RU2467831C1 - Gasostatic extruder - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to industrial equipment for machining large-size parts from solid and discrete materials at up to 500 MPa and 2000°C created in gasostic extruder working chamber medium. Proposed device comprises bearing bed and container with plugs to make its working chamber communicated via gas pipeline with gas system shutoff normally-closed valves with increased stop needle lift above the seat and gas release cylinder with stepped rod. Said cylinder houses the spring to allow permanent pressing of cylinder rod to servo rod. Every valve comprises piston, gas cylinder of unloading, needle with through inner channel communicating gas cylinder with under-valve chamber. Set of disc springs is arranged above valve piston. Needle cylindrical surface central zone has cylindrical groove with diameter smaller than outer diameter. Needle bottom end, above shutoff cone, has solid cylindrical bead while needle top end is provided with cylindrical washer with diameter exceeding that of the needle. Said cylindrical surface central zone may be provided with boring to fit semi-rings therein.

EFFECT: higher tightness, simplified design.

2 cl, 5 dwg

Description

The invention relates to the field of creating industrial equipment for the processing of large-sized products from solid and discrete materials with simultaneous or combined exposure to high pressures and temperatures up to 500 MPa and temperatures up to 2000 ° C created in the gas environment of the working chamber of a gas thermostat.

The main components of the gas thermostat are:

- the actual gas thermostat, including a container with upper and lower plugs and a power bed;

- gas and vacuum systems providing the necessary technological parameters of the gaseous medium in the working chamber of the machine;

- heating and cooling systems;

- control system.

The efficiency of a gas thermostat largely depends on the reliability and performance of its main gas system. In turn, the quality level of the latter is determined by the conditional passage and throughput of the locking equipment and the gas pipeline, through which the working medium moves during the process, the performance of the compressors and vacuum pump that pump gas from the balloon station to the container and back at the end of the work cycle , as well as with multiple evacuation of the working chamber of the machine. The development and use of reliable gas pressure equipment with increased nominal bore is of particular importance when creating modern industrial gas thermostats with a working chamber volume reaching several cubic meters.

In the case of the use of shut-off valves with increased nominal bores, the axial load of the working medium on the needle critically increases. So, at a working pressure of a gas thermostat of 200 MPa in a valve with a nominal bore DN = 5 mm, it is 390 kg, and in a valve with a DN = 15 mm - 3530 kg, i.e. - increases by almost 10 times, which necessitates the use of springs of high stiffness, and hence increased dimensions. At the same time, the piston diameter of the servo cylinder, which is necessary to compress the spring when the valve is opened, increases proportionally, as well as the dimensions and metal consumption of the valve as a whole.

An analogue of the claimed invention is a gas thermostat described in the copyright certificate SU No. 1748940, bulletin No. 27 dated 07/23/1992, the analog gas thermostat contains a container closed at the ends with stoppers with sealing seals. In the upper and lower plugs, gas inlets are made, connected through a system of gas shut-off valves to a pressure source (compressor), balloon station, instrumentation and the atmosphere. The gas system of the machine is equipped with standardized normally closed valves with an increased passage - DN 15 mm. A gas unloading cylinder is installed on the valve, the stem of which rests on the valve needle, and its subvalvular cavity is connected via an external high-pressure capillary to the unloading cylinder. Despite the fact that the use of an unloading cylinder in order to balance the “needle-rod of the gas cylinder” system with the pressure of the working medium made it possible to reduce the dimensions and metal consumption of the valve in comparison with the similar parameters of the direct-acting shut-off valve, in which the needle is not balanced, the disadvantage of the analog gas thermostat valve is that that its diametric size is determined by the location of several clamping springs on the periphery of the servo piston beyond the outer diameter of the unloading cylinder and then tightening their studs, and the total height of the valve includes the height of the gas cylinder mounted above the upper flange of the valve, which affects the metal consumption and, as a result, its cost.

Another significant drawback of the analog gas thermostat valve is the connection of its subvalvular cavity and the gas discharge cylinder by means of an external high pressure capillary. The capillary is a thick-walled metal tube of small diameter with a small nominal bore, used only to equalize the pressure in the connected cavities. So, for example, a capillary f5 × 1.6 is used in an analog gas thermostat, where 5 mm is the outer diameter and 1.6 mm is the wall thickness. Currently available capillaries are made of either stainless or thermally hardened structural steels that do not have sufficient hardness. The connection of the capillary with the corresponding body part is as follows. At the end of the capillary, a cone with a sharp edge is machined at its truncated apex, and a left thread corresponding to the outer diameter of the capillary onto which the sleeve is screwed is cut behind the cone. With the help of a compression nut, the sleeve moves forward, pressing the sharp edge of the capillary to the surface of the body part with a cone several degrees higher than the angle of the cone of the capillary, thus creating a sealed “capillary - case” connection. In the case of using the described capillary connection, which does not have sufficient hardness and strength, its sharp edge is crushed during the operation of the equipment, leading to the valve failure as a result of a violation of internal tightness and the creation of an emergency. A thread made on a capillary of a small outer diameter weakens its cross section, creating stress concentrators, and, as a result, in the zone of concentrators, the capillary wall often ruptures under the influence of the working medium pressure. In addition, the processing of the cone and threading on capillaries of considerable length, and especially on curved (not straight) ones, cannot be performed on metal-cutting machines, but are manufactured using special, expensive tools and tools. The same problem occurs when restoring the thread and capillary cone during operation of the gas thermostat at the place of its operation. In the case of the connection of the aforementioned high-pressure cavities with an external capillary, there is also the possibility of destruction of both the capillary itself and its connections as a result of an accidental external mechanical action.

The prototype of the invention is a gas thermostat described in patent RU No. 2402409 of 02/05/2009. The prototype gas thermostat contains a power frame, fastened with a bandage of high-strength tape, a container closed at the ends of the upper and lower plugs, normally-closed gas valves, a compressor and a balloon station. In the valve body, the bores of the supravalvular and subvalvular cavities form a sharp edge of the seat on which the needle rests in the closed state of the valve. An inner channel is made in the rod of the unloading cylinder and the needle, connecting the gas cylinder to the subvalvular cavity. The needle and the stem are interconnected by a conical metal-metal connection.

The disadvantages of the shut-off valve of the prototype gas thermostat include the inability to remove the seal blocks from the discharge cylinder and valve body intact with the help of the stem and needle, respectively, for re-examination. When disassembling the valve, for example, to restore the working conical surface of the needle or to replace one of the elements of the seal block, homemade pullers are used that destroy the fluoroplastic, rubber and bronze elements of the block compressed by the pressure of the working gas, as well as the seating surfaces of the valve bores and the discharge cylinder.

Another disadvantage of the valve is a composite (non-monolithic) element of the needle - the stem. During operation, their threaded connection is deformed, which leads to its depressurization and failure of the valve. This state of the valves of the gas system does not allow to reliably carry out regular operations of the working cycle of the machine and can cause emergency situations with severe consequences, given the huge energy reserve of compressed gas in the working chamber of the gas bath.

The objective of the invention is the creation of high-performance, reliable gas baths for processing industrial products from discrete, solid and nanopowder materials with high (up to 500 MPa) gas pressure at temperatures up to 2000 ° C.

The objective of the invention is achieved by the fact that the gas thermostat contains a power bed and a container with an upper stopper and a lower stopper forming its working chamber, connected by a gas pipeline to a gas system, including shut-off valves with an increased nominal passage. Each of the valves is equipped with a servo-drive with a piston, a needle with a cylindrical surface, an unloading cylinder located on the bottom cover of the servo-drive, over which the disk spring unit is mounted. A cylindrical groove is made on the cylindrical surface of the middle zone of the needle, the diameter of which is smaller than its outer diameter. A continuous cylindrical collar is made at the lower end of the needle above the locking cone, and a cylindrical washer with a diameter greater than the diameter of the needle is installed using a bolt with through axial drilling on the upper end of the needle located inside the discharge cylinder.

The technical result is to reduce the metal consumption and dimensions of the valve gas thermostat.

The design of the proposed gas thermostat is presented in figures 1-5, where:

- figure 1 shows a gas thermostat with a fragment of the gas system;

- figure 2 shows a normally closed valve with an enlarged passage and a gas unloading cylinder mounted on the bottom cover of the servo;

- figure 3 presents the upper part of the rod of the gas discharge cylinder;

- figure 4 shows the fastening of the cross member to the valve needle;

- figure 5 shows the lower part of the needle with a shoulder and a block of seals.

The gas thermostat (figure 1) contains a power frame 1, fastened with a bandage of high-strength tape 2, a container 3, closed at the ends of the upper 4 and lower 5 plugs, normally-closed valves 6, 7, 8 and 9, a gas compressor 10 and a balloon station 11. To control the flow of the working medium during the execution of technological operations of the working cycle, the valves 6, 7, 8 and 9 are interconnected and with other components of the gas system by a pipe 12, while the gas inlet 13 into the container 3 is made in the upper tube 4. Valve (figure 2 ) contains a housing 14, in which the bores of the valve 15 and the subvalvular 16 cavities form a sharp edge 17 of the seat, on which the needle 18 rests when the valve is closed. The hydraulic or pneumatic actuator 19 is connected to the housing 14 by pins 20. The actuator consists of a sleeve 21, a piston 22, an upper cover 23 and a lower cover 24, fixed inside the sleeve by means of spring rings 25. A cup 26 is installed on the top cover 23, inside of which there are Belleville springs 27. The force exerted by the springs on the needle 18, transmitted by the piston 22 through the studs 28 and the cross member 29, is regulated by a screw 30. the list 29 is connected to the needle 18 using two half-rings-dowels 31 mounted in the groove of the needle 18, directed to the axis of the needle. The gas unloading cylinder 32 is fixed to the bottom cover 24 with bolts 33. In the needle 18, an internal channel 34 is made connecting the undervalve cavity 16 with the unloading cylinder. When the discharge cylinder 32 is located on the bottom cover 24, the dimensions and metal consumption of the valve are significantly reduced, as well as the cost and laboriousness of its manufacture. Replacing several cylindrical springs located on the periphery of the piston of the servo valve of the gas thermostat prototype, one block of centrally located disk springs 27 also leads to a decrease in size and simplification of the valve design. With the same stiffness, the diameter of the Belleville springs is 4-5 times smaller than the diameter of the cylindrical. If the diameter of the upper end 35 of the needle 18 is slightly larger than the diameter of its lower end 36, then the needle is pressed against the seat with an additional force equal to the difference in the forces acting on the opposite ends of the needle of the valve, reliably ensuring its internal tightness in the closed state. Moreover, the magnitude of this force increases with increasing working pressure in the system. The valve opens when the control pressure is applied under the piston 22 of the servo drive 19. For convenience of removing the seal block 37 of the plunger of the unloading cylinder 32 without destroying its separate elements and reusing them, a washer 38 is installed on the upper end of the needle, with which the seal is removed from the bore of the unloading cylinder when removed their needles 35. The washer is fixed to the needle with a bolt 39 having axial through-hole drilling 40. A shoulder 41 performs the same function, made on the lower end of the needle 36 and located above its cone CA 42, but below the needle seal assembly 43 in the valve body. Both seal and traverse blocks are put on the needle through its upper end before installing the washer 38 and assembling the valve as a whole.

The thermostat operates as follows. In the initial position, the power frame 1 is shifted from the axis of the container 3. On the lower tube 5, located outside the container, the workpiece is installed and introduced into the working space of the gas thermostat chamber. The power bed is mounted on the axis of the container. The control pressure is supplied to the valve actuator 8, the valve opens and gas flows by gravity from the cylinders 11 into the container. After equalizing the pressure in them, the valve 8 closes. Then, valves 7 and 9 are opened and, using compressor 10, the pressure in the container rises to a predetermined value. Next, the compressor stops, and valves 7 and 9 are closed. The heating system is turned on, warming up the workpiece to the required temperature. At a given pressure and temperature, the workpiece is aged for the required time. Then the working space of the chamber with the workpiece is cooled. Valve 8 opens and gas flows by gravity from container 3 into cylinders 11. The remaining gas is discharged through open valve 6 from the container to a low-pressure balloon station (not shown) or to the atmosphere. After reducing the pressure in the container to atmospheric pressure, the power bed 1 moves from the axis of the container, releasing the lower plug 5, which together with the processed product is removed from it, and the cycle repeats.

Thus, the present invention allows to create a reliable and high-performance gas thermostat due to the use of compact shut-off valves with increased nominal bore in its gas system;

- reduce the execution time of the operations of the work cycle associated with the movement of the working medium through the gas pipeline and through the locking equipment with increased throughput;

- reduce the total cycle time, increase the productivity of the gas bath and reduce the cost of products.

Claims (2)

1. A gas thermostat comprising a power bed and a container with an upper stopper and a lower stopper forming its working chamber, connected by a gas pipeline to a gas system, including shut-off valves with increased nominal bore, each valve being equipped with a servo-drive with a piston and a needle with a cylindrical surface , an unloading cylinder located on the bottom cover of the servo-drive, above the piston of which a Belleville spring unit is installed, characterized in that the cylinders are made on the cylindrical surface of the middle zone of the needle A solid groove, the diameter of which is smaller than its outer diameter, has a continuous cylindrical collar at the lower end of the needle above the locking cone, and a cylindrical washer with a diameter greater than the diameter of the needle is installed using a bolt with through axial drilling on the upper end of the needle located inside the unloading cylinder. 2. The thermostat according to claim 1, characterized in that the cylindrical surface of the middle zone of the needle is made with a groove for installing half rings.

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