EP0076297A4

EP0076297A4 - Back-pressure valve in particular for pipelines, for ensuring the one-way flow of the streaming medium.

Info

Publication number: EP0076297A4
Application number: EP19820901148
Authority: EP
Inventors: Laszlo Imre
Original assignee: GATI LASZLO; KORODI MIHALY
Current assignee: GATI LASZLO; KORODI MIHALY
Priority date: 1981-04-17
Filing date: 1982-04-16
Publication date: 1983-08-09
Also published as: EP0076297A1; DE76297T1; AU8335782A; JPS58500535A; HU184425B; WO1982003673A1

Abstract

The back-pressure valve - serving mainly for ensuring the one-way flow of media streaming in pipelines - is provided with an axially displaceable closing head having been arranged in the streaming medium. The closing head being formed with a surface following the stream lines of the streaming medium is guided on the guide pin of the bearing element fixed in the streaming medium by means of the ribs promoting the flow of the medium. The inner surface of the house and the bearing element and the outer surface of the ribs and the closing head are formed in such a manner that in downstream, in an open position the flowcross-section should be constant or decreasing between the closing diameter and the end of the closing head profile surrounded by the streaming medium.

Description

Back-pressure valve in particular for pipelines, for ensuring the one-way flow of the streaming medium

Technical field

The invention relates to a back-pressure valve , in particular for pipelines, for ensuring the one-way flow of the streaming medium by means of the closing head which is able to move axially in the streaming medium.

Background art

Presently armatures with different structures are used for achieving a one-way stream. Beside the usual passing ball check valves and regulating flaps the catalo gue of the company GUSTAV F. GERDTS KG. BREUEN presents check valves with a disc-shaped closing element having been fixed in the house with ribs on the outer part or intruding into the medium, i.e . a special bearing element , a piston, are serving for guidance . The house of said valves is widened for achieving proper passing cro ss-section. Due to the flat-disc-shaped closing element the structural length is utmost short involving significant savings in material compared with the traditional solutions. However, it can be stated from the dates of the catalogue that the stream losses are equal to those of known constructions or even higher, resulting in significant energy loss mainly in systems with a forced stream. The losses are mainly caused by the sharp corners inducing flow separation, e. g. by the disc-shaped closing element and the changing transfer cross-section in downstream. Furtheron, an un equal pressure is formed before and after the disc affecting the measuring characteristics. The outer guidance of the flat disc-shaped closing element does not yield the desired operational safety, since the sediments or corrosion may lead to sticking.

Disclosure of Invention

The aim of the invention is to provide a valve for preventing backflow, which can be installed in an optional direction and which - compared to the known solutions (with the exception of the previously described type) - is operating with a more advantageous streaming loss factor and with a more economical specific material consumption rate. A further requirement lies in the defined closing characteristics and that it could be adjusted within the practically required range , the formation should be simple and operational safety could be ensured. The structural design has to enable application in the pressure-, size-, temperature and medium ranges being in compliance with industrial requirements and a coating could be applied thereon. Besides it should be suitable for special purposes, so e . g. heating and cooling and should indicate the closed and open state, respectively, simultaneously enabling a retarded closing. In accordance with the invention the task set is solved in such a manner that the back-pressure valve is provided with a closing head the confining surfaces of which are following the stream lines of the streamin g medium stream, on the bearing element having been fixed in the medium stream, a guide pin is formed guiding the closing head, while the house is formed with a surface enabling the closed state by means of the closing head; the bearing element is fixed to the house, at the same time the inner surface of the house and the bearing element, as well as the outer surface of the closing head and the ribs are formed so, as to yield a transitional cross-section being constant or reduced between the closing diameter and the end of the closing head profile being surrounded by the streaming medium.

With a preferred embodiment of the back-pressure valve between the closing head and the guide pin on the bearing element a spring has been inserted. The embodiment is also to be considered as advantageous, with which in downstream the flow cross-section is continuously narrowed from the closing diameter up to the end of the closing profile surrounded by the streaming medium and increased continuously therefrom.

Advantageously the house of the back-pressure valve is enclosed by jointing flanges which are connected to the valve in a sealed manner.

The closing head may be formed as a solid body, however, a hollow construction is also possible. The solid closing head may be made of a material with sealing properties with a metal reinforcing element inside.

In case of chemically agressive or erosive media it is expedient to coat the surfaces of the valve being in contact with the medium with a material being resistant to the medium, e.g. with rubber, a synthetic material, PTFE, enamel, chrome, nickel, etc.

The back-pressure valve according to the invention may be installed in any optional direction, it is well suitable for closing processes with required closing characteristics, the more, for retarded closing. The profile to be followed by the streaming mediums, as well as the flow cross-section not being increased downstream ensure the reduced streaming losses in comparison to known types, since by said measurements the pressure losses resulting from the mutual transformation of the energies of flow separation, pressure and velocity are considerably reduced, i.e. the continuously reduced cross-section in downstream simultaneously eliminates the flow separation induced by the directional deviations.

Compared to the known types, a reduced specific material consumption rate may be achieved, in particular by clamping the house between the flanges. By using a house with a closed cavity tasks relating to heat power engineering may be also solved. Simultaneously considerable savings of handwork and mashining capacity may be achieved by forming the house and the bearing element as a monolithic valve body.

Maintenance of the valve according to the invention may be performed in a simple and economical manner, especially, when the valve seats are used on the closing surfaces. As the construction is simple and there are no sliding surfaces subjected to the streaming medium, highgrade operational safety may be achieved, when a magnet is installed in the closing head and a coil is contained in the house, the valve can be well used as an indicator indicating the direction of streaming; due to its simple construction, a protective coating can be easily applied. The special advantage lies in that the house is formed as a cylindrical shell subjected to an internal overpressure, accordingly, it may be prepared within the pressure- and dimensional range required in the industry: at a given dimension the structural length is the same for any pressure.

Brief Description of Drawings

The invention will be described in detail by means of some preferred embodiments, by the aid of the enclosed drawings, wherein:

Figure 1 is a longitudinal section of one of the embodiments,

Figure 2 is a longitudinal section of another embodiment,

Figure 3 is a longitudinal section of an embodiment, with which the house and the bearing element are formed as a monolithic valve body,

Figure 4 is a sectional view of a solid closing head having been provided with a metal reinforcing element,

Figure 5 is a further preferred embodiment shown in the longitudinal section and

Figure 6 illustrates an embodiment with a hollow house and a closing head.

Best Made of Carrying out the Invention

The house 3 of the embodiment according to figure 1 is clamped between the jointing flanges 6 by means of screws and on the entering side, at the entrance of the medium, on the closing diameter there is the valve seat 12 arranged having been, fixed by luing or by shrink fit. The solid closing head 1 is provided with the aperture 20. In downstream, the bearing element 2 is provided with the ribs 2a with an airfoil cross-section being connected to the guide pin 2b carrying the closing head being arranged in the streaming medium, fthen the valve is opening or closing, the aperture 20 in the closing head 1 ensures inflow or outflow of the medium to/from the space 20a lying before the guide pin 2a. On the screw 17 - having been fixed to the closing head 1 by means of a thread - there is the spring 4 arranged between the guide pin 2b and the closing head 1, which exerts a pressure onto the closing head 1. As it is to be seen in figure 1, by the simple rearrangement of the spring 4 tension may be applied onto the closing head 1. Accordingly, this embodiment can be installed in any optional direction, at the same time the desired closing characteristics may be adjusted by the calculated compression of the spring and installation to the proper place.

On the discharge side the bearing element 2 is fixed to the house by means of the threaded connection within the sealing diameter of the flange 6, accordingly, and separate sealing becomes superfluous. By the choice of the suitable profile a flow cross-section can be formed, which is continuously narrowed from the valve seat 12 to the end of the guide pin 2b, whil.e therefrom a diffuser tract with a high efficiency is leading to the entering cross-section. At a given dimension and identical installation length the back-pressure valve having been formed in the specified manner can be applied to media of any pressure by simply changing the outer dimension of the house in dependence of the pressure. With the embodiment shown in figure 2 the bearing element 28 is fixed to the house 7 on the entering side within the sealing range (not illustrated here) by means of a threaded connection in such a manner, that simultaneously the valve seat 11 is also fixed . Fluid mechanical formation and clamping by the spring are identical to those shown in figure 1.

In the open position of the valve the screw 17 is limiting the extrem position of the closing head 29, which has to be adjusted in course of installation. When the closing head is moving, the aperture 18 formed in the guide pin of the bearing element 28 ensures the out-or inflow of the medium. The diffuser is arranged on the discharge side . The closing head 29 is formed with a cavity resulting in the advantage of a minimal material requirement and lightweight.

With the embodiment shown in figure 3 the diffuser is formed in the connecting element 5. The guide pin 13a of the monolithic valve body 13 is arranged on the discharge side, where the medium is leaving the system; an axial aperture 21 thereon is promoting the inflow and outflow of the medium in course of the displacement of the closing head 32. The solid closing head is connected to the feuide pin 13a, the nose-part is slightly elongated, as a consequence, streaming resistance will be less. In the groove having been formed on the closing diameter the valve seat 22 is arranged . On the inflow side of the valve body 13 the valve seat 11 is clamped by means of the insert 14; this solution enables a quick repair.

To achieve this, the diameter has been chosen in such a manner that after having removed the components 11 and 14 the closing head 32 can be lifted out or in stalled. The embodiment according to figure 3 can be installed in the illustrated position only, while the closing characteristics may be changed by the weight of the closing head 32. By inserting the spring 4 - having been used in the previously described embodiment - installation in the contrasting vertical and horizontal direction becomes also possible. The valve body 13 is connected to the system via the thread 8. From the embodiments described this type can be manufactured with the least material requirement, as the valve body 13 is formed as a shell.

With the embodiment shown in figure 4 the closing head 41 is made of the sealing material itself, so e.g. of rubber, polyurethane etc., preferably with an elongated nose. In the inside there is a metal reinforcing element 15 having been provided with the aperture 15a and being connected to the guide pin 2b. The main advantage of this structure lies in that it can be well applied for high pressures too, furtheron a closure being less sensitive to contimations may be obtained.

By the embodiment according to the invention shown in figure 5 special requirements may be met, as in the pressure ring 25 - being fixed in the closing head 34 by means of a thread - the magnet 25 is arranged, while on the inlet sice of the house 36 the coil 26 is to be found. The pressure ring 23 is keeping the ventil seat 24 in the proper position. When the closing head 34 is displaced, the lines of magnetic force of the magnet 25 are intersecting the coil 26, as a consequence current is induced. The pulses thus generated can be used for starting resp. stopping e.g. rotary machines, technological processes. Other components may be formed in accordance with figures 1,2 and 3. With the embodiment according to the figure 6 the house 27 is formed with the closed cavity 9 into which a cold or warm energy carrier is led through the opening 10. In such a manner the valve may be well adapted to media with temperatures being otherwise harmful for the armatures. The guide pin 19 was formed as an independent piece which is connected to the bearing element 39 by means of a threaded bond. The hollow closing head 30 is shaped as a spherical shell and it is connected to the guide pin 19 via the insert 16 which is connected thereto with a threaded bond. In order to be able to ensure outflow and inflow of the medium, in the closing head 30 the aperture 33, in the insert 16 the aperture 31 have been provided for. Such a formation of the closing head 30 is to be considered as most advantageous in the range of large dimensions and high pressures. Other parts of the armature may be formed in accordance with figures 1,2 and 3.

The back-pressure valve operates, as follows: prior to the start of streaming the closing head is in, a closed position. When the stream of the medium is put into motion, the closing head is displaced on the guide pin in dependence of the closing characteristics, whereby the flow cross-section is set free. When the flow is stopped, in dependence of the closing characteristics of the valve, prior to, simultaneously with or following the backflow the closing head is repeatedly displaced and closes the flow cross-section.

Claims

1. Back-pressure valve, in particular for pipelines, for ensuring the one-way flow of the streaming medium, with an axially displaceable closing head, c h ar a c t e r i z e d in that it is provided with a closing head (1, 29, 30, 31, 32, 34) the surface of which is following the stream lines of the flowing medium, furtheron it has a bearing element (2, 28, 35) being fixed in the streaming medium by means of the ribs (2a) promoting the passing of the medium and it is provided with the guide pins (2b, 13a, 19, 28a) guiding the closing head (1, 29, 30, 31, 32, 34), while the house (3, 7, 27, 36) forms a closure-proof surface with the closing head (1, 29, 30, 31, 32, 34) and provides for the fixation of the bearing element (2, 28, 35), at last the inner surface of the house (3, 7, 27, 36) and the bearing element (2, 29, 30, 32, 35), the outer surface of the ribs (2a) and the closing head (1, 29, 30, 31, 32, 34) are formed in such a manner that in an open position, in downstream, the flow cross-section is constant or narrowed from the closing diameter to the end of the closing head profile having been surrounded by the stream- ing medium.

2. Back-pressure valve as claimed in claim 1, c h ar a c t e r i z e d in that between the closing head (1, 29, 30) and the guide pin (2b, 28a, 19) of the bearing element (2, 28, 35) there is a spring (4) arranged.

3. Back-pressure valve as claimed in claim 1 or 2, c h a r a c t e r i z e d in that in the open position, in downstream, the flow cross-section is narrowed between the closing diameter and at least the end of the closing profile, while therefrom it. is continuously increasing.

4. Back-pressure valve as claimed in claims 1 to 3, c h a r a c t e r i z e d in that the house (3, 27,

36) is clamped between the jointing flanges (6) via a sealed connection.

5. Back-pressure valve as claimed in any of the claims 1 to 4, c h a r a c t e r i z e d in that in the house (27) there is a closed cavity (9) and the apertures 110 thereon serve for the introduction of the cooling or heating medium.

6. Back-pressure valve as claimed in any of the claims 1 to 5, c h a r a c t e r i z e d in that the bearing element (2) is connected to the house (3, 36) on the discharge side.

7. Back-pressure valve as claimed in any of the claims 1 to 5, c h a r a c t e r i z e d in that the bearing element (28) is connected to the house (7) on the entering side.

8. Back-pressure valve as claimed in claim 1, c h a r a c t e r i z e d in that the house is formed as a valve body (13) being connected via the ribs (2a) to the guide pin (13a) carrying the closing head (32), furtheron in the seating on the opposite end of the valve body (13) a valve seat is fixed by means of the insert (14).

9. Back-pressure valve as claimed in claim 1, c h ar a c t e r i z e d in that it has a solid closing head (1) matching to the guide pin (2b) of the bearing element (2) with an aperture (20) thereon.

10. Back-pressure valve as claimed in claim 1, c h ar a c t e r i z e d in that it has a hollow closing head (30) matching to the guide pin (19) carried by the ribs (2a), with the apertures (31, 33) thereon.

11. Back-pressure valve as claimed in claim 1, c h a r a c t e r i z e d in that the closing head (31) is made of a sealing material with a metal reinforcing element (15) in the inside thereof.

12. Back-pressure valve as claimed in claim 1, c h a r a c t e r i z e d in that on the closing diameter in the closing head (32, 34) and/or in the house (3, 7, 36) and/or in the valve body (13) a valve seat (11, 12, 22, 24) is arranged.

13.Back-pressure valve as claimed in claim 1, c h a r a c t e r i z e d in that in downstream, behind the closing diameter, in the closing head (1,30) and/or in the guide pin (2b, 28a) there is an aperture (18, 20, 21, 16a, 31) discharging into the space inbetween.

14. Back-pressure valve as claimed in claim 1, c h a r a c t e r i z e d in that in the closing head (34) a magnet (25) and in the house (36) or in the valve body (13) a coil (26) is arranged.

15. Back-pressure valve as claimed in any of the claims 1 to 14, c h a r a c t e r i z e d in that onto the surfaces being in contact with the streaming medium a coating being resistant to chemically aggressive or erosive media, e.g. rubber, a synthetic material, PTFE, enamel, chrome, nickel etc. is applied.