RU2276301C2 - Safety unit (versions) - Google Patents

Abstract

FIELD: general engineering.

SUBSTANCE: invention relates to safety valves and fittings for pipelines and it is designed for cutting off working medium in different pipelines at higher flow rates and low pressures in case of rise of pressure of liquid or gaseous medium in pipelines over tolerable values and in can be used in process lines of thermoelectric plants, nuclear power plants and gas and oil processing enterprises. Proposed safety unit contains housing with inlet and outlet branch pipes and direct-acting safety valve. The latter is arranged in housing and is provided with seat with through hole for engaging with locking member. Locking member is spring-loaded relative to housing and is installed for closing through hole in case of pressure drop of working medium. Locking member is furnished with screen enclosing the seat. Restrictor is arranged on inlet branch pipe. Restrictors of different design versions are provided. According restrictors of different design versions are provided. According to first design version, restrictor is made in form of spring-loaded piston installed on inlet branch pipe for changing area of ring hole between piston and screen when opening and closing the valve. According to second design versions, restrictor is made in form of disk of elastic flexible material for changing are of ring hole between piston and screen when opening and closing the valve. According to third design version, restrictor is made in form of spring-loaded disk of elastic flexible material installed on inlet branch pipe for movement and changing area of ring hole between piston and screen when opening and closing the valve.

EFFECT: prevention of influence of working medium forces in outlet channel of safety valve members at final stage of valve closing.

4 cl, 6 dwg

Description

The invention relates to general engineering, namely to safety pipe fittings, and can be used to shut off the working medium in various pipelines of high flow rates and low pressures when the required pressure of the working liquid or gaseous medium is exceeded. The invention is intended for use in various technological lines of thermal power plants, nuclear power plants and gas and oil refining enterprises.

A known safety valve comprising a housing with inlet and outlet nozzles, a saddle installed in it with a conical sealing surface for communication with the spindle of the locking element and a cylindrical sealing surface for the throttle element, and the throttling element is made in the form of a cylindrical shank connected to the locking element with a fairing at the end and the sealing surface on the saddle for the locking element is associated with its bore (see SU 666359, class F 16 K 47/08, publ. 05.06.1979).

A disadvantage of the known valve is the low reliability and durability of the valve, caused by the relatively large valve actuation period when the pressure drops in the pipe fittings.

As the closest analogue, a safety assembly has been adopted, comprising a housing with inlet and outlet nozzles, a direct-acting relief valve located in the housing and having a seat with a passage hole for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage hole in case of pressure drop working medium, while the locking element is made with a screen covering the saddle, and on the inlet pipe there is a throttling means (book. "Modern “Structural Designs of Pipe Fittings for Oil and Gas”, under the editorship of Yu.M. Kotelevsky, Moscow, Nedra, 1976, p. 363, fig. ХШ.30 (1)).

The problem to which the present invention is directed, is to ensure the speed of closing the inlet channel while lowering the pressure of the working medium and thereby eliminating the negative consequences of low pressure in pipe fittings operating at a strictly specified high pressure of the working medium and not allowing it to decrease. The technical result consists in eliminating the influence on the elements of the safety valve of the pressure of the working medium in the outlet channel at the final stage of closing the valve.

To solve this problem, three variants of the safety unit are proposed.

According to the first embodiment, the safety assembly comprises a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the seat, and on the inlet pipe there is a throttling means made in the form of a slide a spring-loaded piston installed on the inlet pipe with the possibility of changing the annular hole between the piston and the screen at the moments of opening and closing of the valve.

In addition, the piston can be spring-loaded by means of a disk spring.

According to a second embodiment, the safety assembly comprises a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage opening in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the seat, and at the inlet there is a throttling means made in the form of a disk from elastic and elastic material with the possibility of changing the annular hole between the piston and the screen at the moments of opening and closing of the valve.

According to a third embodiment, the safety assembly comprises a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the seat, and at the inlet there is a throttling tool made in the form of It is also installed on the inlet pipe of a spring-loaded disk of elastic and elastic material with the possibility of changing the annular hole between the piston and the screen at the moments of opening and closing of the valve.

These signs are essential and interconnected causally with the formation of a set of essential signs sufficient to reduce the valve closing time and to exclude pressure fluctuations in the pipe fittings.

The invention is illustrated by drawings.

Figure 1 shows the safety unit - option 1.

In Fig.2 - the valve of Fig.1 (enlarged) in the "open" position - option 1.

In Fig.3 - the valve of Fig.1 (enlarged) in the position before closing - option 1.

In Fig.4 - the valve of Fig.1 (enlarged) in the closed position - option 1.

In Fig.5 - the valve of Fig.1 (enlarged) in the position before closing in the case of a disk made of elastic and elastic material - option 2.

In Fig.6 - the valve of Fig.1 (enlarged) in the position before closing in the case of a disk made of elastic and elastic material and spring-loaded relative to the inlet pipe - option 3.

The safety valve according to the invention (Figs. 1, 2, 3, 4, 5, 6) comprises a housing 1 with inlet 2 and outlet 3 nozzles. Inside the housing 1 there is a safety valve having a seat 4 with a through hole 5, fixed, in particular, on the inlet pipe 2.

Opposite the seat 4 there is a locking element 6, connected with the rod 7, spring-loaded with a spring 8 relative to the housing 1 and installed with the possibility of opening-closing the passage hole 5.

The locking element 6 is made with a screen 9, the radial dimensions of which — diameter 10 exceed the corresponding dimensions — the diameter 11 of the locking element 6. The screen 9 is made in the shape of a truncated hollow cone facing the saddle 4 with the possibility of forming a “damping” cavity and increasing the area of the locking element 6 for interaction with the working environment.

In order to provide the possibility of changing the response time of the safety valve in the "open" and "close" modes on the housing 1, in particular on the inlet pipe 2 connected to the housing 1, there is a throttling means forming an annular opening with respect to the screen 9, providing an increase in area throttling the fluid when closing the valve and reducing the closing time.

Figures 1-4 show an embodiment 1 of a throttling means in the form of a piston 12 movably mounted by means of an elastic element, forming a cavity 13 with a screen 9. The piston 12 is located relative to the screen 9 with a throttling ring hole 14, which makes it possible to change this hole 14 when fitting the locking element 6 on the seat 5. The parameters of the elastic element 15, through which the piston 12 is spring-loaded, and the dimensions of the latter are selected experimentally from the condition of ensuring the opening and closing of the piston 12 by Lost 13 with different speed response. The piston 12 is spring-loaded with an elastic element 15 from the entrance to the safety unit and in the direction of the throttling annular hole 14.

In option 2 (Fig. 5), the throttling means is made in the form of an elastic and elastic material located on the inlet 2 of the disk 16, which is located relative to the screen 9 with the possibility of forming a throttling annular hole 14 to increase the throttling area of the working medium when closing the valve and reducing the closure time of the valve. This is due to a change in the geometric shape of the elastic and elastic disk 16 from the working medium acting on the disk 16.

In option 3 (Fig. 6), the throttling means is made in the form of a spring-loaded disk 16 made of elastic and elastic material movably mounted on the inlet pipe 2 and arranged in relation to the screen 9 with the possibility of forming a throttling ring hole 14 for changing to increase the throttling area of the working medium when closing the valve and thereby reducing its closing time. This is due to a change in the shape of the elastic and elastic disk 17 and its position relative to the inlet pipe 2 from the working medium acting on the disk 17.

During the opening of the safety valve on the locking member 6 acting force P -P + P _{n, etc.,} where P - pressure of the working medium in the inlet pipe, _etc. P - pressure spring rod, P _n - fluid pressure in the cavity 13, the force of the pressure environment within the cavity 13 are also aimed at overcoming the force of the elastic member 15 and the piston 12, and in the process closing the subject P <P _etc. on the locking member 6, forces F and F and _straight part of the pressure inside the cavity 13. in this regard, while valve actuation upon closing is reduced, while Shade 12 with an elastic member 15 constantly adjusted during opening and closing of the valve under pressure _Pn in the cavity 13 and occupies a respective spatial position. Due to the use of a spring-loaded piston 12, the locking element 6 is able to move axially relative to the seat 4 and the screen 9, thereby changing the size of the gap of the annular hole. Increasing the gap to a value A * (Fig. 3), exceeding the gap A (Fig. 4), allows to increase the area of the expiration of the working medium from the cavity 13 and thereby reduce the time of pressure drop in this space of the screen 9 and dramatically reduce the closing time valve, i.e. the seating time of the locking element 6 on the seat 4. Reducing the closing time of the safety valve allows you to increase the value of the closing pressure.

The embodiments of the throttling device shown in FIGS. 6 and 7 operate in a similar manner to the described example.

For use in the piping systems of nuclear power plants and for the chemical and oil and gas industry, the valve is made of stainless steel or carbon steel. The invention meets the condition of patentability "industrial applicability", since its implementation is possible using existing means of production using known technological operations.

Claims (4)

1. A safety assembly comprising a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the seat, and at the inlet there is a throttling means, made in the form of movably mounted on the inlet pipe of the spring-loaded piston with the possibility of changing the area of the annular hole between the piston and the screen at the time of opening and closing of the valve. 2. The safety assembly according to claim 1, characterized in that the piston is spring-loaded by means of a cup spring. 3. A safety assembly comprising a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the seat, and on the inlet pipe there is a throttling means made in the form of a disk of elastic and elastic th material capable of changing the area of the annular opening between the piston and the screen in the opening and closing valve. 4. A safety assembly comprising a housing with inlet and outlet nozzles, a direct-acting safety valve located in the housing and having a seat with a passage opening for interacting with a locking element spring-loaded relative to the housing and installed with the possibility of closing the passage in the event of a pressure drop in the working medium, while the locking element is made with a screen covering the saddle, and at the inlet there is a throttling means, made in the form of movably mounted on the inlet pipe of the spring-loaded disk of elastic and elastic material with the possibility of changing the area of the annular hole between the piston and the screen at the moments of opening and closing of the valve.

Images