JP3161641B2 - Differential pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential pressure sensor used for process instrumentation and the like, and more particularly to a differential pressure sensor which is small in size, reduced in cost and improved in corrosion resistance.

[0002]

2. Description of the Related Art FIGS. 2 (a) and 2 (b) show a conventional example of a generally used differential pressure sensor. FIG. 2 (a) is a front view partially showing a cross section, and FIG. (A) It is a side view of a figure. In these figures, reference numeral 1 denotes a pressure receiving portion, on both sides of which a pressure receiving diaphragm 2 is formed.
Reference numeral 3 denotes a converter to which the differential pressure sensor 4 is fixed, and has an electric circuit (not shown) for converting a signal generated from the differential pressure sensor 4 into a predetermined electric signal. 5 is a pressure receiving diaphragm 2
And a pressure guiding thin tube formed by communicating the pressure difference sensor 4 with
For example, silicone oil is sealed in the pressure guiding thin tube.

[0003] Reference numeral 6 denotes a flange formed so as to cover the diaphragm 2 of the pressure receiving portion, which is air-tightly fixed by an O-ring 7, a bolt 8 and a nut 9. As shown in FIG. 2 (b) , the bolt 8 is fixed with the pressure receiving portion sandwiched therebetween, but the thickness of the pressure receiving portion 1 is exposed to the atmosphere. 1
Reference numerals 0 and 10 'denote pressure guiding holes formed in the flange 6 and formed such that the bottom communicates with the gap between the flange 6 and the diaphragm 2.

In the above arrangement, the pressure guiding holes 10, 10 '
Pressurizes the pressure receiving diaphragm 2. The fluid pressure is applied to the differential pressure sensor 4
And the differential pressure sensor 4 detects a pressure corresponding to the pressure difference of the fluid applied to the diaphragm 2 as an electric signal.

[0005]

However, the differential pressure sensor having the above configuration has the following problems. 1) Recently, a semiconductor sensor has been adopted as the differential pressure sensor 4, and the size thereof has been reduced, and accordingly, the pressure receiving portion has also been reduced in size. However, in a structure in which the pressure receiving portion is sandwiched between the flanges 6 and tightened with the bolts and nuts 8 and 9, there is a limit to miniaturization. 2) An airtight structure using a seal member such as an O-ring is not perfect, and the seal is incomplete due to deterioration of the seal member, a decrease in bolt tightening force, and the like. 3) Since bolts are used with high stress, high-tensile steel such as carbon steel is often used, but in the above conventional example, a portion corresponding to the middle of the bolt (thickness of the pressure receiving portion) is exposed. Therefore, when used in a highly corrosive environment, the corrosion resistance is not sufficient and the durability is poor. The present invention has been made to solve the problems of the prior art, and an object thereof is to provide a differential pressure sensor which solves the problems above Symbol 1-3 Section.

[0006]

Means for Solving the Problems The present invention to solve the above problems, a converter for converting the output of the differential pressure sensor into an electrical signal, the differential pressure sensor is fixed to the conversion unit is provided
A pressure receiving blocks, a pair of guide pressure port formed on a surface of one (or both) of the receiving pressure block, its conductor pressure port
A pressure-receiving diaphragm formed at the bottom of each
Drain hole formed between the port and the pressure receiving diaphragm
And a pressure guiding hole formed by connecting the pressure receiving diaphragm and the differential pressure sensor, and a sealing liquid sealed in the pressure guiding hole.

[0007]

A pair of pressure guiding ports are formed in the pressure receiving block, and a diaphragm is formed at the bottom of the pressure guiding port. If the process fluid piping is directly connected to the pressure introducing port, there is no need to cover the diaphragm with flanges or bolts, so that the number of parts can be reduced and the size can be reduced. Further, it should also have a name that is sealed with an O-ring or the like.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
(A), (b) is a block diagram showing one embodiment of the first aspect of the present invention, (a) is a front view showing a part in section,
(B) is a side view showing a part of (a) in cross section.
In these figures, the same elements as those in the conventional example of FIG. 4 are denoted by the same reference numerals. Reference numeral 20 denotes a pressure receiving block. The pressure receiving block 20 has a pair of pressure guiding ports 10, 1 of PT1 / 4 or PT1 / 2, for example, provided on one side surface at a predetermined interval.
0 'is formed at the bottom of this hole.
Are formed by, for example, electron beam welding or laser beam welding. Reference numeral 26 denotes a drain hole formed in a direction perpendicular to the bottom side surface of the pressure guiding port, and reference numeral 30 denotes a screw hole for mounting the pressure receiving block.

In the above configuration, the pipe of the process fluid is directly connected to the pressure introducing ports 10 and 10 ′, and the introduced process fluid presses the pressure receiving diaphragm 2. The fluid pressure is transmitted to the differential pressure sensor 4 via the pressure guiding thin tube 5, and the differential pressure sensor detects a pressure corresponding to the pressure difference of the fluid as an electric signal.

According to the above configuration, the flange, the bolt and the nut shown in the conventional example of FIG. 2 are not required, and the seal between the flange and the pressure receiving portion is not required. The pressure-guiding port and the pressure-receiving diaphragm may be provided on different surfaces of the pressure-receiving block. If the diameter of the pressure-receiving diaphragm 2 is larger than the inner diameter of the pressure-guiding port 10, as shown in FIG. After drilling a hole larger than the inner diameter and welding the diaphragm to the bottom,
The adapter 25 having the prescribed pressure guiding port may be inserted and hermetically fixed by welding or the like.

[0011]

[0012]

[0013]

[0014]

[0015]

According to differential pressure sensor of the invention as specifically described with above embodiments according to the present invention, reliability is improved with size reduction because unnecessary also bolts and nuts for even flanges and clamping sheet seal member , Ru can be realized also less and less cost parts.

[Brief description of the drawings]

FIG. 1A is a front view (a part of which is shown in cross section) of an embodiment of a differential pressure sensor according to the present invention. (B) is a side view (a part is shown in section) of (a). (C) is sectional drawing of an important section showing other examples.

FIG. 2A is a front view showing a conventional example (a part is shown in cross section). (B) It is a side view of (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure receiving part 2 Pressure receiving diaphragm 3 Conversion part 4 Differential pressure sensor 5 Pressure guiding hole 6 Flange 8 Bolt 9 Nut 10,10 'Pressure guiding port 20 Pressure receiving block 25 Adapter 26 Drain hole 30 Mounting screw hole

Continuation of front page (56) References JP-A-2-25725 (JP, A) JP-A-4-45945 (JP, U) JP-A-2-133645 (JP, U) US Patent 5094109 (US, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01L 13/00 G01L 19/00

Claims (1)

(57) [Claims] 1. A converter for converting an output of a differential pressure sensor into an electric signal, and the differential pressure sensor fixed to the converter is provided.
A pressure receiving blocks, a pair of guide pressure port formed on a surface of one (or both) of the receiving pressure block, its conductor pressure port
A pressure-receiving diaphragm formed at the bottom of each
Drain hole formed between the port and the pressure receiving diaphragm
And a pressure guiding hole formed by connecting the pressure receiving diaphragm and the differential pressure sensor, and a sealing liquid sealed in the pressure guiding hole.