GB1582058A - Pressure fluid operated valve - Google Patents

Description

(54) PRESSURE FLUID OPERATED VALVE (71) We, KOCKUMS AB, a Swedish company, of Fack, S-201 10, Malmo 1, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: For cutting off and controlling hot water pipelines in remote heating systems there are used today preferably ball slide valves, valves having a so called pressure lubricated plug, ball valves and butterfly valves, and in some countries also wedge slide valves.All these valves are in one way or other less advantageous because they are either expensive or heavy, require a large headroom, are available for specific size ranges only, or are provided with stuffing boxes and seals which require extensive maintenance and may render the operation difficult. Some types moreover have a tendency to get stuck due to corrosion. If these valves shall be arranged for remote operation the apparatus required for such operation will be expensive and complicated in most cases. Therefore, in remote heating systems the valves are practically always arranged for manual operation which means that the operation in many cases must be formed at the valve proper where it is located in a narrow well or other underground space, which may involve a risk for injuries to persons if leakage should arise for some reason or other when the valve is being operated.In this connection some severe accidents and nearaccidents have occurred.

However, in the thermal power industry and especially in case of remote heating systems valves are required which are maintenance-free, are easy to handle and to install -known valves for large pipe dimensions are often big things weighing several tons- can be produced at reasonable costs and, above all, can be remotely operated in a simple manner and are reliable regarding the function of the valve as well as the safety of those who are working with the valves. In this connection it is particularly important that the valves can be opened and closed although they have been left untouched for a long time, e.g. for disconnecting a pipeline section which has failed in some way or other.

The purpose of the invention is to provide a pressure fluid operated valve which satisfies these requirements and wishes.

The valve of the invention is of the type comprising a valve body and a valve closure element therein supported at one end of a bellows which is arranged in the flow passage of the valve body and connected to the valve body at the other end thereof and has a connection for the supply and discharge of pressure fluid, the closure element being pressed towards a seat arranged in the valve body by the supply of pressure fluid to the bellows.

Prior art valves of this type have been provided with a rubber bellows which is connected to the valve body at one end thereof and projects freely therefrom to support the closure element at the other end thereof. Valves of this construction are not suited for use with fluids which are under high pressure and at high temperature because the closure element is not guided as is necessary for a satisfactory co-operation with the seat and often cannot stand the existing high temperatures and pressures.

According to the invention there is proposed a valve of the type referred to above characterized in that the closure element is yieldably biassed from the seat thereof and that the bellows is surrounded by a stationary shell fixedly mounted in the valve body and forming a support for the closure element when it is lifted from the seat thereof.

In order to elucidate the invention embodiments of such a valve intended for hot water pipelines in remote heating systems are described in more detail below, reference being made to the accompanying drawings.

However, it shall be emphasized already that the valve according to the invention is in no way limited to this specific use but can be used for steam, oil and other hydrocarbons, cooling water and raw water and for pressurized air and other gases in the chemical industry, the pharmaceutical industry and the cellulose industry as well as for industrial water treatment.

In the accompanying drawings, Fig. 1 is a longitudinal sectional view, partly a side view, of an embodiment of the valve according to the invention, Fig 2 is a corresponding view of another embodiment wherein two valve closure elements are provided, Fig. 3 is a corresponding view of a third embodiment having two closure elements but no spring, and Fig. 4 is a fragmentary axial sectional view of the embodiment shown in Fig. 3.

The valves disclosed in the drawings have been developed for use in remote heating systems but, as indicated above, they can also be used generally in other connections for the control of varying types of fluids at high pressure and high temperature. The pressure in question can be 5 or 6 atm.

gauge which is a common water pipeline pressure, and higher pressures of the order of 150 atm. gauge existing in steam generators, and pressures therebetween of 16 to 40 atm. gauge which is the pressure range in remote heating systems. The temperature can be between 0 C and about 400"C, the temperature range of interest in the case of remote heating systems extending from 1200C to 2200C.

The valve according to Fig. 1 comprises a valve body of steel which is welded together of several parts, namely a cylindrical main part 10, an internally concave annular transition part 11 and an internally convex annular transition part 12 at each end of the main part 10, as well as a cylindrical connection piece 13 at each end of the valve body. It is the intention that the valve shall be included into a pipeline simply by welding it to the pipes at the connection pieces of the valve, but it is of course possible to arrange thread or flange connections or connections of another type on the valve body.

A cylindrical tube 14 is supported coaxially in the valve body by means of arms or webs 15 which are welded to the tube and to the valve body, and this tube 14 is open at one end thereof at 16, while the other end thereof is closed by means of a semi-spherical end wall 17 welded thereto.

The end wall has a central opening 18 to which there is connected a conduit 19 which is extended from the valve body through the wall of one of the connection pieces 13.

Inside the tube there is connected by welding adjacent the end closed by means of the end wall 17 a transverse wall 20 having a through opening 21, and in an enlargement 22 of this opening there is mounted a bellows 23. This bellows is of a type which is known per se in connection with so called compensators in pipelines, that is an element which allows the pipes to expand and con tract, but it has not so far, as in the present case, been used as an operating member in a pressure fluid operated valve.

This special bellows is constructed of stainless steel which is soft and resistant.

The bellows wall consists of a great number of thin layers of such steel. Each layer can have a thickness of 0.3 to 1 millimeter and the number of layers preferably can range from 2 to 10. There are two different manners of manufacturing such a bellows.

One manner consists in forming individual layers of steel banding to a cylinder, the mutually abutting edges of each layer being welded together. On one layer of this type there is provided another layer which is welded individually the weld thereof being displaced circumferentially in relation to the preceding layer, and in this manner the bellows is continuously built up layer after layer. The other embodiment includes a continuous steel band which is initially formed to a single cylindrical layer and is connected in this form by welding, the steel band then being wound continuously around the cylinder thus initially formed in order to provide a desired number of layers. The free end of the steel band is welded to the other side of the helically applied layers. Said latter method is the best one because leakage, if any, arising in the bellows is more easily checked.When the bellows has been built up in this manner of steel band layers it is grooved externally and internally in order to be given the bellows form shown.

To use a bellows of this type as an operative member in a valve has turned out to be advantageous according to the invention because the bellows requires a very low pressure for axial movement. It is easy to manfacture and it can take up alternating loads.

At the end of the bellows 23 which is opposite to the end thereof which is connected to the wall 20, there is provided a cylindrical head 24 which has a through opening 25 with an enlargement 26 for receiving the bellows. This head has a spherical annular surface 27 at the outer free end thereof, and to this surface there is welded a spherical hollow valve closure element 28 of steel, preferably stainless steel.

Inside the closure element there is attached by welding a cross bar 29, and between this cross bar and a corresponding cross bar 30 at the side of the wall 20 which is opposite to the bellows there is engaged a helical tension spring 31.

The tension spring serves to contract the bellows when the closure element 28 is to be displaced to the left in Fig. 1 to engage the open end 16 of the tube 14 which forms a shell about the bellows. In this position the closure element 28 is withdrawn from the seat thereof which is formed by the transition portion 12 at the right-hand end of the valve body. The closure element is brought to engage this seat by means of a pressure fluid, liquid or gas (air) supplied to the interior of the bellows 23 through the conduit 19 the bellows being brought to expand against the bias of the tension spring 21 and the closure element 28 being engaged with said seat thereof under the pressure of the pressure fluid.

Since a tension spring 31 is provided for contracting the bellows when the closure element 28 is lifted from the seat thereof, and accordingly the inherent contraction force of the bellows only is not relied upon which is possible, however-the bellows can be given a shorter constructive length for a predetermined stroke. Preferably the bellows is arranged in such a way that it is compressed against the inherent spring action thereof when the closure element is drawn against the end 16 of the tube 14, and is expanded against the inherent spring action thereof when the closure element is engaged with the seat thereof under the action of pressure fluid in the interior of the bellows. The bellows thus will operate on each side of a normal position in which it is substantially relieved.

Since the closure element 28 is hollow it is light and since it is spherical it is shapepermanent. The spherical closure element is self-centering against the seat and it moves easily towards and away from the seat without hanging down at the free end of the bellows. In the embodiment according to Fig. 1 the bellows is guided by means of the head 24 inside the tube 14. If contaminants are entrained in the fluid controlled by means of the valve it may be desired to exclude such guiding in view of the fact that the surfaces sliding against each other may be sensitive to such contaminants. An embodiment wherein there is no head shall be described later in connection with Fig. 2.

If the valve is used for controlling a fluid which flows from the left to the right as seen in Fig. 1 through the valve body the pressure of the fluid will support the force of the bellows 23 with regard to the engagement of the closure element 28 with the seat.

In that case there is also the possibility to provide hydraulic control of the closure element. In the tube 14 there is provided an opening 32, and the fluid controlled by means of the valve therefore has the possibility to flow into the tube 14 and to fill the space around the bellows 23 where the pressure of the fluid serves to support or stiffen the bellows against downward bending.

In the embodiment of the closure element shown the three functions of cutting off, throttling and regulating can be achieved.

However, the closure element may be provided with a so called "nose rod" in order to further improve the flow of fluid past the closure element. The "nose rod" is directed substantially axially towards the adjacent connection piece 13. The closure element can also have a more or less conical form or some form between spherical and conical form. Furthermore, it can be suitable to provide the seat or the closure element with an elastic coating such as rubber vulcanized thereto if the valve is to be used for fluids the temperature of which does not exceed 120 or 130"C. If there is no coating of this type it may be necessary to make the fit between closure element and valve seat with greater precision, the elastic coating can equalize irregularities in the fit between the closure element and the seat.

The operation of the valve suitably can be performed by means of gas, preferably air, which is stored in a pressure container connected through a valve to the conduit 19.

The valve in the conduit 19 can be operated manually and/or can be operated by means of a pressure sensing device which senses a pressure decrease in a section of the remote heating system-such pressure decrease may be caused e.g. by leakage-and then immediately brings the valve in conduit 19 to open so that the closure element 28 is brought to closed position for cutting off the supply of hot water to said section of the remote heating system.

As will be realized the valve described is very simple as far as the construction thereof is concerned and particularly it should be noted that this valve lacks completely seals and stuffing boxes. It is included into a pipe conduit as easily as it is connected to suitable control means for the supply and the discharge, respectively, of pressure fluid to and from the bellows 23.

The valve according to Fig. 2 is constructed substantially in the same way as the valve according to Fig. 1 but as indicated above there is in this case no head 24 on the bellows. The valve according to Fig. 2 moreover is double-acting so that it can be used for fluid which flows through the valve alternatingly in one direction or the other the supplementary closing force supplied by the fluid proper on the downstream valve closure element being obtained. In Fig. 2 the valve body is of the same construction as in Fig. 1 and the several parts thereof are provided with the same references as in Fig. 1.

Two closure elements designated 28 and 281 are arranged in the valve body and they have each a bellows 23 and 231, respectively, these bellows being arranged in a tube 14 as in the embodiment according to Fig. 1.

Centrally in the tube there is arranged a housing 33 supported by means of arms or webs 34 coaxially in the main part 10 of the valve body, and the interior of the two bellows communicates with this housing which is connected by the conduit 19 to the pressure fluid source provided for the operation of the valve. One spring 31 only is provided in this case the spring being engaged between a cross bar 29 attached by welding in each valve element in the manner shown in connection with the closure element 28 in Fig. 2.

If it is assumed that fluid flows through the valve in Fig. 2 from the left to the right and that it is intended to close the valve the pressure of the fluid will support the closing of the right-hand closure element 28 and the same support will be obtained when the closure element 281 is closed in case the fluid flows through the valve from the right to the left. Thus, the valve according to Fig. 2 is preferred due to the fact that it can be used for flow in either direction. The pressure support obtained when closing the valve provides a safety factor since at least one closure element will be kept in closed position if the pressure in the bellows should fail.

The valve according to Figs. 3 and 4 has also two closure dements and is constructed principally in the same manner as the valve according to Fig. 2. However, there is no spring. The valve body comprises two parts 10 which are welded to a ring 35 arranged between said two parts. Each part 10 consists of metal sheet and is formed by pressure turning to a seat 36. Moreover, it is provided with a connection piece 13 welded thereto.

A cylindrical transverse wall 20 is supported by the ring 35 by means of webs 15.

Two valve closure elements 28 and 281 are arranged in the valve body and they are both constructed and arranged in the manner which will be described in more detail with regard to the closure element 28 reference being made to Fig. 4. The closure element proper has torpedo form and is welded together of three parts, namely a base part 37, a cap part 38 and an intermediary part 39 welded to the inner surface of parts 37 and 38. The intermediary part forms the bottom of a shallow circumferential groove formed between the base part and the cap part said groove being filled with a layer 40 of elastic material, e.g. vulcanized rubber which equalizes irregularities in the fit between the closure element and the seat.

The closure element 28 is welded to an annular head 24 at the base part 37, and the associated bellows 23 is connected to said head at one end thereof, while the other end of the bellows is connected to the transverse wall 20. The bellows can be of the same construction as has been described above with reference to Fig. 1. The bellows is surrounded by a telescope tube comprising an outer cylindrical tube portion 14 which is connected to and supported by the transverse wall 20, and an inner cylindric tube portion 141 which is connected to and supported by the head 24. This telescope tube guides the bellows as is necessary during the expansion and contraction thereof.

In this embodiment there is no spring inside the bellows and thus the inherent spring action of the bellows only is relied upon as far as the contraction of the bellows is concerned for the displacement of the closure element to the opened position which is shown with regard to the left-hand closure element 281 in Fig. 3, the head 24 engaging the end of the tube portion 14 in this position. Then, the tube portion 141 is completely slid into the tube portion 14.

For the expansion of the bellows against the inherent spring action thereof there are provided two passages 19 one for each bellows through the ring 35, the webs 15 and the transverse wall 20 for the supply of gas (air) but a common passage can be provided for both bellows. Since a great volume of gas (air) is required for the operation of the closure element to the closed position if the interior space of the closure element and the bellows is large, said space can be filled partly with an anticorrosion liquid or with light filler bodies such as plastic balls.

A passage 41 is arranged through the ring 35 to make it possible to connect the interior of the valve body to the surroundings so that the pressure inside the valve body can be relieved.

The embodiments shown and described are examples only which serve the purpose of illustrating the invention, and it would be obvious that modifications can be made within the scope of the appended claims as far as the several constructive details of the valve are concerned, considering the temperature, pressure and type of fluid for which the valve shall be used. It should be mentioned especially that it is possible to influence the flow resistance of the valve by adjusting the diameter of the closure element 28 and the diameter of the tube 14 in a suitable manner in relation to each other so that there is obtained the flow pattern which is desired in the individual case. The valve body can of course also be constructed in another manner than that shown here in order to be included in a specific pipeline system.

WHAT WE CLAIM IS:- 1. Pressure fluid operated valve comprising a valve body and a valve closure element therein supported at one end of a bellows which is arranged in the flow passage of the valve body and connected to the valve body at the other end thereof and has a connection for the supply and discharge of pressure fluid, the closure element being pressed towards a seat arranged in the valve body by the supply of pressure fluid to the bellows, characterized in that the closure

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. pressure fluid source provided for the operation of the valve. One spring 31 only is provided in this case the spring being engaged between a cross bar 29 attached by welding in each valve element in the manner shown in connection with the closure element 28 in Fig. 2. If it is assumed that fluid flows through the valve in Fig. 2 from the left to the right and that it is intended to close the valve the pressure of the fluid will support the closing of the right-hand closure element 28 and the same support will be obtained when the closure element 281 is closed in case the fluid flows through the valve from the right to the left. Thus, the valve according to Fig. 2 is preferred due to the fact that it can be used for flow in either direction. The pressure support obtained when closing the valve provides a safety factor since at least one closure element will be kept in closed position if the pressure in the bellows should fail. The valve according to Figs. 3 and 4 has also two closure dements and is constructed principally in the same manner as the valve according to Fig. 2. However, there is no spring. The valve body comprises two parts 10 which are welded to a ring 35 arranged between said two parts. Each part 10 consists of metal sheet and is formed by pressure turning to a seat 36. Moreover, it is provided with a connection piece 13 welded thereto. A cylindrical transverse wall 20 is supported by the ring 35 by means of webs 15. Two valve closure elements 28 and 281 are arranged in the valve body and they are both constructed and arranged in the manner which will be described in more detail with regard to the closure element 28 reference being made to Fig. 4. The closure element proper has torpedo form and is welded together of three parts, namely a base part 37, a cap part 38 and an intermediary part 39 welded to the inner surface of parts 37 and 38. The intermediary part forms the bottom of a shallow circumferential groove formed between the base part and the cap part said groove being filled with a layer 40 of elastic material, e.g. vulcanized rubber which equalizes irregularities in the fit between the closure element and the seat. The closure element 28 is welded to an annular head 24 at the base part 37, and the associated bellows 23 is connected to said head at one end thereof, while the other end of the bellows is connected to the transverse wall 20. The bellows can be of the same construction as has been described above with reference to Fig. 1. The bellows is surrounded by a telescope tube comprising an outer cylindrical tube portion 14 which is connected to and supported by the transverse wall 20, and an inner cylindric tube portion 141 which is connected to and supported by the head 24. This telescope tube guides the bellows as is necessary during the expansion and contraction thereof. In this embodiment there is no spring inside the bellows and thus the inherent spring action of the bellows only is relied upon as far as the contraction of the bellows is concerned for the displacement of the closure element to the opened position which is shown with regard to the left-hand closure element 281 in Fig. 3, the head 24 engaging the end of the tube portion 14 in this position. Then, the tube portion 141 is completely slid into the tube portion 14. For the expansion of the bellows against the inherent spring action thereof there are provided two passages 19 one for each bellows through the ring 35, the webs 15 and the transverse wall 20 for the supply of gas (air) but a common passage can be provided for both bellows. Since a great volume of gas (air) is required for the operation of the closure element to the closed position if the interior space of the closure element and the bellows is large, said space can be filled partly with an anticorrosion liquid or with light filler bodies such as plastic balls. A passage 41 is arranged through the ring 35 to make it possible to connect the interior of the valve body to the surroundings so that the pressure inside the valve body can be relieved. The embodiments shown and described are examples only which serve the purpose of illustrating the invention, and it would be obvious that modifications can be made within the scope of the appended claims as far as the several constructive details of the valve are concerned, considering the temperature, pressure and type of fluid for which the valve shall be used. It should be mentioned especially that it is possible to influence the flow resistance of the valve by adjusting the diameter of the closure element 28 and the diameter of the tube 14 in a suitable manner in relation to each other so that there is obtained the flow pattern which is desired in the individual case. The valve body can of course also be constructed in another manner than that shown here in order to be included in a specific pipeline system. WHAT WE CLAIM IS:-

1. Pressure fluid operated valve comprising a valve body and a valve closure element therein supported at one end of a bellows which is arranged in the flow passage of the valve body and connected to the valve body at the other end thereof and has a connection for the supply and discharge of pressure fluid, the closure element being pressed towards a seat arranged in the valve body by the supply of pressure fluid to the bellows, characterized in that the closure

element is yieldably biassed from the seat thereof and that the bellows is surrounded by a stationary shell fixedly mounted in the valve body and forming a support for the closure element when it is lifted from the seat thereof.

2. A valve as claimed in claim 1, characterized in that the closure element has spherical or conical form or a transition form between the spherical and conical forms.

3. A valve as claimed in claim 1 or 2, characterized in that the shell is cylindrical and is arranged in a cylindrical part of the valve body coaxially therewith spaced from the inner surface of the cylindrical part.

4. A valve as claimed in claim 3, characterized in that the shell is supported by the valve body by means of arms, webs or the like allowing flow through the space between the cylindrical part of the valve body and the shell.

5. A valve as claimed in any of claims 1 to 4, characterized in that the end of the bellows carrying the closure element is slidably guided on the inner surface of the shell.

6. A valve as claimed in claim 5, characterized in that the shell comprises one portion of a telescope tube the other portion of which is connected with the end of the bellows connected to the closure element.

7. A valve as claimed in any of claims 1 to 6, characterized in that the wall of the bellows is constructed of several layers of thin steel sheet which is bent to cylinder form and is formed with pressed grooves internally and externally.

8. A valve as claimed in any of claims 1 to 8, characterized in that two closure elements with associated bellows are arranged in the valve body for co-operation each with a seat at one end and the other, respectively, of the flow passage of the valve.

9. A valve as claimed in any of claims 1 to 8, characterized in that the shell is provided with a perforation to admit the fluid passing through the valve into the interior of the shell.

10. A valve as claimed in any of claims 1 to 9, characterized in that the closure element is provided with a layer of elastic material in the region for co-operation with the seat.

11. A valve as claimed in any of claims 1 to 10, characterized in that the closure element is yieldably biassed from the seat thereof by means of a tension spring arranged inside the bellows and connected with the closure element.

12. A valve as claimed in any of claims 1 to 10, characterized in that the closure element is yieldably biassed from the seat thereof by the inherent spring action of the bellows.

13. A pressure fluid operated valve substantially as hereinbefore described with reference to Figure 1, Figure 2, or Figures 3 and 4 of the accompanying drawings.