JPS61129545A - Fine differential pressure transducer - Google Patents

Abstract

PURPOSE:To detect a fine differential pressure with relatively simple constitution by increasing a fine force corresponding to the fine differential pressure obtained by a force transducing means composed of a diaphragm, etc., and detecting the result by a force detector. CONSTITUTION:Pressures at two measurement points to be measured are introduced to the 1st chamber 68 and the 2nd chamber 70 through pressure intakes 72 and 74, respectively. Then, the force corresponding to the difference between those pressures operates on the diaphragm 78 and is applied to one terminal of a force increase lever 90 through a leaf spring 88, so the force is increased and operates on the forces detector 96. Consequently, even a fine differential pressure is detected and a signal corresponding to the differential pressure is sent out to a terminal 104. When an abnormal pressure is applied, the excessive movement of the force increase lever 90 is inhibited by a stopper plate 80 and a stopper screw 108 to protect the force detector 96.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a micro-differential pressure transducer, which is particularly capable of detecting a micro-pressure difference with a relatively simple configuration, and is capable of detecting a small pressure difference between indoor and outdoor. It can also be used to detect pressure differences between one room and another, and can be used in clean rooms, air conditioning equipment, etc.

[Background Art and its Problems] Conventionally, a differential pressure transmitter shown in FIG. 2 has been known as a means for detecting the pressure difference between two measurement points (for example, Japanese Utility Model Publication No. 57-33406). ).

In the figure, a tribute hole 12 provided in the center of the main body 10
A converting section 16 for converting the force into an electrical signal is installed at the upper end of the force transmitting section 8-14 loosely fitted therein. Further, a hole 18 is formed in the main body 10 and is in communication with and orthogonal to the through hole 12, and a connecting shaft 20 is slidably inserted into this hole 18. A relatively large hole 22 for passing the lever 14 through, and a screw hole 24 perpendicular to the hole 22 are formed.
6 is screwed in.

Further, both sides of the main body 1O are formed in a waveform, and diaphragms 28 and 30 are formed in a waveform corresponding to the waveform.
are attached to the main body 10 by means such as welding their outer peripheral parts so as to oppose both sides of the main body 10 with a predetermined gap between them.

The connecting shaft 20 is attached to these diaphragms 28 and 30.
Both end surfaces of the through hole 12) are fixed, and a predetermined sealing process is performed between the through hole 12) hole 18, etc. and the outside, and a sealed liquid 31 is filled.

Further, the diaphragms 28 and 30 are covered with cover plates 32 and 34 provided so as to form a predetermined interval therebetween, and pressure receiving chambers 36 and 38 are respectively formed. Pressure inlets 40 and 42 are provided, respectively.

Therefore, if comparative pressures are introduced into the pressure introduction ports 40 and 42, those pressures will be applied to the diaphragm 28.
and 30, and a force corresponding to the pressure difference between them is transmitted to the converting section 16 via the screw 26 and the force transmission lever 14, and the converting section 16 sends out an electric signal corresponding to the pressure difference. It is something that

Such conventional differential pressure transmitters are generally designed for industrial equipment such as process measurement, and are used in relatively high pressure areas.

For this reason, differential pressure detection and overpressure protection in high pressure areas are configured in a circular manner, and this configuration makes it difficult to detect minute differential pressures. In order to be able to detect pressure, the diaphragm must be extremely large.

Furthermore, in order to be able to detect minute differential pressures, high precision of the component parts is required, which is not desirable in terms of assembly and processing, and the overpressure protection mechanism is complex and heavy, increasing installation costs. , it ends up being expensive.

Therefore, the conventional differential pressure transmitter cannot be used as a minute differential pressure converter for air conditioning equipment, etc.

[Object of the Invention] An object of the present invention is to provide a differential pressure transducer capable of detecting a differential pressure with a relatively simple configuration.

[Means and effects for solving the problems] The present invention has 1
For example, by using a force amplifying means such as a force amplifying lever that applies the principle of a lever, the minute force corresponding to the slight pressure difference obtained by the force converting means consisting of a diaphragm etc. can be expanded. By detecting this magnified force with a force detector, it is possible to detect a slight differential pressure with a relatively simple configuration.

Specifically, the first chamber receives the pressure at the first measurement point, the second chamber receives the pressure at the second measurement point, and the first chamber receives the pressure at the second measurement point.
a force converting means that converts the differential pressure between the room and the second room into a force corresponding to the pressure difference, a force amplifying mechanism that amplifies the converted force, and a force amplifying mechanism that receives the force amplified by the force amplifying mechanism The structure includes a force detector that sends out a signal corresponding to the force.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the figure, a first casing 52 having a shallow cylindrical shape is bonded to one surface of a disk-shaped substrate 50, that is, the bottom surface in the figure, by means such as welding the edges thereof, On the other surface of the substrate 50, that is, on the upper surface in the figure, a second casing 54 having a cylindrical shape with a bottom is provided.
It is attached so that its opening surface faces the upper surface of the substrate 50.

That is, a flange portion 56 is formed at the edge of the opening of the second casing 54, and a through hole 58,58 is formed in the flange portion 56, and the substrate 50
has a screw hole 60.60 corresponding to the through hole 58.58.
is provided, and a screw hole 62.62 is screwed into the screw hole 60.60 through the through hole 58.58.

Further, a circumference 1464 is cut in the flange portion 56, and an O-ring 66 is fitted into this circumferential groove 64.

Accordingly, said second casing 54 has port 62.62.
By tightening, it is fixed in close contact with the substrate 50, and the O-ring 66 seals the contact portion.

A chamber 68 formed by the substrate 50 and the first casing 52 constitutes a first chamber that receives the first measurement point pressure, and a chamber 7o formed by the substrate 5o and the second casing 54 constitutes a first chamber that receives the first measurement point pressure. constitutes the second chamber that receives the pressure at the second measurement point, and each ? LPl is provided with pressure introduction lowers 2 and 74.

Further, an annular projection 76- is provided on the lower surface of the substrate 50, and a diaphragm 78 is closely attached to this projection 76 by welding or other means, and a stopper plate 80 is provided at the center of the diaphragm 78. is fixed.

A screw hole 82 is bored in the center of the substrate 50, and a cylindrical screw 84 is provided in the screw hole 82.
are screwed together.

A lock nut 86 is screwed into the upper end of this male screw 84, and the male screw 84 is locked, and its lower end constitutes a stopper member that restricts the upward movement of the stopper plate 80.

A leaf spring 88 is installed on the upper surface of the stopper plate 80, and this leaf spring 88 passes through the hollow part of the cylindrical screw 84 and reaches the second chamber 70, and its upper end is connected to the force amplifying lever 90. It is fixed at one end.

The other end of the force magnifying lever 90 passes through a through hole 94 formed in a protruding piece 92 protruding from the upper surface of the plate 50 and reaches the detection end of the force detector 96. The lever 9 is connected to the lever 9 in the vicinity of the through hole 94.
It is supported by the protruding piece by fixing a leaf spring 98 fixed to the protruding piece.

That is, the force amplifying lever 90 constitutes a lever with the leaf spring 98 as a fulcrum, and the minute force acting on the diaphragm 78 is transmitted to the lever 90 through the leaf spring 88.
is applied to one end of the force detector 96, which is then magnified by the lever principle and applied to the force detector 96.

In this embodiment, the ratio of the distances from the fulcrum of the force magnifying lever 90 to the point of application of the six forces is 1:3 to 1:1.
It is selected as 0.

Therefore, when a cantilever-shaped cantilever/- set detector using a strain gauge is used as the force detector 96, for example,
Although the amount of displacement during force detection is small at 0.05 to 0.10 mm, it is magnified to the above ratio by the force magnification lever, so the amount of movement of the center portion of the diaphragm 78 is 0.3 to 1.0 mm.
It can be as large as hm.

Further, the force detector 96 is fixed to the protruding piece 92, and its protruding end is connected to the terminal 104 of the hermetic seal 102 provided on the second casing 54 by the lead wireworker 00. It transmits signals to the outside while maintaining airtightness.

Note that the lower part of the force magnifying lever 9o and the base plate 5
A screw hole 106 is cut in the upper surface of the 0, and a stopper screw 108 is screwed into this screw hole 106, and a lock nut htio is screwed into this stopper screw 108. .

This stopper screw 10g limits the downward movement range of the force magnifying lever 90, and activates the force detector 96 when abnormally high pressure is applied to the second chamber or when the first chamber becomes abnormally low pressure. It is something to protect.

Next, the operation of the above embodiment will be explained.

Now, the pressures at the two measurement points to be measured are introduced into the first chamber 68 and the second chamber 70 through the pressure introduction lowers 2 and 74, respectively.

Then, depending on these pressure differences, the diaphragm 78
Since a force is applied to one end of the force amplifying lever 90 through the leaf spring 88, the nuclear force is amplified by the action of this lever 90 and acts on the force detector 96.

Thereby, even if the differential pressure is extremely small, it is detected and a signal corresponding to the differential pressure is sent to the terminal 104.

Further, when abnormal pressure is applied, the stopper plate 80 and the stopper screw 108 prevent excessive movement of the force magnifying lever 90, and the force detector 96 is protected.

According to the embodiment, when the differential pressure is extremely small, the force acting on the diaphragm is extremely small, but the force is magnified by the force magnifying lever 90 and applied to the force detector 96, so it can be easily detected. be done.

In addition, since the force magnifying lever 90 is used, which applies the principle of a lever, when detecting a force corresponding to a differential pressure, it is possible to take a large amount of displacement of the part connected to the leaf spring 88 at one end of the magnifying lever 90. can.

Therefore, it is possible to accurately measure minute differential pressures, and there is no need for a highly accurate stopper mechanism to protect against overpressure. protection can be provided.

Therefore, there is no need to use a filling liquid as in the conventional case, so there is no need to consider the influence of the temperature characteristics of the filling liquid, and there is no need for a structure for filling the liquid, a filling operation, etc.

Further, the force magnifying lever 90 has its fulcrum at the plate spring 98.
The leaf spring 8
8, it is less affected by vibrations and other disturbances, and there is no friction or play in the movable part during force detection, so force is transmitted faithfully and is not carried out discontinuously. There are no inconveniences such as getting caught.

Therefore, the slight differential pressure can be measured with extremely high accuracy.

When an experiment was conducted using the differential pressure converter according to the above embodiment, it was confirmed that a differential pressure of several +111H20 could be measured with extremely high accuracy.

In the above embodiments, a diaphragm with a simple structure and installation is used as a force transducer, but this may be a bellows phragm, a bellows module, a piston, etc. based on the principle. .

Further, although the force magnifying lever 90 is used as the force magnifying mechanism, it may also be a hydraulic cylinder, for example.

Furthermore, although the fulcrum of the force amplifying lever 90 is constructed from a leaf spring 98, this may be constructed from an elastic member such as a coil spring, and the pivot and other bearings may also be constructed from other means. .

[Effects of the Invention] As described in detail above, according to the present invention, since the force amplification mechanism is used, it is possible to accurately measure a slight differential pressure.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. 68... first chamber that voltages the first measurement point pressure, 7
0...Second chamber that receives the second measurement point pressure, 78
...Diaphragm, 88.90.98...Plate spring constituting force amplification mechanism, force amplification lever and plate spring, 96.
...Force detector.

Claims (4)

[Claims] (1) A first chamber that receives the pressure at the first measurement point, and a second chamber that receives the pressure at the first measurement point.
a second chamber that receives pressure at a measurement point; a force converting means that converts the differential pressure between the first chamber and the second chamber into a force corresponding to the pressure; and a force amplifying means that amplifies the converted force. A micro differential pressure transducer including a mechanism and a force detector that receives the force magnified by the force magnification mechanism and sends out a signal corresponding to the force. (2) The differential pressure transducer according to claim 1, wherein the force transducer is a diaphragm that partitions the first chamber and the second chamber. (3) In claim 1, the force magnification mechanism has one end connected to the force conversion means, the other end connected to the force detector, and has a force magnification ratio corresponding to a desired force magnification ratio. A slight differential pressure transducer characterized by being a force amplifying lever that forms a lever with a point as a fulcrum. (4) In claim 3, the force magnifying lever has one end connected to the force converting means by an elastic member, and the fulcrum is fixed to a fixed member via the elastic member. A micro differential pressure transducer characterized by: