DE1960735B1 - Switching valve for compound meter - Google Patents

Description

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The invention relates to a switching valve for power. Furthermore, the constructive and processing bundle counter, in which one within the switchover technical effort is considerable. The latter applies in

valve housing movable in the axial direction special dimensions for flap valves, especially if the Closing element by the flow pressure of the measuring improvement of the control effect by liquid in the main line and one of these 5 curved throttle surfaces is to be achieved, which in

counteracting force arranged in the last closing of the path of movement of the valve body

phase is increased, is operated. Switching valves are.

are connected to a main power line, the aim of the present invention is to provide the one Has main counter, and to switch off and in particular a secondary flow named disadvantages line, which is provided with a secondary meter. The io to create a switching valve, the measurement errors in the The secondary meter is used to measure a small through-switchover range in which the closing flow rates, while in a corresponding manner the organ in the open position is more effective than previously ent-main counter large flow rates determined. and that is significantly lighter than before

In addition to the reversing valve discussed at the beginning, there is also known designs.

type is another, particularly frequently used type 15 weight movably mounted closing element is held to its blocking position '■ only in the immediate area of the Sitzin. Due to the flat part of the actuation path with a flow pressure, the closing element is lifted from the seat by the weight of the valve body, counter to the effect of the control force. a hydraulic pusher is movable, which in such arrangements it is also known to constantly control the differential pressure of the measuring fluid in front of the movement of the flap body at the same time and behind the closing member and one of this entden inflow from the secondary meter. This counteracting force is applied, and this happens, for example, because the main and 25 lever handles are lifted from this secondary line into a common housing space when the closing element is opened Flow pressure difference in the direction of the closing element can be used for control processes. moves and this contrary to and depending on

With the two types of switching from the flow pressure of the measuring liquid to the

valves is a major disadvantage that 30 takes until after covering a certain

the change from secondary meter operation to the main route, the first spring element becomes effective and that

counter operation does not push the closing element suddenly into the blocking position in the case of exact flow conditions,

is achievable, but the main counter when it increases According to a further feature of the invention

the flow rate starts too early and when it is down, only the first acts directly on the closing element

the flow rate has been in operation for too long. 35 kende spring element on the switching pressure of the valve

This affects the measurement accuracy considerably, set and that of the hydraulic trigger on

and DEN 19 625 significantly contributes to this force that has not previously been applied to the closing element

highlighted defects account by admitting a smaller one.

In this way, according to the invention, there is a safe switch-over range of an unlimited amount of measurement error in the specified range the compound meter. To limit 40 put that a large closing force on the closing of this Measurement errors and the switching range are organ acts, while in the open position one Devices such as permanent magnets, changing particularly sensitive adaptation to the flow weights and the like, known to initially be in front of the still conditions and thus movement of the closing member closed valve body an increased pressure is achieved, which is due to the fact that the to set up for a sudden opening and 45 hydraulic levers depending on the closing the flap in the interest of the total pressure of the measuring liquid in the main line is required. These facilities satisfy is controllable. For an exact activity of the head, however only to a small extent, as the exact closing counter is the final phase of the closing path of the operations are not enabled. Closing organ decisive. The well-known folding

The use of permanent magnets in 50 penventilen is a jerky prevention of the

a switching valve of the type explained at the beginning of the inflow from the main meter due to the geometrical

namely only when opening the main line does not represent Irish or constructive conditions

an exact transition to the main meter operation is possible, especially since the dynamic pressure of the

secure. This is due to the fact that the moving fluid column on the closing

Permanent magnet when the gap 55 area of the valve body is enlarged, it is fully effective. To the

has a steeply decreasing force characteristic and therefore when the dynamic fluid pressure is reduced by

Closing only in the very last closing phase, the movement of the closing member up to a certain point

is sam, d. That is, the increased closing force must also know how to make degrees independent, is in accordance with

are applied by the spring member, which provides a further feature of the invention,

Force in this area has already decreased and 60 that the closing member has an auxiliary valve, which in

which would therefore have to be designed to be correspondingly strong. the open position of the closing member as well

This in turn disrupts the operation in which something is open and only towards the end of the accelerated

the open position of the closing member, in that this closing phase is also closed suddenly,

"Flutters". To the required in the closing phase the same effect can be achieved that

To be able to apply high forces, the 65 must, according to a further feature of the invention, the

Magnets are designed to be strong. This has a large closing member has a throttle member in the

measurements and a considerable weight result, the closing phase accelerated the total flow

what large and heavy valve housings required of the main and secondary meter throttles strongly for a short time.

3 4

This throttling effect also has an effect when opening At 60, an auxiliary valve is shown, which the of the closing member advantageous, since in itself closing member 50 is assigned. The plate 52 has

known way the total fluid pressure the through bores 61 on the circumference Closing member quickly in the open position over the plate 52 are evenly distributed and their

leads. 5 Number and size in adaptation to the respective

In the drawing, exemplary embodiments of the flow parameters are selected. Furthermore, the

Invention reproduced on the basis of the after-plate 52 with three sockets distributed around the circumference

will be explained in more detail below. It is provided 62, in which pins 63 are slidably guided,

The pins 63 connect an auxiliary valve disk 64 to.

F i g. 1 shows a section through the switching valve in io a stop 65 on which a ring 66 with radial

the rest position, arms 67 is arranged, which is through the openings

F i g. 2 a further embodiment of the liquid entering 61 no resistance entr

switching valve, oppose. Between the arms 67 and the

F i g. 3 to 6 schematically different operational-speaking surface of the plate 52 is one

Positions of the switching valve, explained on the basis of the weak compression spring 68, are provided. The compression spring

Embodiment according to FIG. 1, and 68 presses over the arms 67 and the pins 63 the

F i g. 7 one opposite FIG. 1 and 2 modified plates 64 against the upstream facing surface

Embodiment. of the plate 52, whereby the openings 61 are closed

1 shows a housing 10 for switching over.

valve shown to which at 11 a main line, the 20 The plate 64 of the auxiliary valve 60 is by means of a

comes from the main meter, is connected and movable at hub 69 on the circumference of the hub 51 of the

12 a secondary line, which is stored by a secondary meter closing member 50. At the front free end

comes. At 13, the entire measuring liquid emerges from the hub 69, there is a projection 70 whose free

the changeover valve housing. The secondary line surface 71 with the corresponding surface of the

branches off in front of the main meter and is during the 25 bearing 23 can be brought into engagement. Further

the entire measuring process acted upon with liquid. the hub 69 is provided with an extension 72 in

The switching device represents a unit that includes three spring elements 73 distributed around the circumference can be inserted as a whole in the housing 10 and is also supported, the one ball 74 against the outer means of a flange 21 on a housing projection perimeter of the hub 51 press. At 75 there is a notch 14 can be attached. The flange 21 is indicated on a 30, of which also three on the circumference cylindrical seat body 20 arranged. From the circumference of the hub 51 are provided distributed and in which the of the seat body 20 extend radially towards the center two corresponding balls 74 snap into place in order to or three ribs 22 having in the middle a bearing 23 valve 60 independent of the movement of the shutter. In the bearing 23, an axis 24 of the rotating member 50 is to be kept in the open position, if fixedly arranged, but the axis 24 with respect to 35 does not have any special control forces on the auxiliary valve 60 the bearing 23 is adjustable in the axial direction. Which are effective.

Axis 24 has a central bore 25, which on the axis 24 is also a hydraulic one

Main line 11 connects to a nozzle 26. Mounted pusher, which is generally designated 80.

On the outer periphery of the seat body 20 are slide The pusher 80 consists of a disk-shaped

metrically opposite, preferably two bearing 40 piston 81, which is designed in one piece with the axis 24

blocks 27 arranged in which rods 28 can be pivoted and a seal on the outer circumference

are managed in cash. Has the outer free ends of the processing ring. The piston 81 is of a

Rods 28 are overlapped by two spring elements 29 with cylinder 82, which by means of an end wall

connected to one another, which is provided with a hub 84 by means of corresponding pins 83. The hub 84 is

30 are hinged to the rods 28 so that the 45 slidably guided on the axis 24, the in the

Springs 29 on both sides of the axis 24 freely moving work space 85 facing part of the hub 84 with a

are cash. Recess 86 is provided through which the connecting piece 26

One protrudes into the work space 85 depending on the required. The free edge of the in

Force application is selectable point between the part of the hub 84 protruding from the working space 85

Bearings 27 and the pins 30 have the rods 28 50 denoted by 87 and forms together with the

Bearing blocks 31 for rollers 32 on. Root of the piston 81 a stop and thus

The closing element is generally designated by 50, a limitation for the cylinder movement,
and consists of a hub 51 which is slidably guided on the axis 24. The hub 51 is acted upon by a spring 88, which is a helically extending plate 52, which is preloaded on the upper 55 spring between the plate 83 and a stop 89 free end with a cylindrical portion 53 which is adjustable on the axis 24 is. Is arranged on the outer circumference of the plate 52.

There is a cylindrical sealing surface 54, while the cylinder 82 has a smaller diameter on the end face of the cylinder 53 than the cylinder 53 of the closing member 50 and the sealing surface 55 with a sealing ring 56 protrudes into the cylinder 53 . The front free forehead is formed. Downstream, the flat cylindrical section of the cylinder 82 is designated by 90 and 53 has an inclined control surface 57. The control surface forms a radial annular surface which can be brought into engagement with the arms 67 forming 57 together with the free surface 58 of the.
Cylinder 53 the cam track for the rollers 32, where- Fig. 2 shows a further embodiment of the at 59 is the switching point. In the rest position 65 valve according to the invention, the. appropriate may be fixed 32 by-a zylindrl · individual elements of the embodiments according to FIGS. \ see collar on the cylinder 53, the position of the rollers ,, adhere to a con- and 7 by the individual elements of this Ausführungsstante bias of the springs 29. shape are replaceable ... ..

5 6

The first spring element consists of two bearing blocks. The closing member 50 is below the

127, which are diametrically opposed to the action of the spring element 27 to 32 on the seat 20

Disc 81 are fixedly arranged and each has a rod close to it. The spring 68 presses the plate 64 of the auxiliary

128 wear. The outer free ends of the rod valve 60 against the upstream face of the

128 are connected to each other by two spring elements 129 5 plates 52. The through bores 61 are connected to them, which are also closed by means of corresponding pins 130.

the rods 128 are articulated so that the springs. The pusher 80 is also in the rest

129 are freely movable on both sides of the hub 51. position in which the compression spring 88 presses the hub 84 against To adjust the spring preload, the piston 81 presses. Between the surface 90 and the pins 130 on the rods 128 in the longitudinal direction of the arms 67 there is advantageously some play,
tion to be slidably fixed. If the secondary meter slowly starts to work between the bearings, 127 and the pins 130 have the rods 128 , the measuring fluid flows through the opening 12 from the bearing blocks 131 for rollers 132 . In this case, the secondary meter in the switching valve housing 10 is initially not required, the arrangement shown in FIG. Rather, the first spring 15 F i g. 3 retained, but will be formed with increasing organ so that the rollers pressed 132 un- differential pressure of the pushers 80 by the transmittable on the pins 130 to rotate the bore 25 is arranged the flow pressure from the main ones are the then free at the front ends line 11 in the nozzle 26 and thus in the rods 128 are firmly mounted. The bearing blocks 131 work space 85 of the pusher 80 arrives. The evidences are then omitted. 20 movement of the cylinder 82 takes place as a function

1, the hub 51 is elongated from the pressure difference on both sides of the disk and has control surfaces 157 and 158 , 83, which in this case are separated from the pressure difference of the liquid by a switching point 159 on both sides of the disk 52 of the closure. Furthermore, a cylindrical organ 50 corresponds to the hub 51. The compression spring 88 has an advantageous collar 151 on which, in the closed 25, a flat spring characteristic curve, with one position of the valve, the rollers 132 rest, but preload, which is about the pressure loss of the secondary at the same time in engagement with the surfaces 157. Counter at half that when switching it- In this way, a constant bias voltage corresponds to the desired output. The area of use springs 129 ensured. The cylindrical section of the secondary meter is usually at a capacity 53 on the valve disk 52 is omitted in this version 30 at which pressure losses of up to 2 mWS occur,
approximate shape, wherein the following still erläu- approaching the differential pressure Umschaltternde the organ to the value 91 shown in FIG 7 directly -. to DIN 19625 max 2mWS -. Plate, as takes is placed 52nd the pusher 80 the position according to FIG. 4 a. The first

To simplify assembly, this spring element 27 to 32 exerts the pressure in the axial direction on the guide shape of the piston 81 with a bushing 181 35 closing element 50, which pressure is attached to the switching device and on the axis 24, one corresponding to pressure.

Through-bore 126 the connection between the central bore 25 and the working space 85 , the closing element 50 opens suddenly, in that the switchover pressure of 2 mWS is reached. The stop 87 of the pressure cylinder roller 32 on the control surface 57 is pressed 82, 83 upwards in this case in the form of the surface 187 40, which exceeds the switching point 59 and on which the disc 83. Alternatively, the hub 84 can roll off surface 58 . Thus, the first spring member 27 finally does not exert any more axial pressure on the closing element within the pressure chamber 85 to 32 , the stops being appropriately adapted so that it is below the flow. pressure can move freely, especially since the handle 80 closes

Furthermore, according to this embodiment, the next 45 is lifted from the closing member. The second spring member 88,89 within the pusher 80- like opening of the closing member 50 will be arranged here, for which the cylinder 82 acts with a lip seal 48, which is provided on the collar 183 , between which and which as a sealing surface 54 slides for so long until the stop 189 formed disc 81 a pressure roller 32 has reached the switching point 59 , and is arranged in spring 188. The collar 183 can be formed with a 50 bond with the axial pressure decreasing behind the switching point 59 through the roller 32 on its way to the free end of the cylinder 82, or it can be formed by a spring washer. This embodiment on the closing member 50. Immediately after the opening has taken place allows a shortened design. The overpressure (FIG. 4) in the working space of the axis 24 and enables - as above, and the handle 80 moves according to FIG . Imagines 5 - greater freedom with respect to the overall 55 to the left in the direction of the closing member 50 of the hub 84. All of these features allow staltung During this movement makes the free edge 90 has a more compact construction of the Umschaltventil- of the cylinder 82 on the arms 67 and presses the housing. Auxiliary valve 60 in the open position. The plate 64

Finally, instead of the arms 67, one can be lifted from the openings 61 , and the

Washer 167 can be used, which come outside of the 60 balls 74 with the notches 75 in engagement.

Cylinder 82 with a concentric cylinder 179 During this process, the compression spring 68 is tensioned,

is provided, which is the interior of the pusher 80 so that the spring 88 on the pusher 80 and

and thus the first and the second spring element act against the organs 65 to 67 on the closing element 50

Protects dirt. sam, and according to FIG. 5, the closing member 50 in

In Fig. 3 to 6 different operating points are shown as a function of the flow conditions.

lungs of the switching valve are highly schematized back and forth under load,

given. The illustration in FIG. 3 corresponds to when the flow pressure falls on the closing element 50

the rest position of the valve and agrees with Fig. 1 to a value that is below the switchover value

is, the closing member 50 assumes the position shown in FIG. If the handle 80 reaches the stop on the piston 81, the roller 32 has already passed the point 59 somewhat, and the front free one Edge of the sealing surface 54 has the lip sealing ring 48 in the sealing surface 49 of the seat body 20 detected. The water must now flow exclusively through the bores 61. The further movement of the Closing member 50 is now determined on the one hand

disc-shaped projection 91 is provided with an annular projection 92 on the inside of the housing 10 cooperates. In Fig. 7 is the changeover valve according to this embodiment in FIG Rest position shown, the F i g. 3 corresponds. The position of the disk is shown in broken lines at 95 91 reproduced, which corresponds to the operating state according to FIG. 5 corresponds. The position of the disk 91 in the operating state 6 is indicated by 96.

the axial thrust of the spring member 27 to 32, and- io In detail, this means the following. Are located on the other hand, by a counteracting force which the disks in position 91-92, the rest is in the bores 61 resulting pressure loss, position before or the secondary meter is running. In the posi-related The main and secondary meters run on the overall cross-section of the locking device 95-92. In the 50, corresponds. These holes are dimensioned so that positions 96-92 will allow further movement of the lock a further movement in the direction of closing only 15 organs 50 determined on the one hand by spring organs then occurs when the flow rate is below the 40-43 and 88, on the other hand by an opposite value has decreased, the force acting to open the closing member, which is due to the throttling 92-96 50 is required. If this is the case, the resulting pressure loss corresponds to, based on The first spring element 27 to 32 accelerates the closing of the total cross-section, which is enlarged by the shoulder 91 organ 50 further in the direction of the seat body 20, wherein 20 of the closing member 50.

in the last phase of this movement the surface 71 The distance between the projection 91 and the projection

at the approach 70 with the corresponding opposite 92 is dimensioned so that a further movement of the lying surface on the bearing 23 comes into engagement. Closing member 50 in the direction of closing only then he-this the balls 74 will follow from the notches 75 when the total flow rate (main and pushed out, and under the effect of the jam counter) has fallen below the value that was used for pressure as well as the spring 68 moves the plate 74 opening was required. If this is the case, then it happens towards the plate 52, as a result of which the passage opening approach 91 forms the projection 92, which allows free sagging 61 are locked. Since the pusher 80 on the aisle cross-section is suddenly expanded, the If the stop is applied, the arms 67 can freely fall when a force counteracting both spring members because of and take the position shown in FIG. 30 suddenly turns off and enables a sudden Between the extension 70 and the front free closing of the closing member 50. the radial surface of the hub 51 occurs during the closing process. The opening of the closing member also takes place suddenly a certain damping, which lent any damage, since with a movement of the closing member 50 on the auxiliary valve as a result of an excessively strong throttling of the passage cross-section he-slamming turns off. The closing process is followed and the closing member 50 is therefore inevitably in ends as soon as the sealing ring 56 is moved to a radial position 92-96. End face 46 of the seat body 20 comes to rest. In this position the flow is distributed

The switching valve is then in the position of the main and secondary meters according to their passage F i g. 3, whereby at most the secondary allowance value, i.e. that is, the one flowing through the secondary meter counter is running. When the pressure increases again, 40 amount is only a small fraction of the total repeat the operating positions shown in FIG. 3 flow, so that the main meter with security

to 6 in a corresponding manner.

Due to the effective relief of the main locking element in the open position, this can be undesirable Running of the secondary meter shortly before the closing process by installing a non-return valve with low pressure loss can be prevented in the secondary line.

The first spring member 27 to 32 can also be designed in a different way. For example,

is loaded with a flow rate that lies within its measuring range and thus accurately detected will.

In addition to the increased measurement accuracy and low pressure loss, the invention has the advantage that the switching valve can also be installed in any inclined position and is operationally safe. The housing 10 is considerably smaller and lighter than

as in Fig. 7 can be seen on the housing 10, the same 50 the previously known switch valve housing, and the moderately distributed over the circumference, guide bushing insert 20 to 91 is provided as a compact unit at any time 40 for springs 41 and pins 43, to adapt to various flow conditions free Ends rollers 42 are mounted. The genes interchangeable. As a result, the maintenance rollers 42 then act on the control surfaces 57 is considerably simplified. The interchangeable inserts 58 and 58 in the same way as the rollers 32. Essential 55 can be supplied ready-adjusted and the only thing that is less high is that both the rollers 32 are installed by expert assistants and the rollers 42 over the entire circumference
a uniform pressure on the closing member 50
exercise so that this is completely tilt-free against
the seat body 20 is pressed or on the axis 60
24 remains freely movable.

Furthermore, in the embodiment according to FIG the auxiliary valve 60 with the organs 61 to 75 omitted. The pusher 80 is with the radial stop surface 90 effective directly on the closing member 50, for which the cylinder 82 is extended accordingly is. Instead of the auxiliary valve 60, there is a firing member 50 on the outer circumference of the cylinder 58

Claims (15)

Patent claims: 1. Changeover valve for compound meters, in which an in axial direction movable closing member by the flow pressure of the measuring liquid in the Main line and a counteracting force that is increased in the last closing phase, is operated, characterized in that 009 549/260 that a first spring member (27 to 32, 40 to 43, 127 to 132) is provided, which is the closing member (50) with only part of the actuation path lying in the immediate area of the seat surfaces (46, 49) a control force is applied, the closing element (50) can be moved by a hydraulic pusher (80) is the constant of the differential pressure of the measuring liquid in front of and behind the closing element (50) and a force counteracting this is applied, and the pusher (80) at Opening the closing member (50) is lifted from this, after opening by removing the Pressure difference moves in the direction of the closing member (50) and this against the and depending on the flow pressure of the measuring liquid, until after covering, a certain distance the first spring member (27 to 32, 40 to 43, 127 to 132) becomes effective and the closing element (52) suddenly pushes into the blocking position. 2. Valve according to claim 1, characterized in that only the first directly to the Closing member (50) acting spring member (27 to 32, 40 to 43, 127 to 132) on the switching pressure of the valve is set and that of the hydraulic trigger (80) on the closing element (50) applied force is much smaller. 3. Valve according to claim 1 or 2, characterized in that the closing member (50) a Has auxiliary valve (60) which is also open in the open position of the closing member (50) is and only closed suddenly towards the end of the accelerated closing phase will. 4. Valve according to claim 1 or 2, characterized in that the closing member (50) is a Has throttle member (91), the total flow of in the accelerated closing phase Main and secondary meter throttled heavily for a short time (Fig. 7). 5. Valve according to one of claims 1 to 4, characterized in that the closing member (50) and the cylinder (82) of the hydraulic trigger (80) on a rigid housing axis (24) are reciprocable. 6. Valve according to claim 1, 2 or 5, characterized in that the hydraulic trigger (80) consists of a piston (81) which is fixed on the axis (24) and the one on the housing axis (24) movable cylinder (82) is overlapped, and the housing axis (24) with one has the main line (11) communicating central bore (25) which is connected to the Pusher working space (85) communicates, and against the movable cylinder (82, 83) second spring member (88, 188) presses and thus represents the force counteracting the pressure difference. 7. Valve according to claim 6, characterized in that the cylinder (82) of the hydraulic The pusher (80) has a collar (84) which, in the rest position, acts on the piston (81) of the second spring member (88) and while maintaining the connection of the handle work space (85) rests with the central bore (25) (Fig. 1). 8. Valve according to claim 6, characterized in that the piston (81) of the hydraulic The pusher (80) has a socket (181) on which the surface (187) of the disc in the rest position (83) rests under the action of the second spring member (188), whereby the connection of the handle work space (85) is ensured with the central bore (25) by a bore (126) (Fig. 2). 9. Valve according to one of claims 1 to 3, characterized in that a plate (52) of the Closing member (50) through the auxiliary valve (60) controllable openings (61) which at certain Flow parameters are adjustable. 10. Valve according to claim 9, characterized in that the openings (61) can be closed by a valve plate (64) loaded in the closing direction by a spring (68), which is closed by means of pins (63) in the plate (52) of the closing member (50) is slidably guided and has no noticeable flow resistance causing arms (67) downstream, which can be acted upon by a free edge (90) of the cylinder (82) of the hydraulic pusher (80). ' 11. Valve according to claim 9 or 10, characterized in that the spring (68) is weaker as a locking element (74, 75) for fixing the valve disk (64) in its open position. 12. Valve according to one of claims 1 to 11, characterized in that the first spring member (27 to 32, 40 to 43, 127 to 132) exceeds the switching point (59) and takes effect, shortly after the front edge of a cylindrical sealing surface (54) of the closing member (50) with a main sealing ring (48) a seat surface (49) has come into engagement, the sealing surface (54) and the ring (48) during the accelerated Closing phase remain engaged and the first spring member (27 to 32, 40 to 43, 127 to 132) in the closed position a sealing ring (56) with the seat surface (46) in engagement holds. 13. Valve according to one of claims 1 to 12, characterized in that the first spring member (27 to 32, 127 to 132) consisting of two rollers (32, 132) arranged on a lever transmission consists, which roll on an inclined control surface (57, 157) on the closing element and so with each other are in connection that at diametrically opposite points on the closing member (50) a uniform axial thrust is exerted, with the closing member in the closed position (50) a constant bias of the springs (29, 129) of the first spring member by a cylindrical The collar (151) on the hub (51) or on the cylinder (53) of the closing member (50) can be reached is on which the rollers (32, 132) rest. 14. Valve according to one of claims 1 to 12, characterized in that the first spring member (40 to 43) consists of a guide (40) which is attached to the housing (10) and a spring (41) and a pin (43) receives, at the free end of a roller (42) is mounted, which with the control surface (57) or the cylinder outer surface (58) of the closing member (50) in engagement Fig. 7). 15. Valve according to claim 1, 2 or 4, characterized in that as a throttle member on the outer Circumference of the cylindrical closing member (50) a radially extending disc (91) is arranged, the free edge of which with one on the valve housing (10) fixed control edge (92) cooperates so that, in addition to a throttle position, different There are control positions (Fig. 7). For this purpose 2 sheets of drawings