JP2000097798A - Throat plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate possibility of deformation of a skirt part and enable sharing with a rocket engine with a different shape of throat part by placing an expandable and contractible body inserted into the throat part and a gas supply path supplying an expanding gas. SOLUTION: A rocket engine 1 provides an injector 4 injecting fuel and an oxidizing agent, a combustion chamber 5 burning fuel, and a nozzle 6 ejecting combustion gas. In an airtight test of the combustion chamber 5, a throat plug 10 is used to block up a throat part 7. The throat plug 10 is inserted into thin space of the throat part 7 under a condition that gas in a sealed space 12 of an expandable and contractible body 11 is released. Then, a valve 15 is opened and an expanding gas is provided in the sealed space 12 through a flexible hose 13 (a gas supply path). Therefore, since the expandable and contractible body 11 is expanded and an outer circumference face is closely contacted to an inner circumference face of the throat part 7, the part 7 is blocked up. At that time, the throat plug 10 is intended to prevent a slip-off by friction force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throat plug for closing a throat portion of a nozzle of a rocket engine and performing an airtight test or the like.

[0002]

2. Description of the Related Art Generally, a rocket / satellite engine such as an apogee engine combusts a liquid fuel supplied through a fuel supply valve and a liquid oxidant also supplied through a valve through an injector. The fuel is injected into the chamber and burns, and the combustion gas blows out from the nozzle to obtain a predetermined thrust. In such a rocket engine, it is necessary to perform an airtightness test to check whether or not the airtightness of the combustion chamber is maintained before the rocket engine is mounted on an actual machine. When performing the airtightness test of the combustion chamber, a jig called a throat plug is used. The throat part of the nozzle is closed using.

[0003] As a conventional throat plug,
A method in which a blind plug is pressed against a throat portion by supporting a skirt portion provided below the nozzle and a rod-shaped body locked to the inside (rear side) of the throat portion and extending to the outlet side. There is a method in which a blind plug is used to attract the blind plug in the direction of the throat and to fix it.

[0004]

However, in the conventional throat plug which supports the skirt portion, a load is applied to the skirt portion which is originally weak in strength, and there is a possibility that the skirt portion may be deformed or damaged. Also, in the method using blind plugs, the shape and size of the blind plug to be used must match the shape and size of the throat part of each rocket engine, and it is necessary to manufacture a throat plug for each engine, It was very troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has no fear of deforming the skirt portion of a rocket engine, and is commonly used for rocket engines having different shapes and sizes of throat portions to some extent. It is intended to provide a throat plug that can.

[0006]

In order to achieve the above object, an invention according to claim 1 is a throat plug for closing a throat portion of a nozzle of a rocket engine, wherein the throat plug has a closed space and a throat portion. And a gas supply path for supplying an inflation gas to the closed space. According to a second aspect of the present invention, in the throat plug of the first aspect, a technique is employed in which the expandable and contractible body is formed of a stretchable material. According to a third aspect of the present invention, in the throat plug according to the first or second aspect, a technology is provided in which the expansion and contraction body is provided with a communication passage communicating with the inside of the throat portion separately from the closed space. The invention according to claim 4 is the throat plug according to claim 1, 2 or 3,
A technique is employed in which a locking member is provided at the tip of the expansion / contraction body, which is expanded in the radial direction of the throat section and is locked inside the throat section when the inflation gas is sent and the expansion / contraction body expands. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The rocket engine 1 shown in FIG. 1 is a so-called apogee engine for obtaining a thrust necessary for placing a satellite or the like on an apogee orbit. As shown in FIG. 1, the rocket engine 1 includes a first valve 2 for supplying fuel, a second valve 3 for supplying oxidant, and an injector 4 for injecting fuel or oxidant.
And a combustion chamber 5 for burning fuel injected from the injector 4 and a nozzle 6 for ejecting combustion gas.

[0008] The first valve 2 and the second valve 3 are both connected to the injector 4. The first valve 2 adjusts the supply amount of liquid fuel such as hydrazine to the injector 4. Is also injector 4
The supply amount of a liquid oxidizing agent such as NTO (nitrogentroxide) is adjusted.

The injector 4 injects fuel supplied through the first valve 2 and oxidant supplied through the second valve 3 into the combustion chamber 5. And a large number of pores for oxidant injection are formed. The combustion chamber 5 ignites the fuel injected from the injector 4 to generate combustion gas, and is formed integrally with the nozzle 6.

The nozzle 6 is for injecting the combustion gas in the combustion chamber 5 to the outside, and is formed in a substantially hanging bell shape integrally with a skirt portion 8 called a nozzle extension from a throat portion 7 following the combustion chamber 5. ing. As an example, the total length of the nozzle 6 and the skirt 8 is about 1 m, and the diameter of the skirt of the skirt 8 is about 50 cm.

The injector 4 and the combustion chamber 5 (nozzle 6) are generally tightly joined by a bolt at a joint 9 with a sealing material such as an O-ring interposed therebetween. In order to confirm the above, an airtight test of the combustion chamber 5 is required. In performing the airtight test, a throat plug 10 is used to close the throat portion 7.

The throat plug 10 is made of a material that can expand and contract,
For example, an expansion / contraction body 11 made of a natural or synthetic rubber material or a plastic material, and a flexible hose (for supplying an inflation gas such as air or nitrogen gas) to a closed space 12 formed inside the expansion / contraction body 11 Gas supply path) 13. The expansion / contraction body 11 is inserted into the throat portion 7 for an airtight test, and is formed in a state penetrating the inside of the throat portion 7, that is, a pipe (communication passage) 14 communicating with the combustion chamber 5. It should be noted that whether or not a material that can expand and contract is used as the material of the expansion and contraction body 11 is optional. However, by using a stretchable material, the throat 7
And the adhesion to the substrate can be improved.

As shown in FIG. 2 (A), the outer shape of the expandable / contractible body 11 is changed from a state in which the expandable body 11 is contracted so as to be inserted into the throat portion 7 through a flexible hose 13 as shown in FIG. 2 (B). As a result, an inflation gas is supplied, and the state changes to a substantially spherical state. However, the shape of the expansion body 11 when expanded is not limited to the shape shown in FIG. 2B, and may be, for example, a substantially gourd shape corresponding to the shape of the throat portion 7. In the case of this approximately gourd shape, the bulge above the approximately gourd shape easily protrudes toward the inlet side (combustion chamber 5 side) of the throat portion 7 when expanded, and the lower bulge easily protrudes toward the outlet side of the throat portion 7. , Ensuring the engagement with the throat 7.

The other end of the flexible hose 13 is connected via a valve 15 to an inflation gas supply source (not shown). The rear end of the pipe 14 is connected to an external or test gas supply source (not shown) via a valve 16.

The throat plug 10 constructed as described above
The state of use will be described. First, throat plug 1
0 is inserted into the narrow space of the throat portion 7 of the rocket engine 1 in a state where the gas in the closed space 12 of the expansion body 11 is evacuated (the state shown in FIG. 2A). Then, the valve 15 is opened while maintaining the inserted state, and the inflation gas is supplied through the flexible hose 13 to the closed space 1 of the inflatable body 11.
Supply to 2. As a result, the expandable body 11 expands, and as shown in FIG. 1, the outer peripheral surface of the expandable body 11 comes into close contact with the inner peripheral surface of the throat section 7, thereby closing the throat section 7.

The supply pressure of the inflation gas is set so that the throat plug 10 does not come off due to the pressure of the test gas supplied to the combustion chamber 5. At this time, the throat plug 10 is prevented from coming off by the frictional force between the outer peripheral surface of the expansion / contraction body 11 and the inner peripheral surface of the throat portion 7, and in order to improve this frictional force, the outer periphery of the expansion / contraction body 11 is reduced. Throat part 7
Irregularities may be formed on the contact surface, or a member having a large friction coefficient may be attached.

After the expansion / contraction body 11 of the throat plug 10 is expanded by the pressure of the expansion gas to close the throat portion 7, the test gas is supplied to the combustion chamber 5 via the pipe 14 or the injector 4. Then, the pressure in the combustion chamber 5 is set to, for example, 10 kg / cm ² , and an airtight test is performed to check for leakage from the joint 9. The discharge of the test gas is performed through the pipe 14 by opening the valve 16. This is to prevent the injector 4 from being clogged.

After the airtight test is completed, the test gas is released to the outside, the valve 15 is opened, and the inflation gas contained in the closed space 12 of the expansion / contraction body 11 is extracted to thereby remove the expansion / contraction body 1.
1 is contracted, and in this state, the throat plug 10 can be removed from the throat portion 7.

As described above, according to the throat plug 10, the throat portion 7 is closed by expanding the inflatable body 11 supplied with the inflation gas via the flexible hose 13. The same throat plug 10 can be used for engines having slightly different shapes and sizes, and versatility can be ensured.

In the above embodiment, the rocket engine 1 is of a two-liquid propulsion type in which a fuel and an oxidant are reacted. However, the present invention is not limited to this. This throat plug 10 is also applicable. The rocket engine 1 is not limited to an apogee engine, but may be applied to other propulsion-type main engines or thrusters for orbit correction, attitude control, speed control, and the like.

FIGS. 3A and 3B are perspective views showing another embodiment of the throat plug. The throat plug 10a expands in the radial direction of the throat portion 7 when the inflation gas is sent to the tip of the expansion / contraction body 11a and expands the expansion / contraction body 11a, and the inside of the throat portion 7 (combustion chamber 5 side). Is provided with a metal locking member 17 which is locked to the base member. As shown in FIG. 3, the four bar-shaped locking members 17 are
They are arranged radially at equal intervals in the circumferential direction at the tip of a.
Each locking member 17 has a small ring 19 passed through a large ring 18 attached to the tip of the pipe 14a, and is rotatable about the large ring 18 as a central axis. Further, a projection 21 is formed on the small ring 19 on each of the locking members 17 so as to be locked to the disk 20 inside the large ring 18 in an expanded state.

In such a throat plug 10a, when the expanding / contracting body 11a is contracted, as shown in FIG. 3 (A), each locking member 17 is in a so-called closed state, so that the narrow throat The section 7 can be passed. When the expansion / contraction body 11a expands, as shown in FIG. 3 (B), each locking member 17 is pushed up by the outer peripheral surface of the expanded expansion / contraction body 11a, and rotates around the large ring 18 to form a radial shape. spread.

FIG. 4 is a sectional view showing a main part of the throat plug 10a shown in FIG. 3 in use. After the expansion and contraction body 11a is inserted into the throat portion 7 in a contracted state, and when the inflation gas is supplied to the closed space 12a of the expansion and contraction body 11a, each of the locking members 17 is moved in the combustion chamber 5 as described above. It will spread radially. Moreover, each locking member 17 is held so that the protrusion 21 hits the disk 20 and does not rotate any more.

Therefore, even when the test gas is supplied to the combustion chamber 5 and the pressure in the combustion chamber 5 rises and a force is applied to the expansion / contraction body 11a in the pulling-out direction, the tip of each locking member 17 is prevented. Is locked inside the throat portion 7 (on the side of the combustion chamber 5), thereby preventing the throat plug 10a from coming off. In addition, instead of rotating around the large ring 18, each locking member 17
The expansion / contraction body 1 is attached to a part of the outer peripheral surface of the
When 1a expands, it may expand and when contracted, it may close.

The various shapes and combinations of the constituent members shown in the above embodiment are merely examples, and various changes can be made based on design requirements without departing from the spirit of the present invention.

[0026]

As described above, according to the throat plug of the first aspect, the expansion gas is sent to the closed space of the expansion / contraction body through the gas supply path, so that the expansion / contraction body expands. Since the throat portion can be closed, there is no need to support the skirt portion, and there is no risk of deformation of the skirt portion. Further, since the expandable and contractible body expands and contracts, it is possible to cope with different shapes and sizes of the throat portion, and it can be shared by different engines, so that versatility can be secured. According to the throat plug of the second aspect, since the expandable and contractible body is formed of a stretchable material, the close contact between the outer peripheral surface of the expandable and contractible body and the inner peripheral surface of the throat portion can be improved. The closure of the part can be performed more effectively. According to the throat plug of the third aspect, a communication passage communicating with the inside of the throat portion is provided in the expansion and contraction body separately from the closed space, so that a test gas is supplied to the combustion chamber or a test gas is supplied from the combustion chamber. The gas is easily and reliably discharged through the communication passage, and the airtight test can be easily performed. According to the throat plug of the fourth aspect, when the inflation gas is sent to the distal end of the expandable member and the expandable member expands, the expandable member expands in the radial direction of the throat portion and is locked inside the throat portion. Because a stop member is provided,
It is possible to reliably prevent the throat plug from falling off.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a throat plug according to the present invention.

FIGS. 2A and 2B show the throat plug of FIG. 1, wherein FIG. 2A is a perspective view showing a state where the expandable body is contracted, and FIG. 2B is a perspective view showing a state where the expandable body is expanded.

3A and 3B show another embodiment of the throat plug according to the present invention, wherein FIG.
(B) is a perspective view of a state where the expandable body is expanded.

FIG. 4 is an enlarged sectional view showing a use state of the throat plug of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rocket engine 6 Nozzle 7 Throat part 10, 10a Throat plug 11, 11a Expansion / contraction body 12, 12a Sealed space 13, 13a Flexible hose (gas supply path) 14, 14a Pipe (communication path) 17 Locking member

Claims (4)

[Claims] 1. A throat plug for closing a throat portion of a nozzle of a rocket engine, said throat plug having an enclosed space and being inserted into said throat portion, and a gas for supplying an inflation gas to said enclosed space. A throat plug comprising a supply path. 2. The throat plug according to claim 1, wherein the expandable and contractible body is formed of a stretchable material. 3. The throat plug according to claim 1, wherein a communication passage communicating with the inside of the throat portion is provided in the expansion and contraction body separately from the closed space. 4. A latch that is expanded in a radial direction of the throat portion and locked inside the throat portion when an inflation gas is sent to the tip of the inflatable and contractible member and the inflatable body expands. The throat plug according to claim 1, 2 or 3, wherein a member is provided.