JPH0617842B2 - Ultra high temperature pressure transducer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pressure transducer, and more particularly to an ultra-high temperature pressure transducer for measuring pressure under ultra-high temperature such as pressure measurement of rocket engine. It is related to vessels.

(b) Prior Art As a pressure transducer for measuring pressure at high temperature, there is, for example, an engine acupressure gauge. This engine acupressure gauge is for measuring the pressure generated in the cylinder of the piston engine and performing analysis for improving the fuel consumption rate and output, etc., and the maximum allowable temperature is usually 150 to 200. It is about ℃. However, when measuring the pressure at the time of ignition by a spark plug of a piston engine or the like, high heat exceeding the allowable temperature is generated. Therefore, in a conventional engine acupressure gauge, a cooling water passage is formed inside, and the cooling water is circulated in the cooling water passage to keep the temperature of the diaphragm and the strain-flexing portion at 15 degrees.
There is one configured so as to be suppressed to 0 to 200 ° C. or lower.

On the other hand, when a jet engine, especially a rocket engine, is operating, the temperature of the combustion chamber becomes significantly higher than that of the piston engine, and usually rises to about 1000 ° C. Then, due to the combustion reaction at that time, the pressure in the combustion chamber also changes rapidly. Also in rocket engines, such measurement of pressure in the combustion chamber is indispensable for knowing propulsive force, combustion efficiency, and the like.

By the way, in the case of a rocket engine, the fuel (propellant) used is generally kerosene, hydrazine, liquid hydrogen or the like, and combustion is performed by adding an oxidizer such as liquid oxygen or nitric acid to generate propulsive force. Some of these fuels are not only easily vaporized, but also spontaneously ignite. Therefore, the periphery of the combustion chamber of the rocket engine is designed to be maintained at an extremely low temperature so as to prevent a fire or an accident.

When measuring the pressure in the combustion chamber of such a rocket engine, if a normal pressure converter having a temperature resistance characteristic of about 150 to 200 ° C. is used, the pressure converter is increased by the temperature of the combustion chamber rising to about 1000 ° C. However, there is a problem that the sensor part is burned out. In order to deal with this problem, when using an engine acupressure gauge of the type in which the sensor section is cooled by cooling water as described above, the cooling water, etc. freezes and circulates because the surroundings are extremely cold. There is a problem in that the temperature of the sensor unit rises and the sensor unit fails. In the end, there is no conventional pressure converter capable of measuring the pressure of the pressure medium under an extremely high temperature such as a rocket engine, which is an obstacle to the development of the jet engine and the like.

(c) Object The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an ultra-high temperature pressure transducer that can accurately measure pressure under ultra-high temperature and that has an extremely simple configuration. To aim.

(d) Structure In order to achieve the above-mentioned object, the present invention transforms the pressure of a fluid into a force by a diaphragm and transmits this force to a strain-flexing portion via a force-transmitting portion to deform the strain-generating portion. In a pressure transducer for detecting an electric signal corresponding to an applied pressure by detecting a strain gauge attached to the strain-flexing part, a pressure introducing part that is fixedly coupled to a pressure detection target and guides the fluid from the target, and a heat-resistant Which has a large heat capacity and is formed in a shape having a large surface area in contact with the fluid, has a heat absorbing member inside, and brings the fluid introduced from the pressure introducing portion into contact with the heat absorbing member. The heat absorbing member in the connecting portion absorbs the heat of the super-high temperature fluid introduced into the pressure introducing portion, and the pressure of the cooled fluid is applied to the diaphragm. It is characterized by being configured as described above.

Hereinafter, the present invention will be specifically described based on the embodiments shown in the accompanying drawings.

FIG. 1 is an enlarged cross-sectional view showing a cross-sectional structure of an ultrahigh temperature pressure converter which is an embodiment of the present invention, and FIG. 2 is a side view showing an external structure of the same embodiment.

In FIGS. 1 and 2, reference numeral 1 denotes a pressure introducing portion for taking out pressure from a combustion chamber of a rocket engine, which is an object with pressure detection, and has a male screw portion 1a on the outer periphery on one end side in the form of a small cylinder.
Is formed, and a hexagonal bolt portion 1 is formed on the outer periphery of the other end of the large tubular shape.
b is formed, and a pressure introducing passage 1c for taking out a fluid as a pressure medium from the combustion chamber is bored in the central portion,
The male screw portion 1a is screwed into a screw hole formed in the fuel chamber with a gasket (not shown) inserted in the step portion 1d formed at one end. Reference numeral 2 denotes a connecting portion in which a radiating fin 2a that is a ridge-like heat radiating portion is formed on the outer periphery of a substantially cylindrical rigid body having a hollow interior, and a male screw portion 2b formed on the outer periphery on one end side introduces pressure. The metal ring 3 is screwed into the female screw portion 1e formed on the inner circumference of the other end of the portion 1 with the metal ring 3 inserted between the end faces. Reference numeral 4 denotes a first perforated plate having a large number of small holes 4a and sandwiched between a step portion 1f in the pressure introducing portion 1 and a step portion 2c formed at one end of the connecting portion 2, and 5 is , Connecting part 2
The second perforated plate is in contact with a step portion 2d formed in the axially intermediate portion of the inner wall and has a large number of small holes 5a.
First and second perforated plates 4 and 5 in the hollow part of
A cylindrical spacer 6 is inserted between the spacers 6, and the space surrounded by the spacer 6 and the first and second porous plates 4 and 5 has the first and second porous plates 4 and 5. A large number of metal balls (steel balls) 7 as a heat absorbing member having a larger diameter, a larger heat capacity, and heat resistance than the small holes 4a, 5a formed in 5 are filled (in FIG. 1, metal). Only part of the ball 7 is shown). 8, a female screw portion 2e formed on the inner periphery of the other end of the hollow portion of the connecting portion 2 is screwed with a male screw portion 8a formed on the outer periphery of one end half through a metallic gasket 9. It is a reaction force support portion, and the outer periphery of the other half portion of the reaction force support portion 8 has a large diameter and has a hexagonal bolt portion 8b.
Are formed. Reference numeral 10 is a diaphragm whose peripheral edge is fixed in an airtight manner by welding or the like to one end of the reaction force supporting portion 8 adjacent to the second porous plate 5, and a catenary curved surface is formed between the peripheral edge and the central portion. It is a thin plate. 1
Reference numeral 1 denotes a sensing portion having one end side inserted into the hollow portion 8c from the other end side of the reaction force supporting portion 8, and the outer diameter of the sensing portion 11 is larger than that of the hollow portion 8c of the reaction force supporting portion 8. Out of the smaller part of
The half portion on one end side is a cylindrical cylindrical force transmitting portion 11a having a large rigidity, and one end of the force transmitting portion 11a has one end.
The strain gauge 12 is fixed to the center of the strain sensing part 11, and the middle part of the sensing part 11 is a thin-walled cylindrical strain-flexing part 11b. Are attached by adhesion, vapor deposition, fusion or other means.
In addition, a stepped portion 11c, 1
1d are sequentially formed, and the step portion 11c is the reaction force support portion 8
Is in contact with a step portion 8d formed on the inner circumference of the other end side of
The step portion 11d is in contact with the other end of the reaction force support portion 8 and is fixed thereto by welding or the like. Further, a step portion 11e is also formed on the inner circumference of the other end of the sensing portion 11, and the peripheral edge of the airtight terminal plate 13 is abutted and fixed to the step portion 11e. Then, the sensing portion 11 sealed by the airtight terminal plate 13
The hollow portion 11f is filled with an inert gas such as nitrogen gas, and the inert gas prevents the strain gauge 12 from being oxidized and from being lowered in insulation resistance due to moisture absorption. The input / output of the electric signal of the strain gauge 12 is performed by the airtight terminal board 1
3 through the conductive pin 14 that is hermetically inserted. Reference numeral 15 denotes a terminal cover, one end of which is fitted and fixed to the stepped portion 11g at the other end of the sensing unit 11 by welding or the like. At the other end of the terminal cover 15, a waterproof connector 16 is provided via a packing 17. It is fixed by a set screw 18 (second shown), the conductive pin 14 of the airtight terminal plate 13 and the lead wire 19 from the waterproof connector 16 are connected in the hollow portion 15a of the terminal cover 15, and the silicone is used. And the like are filled. And the waterproof connector 16
The lead wire led to the outside is connected to a strain measuring device (not shown).

Next, the operation of the embodiment having the above configuration will be described.

First, the rocket engine is rotated while pressing the female screw portion 1a of the pressure introducing portion 1 of this ultra-high temperature pressure transducer (hereinafter, simply referred to as "transducer") against the hexagon bolt portion 1b by pressing a tool such as a spanner. It is attached by screwing it into the screw hole that is drilled in the combustion chamber of. Here, the converter mounted in the combustion chamber is placed in a cryogenic environment together with the rocket fuel kept in a cryogenic temperature.

Next, when the rocket engine is started, the fuel rapidly burns and the pressure and temperature inside the combustion chamber rapidly rise. The temperature at this time reaches up to about 1000 ° C. as described above. This combustion pressure medium is taken out from the pressure introducing passage 1c of the pressure introducing portion 1 to the converter side and first reaches the first porous plate 4. Next, the pressure medium is the small holes 4a of the first porous plate 4.
From the small hole 5a of the second perforated plate 5 and the diaphragm 10
Reach on the pressure receiving surface of. At this time, the pressure medium is absorbed by the large number of metal balls 7 serving as heat absorbing members that are sufficiently cooled in an extremely low temperature environment, and reaches the diaphragm 10 in an extremely low temperature state.

The diaphragm 10 receives the pressure from the pressure medium on its surface, converts the pressure into a force, and compresses the force transmitting portion 11a having high rigidity. Then, the thin strain element 11b integrally connected to the force transmitting portion 11a of the sensing portion 11 is deformed (that is, compressive strain is generated in the direction in which the force is applied, and tensile strain is generated in the direction orthogonal thereto). . This strain is detected as an electric signal by the strain gauge 12 attached to the inner wall of the strain-flexing portion 11b by means such as adhesion or vapor deposition, and the airtight terminal board 13 is then detected.
And, the pressure is measured by being output to a strain measuring device (not shown) through the waterproof connector 16, and the waveform is recorded on the recording paper in some cases. Thus, in the above embodiment, about 10
The temperature of the pressure medium reaching a high temperature of 00 ° C. is rapidly lowered by a large number of metal balls 7 which are heat absorbing members formed in a shape having a large heat capacity and a large surface area in contact with the pressure medium. The heat of the pressure medium is also radiated from the heat radiation fins 2a of the connecting portion 2. Therefore, the diaphragm 10 and the force transmitting portion 11a of the sensing portion 11 fixed to the diaphragm 10 hardly increase in temperature for a fixed period of time, and therefore, the pressure of the fluid introduced from the pressure introducing passage 1c depends on the pressure. The electrical signal can be detected by the strain gauge 12.

Further, in the case of this embodiment, since the diaphragm 10 is formed in a catenary shape, for example, a temperature difference occurs between the diaphragm 10 and the force transmitting portion 11a, and the diaphragm 10
Even if a deformation occurs, the influence of the deformation is not transmitted to the force transmitting portion 11a of the sensing unit 11, and the force transmitting portion 11a is
Since only the force component corresponding to the applied pressure is transmitted to the strain-flexing portion 11b, accurate pressure measurement is possible. Further, by making the diaphragm 10 in a caterina shape, there is also an advantage that the nonlinearity of the strain output is improved.

Further, in the above-described embodiment, the force transmitting portion 11a of the sensing portion 11 is formed to be long to some extent, and the diaphragm 10
Strain element 1 to which a strain gauge 12 is attached
Since the distance from 1b is set to be long, even if the diaphragm 10 is heated to some extent, the temperature change of the strain-flexing portion 11b is reduced and the measurement accuracy is improved accordingly.

FIG. 3 (a) is a temporal change between the temperature immediately before the first perforated plate 4 (graph A in the same figure) and the temperature immediately after the second perforated plate 3 (graph B in the same figure). Fig. 3 (b) is a diagram showing the experimental results obtained by measuring
It is the diagram which showed the time change of the strain output value (graph C of the figure) from the strain gauge 12 at that time. As can be seen from these figures, by constructing as in the above embodiment, at least 2 to 2 from the start of the rocket engine.
During the period of 3 minutes, the temperature immediately after the second perforated plate 5 hardly rises, so that the strain output value hardly changes regardless of the temperature of the pressure medium. Therefore, as the strain-flexing part 11b and the strain gauge 12 that easily affect the strain output value when there is a temperature change, the conventional pressure transducer (allowable temperature (150 to 200
The same thing (structure, material) as that of about ° C) can be used. Further, in most rocket engines, in most cases, combustion ends in a relatively short time, and even if it burns for a long time, the pressure from ignition of the fuel until the thrust becomes almost constant is maintained. Since the purpose can be achieved by measuring, it is sufficient if the strain-flexing part 11b is kept at a low temperature for about 2 to 3 minutes.

In addition, the strain gauge 1 is provided in the hollow portion 11f of the sensing unit 11.
2 and the like are filled with an inert gas for preventing insulation deterioration and oxidation due to moisture absorption, and the terminal cover 15
Since the inside of the hollow portion 15a of the strain gauge 12 is filled and solidified with a filler that prevents insulation and abnormal vibration, the strain gauge 12
Strain output maintains stable accuracy for a long time.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

For example, as shown in FIG. 4, a net 20 is provided between the first perforated plate 4 and the metal balls 7 (not shown), and between the second perforated plate 5 and the metal balls 7. If you do, first
Further, a part of the metal ball 7 is not fitted into the small holes 4a and 5a of the second perforated plates 4 and 5 and is not blocked, and the applied pressure is efficient and stable and the diaphragm 11 is stable.
Will be transmitted to.

Further, as the heat absorbing member, a large number of metallic wires 21 are arranged between the first and second porous plates 4 and 5 as shown in a sectional view in FIG. 5 instead of the metal balls 7. However, the same effect can be obtained.

Further, in the illustrated embodiment, the connecting portion between the pressure introducing portion 1 and the connecting portion 2 and the connecting portion between the connecting portion 2 and the reaction force supporting portion 8 are shown as being detachably configured. If necessary, they may be fixed by welding or the like. However, the metal balls 7 and the net 20 as the heat absorbing member
It is convenient that at least the pressure introducing portion 1 and the connecting portion 2 are separable from each other as shown in FIG.

Further, the connecting portion 2 and the reaction force supporting portion 8 may be integrally formed.

Furthermore, this ultra-high temperature pressure converter can be naturally used not only for measuring the pressure in the combustion chamber of a rocket engine, but also for measuring the pressure under various high temperature environments for a short time.

(e) Effects As described in detail above, according to the present invention, there is provided an ultrahigh temperature pressure transducer capable of accurately measuring the pressure of a fluid under ultrahigh temperature without being affected by temperature. can do.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a sectional structure of an ultrahigh temperature pressure transducer according to an embodiment of the present invention, FIG. 2 is a side view showing an external structure of the embodiment, and FIG. ) And (b) are
FIG. 4 is a diagram showing the results of experiments conducted with respect to temperature changes and strain output changes at predetermined locations in the same embodiment, FIG. 4 is a front view showing the configuration of the essential parts of another embodiment, and FIG. It is sectional drawing which shows the principal part structure of an Example. DESCRIPTION OF SYMBOLS 1 ... Pressure introduction part, 1c ... Pressure introduction path, 2 ... Connection part, 4,5 ... 1st and 2nd perforated plate, 7 ... Metal ball, 8 ... Reaction force support part, 10 ... ... Diaphragm, 11 ... Sensing part, 11a ... Force transmitting part, 11b ... Straining part, 12 ... Strain gauge, 13 ... Airtight terminal plate, 15 ... Terminal cover, 16 ... Waterproof connector, 19 ……Lead.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-198740 (JP, A) Actually opened 61-115944 (JP, U) Actually opened 48-023086 (JP, U)

Claims (5)

[Claims] Claim: What is claimed is: 1. A pressure of a fluid is converted into a force by a diaphragm, and this force is transmitted to a strain-generating portion via a force transmitting portion to deform the strain-generating portion, and the strain gauge attached to the strain-generating portion causes the deformation. In a pressure converter that detects and obtains an electric signal corresponding to an applied pressure, a pressure introducing part that is fixedly coupled to a pressure detection target and guides the fluid from the target, and a fluid having a heat-resistant and large heat capacity material. And a connecting portion for guiding the fluid while bringing the fluid introduced from the pressure introducing portion into contact with the heat absorbing member and having a heat absorbing member formed in a shape having a large surface area in contact with
The heat of the super-high temperature fluid introduced into the pressure introducing portion is absorbed by the heat absorbing member in the connecting portion, and the pressure of the fluid whose temperature is lowered is applied to the diaphragm. High temperature pressure transducer. 2. The ultra-high temperature pressure transducer according to claim 1, wherein the heat absorbing member is composed of a large number of metallic heat absorbers. 3. The heat absorbing body is a steel ball.
Ultra high temperature pressure transducer according to the item. 4. The ultrahigh temperature pressure transducer according to claim 2, wherein the heat absorber is a steel wire. 5. The ultrahigh temperature pressure transducer according to claim 1, wherein the connecting portion has a heat radiating portion formed on the outer surface side thereof.