UA79333C2 - Bi-metal membrane unit - Google Patents

Abstract

The invention relates to safety valves of pipelines with membrane that can be destroyed, in particular in units for separation of cavity of engine and tank in systems for hot supercharge of rocket tanks. In the joint between two sections of steel pipeline thickened in periphery aluminum membrane is installed. It is welded to pipeline through aluminum-steel adapter. Expanded flanges of pipeline enclose the place of joint and are welded to each other. The invention promotes reliable sealing of membrane unit and joint of pipeline under conditions of alternating in sign loads and durable storage, transportation and testing.

Description

Description of the invention

The proposed membrane unit refers to the area of designing units for systems of hot 2 inflation of rocket tanks, namely to the units of separation of the engine and tank cavities.

Known constructions of membrane nodes of inflation mains of various types, detachable (threaded and screw) or semi-detachable (a combination of welded and detachable) connections | Dobrovolsky M.V. "Liquid rocket engines" (pp. 239, 242, 1968), A.A. Kozlov. etc. "System of power supply and control of liquid rocket propulsion installations" (p. 192, 1988) 70 These membrane units are designed to separate either two cavities or each of the cavities from the external environment. In the conditions of long-term action on the point of contact of alternating loads during long-term storage or after transportation in such connections, a loss of the main quality of the membrane assembly is possible - loss of tightness. Under the influence of the specified factors, the wrinkling of the membrane at the joint is weakened, a microleakage appears, which leads to a significant deterioration of the operational characteristics of such a joint. 12 In the analogue given in the book by Kozlov A.A. etc. "Power and control systems of liquid rocket propulsion installations"), the tightness of the joint is achieved by crimping the aluminum membrane between the flanges, when it is kept in a compressed state due to residual welding stresses. Such a connection ensures hermetic isolation of the internal cavities of the pipeline from the external environment. However, such a design does not guarantee reliable hermetic separation of pipeline cavities from each other, especially during long-term storage.

The main drawback of the given design is the impossibility of ensuring sufficient sealing of the cavities under the conditions of operation of the hot inflation system of the fuel tank.

The prototype of the proposed solution is the design of the membrane connection given in (book

Dobrovolsky M.V. "Liquid rocket engines" (p. 241)). In this design, the membrane c 22 is installed in the pipeline between the flanges. For low breakthrough pressure under operating conditions, a Ge) aluminum membrane with directional free breakthrough is installed.

Tightening for crumpling the membrane is provided by a bolted connection. However, this design does not guarantee maintenance of tightness under the influence of vibrations during transportation, alternating loads during tests and long-term storage (temperature and pressure changes). The tightness between the cavities of the pipeline or between one of the cavities and the environment may be broken. In the worst case, complete depressurization of the joint will occur. One way to increase the reliability of the seal would be to introduce welding or brazing at the joint with a corresponding replacement of the membrane material. Reliable separation of cavities and. can be provided by welding a steel membrane. However, with a relatively low breakthrough pressure in the systems of He») of inflation of rocket tanks, the steel membrane must have a small thickness of the main material, which becomes even thinner at the place of the notch 3o. Such membranes have low resistance to cyclic loads and are non-technological in production. In addition, due to the high elasticity of the petals of such a membrane, they vibrate in the gas flow after the membrane ruptures, their cracking and separation occurs, and this requires the installation of special traps.

One of the flanges of the prototype is made together with a seat under the membrane. The second flange is a component "with a wrap-around part, while the landing place under the membrane is on the stationary part of the pipeline, Z 70 is also made together with the pipeline. c The node is quite simple in terms of design and compact. It allows to use different materials for pipeline and membrane. However, the mechanical connection in the joint does not meet the increased requirements for tightness and therefore requires the use of special measures.

The invention is based on the task of ensuring reliable sealing of the junction of two sections of the pipeline at a relatively low burst pressure, under variable loads under conditions of long-term storage and 7 tests, transportation vibrations due to the installation of a profiled variable cross-section of an aluminum (Te) membrane at the junction between two sections of a steel pipeline according to by means of welding through a bimetallic adapter.

Mami The new significant distinguishing features of the proposed invention are: oz 20 - the membrane is thickened on the periphery; - the membrane is profiled at the junction; c" - flanges at the junction are made in the form of pipeline expansion; - the membrane is installed by welding through a bimetallic adapter.

Known essential distinguishing features are: 52 - aluminum separating membrane;

ГФ) - disconnecting joint of a high-temperature steel gas main.

A set of new and known features allows to provide a new technical result, namely: to ensure reliable sealing of the junction of two sections of the pipeline at a relatively low breakthrough pressure, with variable loads in conditions of long-term storage and testing, transportation vibrations. because To explain the operation of the membrane assembly, drawings are attached (Fig. 1, 2, 3). Fig. 1 shows the general view of the membrane unit, Fig. 2 shows a section at the junction of the membrane with the pipeline before welding the membrane to the bimetallic adapter, Fig. 3 shows a section at the junction of the membrane with the pipeline after welding the membrane to the bimetallic adapter.

In Fig. 1: item 1 - membrane; because pos. 2 - bimetallic adapter;

item 3 - inlet section of the pipeline; item 4 - the outlet section of the pipeline;

Fig. 2: item 1 - membrane; item 2 - bimetallic adapter;

In Fig. 3: item 1 - membrane; item 2 - bimetallic adapter.

The element that separates the cavities of the pipeline sections in this design is an aluminum membrane item 1 of variable thickness. The thinned central part of the membrane with a notch made on it ensures its opening 7/0 at the given value of the breakthrough pressure. Membrane item 1 is installed in the unit by welding. For this purpose, the profiled periphery of the membrane is selected in such a shape and thickness that it acts as a compensator when welding with a bimetallic adapter item 2. Profiling gives the membrane pos. 1 a cup-shaped shape and allows bilateral deformation of the material during pressure welding, ensures the optimal thickness of the weld seam and protects the membrane pos. 1 from distortion (Figs. 2 and 3). The membrane installed between the inlet pos.Z and /5 Output pos.4 sections of the pipeline (cavities B and B, respectively), is crumpled due to the residual stresses of weld A. In turn, the adapter is made of a bimetallic rod, which consists of two elements : aluminum and steel, connected to each other by means of friction welding.

Thus, two sealing circuits are created in the membrane assembly of the proposed design. One - due to crumpling of the membrane, the second - due to welding of the membrane and welding of flanges.

During tests during the production of the system and the rocket as a whole, vibrations of transportation, sign-changing effects of the environment, such a membrane assembly retains its tightness with any weakening of the mechanical seal (creasing): - the connection between the cavities of the pipeline B and B cannot occur due to the welding of the membrane to the original sections of the pipeline; сч - connection with the external environment of any of the pipeline cavities will not be possible due to the welding of weld A. i)

Under the operating conditions of the hot inflation system at start-up, a breakthrough occurs along the notches of the thinned central part of the membrane, and its petals are laid out on the inner surface of the outlet part of the pipeline, without interfering with the gas flow. Mechanical compression between the inlet and outlet parts of the pipeline keeps them from breaking off. At the same time, the welding place of the membrane pos. 1 and the bimetallic adapter pos. 2 are protected by a steel section pos. 5 of the output part of the pipeline, which prevents the delamination of the bimetallic seam under the influence of high temperature during the operation of the inflation system. In the event of destruction of the bimetallic adapter item 2, its elements and the peripheral part of the membrane item 1 will remain inside the cavity G formed by the expanded inlet and outlet sections of the pipeline. At the same time, during the operation of the system, the bimetallic connection is relieved from power loads at the expense of the power element, which is a common part of the main line after welding of seam A.

Thus, the proposed design of the membrane assembly of the pipeline guarantees compliance with the increased requirements for this assembly in terms of tightness.

Used literature « 1. Dobrovolskyi M.V. "Liquid rocket engines" (p. 241, 1968) - prototype from p. 2. Kozlov A.A., V.N. Novikov, E.V. Solov'ev, "System! Power and control of liquid rocket propulsion installations" (p. 192, 1988)

Claims (1)

;" The formula of the invention -I Bimetallic membrane assembly for a high-temperature steel gas main, containing an aluminum re) membrane installed between the flanges of the pipeline, which is characterized by the fact that the aluminum membrane is thickened at the periphery, profiled at the point of contact with the pipeline and welded to it Through the bimetallic aluminum-steel adapter, and the flanges of the pipeline are made in the form of an expansion of the pipeline, which covers the joint with the membrane, and are welded together. this" F) name) 60 b5