RU2228476C2 - Thermal seal - Google Patents

Abstract

FIELD: shut-off fire-fighting devices sensitive to temperature rise and mounted in pipe lines handling highly inflammable and inflammable media. SUBSTANCE: proposed thermal seal has body with branch pipes, flow section, seat and outer sleeve, flapper valve and its locking mechanism which is sensitive to temperature rise. Flapper valve locking mechanism is located in outer sleeve whose interior is insulated from outside medium by cover provided with gasket and is communicated with flow section of body by means of through hole. Mounted in through hole in body is bush with fork located in outer sleeve. Said fork is provided with ears for spring-loaded stops and swivel coil with rope wound on it. One end of this rope is secured on coil and other end is passed through bush to flow section of body and is connected to flapper valve. Secured on end faces of coil are ratchet wheels with teeth which are engageable with swivel stops. Stops are made from low-melting materials at different melting points. Ratchet wheels are mounted on end faces of coil at angular shift in such position that after breaking of stop at lower melting point, flapper valve is partially shut-off under action of flow of working medium and gravity force of movable parts of seal. EFFECT: enhanced reliability and universality of seal. 2 cl, 3 dwg

Description

The invention relates to shut-off fire-fighting devices that are sensitive to temperature increase and intended for installation in pipelines with flammable and other flammable environments.

A device is known for shut-off fire-cover-flaps for ventilation openings, protected by US patent No. 4650154, IPC 7 F 16 K 31/64, publ. 03/17/87. A flap-cover is installed on the ventilation openings in the walls of buildings to isolate the premises during a fire. The swivel-cover is held open automatically by an electromagnet. The overlapping of the ventilation hole in the wall at the time of the fire occurs as a result of the de-energization of the electromagnet and under the influence of gravity of the cover-flap.

The disadvantage of the analogue is the complex control system of the lid-flap. In case of failure of the electromagnetic control system, a mechanical overlap system is provided for in the lid-flap design, including control levers mounted on the same rotary axis as the flap-lid.

Known normally open shut-off fire gate valve with a sliding stem, protected by US patent No. 5004003, IPC 7 F 16 K 31/64, publ. 04/02/91 and designed for installation on pipelines with flammable or other flammable gaseous or liquid medium, such as, for example, gasoline. In the event of an external fire, the prototype thermal shutoff shuts off the medium flow in the pipeline.

Fire gate valve contains a housing with nozzles, flow part and a seat. A locking element is made in the body, made in the form of a gate mounted on a retractable rod and held in an open position by means of a locking mechanism that is sensitive to an increase in ambient temperature. The locking mechanism is located in a glass mounted on the valve body, and includes a spring-loaded piston fixed to the valve stem, a rotary latch-stop for the spring-loaded piston, and a fusible latch lock. The latch is pivotally fixed on the outside of the cup, the stop of the latch is inserted into the slot of the cup and engaged with the spring-loaded piston. The rotary latch is held in position by a latch made of fusible material. The connector of the glass and the valve body is sealed with a gasket, which simultaneously seals and extends the valve stem.

In case of fire, when the ambient temperature rises to the melting temperature of the material from which the latch is made, the latter melts and releases the stop latch. Under the action of the spring, the piston pushes the stop of the rotary latch out of the slot in the glass and, being released, pushes the rod and gate to close the pipeline. After landing of the gate on the saddle, the flow of flammable medium to the ignition source stops.

The disadvantages of the fire damper are its bulkiness and low reliability of operation in emergency situations. The disadvantages are caused by the design features of the gate valve: as the gate approaches the seat, the resistance of the working medium to closing the valve increases, at the same time, the sealing gasket provides an additional obstacle to closing the valve, expanding to a greater extent than the nest with increasing ambient temperature (gasket material has a larger coefficient of thermal expansion than the materials of the valve body, the cup and the stem).

The prototype of the inventive thermal shutter is a butterfly valve for gas lines, equipped with a fire safety device and protected by patent US 3835875 (IPC 7 F 16 R 17/38, publication date - 09/17/74).

The prototype contains a housing with a lid and a seat for a rotary flap mounted in the housing on a rotary lever. At normal ambient temperature, the shutter is open and the flap is connected by a flexible connection to the body. Flexible connection of the flap with the housing is made in the form of tensile springs connected in series. The fire safety device also includes a blind threaded sleeve screwed into the housing cover and provided with external ribs for accumulating heat from the surrounding space. The inner surface of the ribbed section of the blind sleeve is also threaded for connection with a safety fusible plug. In a low-melting plug at normal ambient temperature, the end of the spring flexible connection of the flap with the body is fixed. The second end of the spring flexible connection is fixed to the flap with a screw.

In the event of a fire, the safety plug melts, the flexible connection between the flap and the body breaks, and the flap drops by the force of gravity onto the saddle, blocking the passage of the gas medium.

The disadvantage of the prototype is the low reliability of the thermal shutter, especially in the case of its installation on vertical and inclined pipelines, when the component of the force of gravity of the shut is not large enough to close at a given temperature. At the same time, in the initial period of melting of the safety plug, the friction force of the spring flexible connection on the internal threaded surface of the safety sleeve counteracts the emergency operation of the shutter. If the thermal shutter blocks the flow of contaminated gas, then the friction is quite large and the shutter is triggered at a higher temperature. At the same time, after the safety plug of the thermal prototype shutter is melted, step closure is not provided, a sharp complete closure occurs (landing of the shutter on the saddle).

The disadvantage of the prototype is also that a set of flexible coupling springs (31 and 37) should be selected depending on the diameter of the pipeline, i.e. from the movement and mass of the shut-off element (5), as well as from the density and velocity (velocity head) of the flow.

The claimed invention solves the problem of increasing the reliability and versatility of the thermal shutter.

The problem posed by the invention is solved in the inventive thermal shutter, which comprises a housing with nozzles, a flow part and a saddle, a locking member in the form of a shutter mounted on a rotary lever, a mechanism for locking the locking member in the open position and a cover sensitive to an increase in ambient temperature. The thermal shutter is equipped with an outer cup, the inner cavity of which is isolated from the external environment and is in communication with the flow part of the shutter body through the through hole of the body. The locking mechanism is made in the form of a sleeve installed in a through hole in the housing and placed in the outer cup with a fork, made with eyes, a rotary coil with a cable wound on it, one end of which is fixed to the coil, and the other is passed through the sleeve into the flow part of the shutter body and attached to a rotary locking body, and a spring-loaded stopper made of fusible material associated with an eye and interacting with a ratchet wheel with teeth fixed to the end of the coil. An additional eyelet for the second spring-loaded stopper can be made of a low-melting material with a melting temperature higher than the melting temperature of the material of the first stopper on the fork of the stopper mechanism, and a second ratchet wheel with teeth can be fixed on the other end of the coil, with an angular displacement relative to the first ratchet wheel the possibility of interaction with the second spring-loaded stopper after melting the first stopper.

The invention is illustrated by drawings. Figure 1 shows the inventive thermal shutter, section; figure 2 is a section along aa of the locking mechanism of the flap in the open position, figure 3 is the same section along BB.

The inventive thermal shutter comprises a housing 1 with nozzles 2 and 3, a flow part 4 and a saddle 5. In the housing 1, a flap 9 is attached to the fork 6 using the axis 7 and the lever 8. A cup 10 is fixed outside the housing 1, the inner cavity of which is isolated from the external environment a lid 11 and is connected with the flowing part 4 of the shutter body through a hole 12 in the housing 1. In the hole 12 is installed a sleeve 13 with a plug 14. In the eyes 15 and 16 of the plug 14, a rotary coil 18 with a cable (rope) wound around it is installed 19, one end of which is mounted on a coil 1 8, and the other passes through the sleeve 13 into the flow part 4 of the shutter body and is attached to the lever 8 or to the flap 9. The plug 14 has eyes 20 and 21 for the axles 22 and 23, on which the movable stops 24 and 25 are mounted. At the ends 26 and 27 coils 18 are fixed ratchet wheels 28 and 29 with teeth. The ratchet wheel 29 is fixed at the end of the coil with an angular offset relative to the ratchet wheel 28 so that the stop 24 is located in the cavity between the teeth of the ratchet wheel 28 and the stop 25 is on top of the tooth of the ratchet wheel 29. The stop 24 is pressed against the tooth of the ratchet wheel 28 by a spring 30 The stopper 25 is pressed against the tooth of the ratchet wheel 29 by a spring 31. The stoppers 24 and 25 are made of fusible materials, for example, alloys of bismuth, tin and lead, Rose alloy and others. The melting temperature of the material from which the stopper 25 is made exceeds, on average, 30-50 ° C the melting temperature of the material from which the stopper 24 is made. The connector of the outer cup 10 and the cover 11 is sealed with a gasket 32.

The inventive thermal shutter operates as follows.

The flap 9 is held open by the tension of the cable 19 wound on the coil 18. The tension of the cable is created by the flow of the working medium and the gravity of the moving parts of the thermal shutter. The coil 18 is fixed from turning on the axis 17 by the stopper 24, pressed by a spring 30 to the tooth of the ratchet wheel 28. This ensures a stable position of the flap 9 in the working stream.

When the ambient temperature during a fire rises to the melting temperature of the material from which the stopper 24 is made, the latter melts and the flap 9 under the influence of the working medium flow and gravity of the moving parts of the shutter is covered, unwinding the cable 19 and turning the coil 18 on the axis 17 to the position in which the tooth of the ratchet wheel 29 abuts against the stopper 25, pressed against it by the spring 31. The flow of the working medium will decrease, and its pressure on the shutter 9 will increase.

With a further increase in ambient temperature, the stopper 25 melts, the coil 18 is released and the cable 19 is further unwound, the flap 9 is closed and it is planted on the saddle 5. The flow of the working medium in the pipeline is blocked.

To bring the thermal shutter to its initial state, it is necessary to remove the cover 11 from the glass 10, remove the ratchet mechanism from the glass, install new stoppers 24 and 25 in it and insert it into the glass. Rotating the coil 18, wind the cable 19 on it and fix it with a spring-loaded stopper 24 in the position in which the shutter 9 of the thermal shutter will not impede the passage of the working medium through the pipeline. Then install the cover 11 with the gasket 32 on the glass 10.

The inventive thermal shutter is simple, reliable and versatile, provides phased (step) closure on horizontal, vertical, inclined pipelines in the conditions of a fire.

Claims (2)

1. A thermal shutter comprising a housing with nozzles, a flow part and a saddle, a locking member in the form of a clap fastened to a rotary lever, a mechanism for locking the locking member in an open position, sensitive to an increase in ambient temperature, and a lid, characterized in that it is provided with an outer glass, the inner cavity of which is isolated from the external environment and is in communication with the flow part of the shutter body through the through hole of the housing, while the locking mechanism is made in the form of a body installed in the through hole and the sleeve and the plug placed in the outer cup, made with eyes, a rotary coil with a cable wound on it, one end of which is fixed to the coil, and the other is passed through the sleeve into the flow part of the shutter body and attached to the rotary locking body, and a spring-loaded stopper made of low-melting material associated with eyes and interacting with a ratchet wheel with teeth fixed to the end of the coil. 2. Thermal lock according to claim 1, characterized in that the plug is made with an additional eyelet for the second spring-loaded stopper made of fusible material with a melting temperature higher than the melting temperature of the material of the first stopper, while the second end of the coil with an angular offset relative to the first ratchet wheel is secured with a second ratchet wheel with teeth with the possibility of interaction with the second spring-loaded stopper after melting the first stopper.

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