RU2821357C1 - Single-action high-pressure valve - Google Patents

Abstract

FIELD: valve industry.

SUBSTANCE: invention relates to valve industry and can be used in designing single-action valves in systems for supplying gaseous working medium in propulsion systems of spacecraft, in various industries for operation with high-pressure gas. Single-action high-pressure valve comprises a housing with an electric heater on its outer surface and inlet and outlet unions on its ends and pre-deformed pusher made from material with shape memory effect placed inside the housing. Part of the inlet fitting inside the housing is made in the form of a shank with a blind hole, on the outer surface of the shank there is an annular groove of a triangular shape, and between the inlet nozzle thrust flange with the centring ledge and the nut screwed on the shank thread, coaxially to the shank of the inlet nozzle there is a pusher in the form of a bushing with two through holes made perpendicular to the axis of the bushing and crossing the hole of the pusher, in initial position, the pusher is pre-tightened by a nut with a tightening torque providing for the pusher squeezing without intermediate gaps.

EFFECT: invention is aimed at providing absolute tightness when separating the cavity of the high-pressure gas storage system and the main line of the gas supply system in storage modes and under conditions of vibration, as well as on reliable opening of valve at actuation.

4 cl, 4 dwg

Description

The invention relates to valve engineering and can be used to create single-acting valves in systems for supplying high-pressure gaseous working fluid in propulsion systems (PS) of spacecraft (SC), and can also be used in various fields of industry for working with high-pressure gases.

In systems for storing and supplying the working fluid in spacecraft propulsion systems, as an element that, before the start of operation of the remote control, hermetically separates the cavity of the working fluid storage system and the main line of the working fluid supply system, and after turning on the remote control and throughout the entire period of their operation, freely passes the working fluid through itself body, a single-acting valve is used. Single-acting valves are subject to high requirements for tightness, up to the so-called absolute tightness, and reliability of operation, as well as restrictions on size and weight characteristics and energy consumption.

Pyrovalves are often used as single-acting valves in systems for storing and supplying working fluid in propulsion systems. The principle of operation of pyrovalves is based on the forced destruction of the explosive locking element using a squib and subsequent depressurization of the internal cavity of the valve and, accordingly, the opening of the free passage of the working fluid through the valve (patents for inventions RU 2092204 C1 dated 05/20/1991, IPC A62S 37/40, RU 2159889 C1 dated 04/04/2000, IPC F16K 17/40, No. RU 2533592 C1 dated 07/22/2013, IPC F02K 9/50).

However, the known pyrovalves have large dimensions and weight, and the manufacture of a burst shut-off element is low-tech. During ground inspections and tests of propulsion systems, working with pyrovalves requires compliance with safety measures, failure to comply with which can lead to premature detonation of squibs in the presence of personnel. Also, during operation on spacecraft, when the pyro-valves are activated, shock-pulse impacts occur, which can lead to the destruction of the locking elements with subsequent depressurization of the internal cavities of the pyro-valves, which can lead to the loss of the working fluid in the spacecraft propulsion system. During shock-pulse action, vibration is also likely to occur, which can lead to partial destruction of both the elements of the propulsion system themselves and the payload of the spacecraft.

A thermal shut-off valve is known for automatically shutting off the flow area of pipelines as a result of an increase in temperature (patent for invention No. RU 2359162 C1 dated June 16, 2008, IPC F16K 17/38), which contains a direct-flow housing with a seat made in it. A spring-loaded shut-off element is installed coaxially with the seat, equipped with a rod, which is passed through the central hole of a partition with a passage channel fixed in the body and is equipped with a stopper for the open position of the valve. An annular bore is made in the partition concentrically with the central hole, and an annular groove is made on the rod. The stopper is located between the side walls of the bore and the surface of the bore and is made in the form of one or several turns of wire made of a material with shape memory effect (SME). According to the shape memory effect, the inner diameter of the wire turns is larger than the diameter of the rod, and the outer diameter is smaller than the diameter of the bore in the partition.

The disadvantages of this thermal shut-off valve are: in the initial position - open state, application only in ground conditions, design complexity, for operation the temperature of the working fluid or the environment must be increased to a critical temperature, unsatisfactory overall weight characteristics for use in space conditions as part of a propulsion system KA, low tightness of the locking element after operation.

A single-acting emergency thermal valve is known, which is initially in the closed position (patent for invention No. RU 2469233 C1 dated November 9, 2011, IPC F16K 17/40). The valve contains a cylindrical body in which first and second spring-loaded rods are axially located, connected to each other by a latch. At the end of the second rod there is a damper, hermetically closing the inlet, and on the wall of the outlet of the cylindrical body there is a perforated sleeve with a fuse. When the temperature rises to approximately 600°C in the area of the outlet hole, the fuse melts and flows out of the holes of the perforated sleeve, while the first rod begins to move, and then the second rod pulls the valve along with it, tearing it away from the seat of the inlet hole and freeing the passage for fluid medium.

A single-acting emergency thermal valve cannot be used as a single-acting valve in the system for storing and supplying the working fluid of a spacecraft remote control, since it has a rather complex design and, as a consequence, on the one hand, increased overall dimensions and weight characteristics, and on the other hand, the corresponding decreased reliability of valve operation. The high melting temperature of the fuse link requires increased power consumption, and after melting there is a possibility of particles of the fuse link getting into the working fluid supply line.

The patent application covers a spacecraft valve with a shape memory alloy actuator (patent application for invention No. US 20050173661 A1 dated 12/23/2003, IPC F16K 31/00), intended for use in pressurization systems of spacecraft propulsion systems, where it allows the pipeline to be opened or closed using a special electrical control. The invention relates to a valve with an actuator made of an alloy with SME and equipped with means for controlling the response temperature, characterized in that these means contain a reverse bias mechanism, which, in one embodiment, is a breakable pin. The valve according to the invention is of the normally open or normally closed type. Activation of the actuator is achieved by heating, for example by directly passing an electrical current through the actuator, which is in the form of wires. This current must be sufficient to bring the wires to a temperature greater than or equal to the activation temperature of the SME material (greater than 100°C), determined by selecting the size of the actuator and changing its length. In the example considered, the actuator is chosen so that it contracts during the temperature transition of the material with the SME.

The disadvantage of the invention is that the valve does not provide absolute tightness, the complexity of the design, high power consumption when heating the actuator by passing direct current through it, as well as the effect of the input pressure on the opening of the valve pair, which increases the risk of valve leakage at high pressures and long-term storage.

The closest in its design features to the claimed high-pressure single-acting valve is the valve (utility model patent No. RU 11290 U1 dated October 20, 1998, IPC F16K 15/02, F16K 17/38), adopted as a prototype, containing a housing with a locking element placed inside it, made of a material with a shape memory effect in the form of a thin-walled tube with a conical head, which is previously subjected to plastic deformation - stretching. In the body, the locking element is secured by means of a thread, and for the passage of the medium, holes are made at an angle at the base of the conical head. In the initial state, the valve is in the open position, with the conical head of the locking element placed with a gap relative to the body. If the temperature of the medium increases, the tube heats up and restores its shape prior to plastic deformation, that is, it contracts. In this case, the conical head gradually blocks the inlet hole, preventing further flow of the working medium.

However, the known valve cannot be used in a working fluid storage and supply system, where an initial closed state is required to hermetically separate the cavity of the high-pressure working fluid storage system and the supply system line before the propulsion system begins to operate. Making the shut-off element in the form of a thin-walled tube with holes located at the base of the conical head reduces the strength of the shut-off element due to the likelihood of its deformation during the process of twisting and tightening, and, as a result, reduces the reliability of the valve.

When creating the invention, the problems of ensuring the reliability of the valve with minimum overall dimensions and mass characteristics and minimum heater power, with hermetically separated storage cavities of the high-pressure working fluid up to 39.2 MPa and supply system lines in standby mode, under conditions of vibration and subsequent single operation, were solved .

The objectives are solved due to the fact that the single-acting high-pressure valve contains a housing with an electric heater on its outer surface and end inlet and outlet fittings with a pusher located inside the housing, made of material with a shape memory effect. According to the invention, part of the inlet fitting inside the housing is made in the form of a shank with a blind hole, above which a triangular ring groove is made on the outer surface to thin the wall thickness. In this case, the pusher, in the form of a bushing with two through holes made perpendicular to the axis of the bushing, intersecting the internal hole of the pusher, for the passage of the working fluid after actuation of the valve, is located coaxially to the shank of the inlet fitting, between the thrust flange of the inlet fitting and the nut screwed onto the thread of the shank and pre-deformed for compression by 3-5% of the original length in the direction of the longitudinal axis. In the initial position, the pusher is pre-pressed with a nut to the flange of the inlet fitting through a set of washers with a tightening torque that ensures compression of the pusher without intermediate gaps, above which a triangular ring groove is made on the outer surface to thin the wall thickness of the inlet fitting shank. The nut is made with four posts on the output end surface for the passage of the working fluid after actuation of the valve, and the position of the nut relative to the end of the shank is adjusted using a set of washers to align the end surfaces of the shank and the nut to lock them by welding. A mesh is installed at the inlet of the outlet fitting, and the gap between the mesh of the outlet fitting and the nut posts is no less than the amount of preliminary compression of the pusher for compression in the direction of the longitudinal axis.

The design of the valve with a pre-compressed and pressed pusher in the valve without intermediate gaps during actuation (restoring the shape of the pusher) provides an axial force of at least 40% of the force created by the pusher, and sufficient to force the rupture of the shank at the point of the groove, while simultaneously ensuring strength in the cross-section of the groove at all stages of valve application before operation, including from the pressure of the working fluid in the opening of the inlet fitting, from additional deformations of the shank when screwing and locking the nut with the tightening torque necessary to eliminate gaps in the connection.

Making part of the inlet fitting in the form of a shank with a blind hole ensures a guaranteed hermetically sealed separation of the cavity of the working fluid storage system and the supply system line before the propulsion system begins to operate. This solution to the valve design allows, in principle, to supply gas to the inlet both from the inlet fitting and from the outlet fitting with the additional installation of a filter mesh on the inlet fitting.

Preliminary compression of the pusher by 3-5% of the original length in the direction of the longitudinal axis makes it possible to guarantee the creation of sufficient force for the forced rupture of the metal at the point of the groove on the outer surface of the inlet fitting shank under thermal influence and restoration of the pusher to its original shape along the length, ensuring through the gap formed in case of forced rupture of the shank, free passage of the working fluid.

Locking the thread of the “nut-shank” connection by welding with a preliminary selection of the number of washers between the pusher and the nut to align their end surfaces helps prevent the nut from self-unscrewing due to the impact of mechanical loads that arise when launching a spacecraft into orbit.

Installing a mesh at the inlet of the outlet fitting allows you to prevent the ingress of metal particles formed during friction in the threaded connection and, possibly, remaining in the valve cavity when the nut is screwed onto the glass, thereby ensuring the cleanliness of the passing working fluid in the outlet fitting.

Introducing a sufficient gap between the nut posts and the outlet fitting grid ensures that the pusher is located with the restored length after operation without affecting the output fitting grid.

To ensure a coaxial position of the pusher relative to the shank of the inlet fitting with a guaranteed gap, a centering ledge with a diameter is made on its flange to ensure a sliding fit of the pusher along its inner diameter.

The coaxial arrangement of the main power elements of a single-acting valve in the body allows the design to be made with the smallest possible diameter, which makes it possible, with minimal overall dimensions and weight characteristics of the valve, to significantly increase the permissible pressure of the working fluid at the inlet. This is also achieved by making such main strength elements of the valve as the body, inlet and outlet fittings, as well as nuts made of high-strength stainless steel.

To reduce the power consumption of the heater, screen-vacuum thermal insulation is installed along the generatrix of the housing with the heater and at the ends of the housing.

The invention is illustrated by drawings, where in Fig. 1 shows a longitudinal section of a single-acting high-pressure valve in its initial closed state; in Fig. 2 is a side view of a single-acting high-pressure valve in its original, closed state; in Fig. 3 - view of the relative position of the shank with a centering ledge and annular duct, and the pusher; in Fig. 4 - view of the relative position of the nut with posts and the mesh in front of the outlet fitting.

The high-pressure single-acting valve (Fig. 1) contains a cylindrical body 1, on the outer surface of which a heater 2 is located, on one side of the body the inlet fitting 3 is hermetically welded, and on the other side the outlet fitting 4 is hermetically welded. Inside the body, on the inlet fitting A pusher 5, made of shape memory material, is located coaxially between the flange 6 of the inlet fitting 3 and the nut 7, screwed onto the shank 8, which is part of the inlet fitting 3, through a set of washers 9 for aligning the end surfaces of the shank and the nut for locking them by welding. To ensure the coaxial position of the pusher 5 relative to the shank 8, a centering ledge 10 with an outer diameter is made on the flange 6 of the inlet fitting with an outer diameter that ensures a sliding fit of the pusher along its inner diameter. To allow the working fluid to pass through after actuation, two through holes 11 are made in the pusher 5 perpendicular to its axis, and four posts 12 are made at the end of the nut 7 to ensure the passage of the working fluid after the valve is actuated. Previously, before installation on the inlet fitting 3, the pusher 5 is compressed in the direction of the longitudinal axis by an amount of 3-5% of the original length, and then installed between the flange 6 of the inlet fitting 3 and the nut 7 with a tightening torque that ensures a connection without gaps. To prevent self-unscrewing of the nut 7 due to vibration, the threaded connection 13 is locked by welding 14 (Fig. 2). In the inlet part of the fitting 3, along its axis there is a blind hole 15, above which an annular groove 16 of a triangular shape is made along the outer surface to thin the cross-sectional area of the shank 8 (Fig. 3). A mesh 17 is installed in front of the outlet fitting 4, which prevents the entry of possible metal particles formed during friction in the threaded connection during screwing of the nut 7 onto the shank 8 and, possibly, remaining in the valve cavity after its final assembly, as well as possible metal particles when the shank ruptures. moment of operation. Between the posts 12 of the nut and the grid 17 of the outlet fitting there is a sufficient gap 18 (Fig. 4) to accommodate the restored length of the pusher after operation without affecting the grid of the output fitting 4. To reduce the power consumption of the heater, a screen is installed along the generatrix of the housing with the heater and at the ends of the housing -vacuum thermal insulation 19.

The high pressure single acting valve works as follows. Before the spacecraft propulsion system starts operating, the single-acting valve is in storage mode, designed for the required time. In the initial state, the pusher 5 is clamped without gaps between the flange 6 of the inlet fitting 3 and the washers 9 with nut 7. To ensure the start of the propulsion system, a supply voltage is applied to the heater 2 of the valve, while the temperature of the pusher begins to increase and when the temperature of the reverse martensitic transformation is reached, the previously deformed pusher begins to lengthen in the direction of the longitudinal axis by 3-5%, creating a force on the flange 6 of the inlet fitting and the nut 7, forcibly breaking the shank 8 at the location of the groove 16 on the outer surface. In this case, the working fluid freely passes through the resulting gap in the shank 8, through two holes 11 in the pusher 5, through the gap between the body and the pusher, through the slots formed by the posts 12 in the nut and the end of the outlet fitting 4, and then enters the hole in the outlet fitting of the valve . After the heater is turned off and cooled down, the pusher remains in an elongated state, ensuring constant passage of the working fluid from the storage system to the supply line throughout the entire life of the propulsion system.

Tests of prototypes of the proposed high-pressure single-acting valve showed absolute tightness at a strength test pressure of up to 58.9 MPa and guaranteed operation at an operating gas inlet pressure of up to 39.2 MPa.

Claims (4)

1. A single-acting high-pressure valve containing a housing with an electric heater on its outer surface and inlet and outlet fittings at its ends, as well as a pre-deformed pusher made of shape memory material located inside the housing, characterized in that part of the inlet fitting is inside the housing made in the form of a shank with a blind hole, on the outer surface of the shank there is a triangular-shaped annular groove, and coaxial to the shank of the inlet fitting, between the thrust flange of the inlet fitting with a centering shoulder and a nut screwed onto the thread of the shank, there is a pusher in the form of a bushing with two through holes, made perpendicular to the axis of the bushing and crossing the internal hole of the pusher, in the initial position the pusher is pre-tensioned with a nut with a tightening torque that ensures compression of the pusher without intermediate gaps. 2. Single-acting high-pressure valve according to claim 1, characterized in that the axial breaking force in the cross-section of the groove on the shank of the inlet fitting is no more than 40% of the force created by the pusher when activated. 3. Single-acting high-pressure valve according to claim 1, characterized in that the nut is made with four posts on the outlet end surface, the threaded connection of the nut with the shank of the inlet fitting is locked by welding, and the gap between the mesh at the inlet of the outlet fitting and the posts of the nut is not less than 5% of the original pusher length. 4. Single-acting high-pressure valve according to claim 1, characterized in that screen-vacuum thermal insulation is installed along the generatrix of the housing with the heater and at the ends of the housing.