Spool Valve

Abstract

The disclosed spool valve is used especially in conveying systems comprising conveying pipes (6, 7) and includes a spool (1) which allows the conveying cross-section of the conveying pipe (6, 7) to be closed. The spool (1) has at least one through-hole (33). The conveying pipe (6, 7) is sealed from the spool (1) by at least one sealing ring (27, 28). Said sealing ring (27, 28) surrounds the conveying line (6, 7) and includes a washer-shaped sealing portion. Said sealing portion lies flat on the spool and seals under the effect of the difference between the pressure in the conveying line (6, 7) and the ambient pressure.

Claims

1. A slide valve, in particular for use in conveying systems with conveying lines (6, 6, 7), with at least one slide (1, 1a), with which the conveying cross section of the conveying line can be closed off and which comprises at least one passage opening (33), and with at least one sealing ring (27, 28; 27, 28), with which the conveying line (6, 6, 7) is sealed against the slide (1, 1a), characterized in that the sealing ring (27, 28; 27, 28) surrounds the conveying line (6, 6, 7) and comprises an washer-like sealing part which lies flat against the slide (1a, 1a) and seals through the pressure differential between the pressure in the conveying lines (6, 6, 7) and the ambient pressure.

2. The slide valve according to claim 1, characterized in that the slide (1, 1a) lies between two retaining plates (2, 3; 2a, 3a), each of which are spaced from the slide (1, 1a).

3. The slide valve according to claim 1, characterized in that a sealing ring (27, 28 27, 28) with an washer-like sealing part each lies against both sides of the slide (1, 1a).

4. The slide valve according to claim 2, characterized in that the two retaining plates (2, 3) are held spaced from one another by way of spacers (8), which penetrate slots (14, 15) of the slide (1) extending in shifting direction (9) of the slide (1).

5. The slide valve according to claim 2, characterized in that at least the one retaining plate, preferentially both retaining plates (2, 3, 2a, 3a) comprise at least one pipe section (6, 6, 7), which is part of the conveying line and projects through an opening (4, 5) of the retaining plate (2, 3, 2a, 3a).

6. The slide valve according to claim 1, characterized in that the sealing ring (27, 28, 27, 28) is held in its installation position through at least one positioning ring (29, 30; 29, 30).

7. The slide valve according to claim 6, characterized in that the positioning ring (29, 39; 29, 30) has a circular cross section.

8. The slide valve according to claim 1, characterized in that the sealing ring (27, 28) has an L-shaped cross section and in that the one leg (34, 35) forms the washer-like sealing part.

9. The slide valve according to claim 8, characterized in that the other leg (36, 37) of the sealing ring (27, 28) extends cylindrically and with its outer cylindrical surface lies against the inside of a support ring (40, 41) surrounding the sealing ring (27, 28).

10. The slide valve according to claim 8, characterized in that the one leg (34, 35) of the sealing ring (27, 28) is radially spaced from the pipe section (6, 6, 7).

11. The slide valve according to claim 8, characterized in that a leg (34, 35) of the sealing ring (27, 28) and the retaining plate (2, 3) and the pipe section (6, 6, 7) and the support ring (40, 41) delimit a receiving space (38, 39) in radial direction.

12. The slide valve according to claim 9, characterized in that in the case of a pressure conveying, the pressure that is present in the conveying line (6, 6, 7) presses the sealing ring (27, 28) against the slide (1) and the support ring (40, 41).

13. The slide valve according to claim 11, characterized in that in the receiving space (38, 39) of the sealing ring (27, 28) a positioning ring (29 30) is accommodated.

14. The slide valve according to claim 13, characterized in that the positioning ring (29, 30) is permeable to the pressure medium.

15. The slide valve according to claim 13, characterized in that the positioning ring (29, 30) comprises at least one passage (42), preferentially multiple passages which are arranged distributed over the circumference.

16. The slide valve according to claim 1, characterized in that the one retaining plate (2) comprises at least two pipe sections (6, 6) which are arranged in shifting direction (9) of the slide (1) spaced one behind the other and the slide (1) comprises at least one pipe section (7), which by shifting the slide (1) can be optionally connected to one of the pipe sections (6, 6) of the retaining plate (2).

17. The slide valve according to claim 1, characterized in that the slide (1a) is pivotably mounted between the two retaining plates (2a, 3a).

18. The slide valve according to claim 17, characterized in that the slide (1a) is approximately formed L-shaped.

19. The slide valve according to claim 18, characterized in that the slide (1a) with its longer leg (46) is pivotably mounted.

20. The slide valve according to claim 17, characterized in that the slide (1a) is pivotable with at least one actuating part (59, 61, 63, 64).

21. The slide valve according to claim 20, characterized in that the actuating part (59, 61, 63, 64) projects through a slot (62) which is provided at least in the one retaining plate (2a, 3a), which extends curved about the pivot axis (48) of the slide (1a).

22. The slide valve according to claim 20, characterized in that the actuating part (59, 61, 63, 64) comprises a clamping element (64), preferentially a rotary handle, with which the actuating part (59, 61, 63) in the respective adjusting position of the slide (1a) can be clamped on at least the one retaining plate (2a, 3a).

Description

[0032] The invention is explained in more detail by way of three embodiments shown in the drawings.

[0033] It is shown in

[0034] FIG. 1 a slide valve according to the invention in top view,

[0035] FIG. 2 a section along the line A-A in FIG. 1,

[0036] FIG. 3 in enlarged representation the detail X in FIG. 2,

[0037] FIG. 4 in a representation corresponding to FIG. 1, the slide valve according to the invention, the slide of which is shifted into another end position,

[0038] FIG. 5 a section along the line A-A in FIG. 4,

[0039] FIG. 6 a top view of a second embodiment of a slide valve according to the invention,

[0040] FIG. 7 a section along the line A-A in FIG. 6,

[0041] FIG. 8 the slide valve according to FIG. 6, slide of which is shifted into another end position,

[0042] FIG. 9 a section along the line. A-A in FIG. 8,

[0043] FIG. 10 the detail X in FIG. 9 in enlarged representation,

[0044] FIG. 11 a top view of a third embodiment of a slide valve according to the invention,

[0045] FIG. 12 a section along the line A-A in FIG. 11,

[0046] FIG. 13 a view in direction of the arrow XIII in FIG. 11,

[0047] FIG. 14 the slide valve according to FIG. 11 in perspective representation,

[0048] FIG. 15 a view in direction of the arrow XV in FIG. 11,

[0049] FIG. 16 a further embodiment of a slide valve according to the invention in view, the slide of which assumes a closing position,

[0050] FIG. 17 the slide valve according to FIG. 16, the slide of which assumes the opening position,

[0051] FIG. 18 a section along the line A-A in FIG. 17.

[0052] The slide valve according to FIG. 1 to 5 is employed with vacuum conveying. It has a flat slide 1, which lies between two retaining plates 2, 3. Each of these lie spaced from the slide 1 and each have an opening 3, 5 through which a pipe section 6, 7 each projects. The two pipe sections 6, 7 lie aligned with one another and have same inner and outer diameters. To the pipe sections 6, 7, conveying lines are connected in the known manner through which a material to be conveyed, such as a plastic granulate, is conveyed. With the slide 1, the inner cross section of the pipe sections 6, 7 can be closed so that no material can flow through the relevant conveying lines any longer. The pipe sections 6, 7 are advantageously securely connected to the retaining plates 2, 3 by welding.

[0053] The two retaining plates 2, 3 are held at the necessary spacing relative to one another by spacers 8. In the exemplary embodiment, four spacers 8 are provided of which in each case two spacers are located spaced one behind the other in shifting direction 9 of the slide 1.

[0054] The spacers 8 are designed identically and each have a screw 10, with which the spacing between the two retaining plates 2, 3 can be adjusted. Manufacturing tolerances can thus be easily compensated without machining of the relevant parts being required. The retaining plate 3 is locked by a lock nut 11, which sits on the screw 10. The screw 10, over a part of its length, is surrounded by a guide bush 12 which, on the screw 10, is axially locked on the screw 10 through a further lock nut 13. With its other end, the guide bush 12 lies against the inside of the retaining plate 2 facing the retaining plate 3. The guide bushes 12 of each spacer 8 project through a slot 14, 15 extending in shifting direction 9 of the slide 1. The slide 1 has an approximately rectangular outline with longitudinal sides 16, 17 which extend parallel to one another and to the shifting direction 9 and narrow sides 18, 19. The narrow side 18 lies perpendicularly to the longitudinal sides 16, 17 and straight in extent. The opposite narrow side 19 has edge sections 19a, 19b which from the longitudinal sides 18, 17 convergingly extend to one another, which merge into one another by way of a straight short edge section 19c extending parallel to the narrow side 18. Because of this configuration, the slide 1 tapers at this end, at which at least one hooking-in opening 20 is located, in which an actuation element for the slide 1 can be fastened, for example hooked in. The two slots 14, 15 lie next to the longitudinal sides 16, 17 of the slide 1 only with minor spacing. Two guide bushes 12 each project into the two slots 14, 15, which guide bushes 12 lie spaced one behind the other in shifting direction 9.

[0055] As shown by FIG. 1, the two retaining plates 2, 3 likewise have two longitudinal sides 21, 22 which are straight in extent, which in top view of the slide valve slightly protrude over the longitudinal sides 16, 17 of the slide 1. In the edges 23, 24 connecting the longitudinal sides 21, 22 a semi-circular recess 25, 26 each is located at half the length. The pipe sections 6, 7 lie in the middle with respect to the retaining plates 2, 3.

[0056] The described outline of the slide 1 and of the retaining plates 2, 3 must not be seen restrictively. The slide 1 and the retaining plates 2, 3 can obviously have any other suitable outline.

[0057] The pipe sections 6, 7 are each surrounded by a flat sealing ring 27, 28, which sealingly lie against the circumference of the pipe sections 6, 7 and are supported (FIG. 2) on both sides of the slide 1. The sealing rings 27, 28 have same outer diameters and consist of material that is suitable for the respective application, for example silicone, polytetrafluoroethylene and the like. These sealing rings can be temperature-resistant, acid-resistant, resistant to aggressive vapours and the like. The material of the sealing rings is selected as a function of the material to be conveyed and/or the ambient conditions of the slide valve. The sealing rings 27, 28 are supported flat over the circumference and their radial width on the two sides of the slide 1.

[0058] Between the sealing rings 27, 28 and the two retaining plates 2, 3 a positioning ring 29, 30 each is arranged. These have a circular cross section and consist of air-permeable material, of elastomer material such as rubber, rubber-like materials, of EPDM and the like. The two positioning rings 29, 30 lie against the circumference of the pipe sections 6, 7 and ensure that the sealing rings 27, 28 do not lift off the slide 1. The sealing rings 27, 28 are loosely supported by the slide 1. It is thereby ensured that the slide 1 can be easily shifted between the opening position (FIG. 1 to 3) and the closing position (FIGS. 4 and 5).

[0059] The slide 1 extends between the two pipe sections 6, 7, whose face ends 31, 32 facing one another each form an annular gap 66, 67 (FIG. 3) with the two sides of the slide 1. It is shown enlarged in FIG. 3. The sealing rings 27, 28 seal the gaps 66, 67 between the pipe sections 6, 7 and the slide 1, which because of the annular gap 66, 67, is contactlessly shiftable.

[0060] In the case of the vacuum conveying of the material to be conveyed the force which acts on the disc shaped sealing rings 27, 28 is determined by the pressure differential between the pressure in the pipe sections 6, 7 and the ambient pressure. The greater this pressure differential is the greater is the force that acts on the sealing rings 27, 28. Because of this it is ensured that no ambient air can enter the pipe sections 6, 7 via the gap between the slide 1 and the pipe sections 6, 7.

[0061] The positioning rings 29, 30 are designed so that the pressure differential can act on the sealing rings 27, 28. With the retaining plates 2, 3 and the spacers 8, the gap 66, 67 between the slide 1 and the pipe sections 6, 7 can be sensitively and precisely adjusted.

[0062] When the manufacturing tolerances permit that the gaps 66, 67 between the pipe sections 6, 7 and the slide 1 are sufficiently small, an adjusting device as provided in the exemplary embodiment is not necessary. The positioning rings 29, 30 ensure that the sealing rings 27, 28 do not move away from the slide 1 in the pressureless state. If this were the case, the self attraction of the sealing rings 27, 28 during the vacuum conveying according to the principle of a non-return valve would no longer be ensured since the low airflow rate that can pass through the gaps 66, 67 between the pipe sections 6, 7 and the slide 1 is so low that the sealing rings 27, 28 would no longer be attracted on account of the described pressure differential.

[0063] The positioning rings 29, 30 can exemplarily consist of air-permeable material, for example of open-pore foam material.

[0064] In the opening position shown in FIG. 1 to 3, the opening cross section of the pipe sections 6, 7 is opened by the slide 1, which comprises a passage opening 33, the diameter of which is equal to the inner diameter of the two pipe sections 6, 7. In this open position of the slide 1, the spacers 8 on the right in FIG. 1 lie with their guide bushes 12 against the adjacent end, of the slots 14, 15 of the slide 1.

[0065] When the passage through the pipe sections 6, 7 is to be closed, the slide 1 is shifted in shifting direction 9 to the right. In the closing position of the slide 1, the guide bushes 12 of the two spacers 8 on the left in FIG. 1 advantageously lie against the in FIG. 1 left end of the slots 14, 15. The slide 1 can be easily shifted since the positioning rings 29, 30 do not exert any or at most only a minimal pressure on the sealing rings 27, 28 which are rectangular in cross section, so that the pressure force on the slide 1 is low. Through the outside pressure acting on the sealing rings 27, 28 perfect sealing between the pipe sections 6, 7 and the slide 1 is ensured.

[0066] In shifting direction 9 of the slide 1, the retaining plates 2, 3 are shorter than the slide 1, which in both end positions (FIGS. 1 and 4) protrudes at least over an edge 23, 24 of the retaining plates 2, 3. In the opening position according to FIG. 1, the slide 1 projects over both edges 23, 24 of the retaining plates 2, 3, which in top view are congruently arranged on top of one another. In the closing position according to FIG. 4, the narrow side 18 of the slide 1 lies approximately at the height of the edge 23 of the retaining plates 2, 3 while the slide 1 protrudes in shifting direction over the opposite edge 24 of the retaining plates 2, 3 by a corresponding amount. In the closing position, the passage opening 33 of the slide 1 lies in the region next to the retaining plates 2, 3 (FIG. 4).

[0067] According to FIG. 6 to 10, the slide valve is employed with a pressure conveying of the material. The slide 1 and the retaining plates 2, 3 as well as their connection to one another by means of the spacers 8 is designed equivalent to that in the previous embodiment.

[0068] The sealing rings 27, 28 have an L-shaped cross section and surround the two pipe sections 6, 7 with minor radial spacing (FIG. 10). With their one leg 34, 35, the two sealing rings 27, 28 are sealingly supported on the two sides of the slide 1. The two legs 34, 35 are washer-like in design and perpendicularly follow the legs 36, 37 which, spaced, surround the pipe sections 6, 7 and in each case form a cylindrical ring, the axis of which coincides with the axis of the pipe sections 6, 7. The legs 34, 35; 36, 37 each delimit an annular receiving space 38, 39 in which the positioning rings 29, 30 are accommodated.

[0069] The two sealing rings 27, 28 are each surrounded by a support ring 40, 41, which extends between the retaining plates 2, 3 and against the inside of which the legs 36, 37 of the sealing rings 27, 28 sealingly lie. The support rings 40, 41 are securely connected to the retaining plates 2, 3, preferentially welded to these. Between the slide 1 and the support rings 40, 41 an annular gap 68, 69 each exists so that the slide can be contactlessly shifted also in the region of the support rings 40, 41.

[0070] Since the washer-like legs 34, 35 surround the pipe sections 6, 7 with radial spacing, the pressure acting in the pipe sections 6, 7 in the case of pressure conveying also acts in the receiving spaces 38, 39 via the gaps 66, 67 between the pipe sections 6, 7 and the slide 1. This results in that through this pressure in the receiving space 38, 39 the washer-like legs 34, 35 of the sealing rings 27, 28 are pressed against the two sides of the slide 1 as a result of which a reliable sealing between the legs 34, 35 and the slide is achieved. Because of this pressure in the receiving spaces 38, 39, the positioning rings 29, 30 are not absolutely necessary. The positioning rings 29, 30 however have the advantage that a pressure acts on the washer-like legs 34, 35 of the sealing rings 27, 28 even when in the pipe sections 6, 7 no pressure has vet been built up. Then, the positioning rings 29, 30 ensure the contact pressure of the legs 35 of the sealing rings 27, 28 on the slide 1 that is necessary for sealing. For this case, the positioning rings 29, 30 are designed so that they lie against the legs 34, 36; 35, 37 of the sealing rings 27, 28 subject to elastic deformation.

[0071] In addition to this, the use of the positioning rings 29, 30 has the advantage that even with manufacturing tolerances of the sealing rings 27, 28 and/or of the support rings 40, 41, perfect sealing is ensured.

[0072] The support rings 40, 41 are connected to the retaining plates 2, 3 in a tightly sealed manner and consist of metallic material such as steal. The sealing rings 27, 28 consist of the same material as the sealing rings 27, 28 of the previous embodiments.

[0073] The positioning rings 29, 30 are provided with at least one annular groove 42 (FIG. 10), through which it is ensured that the pressure that is created during the pressure conveying can act on the legs 36, 37 of the two positioning rings 29, 30. Advantageously, multiple such annular grooves 42 are present over the circumference of the positioning rings 29, 30 which are circular in cross section. The positioning rings 29, 30 can also consist of air-permeable material such as foamed material.

[0074] When for pressure conveying higher pressures are employed, annular coil springs are used as positioning rings 29, 30 if these are provided, which exert an adequate pressure on the two legs 34, 35; 36, 37 of the sealing rings 27, 28.

[0075] Since in the pipe sections 6, 7 the material to be conveyed is conveyed by means of pressure which is higher than the ambient pressure, the positioning rings 29, 30 are not absolutely essential. The higher the pressure in the pipe sections 6, 7 is, the greater the sealing rings 27, 28 are loaded. Accordingly, the legs 34, 35 of the sealing rings 27, 28 press onto the two sides of the slide 1 so that no air can escape from the receiving spaces 38, 39. The positioning rings 29, 30 have the advantage that the sealing rings 27, 28 are under sealing force even when no conveying in the pipe sections 6, 7 takes place and accordingly no pressure built up vet in the pipe sections.

[0076] In the position according to FIG. 6 the slide 1 is in the closing position, in which the passage opening 33 is located in the region next to the two retaining plates 2, 3. The passage through the pipe sections 6, 7 is thus closed. The in FIG. 6 left spacers 8 lie with their guide bushes 12 against the in FIG. 6 left end of the two slots 14, 15.

[0077] In FIG. 8, the slide 1 is shifted in shifting direction 9 so far to the left that the passage opening 33 opens the passage through the pipe sections 6, 7. This opening position is advantageously achieved in that the in FIG. 8 right spacers 8 lie against the right end of the slots 14, 15 of the slide.

[0078] FIGS. 11 to 15 show a slide valve the retaining plate 2 of which is provided with two pipe sections 6, 6, which in shifting direction 9 of the slide 1 are located spaced one behind the other. The opposite retaining plate 3 comprises an elongated opening 43 at half the width (FIG. 11), through which the pipe section 7 projects, which is securely connected to the slide 1. With the slide 1, the pipe section 7 can be shifted so that it is aligned either with the pipe section 6 or with the pipe section 6. Because of this it is possible to optionally convey the material to be conveyed through the pipe section 6 or the pipe section 6 and the respective line connected thereto.

[0079] The two pipe sections 6, 6 are securely connected to the retaining plate 2, preferentially by welding. Both pipe sections 6, 6 are surrounded in the region between the retaining plate 2 and the slide 1 corresponding to the previous embodiment by a sealing ring 27 and a positioning ring 29 each. The sealing rings 27 are surrounded by the support rings 40. The design and arrangement of these rings 27, 29, 40 entirely corresponds to the previous embodiment.

[0080] The slide 1 is designed identically to that in the exemplary embodiment according to FIG. 1 to 5 and on its longitudinal sides comprises the two slots 14, 15 through which the spacer 8 project in the described manner. The pipe section 7, which is securely connected to the slide 1 for example through welding, projects through the opening 43 of the retaining plate 3 to the outside. The conveying line that is connected to the pipe section 7 can be optionally connected with the help of the slide 1 to the pipe section 6 or to the conveying line that is connected to the pipe section 6. The inner cross section of the pipe sections 6, 6, 7 is identical, so that conveying of the respective material through the pipe sections is ensured without problem.

[0081] The connection of the retaining plates 2, 3 to one another and to the slide 1 is formed identically as with the previous exemplary embodiments.

[0082] In the representations according to FIG. 11 to 15, the slide 1 is shifted so far that the in FIG. 11 two right spacers 8 lie against the right edge of the slots 14, 15. In this position, the pipe sections 6 and 7 are connected to one another so that the material fed in via the conveying line of the pipe section 7 is conveyed into the line that is connected to the pipe section 6.

[0083] If the material is to be conveyed into the line that is connected to the pipe section 6, the slide 1 is shifted in shifting direction 9 (FIG. 11) towards the right so far that the in FIG. 11 two left spacers 8 come to lie against the left edge of the slots 14, 15. Then, the two pipe sections 6, 7 are flow-connected to one another so that the fed-in material is conveyed via the pipe section 6 and the conveying line connected thereto.

[0084] Since the slide 1 is provided with the pipe section 7 that is connected to it in a pressure-tight manner, the sealing rings 27 are adequate for sealing. The function corresponds to the embodiment according to FIG. 6 to 10. The pressure that is created during the pressure conveying in the respective pipe section 6, 6 enters the receiving space 38 receiving the positioning rings 29, as a result of which the sealing ring 27 is firmly pressed against the slide 1 and the inner wall of the support rings 40.

[0085] In the case of the described exemplary embodiment, the material to be conveyed is fed in each case via the line that is connected to the pipe section 7. However it is also possible that the material to be conveyed is fed in via one of the pipe sections 6, 6 or the line that is connected thereto. In this case, the material to be conveyed is conveyed to the respective recipient via the line that is connected to the pipe section 7 of the slide 1, which for example can be a processing machine.

[0086] As is evident from FIG. 15, the retaining plate 3 is not absolutely essential for the function of the slide valve. The slide 1 is guided between two nuts 44, 45 each which are screwed onto the screw of the spacer 8. In this case, the slide 1 in the respective end position strikes the screws of the spacer 8 with the ends of its slots 14, 15. The use of the retaining plate 3 however has the advantage that it imparts greater stability and strength to the entire slide valve.

[0087] However, the slide valve can also be utilised in order to open the outlet end of containers or in order to seal the containers in a pressure-tight manner.

[0088] FIG. 16 to 18 show a further embodiment of a slide valve. The slide 1a in this embodiment is not shiftable but pivotably mounted between the two retaining plates 2a, 3a. FIG. 16 shows the slide 1a in the closing position and FIG. 17 in the opening position. The slide 1a has an approximate L-shape with a long leg 46 and a short leg 47. Near the free end of the longer leg 46 the slide 1a is fastened on an axis 48 which extends perpendicularly to the two retaining plates 2a, 3a and is rotatably mounted in openings 49, 50 of the two retaining plates 2a, 3a.

[0089] As is evident from FIG. 18, the axis 48 has two axis parts 48, 48b which are aligned with one another, which slightly project through the openings 49, 50. The axis part 48a is locked against axial shifting by way of a locking ring 51. The locking ring 51 lies against the inside of the retaining plate 2a facing the retaining plate 3a. In the region between the two retaining plates 2a, 3a, the two axis parts 48a, 48b are connected to one another in a rotationally fixed manner.

[0090] With a radial ring shoulder 52, the axis part 48b lies against the inside of the retaining plate 3a facing the retaining plate 2a and with an end section 53 tapered in the outer diameter slightly projects through the opening to the outside.

[0091] The end of the axis part 48b facing the axis part 48a comprises a ring flange 54 Which radially extends to the outside, which is advantageously formed in one piece with the axis part 48b. The leg 46 of the slide 1a lies flat against the side of the ring flange 54 facing away from the retaining plate 2a. The leg 46 to this end is provided with a corresponding opening 54 through which the axis part 48b projects. The leg 46 of the slide 1a is detachably fastened to the ring flange 54. In the exemplary embodiment, the leg 46 is held on the ring flange 54 with screws 56. Advantageously, multiple screws 56 are provided over the circumference of the opening 55.

[0092] The end of the axis part 48a which projects through the opening 49 in the retaining plate 2a has an end section 57 that is tapered in diameter, which stands away from a ring shoulder 58. The one end of a flat lever 59, which sits on the axis 48 or the axis part 48a in a rotationally fixed manner, lies against the ring shoulder 58. The lever 59 is axially locked on the end section 57 by means of a locking ring 60. The lever 59 is thus held against axial shifting between the locking ring 60 and the ring shoulder 58.

[0093] The lever 59 is supported with little spacing on the outside of the retaining plate 2a facing away from the retaining plate 3a and at this end is securely connected to the leg 46 of the slide 1a. From the leg 46, a threaded bush 61 stands away perpendicularly, which projects through an arc-shaped slot 62 in the retaining plate 2a. The slots 62 lies on a circular arc about the axis of rotation of the slide 1a or its leg 46. In the threaded bush 61 a threaded pin 63 projects, which protrudes from the threaded bush 61 and carries a rotary handle 64, with which the threaded pin 63 can be screwed into the threaded bush 61. The rotary handle 64 comprises a face-end annular surface 65, with which it lies against the outside of the retaining plate 2a in a clamping position. The diameter of the annular surface 65 of the rotary handle 64 is greater than the width of the slot 62.

[0094] In the two end positions of the slide 1a (FIGS. 16 and 17), the threaded pin 63 is screwed into the threaded bush 61 by means of the rotary handle 64 so far that the annular surface 65 securely lies against the outside of the retaining plate 2a and thus clamps the slide 1a relative to the retaining plates 2a, 3a in the respective end position. In the opening position (FIG. 17), the threaded bush 61 lies against the one edge and in the closing position (FIG. 16) against the other edge of the arc-shaped slot 62. For pivoting the slide 1a, the rotary handle 64 is turned back slightly as a result of which the clamping between the rotary handle 64 and the retaining plate 2a is cancelled. The slide 1a can then be easily shifted into the respective position.

[0095] As is evident from FIGS. 16 and 17, the lever 59 extends at half width of the leg 46 of the slide 1a, seen in the direction of the pivot axis of the slide.

[0096] The leg 46 of the slide 1a merges arc-like into the short leg 47. In the transition region between the two legs is located the passage opening 33, which in the opening position according to FIG. 17 opens the passage between the two pipe sections 6, 7.

[0097] The two pipe sections 6, 7 are surrounded by the flat sealing rings 27, 28 which are supported on the two sides of the slide 1a and in the described manner seal the gaps 66, 67 (FIGS. 3 and 10) between the pipe sections 6, 7 and the slide 1a. Corresponding to the embodiment, the two sealing rings 27, 28 are formed according to FIG. 1 to 5. According to the embodiment, the material to be conveyed is conveyed with vacuum according to FIG. 1 to 5 so that the two sealing rings 27, 28 reliably seal the gaps 66, 67 between the slide 1a and the pipe sections 6, 7 because of the pressure differential between the pressure within the pipe sections 6, 7 and the ambient pressure.

[0098] The spacing between the two retaining plates 2a, 3a can be adjusted, as was explained by way of FIG. 1 to 5, in the described manner by means of the spacers 8 so that the sealing gaps 66, 67 between the pipe sections 6, 7 and the slide 1a are minimal.

[0099] The two sealing rings 27, 28, which in the manner described by way of FIG. 1 to 5 sealingly lie against the pipe sections 6, 7 and against the two outsides of the slide 1a, are advantageously positioned through the two positioning rings 29, 30 so that they always lie against the slide 1a. The two positioning rings 29, 30 surround the pipe sections with a spacing. The two positioning rings 29, 30 are secured against shifting in the direction of their axis between the two retaining plates 2a, 3a. Here, the positioning rings 29, 30 are designed so that the outside pressure can act on the sealing rings 27, 28. For example, the positioning rings 29, 30 can consist of air-permeable material, for example of foamed material.

[0100] The two retaining plates 2a, 3a in view each have an approximately rectangular outline and congruently lie on top of one another. One of the corners of the retaining plates 2a, 3a is rounded with a larger radius of curvature. The pipe sections 6, 7 are located near a corner region of the retaining plates 2a, 3a. They are designed so that the slide 1a in its blocking position (FIG. 16) lies completely between the two retaining plates 2a, 3a and not protrudes over these. In the opening position, by contrast, the short leg 47 of the slide 1a protrudes over the two retaining plates 2a, 3a (FIG. 17). Since the opening position and the closing position of the slide 1a is determined by the stop position of the threaded bush 61 on the two ends of the slot 62, a simple yet precise adjustment of the slide in both end positions is ensured.

[0101] The short leg 47 of the slide 1a is configured so that during the pivoting it always closes the passage of the two pipe sections 6, 7 opening these only when the passage opening 33 enters the region of the pipe sections 6, 7.

[0102] The lever 59 ensures that the slide 1a can be pivoted without major expenditure of force.

[0103] The slide valve according to FIG. 16 to 18 cane also be utilised for pressure conveying as was described by way of FIG. 6 to 10. In this case, the sealing rings 27, 28 have the cross-sectional shape described by way of FIG. 6 to 10.