Field of the Invention

The present invention concerns a method for making a valve wherein the valve comprises a valve housing with a central part and with two or more connection ends, the connection ends extending away from the central part, and where internally of the central part there is arranged a valve body arranged in a valve seat.

The invention also concerns a valve for regulating a fluid, the valve including a valve housing with a central part and with one, two or more connection ends, the connection ends extending away from the central part, wherein internally of the central part there is arranged a valve body, the valve body arranged in a valve seat and connected to a valve spindle, the valve spindle arranged in a spindle guide stub on the valve housing.

Background of the Invention

It is commonly known to make valves, e.g. ball valves, and thereby valve housings of several parts and then assemble these parts around a valve seat and a valve body. Such valves are typically made of brass or other copper-based alloys and are typically assembled by corresponding screw threads in respective parts, alternatively by means of bolts, e.g. by flange joints.

When speaking of a ball valve, the valve body is, as indicated by the name, spherical and with an outer size which is greater than the connecting openings in the valve housing. Such a valve therefore has a valve housing with an internal geometry in which valve seat and valve body are disposed. The valve housing is typically joined in the vicinity of the valve body as the latter requires the largest internal dimension. Such valves are typically made of cast items which are formed and shaped by machining to the desired geometry. This shaping process is, however, rather cost-intensive for several reasons. The individual work pieces are to be cast, handled and machined one by one in a suitable metal cutting unit. Since the work pieces are individually machined, the process is time-consuming, irrespective of the application of modern and rapid processes. In addition to the handling and machining of the cast work pieces prior to assembling around a valve seat and a valve body, the cost of the material also plays a significant role. Brass or other suitable alloys are expensive and imply an appreciably greater cost than e.g. common weldable carbon steel.

US 3819150 A discloses the making of a ball valve by shaping the valve housing by plastic deformation of a tubular workpiece around the ball and the valve seats. The valve seats are kept in position against the inner side of the valve housing by an internal welding that holds the valve seats in position in the valve housing. The connection ends are welded on the central part of the valve housing after shaping the central part of the valve housing, or are kept in position by a tubular sleeve. During the shaping of the valve housing the ball and the valve seats are loosely fitted in the valve housing, implying the possibility of production errors if one or more of the loose parts are displaced during the shaping of the valve housing.

There is thus an expressed desire for making valves for e.g. heating and cooling systems, for potable water and for other purposes in steel, e.g. carbon steel or stainless steel which is cheaper and which can be worked with modern production equipment directly from a plate piece or a tube piece by a faster and cheaper process than which is possible when casting and machining work pieces of brass.

Furthermore, there is a strong wish as to completely avoid screw connections or bolted flange joints in the valve housing. At the same time, it is greatly desired to avoid performing welding processes on a valve as such processes cause the work pieces to be set up at least one more time and that a welding process is to be performed, which of course raises the cost of the product.

Object of the Invention

It is the object of the invention to indicate a solution to the above problems wherein a valve housing is made in one piece without joints from a workpiece with tubular end parts, such as a tubular part, wherein a minimum number of chip removing and cutting processes are performed, and to avoid welding processes or to reduce these as much as possible before mounting a valve seat and a valve body, which mounting is performed before final shaping of the valve housing itself.

Description of the Invention

These objects are achieved by the invention by a method for making a valve which at least comprises providing a workpiece with tubular ends and on which a spindle guide is mounted. A valve spindle is mounted in the spindle guide, and a valve body and one or more valve seats are mounted in the central part of the workpiece, as each valve seat includes a fixing member which is urged to bear against the inner side of the central part of the valve housing for mechanical fixing of each valve seat and the valve body, and possibly the valve spindle in the central part of the valve housing as well. The central part of the valve housing is shaped before shaping the connection ends as the shaping of the central part includes reduction of the tube diameter of the tubular end parts; and the connection ends are then provided by shaping the end parts of the tubular workpiece.

It is achieved hereby that it will be possible to produce a valve by shaping the valve housing after mounting parts in the central part of the valve housing, including e.g. valve seat, valve bodies and possible sealings, as there may be produced a valve housing which is only constituted by a single workpiece formed as one piece without any kind of joining by welding, bolting or similar joining methods.

When using valve seats including a fixing member which is urged to bear against the inner side of the central part of the valve housing for mechanical fixing of each valve seat and the valve body and possibly the valve spindle in the central part of the valve housing, it is achieved that valve seats and the valve body, e.g. a ball, can both be held fixed in relation to the central part of the housing prior to the shaping itself and during the shaping of the central part of the housing without using any tools or without using other means, e.g. a weld seam at the inner side of the valve housing, for retaining the valve seats and possibly the valve body. This entails that the making of the valve is effected with great precision and becomes significantly easier than if the parts are not fixed. The production costs can thereby be further reduced, and hereby is also achieved that the risk of errors during production is reduced because valve seats and valve body are less prone to be displaced during the deformation of the central part of the valve housing. This will result in higher and more uniform quality of the valves, and the number of wrongly produced valves is considerably reduced. The valve is hereby produced with very few parts as well, also reducing the risk of a single loose part being displaced and causing error during production.

Since the valve housing can be made from a tube piece, the invention is therefore very suited in the case of common stop valves and through-flow valves. The invention may advantageously be used in shaping other types of valves, e.g. three-way valves or similar with more than two connection ends where the valve seat is located in a central part that has larger dimension and/or a shape different from the connection ends, and where it is thus advantageous to dispose valve body, valve seat and possible packings in the central part before shaping the connection ends.

The shaping of the central part of the valve housing and reduction of the tube diameter of the tubular end parts is preferably effected by plastic deformation, such as axial deformation by dies and/or mandrels in one or more steps. By the diameter reductions radial deformation can be applied as well. Also, the shaping of the connection ends can preferably be effected by plastic deformation of the tubular end parts by dies and/or mandrels in one or more steps, including by axial or radial deformation as described above.. Hereby it becomes possible to adapt the shape of the central part of the valve housing, in particular the connection ends, to the desired final shape. When using several steps for shaping the connection ends, it becomes possible to design the same type of valve with several variants of connection ends, e.g. press-fit or flange ends, by using a different shaping tool, in particular mandrels and/or dies, in a single or possibly several of the final shaping steps. Great flexibility in the production of the valves is thereby achieved as switching from one variant to another can easily be performed. At the same time the number of shaping tools, i.e. mandrels and/or dies, can be reduced as a part of the shaping tools can be used for a plurality of product variants. This also contributes to reducing the production costs of the valves. The method is moreover suited for shaping cheaper materials than brass and other copper-based alloys normally used in cast valve housings, as the shaping by the method enables use of e.g. carbon steel or stainless steel or copper for making the valve housing.

The invention is therefore also suited for making valves which are peculiar in that the valve housing is made of a workpiece with tubular end parts, and that the valve body and one or more valve seats are mounted in the central part of the valve housing before the shaping of the valve housing, as the central part of the valve housing and then the connection ends are shaped by plastic deformation of the tubular end parts, preferably by dies and/or mandrels in one or more steps

Use of this shaping of the valve housing enables mounting of valve seats, valve bodies and possible packings in the semi-finished valve housing, and the forming the valve housing into its final shape. By many valves, including particularly ball valves, the diameters of the connection ends are less than the central part of the valve housing where the valve seat and valve body are mounted. Besides, it is allowed that the valve housing is made with substantially reduced material thickness, further contributing to substantially reduced production costs. The valve is thus well suited for use in connection with other thin-walled materials which at the time being gain a foothold in the industry and are increasingly applied to industrial solutions as well as to plumbing installations in residential buildings. There are innumerable advantages connected with thinwalled pipes and fittings and the jointing methods are very simple, why time- consuming and cost-raising work of threading, welding or soldering is avoided.

A variant of the method and the valve comprise subsequent annealing and cooling of the connection ends of the valve housing. Hereby is achieved stress relief of the wall material of the valve housing at the connection ends, entailing that the original properties of the material are restored with regard to corrosion resistance, also resulting in a lower production cost of the finished product. The temperature in the metal during the annealing depends on which type of steel or steel alloy the valve housing is made, but will typically be in the range 800-1300°C, including preferably 900-1200°C, and in particular 1000-1100°C, as the annealing is e.g. performed at about 1050°C when using acid-proof stainless steel alloys.

It is preferred that the annealing and the subsequent cooling occur under application of a protective atmosphere as possible oxidation of the metal due to the presence of oxygen during annealing and de-stressing is avoided when using a protective atmosphere. A longer service life for the vale is thereby attained, and in addition the risk of rusting of the valve housing is reduced e.g. when mounted in an area with high atmospheric humidity. The protective atmosphere includes e.g. argon (Ar), helium (He), nitrogen (N ₂ ) or a combination of one or more of these gases. The protective gas may possibly contain small amounts of other gasses, including e.g. hydrogen. A suitable protective gas for stainless steel is e.g. FORMER™ gas which is based on nitrogen and contains a small amount of hydrogen, e.g. in an amount up to 5-10%. If the valve housing is made of copper, the inactive gas is preferably based on argon, nitrogen or helium, or mixtures thereof.

In a variant of the method and the valve, the central part of the valve housing are shaped before shaping the connection ends as the shaping of the central part includes reduction of the tube diameter of the tubular end parts. Hereby is achieved that it becomes possible to produce a valve housing where the diameter in the cross-section of the central part around valve body and a valve seat is greater than the diameter at the connection ends, for example when making a ball valve, e.g. a so-called full-flow ball valve, wherein the diameter in the aperture in the ball corresponds to the diameter in the connection ends and thereby also the diameter of the pipe system. This necessitates that the central part of the valve housing where ball and valve seats are located has greater diameter than the connection ends. The method is thus very well suited for making ball valves.

In a variant of the method, the valve spindle is mounted simultaneously with the spindle guide being fastened on the workpiece with the tubular connection ends, implying fewer joints on the finished valve housing as the spindle guide can be formed as a unit in that the spindle guide stub is equipped with an end face that keeps the valve spindle in position in the spindle guide. When the threaded stub then is fastened on the central part of the workpiece with the tubular end parts, it is avoided to form the spindle guide with a screw thread or a flange assembly for the end part holding the valve spindle in position in the spindle guide of the valve housing. Alternatively, the valve spindle can be mounted after mounting the spindle guide as the end of the valve stub therefore must comprise a threaded or flanged assembly or similar for an end part which is the only assembly in the valve housing.

Description of the Drawing

The invention will now be explained below with reference to the drawing, where:

Fig. 1 shows a valve with a valve housing with connection ends shaped according to the invention;

Fig. 2 shows a tubular workpiece with a spindle guide with valve spindle mounted; Fig. 3 shows a cross-section of the tubular workpiece in Fig. 2 where the valve body is mounted;

Fig. 4 shows a cross-section of the tubular workpiece in Fig. 2 where the valve body is mounted, and with indication of applied adhesive for use in positioning and/or mounting of valve seat, packings and/or retention rings for the valve seat;

Fig. 5 shows a cross-section of the tubular workpiece in Fig. 2 where valve body, packings and possible retention rings for the valve seat are mounted;

Figs. 6-8 show formation of the central part of the housing with increased diameter relative to the end parts;

Figs. 9-11 show an example of shaping of the connection ends.

In the explanation of the Figures, identical or corresponding elements will be provided with the same designations in different Figures. Therefore, no explanation of all details will be given in connection with each single Figure/embodiment.

Detailed Description of Embodiments of the Invention

In Fig. 1 appears a valve 1 with a valve housing 2 where the valve housing 2 has a central part 3 and at least two connection ends 4, as the shown valve housing 2 is designed with two connection ends 4. The invention is not limited to application for through-flow valves, including ball valves, and may also be applied to e.g. stop valves, three-way valves and other current types of valves; however, the invention will be illustrated by the making of a ball valve in the following. The invention is thus well suited for making ball valves.

The connection ends 4 on a finished valve housing 2 are here shown with a design adapted with so-called press-fittings. However, the shape of the connection ends 4 themselves is irrelevant to the invention and only an example of how these connection ends 4 can be made. In the central part 3 is arranged a valve body 5, e.g. with a through-going aperture 6 in a valve seat 7. From the valve body 5, which in the shown valve is constituted by a traditional ball as seen on Figs. 3-8 known from various ball valves, a valve spindle 8 extends up through a spindle guide stub 9. By turning this valve spindle 8 about its longitudinal axis, the valve body can be moved between an open position and a closed position.

By the making of the valve 1, the spindle guide 9 and the valve spindle 8 are preferably mounted before the shaping of the valve housing 2 itself. Then the valve body 5 is mounted and fastened to the valve spindle 8, see Fig. 3.

By the shown variant, see Figs. 4-8, the valve seats 7 are possibly temporarily mounted by an adhesive 10, see Fig. 4. Each valve seat 7 includes a fixing member 13, preferably a flange 13 facing away from the valve body 5 and e.g. conical. The fixing member 13 can be pressed to bear against the inner side of the central part of the valve housing 2. The valve body 5 and the valve seats 7 may thus easily and without any substantial effort be placed in the desired position where a sufficient contact pressure is established between the valve body 5 and the valve seat 7. The valve seats 7 and the valve body 5 are thus fixed only by the flange member 13 being urged against the internal side of the valve housing. Valve body 5 as well as valve seats 7 and associated packings can be mounted in the central part of the valve housing 2 through one or both of the connection ends 4. Therefore there is no need for the valve housing 2 to be composed of several parts. At least the fixing member 13 on the valve seat 7 includes e.g. a layer of steel. The steel layer has the purpose of providing rigidity and resiliency to the fixing member 13.

These loose parts are then permanently fixed, preferably by deforming the two connection ends 4 to a smaller internal cross-section as shown on Figs. 6-8. The valve seats 7 are thereby locked into their position in relation to the valve body 5 as well as to the valve housing 2. Such a deformation can include a securing of the valve seat or valve seats 7 in a given position as the valve housing 2 is deformed by reducing the radius in the end parts 4, but alternatively there may also be effected a deformation of valve housing 2 as well as the fixing member 13 on the valve seat 7 for locking the position of the valve seat 7 in the valve housing 2.

The shaping of the central part 2 of the valve housing and the connection ends 4 occurs preferably by axial plastic deformation in one or more steps, e.g. two, three, four or more steps, under application of one or more shaping tools such as mandrels and/or dies. Figs. 5-8 show an example of possible shaping of the central part 2 of the valve housing where the diameters of the end parts 4 are gradually reduced relative to the diameter of the central part 2 of the housing under simultaneous formation of the central part 2 of the valve housing by axial plastic deformation with various dies and mandrels in three steps, see particularly Figs. 6-8 for achieving the final shape of the central part 2 of the valve housing. However, it is possible to use fewer steps, e.g. one or two, or more steps, e.g. four, five or more during the axial deformation, as the shape of dies and/or mandrels used by the diameter reduction are adapted to the applied number of steps. The number of steps can be varied according to need as allowance is made for factors such as material thickness in the wall housing, the material properties of the used steel alloy by plastic deformation and the magnitude of the desired diameter reduction of the end parts. As seen on the Figures 1 and 9-11, the diameter of the central part 2 of the valve housing is greater than the diameter of the connection ends 4 as usually is the case with conventional ball valves.

The connection ends 4 are then shaped into their final shape. Figs. 9-11 show an example of possible and non-limiting shaping of a valve housing with ends of the press-fit type. The connection ends 4 are here shaped in at least one step, as Fig. 9 shows that the diameter of the end parts is increased by one or more mandrels, including possibly with associated dies, for attaining a slightly increased diameter in the central part 4a and a further increased diameter in the outer part 4b of the end parts 4. The outer end is then shaped as shown in Figs. 10-11 as a die and a possible associated mandrel at first reduce the diameter of the outermost end 4c and a second die and possible associated mandrel then provide a final rounded shaped on the outer part 4b of the connection end. As an alternative to axial deformation, by diameter reduction there may advantageously be used radial deformation where the workpiece is squeezed by dies in order to reduce the tube diameter.

However, it is possible to shape the connection ends 4 in any other desired way as it is possible to vary the number of steps and the shape of the dies and/or mandrels that provide the desired shape on the connection ends 4. Another shape of the connection ends, e.g. providing a flange assembly at the connection ends 4, can be provided by designing shaping tools, i.e. dies and/or mandrels, for the axial and/or radial plastic deformation such that a desired shape of the connection ends 4 is achieved. The shaping according to the invention enables using e.g. copper or carbon steel or stainless steel, including acid-proof stainless steel alloys for making the valve housing, and that the valve housing can be made in one piece such that it is no longer necessary to design the valve housing with joints. Thereby it will be possible to make the valve housing of thin-walled materials and the production of the valve can occur in fewer steps, and the total production cost per valve can be reduced.

After shaping the connection ends 4 of the valve housing 2, the connection ends 4 can preferably be annealed and subsequently cooled. By the annealing and subsequent cooling of the metal, particularly steel types, it can be achieved that the original properties of the material are restored with regard to corrosion resistance.

The temperature in the metal during the annealing depends on which type of steel or steel alloy the valve housing is made, but will typically be in the range 800-1300°C, including preferably 900-1200°C, and in particular 1000-1100°C, as the annealing is e.g. performed at about 1050°C when using acid-proof stainless steel. The annealing, shaping and subsequent cooling is effected under a protective atmosphere. The protective atmosphere includes e.g. argon (Ar), helium (He), nitrogen (N ₂ ) or a combination of one or more of these gases. The protective gas may possibly contain small amounts of other gasses, including e.g. hydrogen. A suitable protective gas for stainless steel is e.g. FORMER™ gas which is based on nitrogen and contains a small amount of hydrogen, e.g. in an amount up to 5-10%. If the valve housing is made of copper, the inactive gas is preferably based on argon, nitrogen or helium, or mixtures thereof.

Shaping of the valve housing according to the invention is particularly suited for fully automatic production. Automation of the production can e.g. be effected under- application of robotics.