CA2820264A1 - Valve for controlling fluid flows - Google Patents

Abstract

A valve (1) is proposed, which has a control unit (3) which is movable in a valve housing (2) and which has a pot-shaped valve member (7) disposed in a valve chamber (8). The valve member (7) can either close a first channel opening (24a) opening out into the valve chamber (8), assuming a closing position, or release it for connection with a second channel opening (25a) disposed laterally on the valve chamber (8). The pot-shaped valve member (7) has a side wall section (34) with an annular cross section, which extends in terms of its height in the closing position of the valve member (7) at least into the area of the upper apex (44) of the second channel opening (25a).

Description

. -Valve for controlling fluid flows The invention relates to a valve for controlling fluid flows, with a valve housing, in which a valve chamber is formed, into which a control unit linearly movable in relation to the valve housing in the axial direction of a main axis projects on an upper side, wherein the control unit has a valve member disposed in the valve chamber, opposite which a first channel opening of a first valve channel is located in the area of an underside of the valve chamber, said channel opening being able either to be released by the valve member or closed by it when assuming a closing position, wherein a second valve channel with a second channel opening communicating n continuously with the valve chamber irrespective of the position of the valve member opens out laterally into the valve chamber, and wherein the valve member is designed in the shape of a pot and has a floor section facing towards the underside of the valve chamber and a side wall section with n an annular cross section projecting upwards from the floor section.
A valve of this type known from DE 25 08 754 Al has a 2/2-way function and has a valve chamber into which two valve 25 channels with a first channel opening disposed below and a laterally disposed second channel opening open out. A control unit linearly movable in relation to the valve housing projects from an upper side into the valve chamber and carries in the valve chamber a pot-shaped valve member, which 30 can be laid onto a valve seat surrounding the second channel opening to close the second channel opening. A side wall section of the valve member with an annular cross section has a conically widening upper end section which enables the - -

2 valve member to adjoin, in a sealing manner, a projection formed on the upper side of the valve chamber in a release position distant from the first channel opening in order to effect a seal which allows a compression gland surrounding the control unit to be replaced without risk of leakage. The compression gland needs to be replaced from time to time since impurities deposited within the valve chamber on the control unit component passing through the compression gland cause wear.
A valve with comparable functionality is known from DE 86 19 497 Ul, in which, however, the valve member is designed in the shape of a plate.
The object of the invention is to propose measures which reduce the susceptibility to wear of the valve.
To achieve this object, the valve member in a valve of the aforementioned type is designed in such a way that its side wall section extends upwards in terms of its height in the closing position of the valve member at least into the area of the upper apex of the second channel opening.
The second channel opening belonging to the second valve channel has an upper apex which defines the area which has the greatest distance between the opening cross section of the second channel opening and the underside of the valve chamber provided with the first channel opening. Due to the fact that the height of the side wall section measured in the n axial direction of the main axis is selected in such a way that this side wall section extends upwards in the closing position at least into the area of the upper apex of the second channel opening, a shielding effect is produced in ,.

3 every position of the valve member, as a result of which a fluid flow entering the valve chamber through the second channel is prevented from being admitted directly into the area of the valve inside the valve chamber in which the control unit projects from above into the valve chamber. In this way, the aforementioned area can be effectively protected against the depositing of impurities which, with the linear movement of the control unit, could cause wear on the control unit or on the valve housing or on a seal n possibly present between these components. Since the shielding effect of the side wall section prevails through to the closing position of the valve member, reliable protection against wear is provided even if the valve only slightly releases the first channel opening. The shielding effect of the side wall section of the valve member is particularly effective in the case of an application of the valve in which the first valve channel is subjected to underpressure, in order to cause a suction effect in a release position of the valve member in the second valve channel.
Advantageous further developments of the invention are described in the subclaims.
The advantageous shielding effect can already largely occur n when the side wall section of the valve member does not extend completely as far as the upper apex of the second channel opening, but ends minimally below it. However, it is regarded as particularly advantageous if the upper edge of the side wall section is located in the closing position of n the valve member at the same height as the upper apex of the second channel opening.
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4 A structural form in which the side wall section, in the closing position of the valve member, extends upwards beyond the upper apex of the second channel opening is regarded as particularly advantageous. In this way, only a small gap can be created between the upper end area of the side wall section and the wall of the valve chamber, said gap forming an effective flow barrier and preventing pressurised medium overflowing between the two valve channels from flowing in through the upward-oriented "pot opening" of the pot-shaped valve member.
The side wall section of the valve member with an annular cross section is expediently designed as widening upwards in the manner of a funnel. This shape favours the flow of the fluid through the valve chamber when the valve is open, outside past the downward-tapering, pot-shaped valve member.
If the second channel opening belongs to a channel end section of the second valve channel which is directed obliquely downwards in relation to the axial direction of the main axis, a preferred direction of the flow, which is directed away from the upward-facing edge of the side wall with an annular cross section, is formed when a fluid flows through the valve chamber. This represents a further circumstance which counteracts a flow around the upper edge of the side wall of the valve member and therefore further reduces the susceptibility to wear of the valve.
For secure blocking of the first valve channel, it is advantageous if an upward-facing valve seat which surrounds the first channel opening is located on a floor wall which limits the valve chamber downwards, wherein the valve member adjoins said valve seat when assuming its closing position to form a seal with a sealing means disposed on the underside of the floor section of the valve member.
The control unit is preferably designed in such a way that,

5 as well as the valve member, it has an actuation tappet which carries the valve member and which projects into the valve chamber on the upper side of the valve chamber. In order to seal the valve chamber at least temporarily in the area of the actuation tappet, a sealing point is preferably located n between an upper closing wall limiting the valve chamber upwards and the actuation tappet passing through this upper closing wall. This sealing point is constantly shielded from the second channel opening, irrespective of the position of the valve member, due to the special design of the side wall n section. The side wall section projects in a manner comparable with a bulkhead wall into the area between the sealing point and the second channel opening. Impurities which are possibly contained in a pressurised fluid flowing into the valve chamber through the second valve channel 20 therefore collide with the side wall section acting as a shield, insofar as they cannot follow the fluid flow directly to the second valve channel, and are then carried along by the pressurised fluid to the first valve channel. An overflow into the area located between the pot-shaped valve member and 25 an upper closing wall of the valve chamber can be largely avoided.
In the previously described design, the valve according to the invention can readily be configured as a simple 2/2-way n valve, either as a selector valve or a proportional valve.
Additionally, however, the concept according to the invention can also be implemented in more sophisticated valve functions, in particular in conjunction with a 3/2-way valve

6 or 3/3-way valve. A three-way valve of this type can advantageously be implemented in that the actuation tappet is designed at least partially as a valve slide which is present in addition to the valve member and which, depending on the position of the control unit, is able to release the connection between a third valve channel and the valve chamber, assuming at least one release position or, assuming a blocking position, to block said connection. This valve function is overlaid on the valve function of the valve member disposed in the valve chamber. The functions of the valve slide and valve member therefore complement each other.
A particularly expedient design of a valve of this type provides that the third valve channel, with a third channel n opening controllable by the valve slide, opens out into the valve chamber which is preferably disposed concentrically around the valve slide and is shielded from the second channel opening by the side wall section of the valve member in every position of the valve member, consequently also in the closing position of the valve member. The third channel opening is expediently located in the area of the upward-oriented "pot opening" or even inside the pot-shaped valve member.
Whereas the valve member in its closing position is preferably designed as axially sealing, a radial sealing takes place in the valve slide in its blocking position. Two different valve concepts are therefore combined here with one another.
The control unit can preferably be positioned in such a way that the second valve channel communicates either with the first valve channel or with the third valve channel, wherein

7 the first or third valve channel which is not instantaneously communicating with the second valve channel is separated from the valve chamber.
A particularly expedient design of the valve has an overlap-free actuation concept. Here, the fluid connection between the second valve channel and the first or third valve channel is not released until the respective other valve channel has first been separated. Unwanted incorrect flows can thereby be avoided.
A mode of operation of this type can advantageously be implemented in that the actuation tappet of the control unit is designed to comprise multiple parts and has, on the one Is hand, the valve slide already mentioned and, on the other hand, a tappet linearly movable in relation thereto in the axial direction of the main axis, referred to as a compensation tappet. Whereas the valve slide is preferably used, inter alia, to effect the actuation of the control unit, the compensation tappet carries the valve member disposed in the valve chamber. The valve slide and compensation tappet are normally movable in a uniformly linear manner. The valve member moves into the closing position, provided that the valve slide still assumes its blocking position. Only when the valve slide is further displaced does the valve slide move into its release position with relative movement in relation to the compensation tappet, wherein the valve member still maintains the closing position.
The valve slide and the compensation tappet are preferably pre-tensioned by spring means into an extended position assumed in relation to one another. If the valve member is

8 supported on the valve housing in the closing position, the two components can assume a retracted position in relation to one another, overcoming the spring force through continued movement of the valve slide.
The valve is preferably designed as an electrofluidically pilot-operated valve. In this case, it has an electrically controllable pilot valve which can cause the fluidic actuation of the control unit. The pilot valve controls the admission of fluid to the actuation tappet and, if the actuation tappet is designed to comprise multiple parts, the admission of fluid to the valve slide.
The invention is explained in detail below with reference to is the attached drawing, in which:
Figure 1 shows a preferred embodiment of the valve according to the invention in a longitudinal section, assuming a basic position in which a fluid connection between a first valve channel and a second valve channel is established, while a third valve channel is simultaneously blocked, Figure 2 shows an intermediate position of the valve shown in Figure 1, in which all three aforementioned valve channels are separated from one another, and Figure 3 shows a further position of the valve, in which the first valve channel is blocked and a fluid connection between the second and the third valve channel is simultaneously released.

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9 The valve designated in its entirety with reference number 1 has a valve housing 2, inside which a mechanical control unit 3 is disposed, which is linearly movable in relation to the valve housing 2 in the axial direction of a main axis 4 indicated by a dot-dash line. The main axis 4 is preferably simultaneously the longitudinal axis 5 of the control unit 3.
The control unit 3 has an actuation tappet 6 preferably designed to comprise multiple parts, and a valve member 7 n carried by the actuation tappet 6.
The valve member 7 is accommodated in a valve chamber 8 formed inside the valve housing 2. The valve chamber 8 has an underside 12, on which it is limited by a lower closing wall n referred to below as the floor wall 13. The valve chamber 8 further has an upper side 14 located opposite the underside 12 in the axial direction of the main axis 4, on which it is limited by an upper closing wall 15. Around the main axis 4, the valve chamber 8 is limited by a side wall 16 extending 20 between the floor wall 13 and the upper closing wall 15. All of the aforementioned walls 13, 15, 16 are expediently components of the valve housing 2.
In the area of the upper side 14, a working chamber 17 25 extending in the axial direction of the main axis 4 and preferably having a longitudinal shape adjoins the valve chamber 8. The working chamber 17 opens out into the valve chamber 8 on an inlet opening 18 formed in the upper closing wall 15. The actuation tappet 6 extends mainly in the working 30 chamber 17 and projects through the inlet opening 18 into the valve chamber 8. The valve member 7 is fixed, preferably by means of a screw connection 23, on its free end area 22 located in the valve chamber 8.

The valve housing 2 is penetrated by a first valve channel 24, a second valve channel 25, and preferably also a third valve channel 26. All three valve channels 24, 25, 26 open 5 out separately at one end on an outer surface of the valve housing 2. With their other ends, the three valve channels 24, 25, 26 open out in each case into the valve chamber 8.
Specifically, the first valve channel 24 opens out into the

10 valve chamber 8 from below with a first channel opening 24a on the floor wall 13. The first channel opening 24a is therefore located on the underside 12 of the valve chamber 8 and points upwards in the axial direction of the main axis 4 in the direction of the upper side 14.
The second valve channel 25 opens out laterally, i.e. in a direction oriented transverse to the main axis 4, into the valve chamber 8 via a second channel opening 25a formed in the side wall 16.
The third valve channel 26 opens out into the valve chamber 8 from above in the area of the upper side 14 via a third channel opening 26a formed in the upper closing wall 15.
In the exemplary embodiment, the third channel opening 26a is formed directly by the inlet opening 18, through which the actuation tappet 6 penetrates. In this connection, a longitudinal section of the working chamber 17 adjoining the inlet opening 18 functions as a longitudinal section of the n third valve channel 26. To make a clearer distinction, it will also be referred to below as the control section 27 of the working chamber 17. A further longitudinal section of the third valve channel 26 leading to the outer surface of the

11 valve housing 2 opens out peripherally into the aforementioned control section 27.
The valve member 7 disposed in the valve chamber 8 is designed in the shape of a pot. It has a longitudinal axis 28 coinciding with the main axis 4. The valve member 7 is aligned in such a way that its "pot opening" 32 faces away from the underside 8 and, in the axial direction of the main axis 4, points upwards in the direction of the upper closing wall 15.
It should be noted at this point that the direction indications contained in this description, such as "upwards", "downwards", "laterally", etc. are used to provide a clearer n understanding and refer to the normal alignment of the valve 1 during operation, as illustrated in the drawing.
Alternatively, the valve 1 can obviously also be operated with a different alignment, so that, for example, the underside 12 of the valve chamber 8 is located above.
The valve member 7 is preferably designed externally as rotationally symmetrical.
On its lower end area adjacent to the floor wall 13, the valve member 7 has a floor section 33, which is expediently designed in the shape of a plate or disc. From the radially outward-oriented edge of the floor section 33, a side wall section 34 with an annular cross section projects, in the axial direction, upwards in the direction of the upper 312 closing wall 15. This side wall section 34 has an annular front surface 35 which faces the upper closing wall 15 and surrounds the "pot opening" 32.

12 In the area of the floor section 33, the outer diameter of the valve member 7 is expediently less than in the area of the annular front surface 35. This diameter difference arises from the shape of the side wall section 34 implemented in the exemplary embodiment, widening upwards in the shape of a funnel. On the whole, the side wall section 34 is preferably designed in the form of a sleeve.
Apart from a sealed fixing perforation 36, with which it is fitted onto the free end area 22 of the actuation tappet 6, the floor section 33 is designed as unperforated. The side wall section 34 expediently also has no perforation. On the whole, the internal area 37 surrounded by the pot-shaped valve member 7 is therefore accessible for a fluid only Is through the "pot opening" 32.
The outer shape of the valve member 7 is preferably selected in such a way that an annular gap 38 is produced, in particular concentrically, around the valve member 7 between the valve member 7 and the side wall 16 of the valve chamber 8. Due to the outer contour of the valve member 7 tapering downwards in the exemplary embodiment, the annular gap 38 spreads downwards.
An annular valve seat 42, oriented in the axial direction of the main axis 4 and facing towards the valve member 7 is preferably formed around the first channel opening 24a on the inner surface of the floor wall 13 facing towards the valve chamber 8. It is, for example, a wall section of the floor wall 13 with a smooth surface.
The valve member 7 expediently has an annular sealing means 43 on its underside facing towards the floor wall 13, for -

13 example a vulcanised or otherwise attached sealing ring made from material with rubber-elastic properties.
The valve member 7 can be placed in different positions, which are also referred to below as switch positions, in relation to the valve housing 2. In this respect, Figure 1 shows a release position, in which the valve member 7 is displaced in the direction towards the upper side 14 and the sealing means 43 is raised from the axially opposite-lying n valve seat 42. In this release position, a free fluid connection is present between the first valve channel 24 and the valve chamber 8 and also the second valve channel 25 through the first channel opening 24a.
is Figures 2 and 3 show the valve member 7 assuming a closing position, in which it is brought close to the floor wall 13, so that the sealing means 43 carried by it adjoins the opposite-lying valve seat 42 in a sealing manner. Since the floor section 33 of the valve member 7 spanning the first 20 channel opening 24a is closed, the first valve channel 24 is thus separated in a fluid-tight manner from the valve chamber 8.
The fluid connection between the second valve channel 25 and 25 the valve chamber 8 is constantly open, irrespective of the switch position of the valve member 7. The second channel opening 25a is radially distanced in relation to the main axis 4 from the valve member 7 in such a way that the valve member 7 is not able to interrupt the fluid connection n between the valve chamber 8 and the second valve channel 25.
According to a special feature in the design of the valve member 7, the height of its side wall section 34 measured in . .

14 the axial direction of the main axis 4 is matched to the position and size of the second channel opening 25a in such a way that the side wall section 34 extends upwards at least into the area of the upper apex 44 of the second channel opening 25a when the valve member 7 assumes the closing position.
In the exemplary embodiment, the second channel opening 25a has a round and preferably circular cross section. The upper lo apex 44 is defined by the point of the outer circumference of the second channel opening 25a which lies furthest upwards in the axial direction of the main axis 4, i.e. has the shortest distance to the upper closing wall 15. If the second channel opening 25a had a rectangular shape, the upper apex could also be formed by one of the four edge surfaces, with corresponding alignment of the second channel opening 25a.
In the exemplary embodiment, a geometric alignment of the aforementioned components has been implemented so that the side wall section 34 of the valve member 7, viewed in the closing position of the valve member 7, extends upwards in the axial direction of the main axis 4 beyond the upper apex 44. The projection in height of the side wall section 34 in relation to the second channel opening 25a which occurs in the closing position of the valve member 7 is illustrated in the drawing at "U". This projection "U" results, for example, from the distance, measured in the axial direction of the main axis 4, between the upper apex 44 and the annular front surface 35 of the preferably annular or sleeve-shaped side wall section 34.
In an exemplary embodiment not shown, the annular front surface 35 is located, in the closing position of the valve member 7, in the axial direction of the main axis 4 precisely at the same height as the upper apex 44 of the second channel opening 25a.
5 Due to the fact that the second channel opening 25a is already covered in the closing position of the valve member 7 over its entire diameter, measured in the axial direction of the main axis 4, by the side wall section 34 inside the valve chamber 8, a corresponding covering also inevitably occurs in n every release position of the valve member 7 in which the entire valve member 7 is moved even closer towards the upper closing wall 15 of the valve chamber 8.
A sealing point 45 is expediently allocated to the inlet n opening 18. This sealing point 45 is defined, for example, by a sealing ring 46 which is permanently fixed in the area of the inlet opening 18 on the valve housing 2 and concentrically surrounds the actuation tappet 6. The sealing ring 46, also referred to below as the first sealing ring 46 to make a clearer distinction, serves to seal the valve housing 2 in relation to the actuation tappet 6. It is therefore important that the first sealing ring 46 has the longest possible service life. The service life could be adversely affected by impurities, which are contained in the preferably gaseous fluid flowing through the valve chamber 8 and which are possibly deposited on the outer circumference of the actuation tappet 6. However, this susceptibility to wear is substantially reduced by the special design of the valve member 7.
Due to its design as described above, the side wall section 34 actually functions as a shielding wall, which, in every switch position of the valve member 7, projects into the area between the second channel opening 25a and the sealing point 45 and in this way prevents the fluid flow entering the valve chamber 8 through the second channel opening 25a from having direct access to the sealing point 45. The incoming fluid collides with the side wall section 34 and is thereby guided to the first channel opening 24a, with simultaneous shielding of the sealing point 45. The conical tapering of the side wall section 34 in the direction towards the floor section 33 similarly has a positive effect in terms of a guide function.
A further advantageous aspect in this connection is the design implemented by preference in the exemplary embodiment of the channel end section 47 of the second valve channel 25 having the second channel opening 25a. This channel end section 47 is designed and aligned in such a way that its longitudinal axis 47a is inclined in relation to the main axis 4 and is oriented obliquely downwards in the direction towards the underside 12 of the valve chamber 8. The fluid flow entering through the second valve channel 25 into the valve chamber 8 as indicated by the arrow 50 essentially follows the axial direction of the longitudinal axis 47a and is consequently directed away from the upper front side of the valve member 7 having the "pot opening" 32.
The valve 1 is preferably characterised in that the optionally present third channel opening 26a is controllable in terms of its open cross section by the control unit 3.
Consequently, the possibility exists of establishing or blocking a fluid connection between the third valve channel 26 and the valve chamber 8 depending on the axial position of the control unit 3.

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The control unit 3 preferably has the special feature implemented in the exemplary embodiment to carry out an overlap-free opening and closing of the first channel opening 24a and the third channel opening 26a. In this way, the aforementioned channel openings 25a, 26a are prevented from simultaneously establishing a fluid connection with the valve chamber 8.
To implement this concept, the actuation tappet 6 is expediently designed to comprise multiple parts, and has two components movable in relation to one another in the axial direction of the main axis 4 or the longitudinal axis 5, of which one forms a valve slide 48 and the other, referred to below as the compensation tappet 49, carries the valve member 7.
The valve slide 48 extends in the working chamber 17, in which it is linearly movable in the axial direction of the main axis 4 while performing an actuation movement 52 indicated by a double arrow. Irrespective of the assumed axial position, the valve slide 48 projects from above through the inlet opening 18 and the sealing point 45 formed there into the valve chamber 8.
n The axial end section of the valve slide 48 facing towards the valve chamber 8 is designed as a control section 53, which can control a fluid flow through the third channel opening 26a formed as one structural unit with the inlet opening 18. It has a closing section 53a, the external diameter of which corresponds to the internal diameter of the annular sealing means 43 in such a way that it is in sealed contact with the inner circumference of the sealing means 43 in order to block the third channel opening 26a when it 4. = 0, assumes an axial position concentrically surrounded by the sealing means 43. This axial position arises when the valve slide 48 assumes a blocking position illustrated in Figures 1 and 2.
A further longitudinal section of the control section 43, which adjoins the sealing section 53a on the side facing away from the valve chamber 8, is designed as an overflow section 53b, the external diameter of which is smaller than the n internal diameter of the sealing means 43. It is, in particular, formed from an annular groove formed in the valve slide 48.
When the control section 53 assumes an axial position at the Is same axial height as the sealing means 43, an annular overflow gap 54 occurs, as shown in Figure 3, between the control section 53 and the sealing means 43, which enables the fluid to overflow through the third channel opening 26a between the third valve channel 26 and the valve chamber 8.
20 This axial position occurs when the valve slide 48 is positioned in a release position shown in Figure 3.
A drive section 56 of the valve slide 48 extending in the working chamber 17 adjoins the control section 53 of the 25 valve slide 48 axially on the side located opposite the valve chamber 8, whereby, in the exemplary embodiment, said drive section has a drive piston 57, which, in particular, is disposed on the end section of the valve slide 48 located axially opposite the control section 53.
Sealing means 58, which constantly separate the control section 27 of the working chamber 17 in a fluid-tight manner from an adjoining drive section 62 of the working chamber 17, are active between the valve housing 2 and the drive section 56 of the valve slide 48. The drive piston 57 is located in the drive section 62 of the working chamber 17. The sealing means 58 are, for example, formed by a second sealing ring 58a, which is fixed on the valve housing 2 and, with a sliding movement, adjoins the outer circumference of the drive section 56 of the valve slide 48.
Spring means 63, which are active between the valve housing 2 and the valve slide 48 and pre-tension the valve slide 48 constantly in the direction of a basic position, which is shown in Figure 1, are disposed in the drive section 62 of the working chamber 17. The spring means 63 consist of, for example, a coil-shaped pressure spring, which surrounds the drive section 56 of the valve slide 48 and which is supported, on the one hand, on a graduation of the valve housing 2 and, on the other hand, on the drive piston 57. The basic position of the valve slide 48 is mechanically defined in that the valve slide 48, with its upper front surface 64 located opposite its control section 53, adjoins a closing wall 65 which belongs to the valve housing 2 or is fixed to the valve housing 2, and which tightly seals the working chamber 17 axially on the side located opposite the valve chamber 8.
The longitudinal section of the working chamber 17 disposed between the drive piston 57 and the closing wall 65 forms a drive chamber 66, into which drive fluid can be admitted in a controlled manner. The drive fluid can be fed from outside into a drive channel 67 which opens out into the drive chamber 66 and in the course of which a preferably electrically actuatable pilot valve 68 is inserted. Depending on the activation condition of the pilot valve 68, the drive chamber 66 is subjected to overpressure or is de-aerated. The actuation movement 52 of the valve slide 48 can be instigated accordingly and the valve slide 48 can be positioned in either a blocking position as shown in Figures 1 and 2 or in 5 the release position as shown in Figure 3. In the basic position of the valve slide 48, a blocking position occurs.
The compensation tappet 49 extends with a part of its length coaxially inside the valve slide 48 and projects out of the 10 valve slide 48 on the lower axial front surface 72 of the valve slide 48 located inside the valve chamber 8. It defines the free end area 22 of the actuation tappet 6, on which the valve member 7 is disposed. The valve member 7 and the compensation tappet 49 are consequently uniformly movable in

15 relation to the valve slide 48 in the axial direction of the main axis 4.
Further spring means 73 active between the valve slide 48 and the compensation tappet 49 pre-tension the valve slide 48 and 20 the compensation tappet 49 constantly in the direction of a retracted position assumed in relation to one another. The compensation tappet 49 is retracted as far as possible axially from the valve slide 48. This retracted position is defined mechanically by a stop means 74, which is disposed n inside the valve slide 48 on the compensation tappet 49 and interworks with a graduation inside the valve slide 48.
The further spring means 73 are expediently located inside the valve slide 48, where they are supported axially between, on the one hand, the compensation tappet 49 and, on the other hand, a supporting wall 75, which is fixed in a cavity of the valve slide 48.

Starting from the extended position, the compensation tappet 49 is movable into a position further retracted in relation to the valve slide 48, which is associated with an axial convergence between the valve slide 48 and the valve member 7 and a compression of the further spring means 73.
An advantageous mode of operation of the valve 1 is described below.
The starting point is the operating condition illustrated in Figure 1, in which the valve slide 48 assumes its basic position and the extended position is present between the valve slide 48 and the compensation tappet 49. The valve slide 48 is located here in a blocking position, in which its control section 53 is surrounded by the first sealing ring 46 and the third channel opening 26a is consequently closed. The valve member 7 disposed on the compensation tappet 49 is in a release position, so that the first channel opening 24a is open and a fluid connection is present between the first n valve channel 24 and the second valve channel 25.
In a preferred mode of operation of the valve 1, the first valve channel 24 is subjected to underpressure, for example due to a connected vacuum generator, so that, with the valve member 7 located in the release position, a suction effect is produced in the second valve channel 25, which results in a fluid flow as indicated by the arrow 50 in the direction of the first valve channel 24. A suction gripper serving to handle objects, for example, is connected to the second valve channel 25.
Starting from the operating condition shown in Figure 1, fluid can be admitted to the drive chamber 66 through , ."

corresponding actuation of the pilot valve 68, so that the valve slide 48 moves linearly in the sense of a deeper projection into the valve chamber 8. The compensation tappet 49 and the valve member 7 disposed thereon also take part initially in this movement, so that the control unit 3 moves uniformly. The blocking position of the valve slide 48 in the area of the sealing point 45 is continuously maintained.
The uniform movement of the control unit 3 ends when, as n shown in Figure 2, the valve member 7 has reached its closing position and, while simultaneously adjoining the floor wall 13 of the valve chamber 8, closes the first channel opening 24a. In this intermediate position of the movement of the control unit 3, the third channel opening 26a also remains is closed, since the closing section 53a has a sufficient length to maintain the sealed contact with the first sealing ring 46 in every axial position of the valve slide 48 between the basic position and the intermediate position.
20 In the intermediate position as shown in Figure 2, the second valve channel 25 is thus separated from both the first valve channel 24 and the third valve channel 26.
The intermediate position is only a snapshot during the n actuation movement 52 of the valve slide 48. Due to further continuing admission of fluid to the drive chamber 66, the valve slide 48 moves further in the direction towards the valve chamber 8, which is possible because the compensation tappet 49, prevented from a further movement by the floor 30 wall 13, is able to travel axially into the valve slide 48.
With this further movement of the valve slide 48, the closing section 53a disengages from the first sealing ring 46 and the overflow section 53b moves into a position at the same axial height as the first sealing ring 46. The valve slide 48 is thus located in the release position, in which a fluid connection between the third valve channel 26 and the valve chamber 8 is established through the third channel opening 26a disposed concentrically in relation to the overflow section 53b. Since the valve chamber 8 furthermore communicates with the second valve channel 25 and the third valve channel 26 remains closed due to the valve member 7 located in the closing position, a fluid connection consequently occurs between the second valve channel 25 and the third valve channel 26 through the valve chamber 8.
In a preferred mode of operation of the valve 1, compressed air under overpressure is applied to the third valve channel 26. In the operating condition just described, i.e. in the release position of the valve slide 48, this compressed air stream can flow, as indicated by the arrow 55, through the valve chamber 8 into the second valve channel 25, so that an overpressure pulse can be applied to a suction gripper possibly connected thereto, effecting a release of an object previously held by suction.

Claims (15)

1. Valve for controlling fluid flows, with a valve housing (2), in which a valve chamber (8) is formed, into which a control unit (3) linearly movable in relation to the valve housing (2) in the axial direction of a main axis (4) projects on an upper side (14), wherein the control unit (3) has a valve member (7) disposed in the valve chamber (8), opposite which a first channel opening (24a) of a first valve channel (24) is located in the area of an underside (12) of the valve chamber (8), said channel opening being able either to be released by the valve member (7) or closed by it when assuming a closing position, wherein a second valve channel (25) which irrespective of the position of the valve member (7) continuously communicates with the valve chamber (8) opens out laterally into the valve chamber (8) with a second channel opening (25a), and wherein the valve member (7) is formed in the shape of a pot and has a floor section (33) facing towards the underside (12) of the valve chamber (8) and a side wall section (34) with an annular cross section projecting upwards from the floor section (33), characterised in that the valve member (7) is designed in such a way that its side wall section (34) in the closing position of the valve member (7) extends upwards in terms of its height at least into the area of the upper apex (44) of the second channel opening (25a).

2. Valve according to Claim 1, characterised in that the side wall section (34), in the closing position of the valve member (7), projects upwards at least to the same height as the upper apex (44) of the second channel opening (25a).

3. Valve according to Claim 1 or 2, characterised in that the side wall section (34) of the valve member (7) in the closing position of the valve member (7) ends in the axial direction of the main axis (4) at a distance above the upper apex (44) of the second channel opening (25a).

4. Valve according to any one of Claims 1 to 3, characterised in that the second channel opening (25a) is formed in a side wall (16) of the valve chamber (8) surrounding the valve member (7), wherein the valve member (7) is expediently disposed irrespective of its axial position at a distance from the side wall (16), radial in relation to the main axis (4).

5. Valve according to any one of Claims 1 to 4, characterised in that the side wall section (34) is designed as widening upwards in the manner of a funnel.

6. Valve according to any one of Claims 1 to 5, characterised in that the second channel opening (25a) is allocated to a channel end section (47) of the second valve channel (25), which, with a longitudinal axis (47a) inclined in relation to the main axis (4), directed obliquely downwards, opens out into the valve chamber (8).

7. Valve according to any one of Claims 1 to 6, characterised in that the first channel opening (24a) and an upward-pointing valve seat (42) surrounding the first channel opening (24a) are disposed on a floor wall (13) limiting the valve chamber (8) downwards, wherein the floor section (33) of the valve member (7), on its lower side facing towards the floor wall (13), has an annular sealing means (43), which rests against the valve seat (42) in a sealing manner in the closing position of the valve member (7).

8. Valve according to any one of Claims 1 to 7, characterised in that the valve member (7) is disposed on an actuation tappet (6) of the control unit (3) projecting in the area of the upper side (14) of the valve chamber (8) into the valve chamber (8).

9. Valve according to Claim 8, characterised in that a sealing point (45), which is shielded by the side wall section (34) of the valve member (7) from the second channel opening (25a) in every position of the valve member (7), including its closing position, is disposed between the actuation tappet (6) and an upper closing wall (15) limiting the valve chamber (8) upwards.

10. Valve according to Claim 8 or 9, characterised in that the actuation tappet (6) is formed at least partially as a valve slide (48) present in addition to the valve member (7), which, depending on the position of the control unit (3), is able to release the connection between a third valve channel (26) and the valve chamber (8), assuming at least one release position or, assuming a blocking position, to block said connection.

11. Valve according to Claim 10, characterised in that the third valve channel (26) opens out into the valve chamber (8) with a third channel opening (26a) controllable by the valve slide (48) which is preferably disposed concentrically around the valve slide (48) and which is expediently shielded from the second channel opening (25a) by the side wall section (34) of the valve member (7) in every position of the valve member (7), including its closing position.

12. Valve according to Claim 10 or 11, characterised in that the actuation tappet (6) has a compensation tappet (49) which carries the valve member (7) and is movable in the axial direction of the main axis (4) in relation to the valve slide (48), so that the valve slide (48) is movable in relation to the compensation tappet (49) from the locking position into a release position, when the valve member (7) carried by the compensation tappet (49) is supported in relation to the valve housing (2) when assuming its closing position.

13. Valve according to Claim 12, characterised in that the valve slide (48) and the compensation tappet (49) are pre-tensioned by spring means (73) into an extended position assumed in relation to one another, from which they are movable into a retracted position assumed in relation to one another, overcoming the spring force of the spring means (73), when the valve slide (48) moves from the blocking position into a release position.

14. Valve according to any one of Claims 1 to 13, characterised in that the control unit (3) is pre-tensioned by spring means (63) into a basic position, in which the valve member (7) assumes a release position releasing the connection between the second channel opening (25a) and the valve chamber (8) and from which the control unit (3) is expediently movable by means of fluid force in order to implement the closing position of the valve member (7).

15. Valve according to one of Claims 1 to 14, characterised in that the first valve channel (24) is or can be subjected to underpressure in order to cause a fluid flow (50) from the second valve channel (25) through the valve chamber (8) into the first valve channel (24) in at least one release position of the valve member (7) through a suction effect.