JPS6329218Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a capacitance type differential pressure detector, and particularly relates to the structure of the detector body.

Conventionally, in a capacitance type differential pressure detector, as shown in Fig. 1, an insulator b is housed in a cavity formed in a detector body a, and an elliptical differential pressure is formed within this insulator b. A detection chamber c is formed, and two liquid passages d and d are formed that open to this detection chamber c and the side surface of the body a, while fixed electrodes e and e are formed on the side surface of the detection chamber c, and a flat plate is formed in the center. A diaphragm type movable electrode f is attached, and seal diaphragms g,
g is fixed at the edge, process pressure acts on the seal diaphragms g, g, and the liquid passages d, d
The movable electrode f is displaced via the sealed liquid h sealed in the detection chamber c, and this displacement is taken out via lead wires i and j as a change in capacitance to detect the differential pressure.

However, in the above differential pressure detector, the body a
is made of metal and insulator b is made of glass, and because the thermal conductivity of the two is different, when a large thermal shock is applied from the process fluid through the seal diaphragms g, insulator b, which is glass, It had the disadvantage of being damaged.

Furthermore, the body a and the insulator b had to be processed, resulting in a complicated structure.

This idea was made in view of these points.The body is made of a single material, ceramic, and a thin metal body ring is integrally attached to the outer circumferential surface of this body, and the inner circumferential surface of this body ring is To provide a capacitive differential pressure detector that is resistant to thermal shock and has a simplified structure by brazing to the outer peripheral surface of the body, fixing a seal diaphragm to the body, and leading a movable electrode to the outside. It is.

This invention will be described in detail below based on embodiments shown in the drawings.

As shown in FIGS. 2 and 3, reference numeral 1 is a capacitance type differential pressure detector which extracts the displacement of the movable electrode 2 as a change in capacitance to detect the differential pressure.

Reference numeral 3 denotes a detector body, which has a substantially rectangular longitudinal section and is made of ceramic. This body 3 is divided into left and right halves at the center, and an oval differential pressure detection chamber 4 is formed in the center of the interior.
Book liquid passages 5, 5 are formed. Further, recesses 3a, 3a are formed on both sides of the body 3, and a seal diaphragm 6 is fixed thereto, and silicone oil or the like is sealed in the recesses 3a, 3a, the liquid passages 5, 5, and the detection chamber 4. Liquid 7 is sealed.

The movable electrode 2 is constituted by a flat diaphragm and is held between the left and right bodies 3, and divides the detection chamber 4 into left and right parts. Fixed electrodes 8 are attached to both sides of the detection chamber 4 facing the movable electrode 2, and lead wires 9 and 10 are connected to both electrodes 2 and 8, respectively.

Further, a body ring 11 is attached to the outer peripheral surface of the body 3, and this body ring 11 is formed of a thin metal plate. This body ring 11 consists of two cylindrical rings 12 and two plate-like rings 13, and the cylindrical ring 12 has a body part 12a.
Outward flanges 12b, 12b are integrally molded on both end edges. This cylindrical ring 12
is fitted into the body 3 and brazed to the body 3 via a solder 14. Furthermore, one flange 12b clamps the outer periphery of the movable electrode 2, and the other flange 12b and the plate-like ring 13 clamp the outer periphery of the seal diaphragm 6, and each end face is welded 1.
5, and the movable electrode 2 is led out to the outside, while the seal diaphragm 6 is fixed to the body 3.

Next, the operation of the capacitive differential pressure detector 1 will be explained.

One side of each seal diaphragm 6 is in contact with a process fluid (not shown), and process pressure is applied thereto. When a pressure difference occurs between the process pressures, it is transmitted to the sealed liquid 7 via the seal diaphragm 6. , the movable electrode 2 is displaced to the low pressure side in the detection chamber 4. This displacement changes the distance between the movable electrode 2 and the fixed electrode 8, causing a change in capacitance, and this capacitance change is derived to detect the differential pressure.

This differential pressure detector 1 has a body 3 made of a single material, ceramic, which has good thermal conductivity, so that no distortion occurs even when thermal shock is applied from the process fluid. Since 9 is made of a thin plate, it is extremely robust against thermal shock.

As described above, according to this invention, the body is made of a single material, ceramic, and a thin metal body ring is integrally attached to the outer circumferential surface of the body.
Because the inner circumferential surface of this metal body ring is brazed to the outer circumferential surface of the body, the ceramic body has good thermal conductivity even when thermal shock is applied, and distortion does not occur unlike conventional metal bodies and glass insulators. There is no damage, and damage etc. can be reliably prevented. Furthermore, since the body ring is made of solid metal, it is extremely durable against thermal shock.

Furthermore, since the structure is simplified, manufacturing becomes easier, and since there are fewer metal parts, machining of recesses and the like becomes easier.

Furthermore, since the body is made of ceramic, it is less susceptible to deformation due to static pressure, etc., so it is less affected by this deformation and can perform highly reliable differential pressure detection. can be taken as a thing.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional capacitive differential pressure detector, Figure 2 is a vertical cross-sectional view of the capacitive differential pressure detector of this invention, and Figure 3 is a cross-sectional view of the same essential parts. be. DESCRIPTION OF SYMBOLS 1... Capacitance type differential pressure detector, 2... Movable electrode, 3... Body, 3a... Recess, 4... Differential pressure detection chamber, 5... Liquid passage, 6... Seal diaphragm, 7 ...Filled liquid, 8...Fixed electrode, 9,10...
... Lead wire, 11 ... Body ring, 12 ... Cylindrical ring, 12a ... Body, 12b ... Flange, 13 ... Plate ring, 14 ... Wax, 15 ...
…welding.

Claims (1)

[Claims for Utility Model Registration] A differential pressure detection chamber is formed in the detector body, two liquid passages are formed with openings in the detection chamber and the side of the body, and a fixed electrode and a movable electrode are formed in the detection chamber. However, a capacitive differential pressure detector has seal diaphragms attached to both sides of the body, and the process pressure acts on the movable electrode via the seal diaphragm, displacing the movable electrode to detect the differential pressure. The body is made of ceramic, a thin metal body ring is integrally attached to the outer circumferential surface of the body, the inner circumferential surface of the metal body ring is brazed to the outer circumferential surface of the body, and the seal diaphragm is attached to the outer circumferential surface of the body. A capacitance type differential pressure detector, characterized in that the movable electrode is fixed to a body and led out to the outside.