead for taking out the output of the pressure sensitive element 14, 18
1 is a hermetic seal, 19 is a part of a circuit storage case, and 20 is a signal processing circuit.

In this transmitter, a pressure transmission medium 1 is also provided on the atmospheric pressure side of the pressure sensitive element 14 by means of a liquid separation diaphragm 15'.
6' is enclosed, so the outside air introduction cover 1
3, even if moisture, corrosive atmosphere, rainwater, etc. enter, the signal processing circuit section 20 is not affected. Also,
The signal processing circuit section 20 has a hermetic seal 18
Since it is isolated from the inside of the casing 11, even if the circuit storage case 19 is sealed, the output of the pressure sensitive element 14 will not be affected in any way. however,
This method has drawbacks such as requiring a cover on the atmospheric pressure side, and as a result, the main body casing 11 and the cover portion become larger, making the entire pressure transmitter larger.

3. Purpose of the invention This invention separates the atmospheric pressure introduction part and the circuit part through a partition plate and arranges them side by side, and also provides a hermetic seal on the partition plate part, so that the circuit part is not affected by the influence of outside air (atmospheric pressure). The purpose of the present invention is to provide a small and inexpensive pressure transmitter that is not subject to

4. Structure of the invention This invention provides a pressure transmission medium enclosed by a liquid-separating elastic member on the atmospheric pressure introduction side of a pressure-sensitive element, and also provides a space for placing this liquid-separating elastic member under atmospheric pressure and a signal. A partition plate is provided to isolate the processing circuit section, and the partition plate includes a mounting section for supporting the center of the liquid partition elastic member and a hermetic seal section for transmitting the pressure of the pressure sensitive element to the signal processing circuit section. It is configured by providing the following.

5 Embodiment of the invention An embodiment of the invention will be described below with reference to FIG. 3.

31 is a cylindrical main body casing, 32 is a circuit storage case coaxially connected to this casing 31, and a partition plate 33 is integrally provided. 34
is a pressure introducing cover coaxially connected to the side of the casing 31 on which the case 32 is attached. 35 is a semiconductor pressure sensitive element arranged to partition the inside of the casing 31, and 36 is a liquid separation diaphragm that partitions the fluid to be measured and a pressure transmission medium 37 that is in contact with one surface of the pressure sensitive element 35. 36' is atmospheric pressure,
Pressure transmission medium 3 in contact with the other surface of the pressure sensitive element 35
7' is a liquid-separating diaphragm. This diaphragm 36' is supported by a mounting portion 33a formed at the center of the partition plate 33. 38 is a lead for transmitting the output signal of the pressure sensitive element; 39
is a hermetic seal section for taking out the output signal to the signal processing circuit section 43. 41 is
Outside air is introduced through a communication hole 40 into an atmospheric pressure introduction chamber partitioned by the liquid separation diaphragm 36' and the partition plate 33. 42 is a circuit storage chamber separated from the atmospheric pressure introduction chamber 41 by the partition plate 33, and is sealed and formed by the circuit storage case 32, cover 44, and the like.

45 is an external connection terminal for transmitting the output signal to the outside.

The liquid-separating elastic member is a diaphragm 36.
Although only the case where 36' is used has been described,
The present invention is not limited to this, and any elastic member capable of transmitting pressure, such as a bellows, can have the same effect. Also, the partition plate 33 does not have to be a rigid body, and may be an elastic body such as a diaphragm.

Next, the operation of one embodiment of the present invention constructed as described above will be explained.

The pressure of the fluid to be measured introduced into the pressure introduction cover 34 is transmitted to the pressure transmission medium 37 via the liquid separation diaphragm 36, and further transmitted to one surface of the semiconductor pressure sensitive element 35. Further, the atmospheric pressure introduced into the atmospheric pressure introduction chamber 41 through the outside air communication hole 40 is transmitted to the pressure transmission medium 37' via the liquid partition diaphragm 36', and is further transmitted to the other surface of the semiconductor pressure sensitive element 35. is transmitted to. Therefore, a pressure difference between the pressure of the fluid to be measured and atmospheric pressure is applied to the pressure sensitive element 35, and the resistance value of the resistance layer formed on the surface of the pressure sensitive element changes according to the value, and an electrical signal is generated. is converted to The output signal of the pressure sensitive element is transmitted to the signal processing circuit section 43 through the lead 38 and the hermetic seal 39.

This configuration provides the following effects.

Since the atmospheric pressure introduction chamber and the circuit storage area are separated, moisture, rainwater, corrosive atmosphere, etc. do not enter the circuit storage area, and therefore electronic components and circuit boards are not corroded and can be used for a long time. Sufficient for use over a period of time.

Since the atmospheric pressure introduction chamber and the circuit storage section are coaxially arranged side by side with a partition plate in between, it is small and can be manufactured at low cost, and is easy to handle.

The atmospheric pressure introduction side of the pressure sensitive element is separated from the atmospheric pressure introduction chamber by a liquid diaphragm and the pressure is transmitted through the pressure transmission medium, so that the pressure sensitive element will not be corroded or deteriorated by outside air.

Errors caused by expansion of the pressure transmission medium sealed on the pressure introduction side due to changes in ambient temperature can be offset by the amount of expansion of the pressure transmission medium sealed on the atmospheric pressure side, resulting in pressure transmission with extremely low temperature errors. A vessel is obtained.

6. Effects of the invention The present invention is constructed in this way, so it is simple and
It has a structure that is easy to handle, and has the effect of preventing corrosion of electronic parts due to intrusion of rainwater, etc.

[Brief explanation of the drawing]

1 and 2 are sectional views showing different conventional pressure transmitters, respectively, and FIG. 3 is a sectional view showing an embodiment of the present invention. 31...Casing, 32...Circuit storage case, 33...Partition plate, 33a...Attachment part, 34...
...Pressure introduction cover, 35...Semiconductor pressure sensitive element,
36, 36'... Separating liquid diaphragm, 37, 3
7'...Pressure transmission medium, 39...Hermetic seal, 41...Atmospheric pressure introduction chamber, 43...Signal processing circuit section.

Claims (1)

[Scope of utility model registration request] A cover for introducing a fluid to be measured, a casing having a pressure-sensitive element therein, a liquid-separating elastic member attached to the casing, and a space formed by the liquid-separating elastic member, the casing, and the pressure-sensitive element. a pressure transmission medium filled with pressure, and is configured so that the pressure of the fluid to be measured is applied to one surface of the pressure-sensitive element and the atmospheric pressure is applied to the other surface, and the pressure generated from the pressure-sensitive element In a pressure transmitter equipped with a circuit section that processes and transmits electrical signal changes according to In addition to filling the space formed by the element with a pressure transmission medium, a partition plate is provided to separate the space for introducing atmospheric pressure into a part of the casing from the part housing the signal processing circuit, and a partition plate is provided in the center of the partition plate. The pressure sensor is characterized in that the part is provided with a hermetic seal part for transmitting a signal from the pressure-sensitive element to the processing circuit, and a mounting part for fixing the central part of the liquid-separating elastic member. transmitter.