AU680114B2 - Housing for sliding valve and method for the manufacturing of the same - Google Patents

Description

Housing for sliding valve and method for the maπufactu .Ing of the same

A cast valve housing intended to be connected between two pipe ends and with an opening in between, which forms a flow path for a fluid, in conjunction with which the housing has an internal guide parallel with a first plane for a slide capable of moving in the housing and so arranged as to open and close the aforementioned flow path, which valve housing has a flange perpendicular to the first plane constituting an attachment for the first end of pillars in a pillar set which extends parallel with the first plane, and at its other end exhibits means for the displacement of the slide, in conjunction with which a recess is provided in the flange to accommodate a packing around the slide, and a gland is so arranged relative to the flange as to be applied against the packing in the direction of movement of the slide.

The aforementioned means for the displacement of the slide may be either a wheel-actuated spindle or a linear motor, such as a pneumatic or hydraulic cylinder.

Valve housings of this kind are encountered in a number of different executions; they may be manufactured in two halves, the contact surfaces of which were plane-machined in a first machining operation, after which the halves were assembled together, usually by means of a bolted joint. The housings can also be cast in a single piece. The valve housings must also be plane-machined in the same kind of machining operation as the aforementioned halves, in order to accept connections in planes parallel with the plane of the slide. Until now, it has been necessary to plane-machine the external surfaces of the valve housing flanges lying perpendicular to the plane of the slide in a second machining operation of the same complicated kind as the first-mentioned operation. In the case of large slide valves, this is only possible by setting up the valve housing in two machine configurations, since plane-machining, usually involving the use of a face milling cutter, cannot take place in two planes that are perpendicular to one another in a single machine configuration for large valve housings. The reason why the external surfaces of the flanges have had to be plane- machined in this complicated way is that plane surfaces were needed in order to be able to drill holes for the aforementioned pillar set and bolts for pressing the gland against the packing. This situation was associated with high manufacturing costs, especially for valve housings for large slide valves.

The object of the present invention is to make available a slide valve housing which has a low manufacturing cost, compared with what was previously the case, but which is still easy to assemble and reliable to use. In accordance with the invention, a valve housing for a slide valve of the kind mentioned by way of introduction is characterized in that the flange has projecting parts which have been plane- machined to provide surfaces perpendicular to the first plane, and in that brought into contact with these surfaces is at least one plane plate which is executed with threaded holes directed perpendicularly in relation to the plate, and in that the gland is so arranged as to be pressed against the packing by means of gland bolts interacting with the threaded holes in the plate.

In accordance with one particular characteristic of the invention, the flange has transcurrent openings produced in conjunction with the casting of the valve housing. The plate is so arranged as to be brought into contact with the aforementioned surfaces by means of bolted joints through the aforementioned openings.

The aforementioned surfaces and the plate are preferably arranged on the side of the flange facing the pillar set.

It is customary to use two symmetrically located plates. It is advisable to provide four long projecting parts per plate. The invention also relates to a method for manufacturing a slide valve housing of the kind mentioned by way of introduction, in conjunction with which the.valve housing is cast as an essentially plane piece parallel with a first plane, or as two essentially plane halves, which, when assembled together, are parallel with the aforementioned plane, with one flange essentially perpendicular to it, or respectively with each flange half essentially perpendicular to it, which valve housing is plane-machined at the time of its manufacture in at least one second plane lying parallel with the first plane in a first machining operation such as a milling operation.

The method in accordance with the invention is characterized in that the flange or the flange halves are provided at the time of casting with a number of projecting parts, of which at least some, in a second machining operation such as a milling operation, are plane-machined to provide external surfaces in a common third plane perpendicular to the first plane, and in that, in conjunction with this, the first and second machining operations are executed with the valve housing in one and the same jig arrangement by performing the first milling operation with a face milling cutter and by performing the second milling operation with an end milling cutter.

The method in accordance with the invention permits the first and the second machining operations to be performed with the valve housing in one and the same jig arrangement, which is made possible, after the plane-machining, e.g. face milling, of a second plane parallel with the first plane, e.g. a contact surface, by changing the tool from a face milling cutter to an end milling cutter, which can be used here for plane-machining the projecting parts, since the surfaces of the projecting parts of the invention are essentially smaller than the surfaces which, in previously disclosed methods, were created by the plane-machining of the entire flange surface with a face milling cutter. The small surfaces of the projecting parts permit them to be machined with the end milling cutter, because the lateral forces acting against the end milling cutter are also small in this case. In previously disclosed methods, a new jig arrangement was required for the valve housing for the slide valve, since the entire flange surface is too large to be capable of being machined with an end milling cutter, because the lateral forces would be excessively high in that case.

In accordance with one particular characteristic of the method in accordance with the invention, the flanges are provided at the time of casting with transcurrent holes for the connection of plates, which are appropriately secured with bolts from the opposite side of the flange. In addition, four extra projecting parts are appropriately arranged on the flange for the attachment of the four pillars constituting the pillar set commonly encountered on slide valves of this kind. These latter projecting parts are also appropriately machined in the same way as the projecting parts just mentioned. In one execution, projecting parts executed on the opposite side of the flange are plane-machined to permit the installation of nuts for securing the pillar set.

The invention is explained below in more detail with reference to the accompanying drawings, in which:

Fig. la illustrates as a front view a part of a slide valve comprising the valve housing of the invention.

Fig. lb shows a view of a longitudinal section through the item in Fig. la.

Fig. 2a shows a plan view of a flange on a valve housing for a slide valve in accordance with the invention.

Fig. 2b shows a side view of the same item as in Fig. 2a.

Fig. 2c shows a section along the markings C-C in Fig. 2a. Fig. 3 shows the composition of the item in Fig. 2c with a gland, packing, plates, pillar set and bolts, as a partially cut-away view.

Fig. 4a illustrates schematically how the contact surface of a valve housing is plane-machined with a face milling cutter in accordance with a previously disclosed method. Fig. 4b illustrates schematically how the flange surface of a valve housing is plane-machined with a face milling cutter in accordance with a previously disclosed method in a new machine configuration compared with that shown in Fig. 4a. Fig. 4c illustrates schematically how the contact surface of the valve housing of the invention is plane-machined with a face milling cutter in a first machine configuration. Fig. 4d illustrates schematically how the projecting parts on the flange of the valve housing of the invention are plane- machined with an end milling cutter in the same machine configuration as in Fig. 4c.

In Figs, la-lb, the reference 1 is used to designate a valve housing in accordance with the invention for a slide valve, 2 to designate a plane slide and 3 the flange of the valve housing. The contact surface 4 of the valve housing 1 is plane-machined in a face milling machine with the axis of the milling cutter perpendicular to the plane of the slide. Pillars 5 are attached to the flange 3 by means of nuts 23 on the underside of the flange. A spindle 6 is so arranged, by rotating a wheel 7, as to cause the slide 2 to be displaced in its guide in the valve housing. A recess 8 is provided in the flange to accommodate a packing 9 around the slide 2, and a gland 10 is so arranged as to press against the packing in the direction of movement of the slide 2 by means of gland bolts 17. In valve housings in accordance with the prior art, the bolts mentioned by way of introduction are in threaded engagement with threaded holes in the flange 3. In order to facilitate the appreciation of the invention, the method in accordance with the invention for the manufacture of a valve housing is now explained in more detail with reference to Figs. 4a-4d.

Figs. 4a-4b illustrate schematically the need, using previously disclosed methods, after performing a plane- machining operation on the contact surface 4 of the valve housing with a face milling cutter 20, to execute a new machine configuration in order to be able to execute plane- machining of the entire flange surface 19 with the same face milling cutter 20. The plane flange surface is necessary, in order to be able, with the required degree of accuracy, to produce threaded holes for the gland bolts 17, the pillar set 5 and bearing holes for the threaded spindle 6.

Figs. 4c-4d illustrate schematically that the flange 3 was executed at the time of casting with projecting parts 11, 13, and how the machining operations are capable in this way, using the method in accordance with the invention, of being performed with the same machine configuration. This is made possible by exchanging a face milling cutter 20, which is used for plane-machining the contact surface 4 of the valve housing, for an end milling cutter 21 shown in Fig. 4d. This machining operation is possible because the projecting parts

11, 13 that are machined are small, and the lateral forces acting against the end milling cutter 21 are correspondingly small.

The projecting parts can be seen in Figs. 2a-2c on the upward-facing side of the flange 3, and other projecting parts 12, 14 can be seen on the downward-facing side. These projecting parts are thus plane-machined with the end milling cutter 21 with a much smaller radius than the face milling cutter 20 that was used for plane-machining the contact surface (reference 4 in Fig. la). Both plane-machining operations are executed in the same machine configuration, i.e. with the valve housing set up in the same jig, and with the axes of both milling cutters parallel. Drilled holes perpendicular to the plane of the slide, for example for use in conjunction with the installation of the valve, can also be produced in the same configuration.

Fig. 3 illustrates more clearly the arrangement in accordance with the invention for pressing the gland 10 against the packing 9. This arrangement, which is executed in such a way as to be supported by a packing retainer 22 arranged in the recess 8, comprises plates 15 secured to the flange 3 by bolts 16 in threaded engagement with the plates and in contact with the plane-machined projecting parts 11. The plates are so arranged, by means of the gland bolts 17 and nuts 18 arranged on them, as to press the gland 10 towards the packing 9. Tightening of the gland 10 as the packing 9 gradually wears is thus permissible by means of these gland bolts 17. A number of details not mentioned here has already been explained in conjunction with earlier Figures.

Claims (5)

Patent Claims

1. A cast valve housing intended to be connected between two pipe ends and with an opening in between, which forms a flow path for a fluid, in conjunction with which the housing has an internal guide parallel with a first plane for a slide (2) capable of moving in the housing and so arranged as to open and close the aforementioned flow path, which valve housing has a flange (3) perpendicular to the first plane constituting an attachment for the first end of pillars (5) in a pillar set which extends parallel with the first plane and at its other end exhibits means for the displacement of the slide, in conjunction with which a recess (8) is provided in the flange to accommodate a packing (9) around the slide (2), and a gland (10) is so arranged relative to the flange as to be applied against the packing (9) in the direction of movement of the slide, characterized in that the flange (3) was provided at the time of casting with projecting parts (11, 13) which have been plane-machined to provide surfaces perpendicular to the first plane, and in that brought into contact with these surfaces is at least one plane plate (15), which is executed with threaded holes directed perpendicularly in relation to the plate, and in that the gland (10) is so arranged as to be pressed against the packing (9) by means of gland bolts (17) interacting with the threaded holes in the plate (15).

2. Valve housing in accordance with Patent Claim 1, characterized in that transcurrent openings were produced in the flange (3) in conjunction with the casting of the valve housing, and in that the plate (15) is so arranged as to be brought into contact with the aforementioned surfaces by means of bolted joints (16) through the aforementioned openings.

3. Valve housing in accordance with Patent Claim 1, characterized in that the aforementioned surfaces and the plate (15) are arranged on the side of the flange (3) facing the pillar set (5).

4. Method for manufacturing a slide valve housing of the kind in accordance with Patent Claim 1, in conjunction with which the valve housing (1) is cast as an essentially plane piece parallel with a first plane, or as two essentially plane halves which, when assembled together, are parallel with the aforementioned plane, with one flange (3) essentially perpendicular to it, or respectively with each flange half essentially perpendicular to it, which valve housing (1) is plane-machined at the time of its manufacture in at least one second plane lying parallel with the first plane in a first machining operation such as a milling operation, characterized in that the flange (3) or the flange halves are provided at the time of casting with a number of projecting parts (11, 13, 12, 14), of which at least some, in a second machining operation such as a milling operation, are plane-machined to provide external surfaces in a common third plane perpendicular to the first plane, and in that, in conjunction with this, the first and the second machining operations are performed with the valve housing in one and the same jig arrangement by performing the first milling operation with a face milling cutter (20) and by performing the second milling operation with an end milling cutter (21).

5. Method in accordance with Patent Claim 1, characterized in that the flange (3) is provided at the time of casting with transcurrent holes for the connection of the plates (15).