Safety valve

Abstract

Safety valve (10) for a cleaning device for a milking system for milking dairy animals, comprising a first block valve (11) with an inlet (110), a second block valve (12) with an outlet (120), a bleed valve (13) with a bleed outlet (130), a piston (25) and an actuator (28), wherein the safety valve (10) can be moved from a blocked position in which the first block valve (11) and the second block valve (12) are closed to block the inlet (110) and the outlet (120) and the bleed valve (13) is open to connect the bleed outlet (130) to a connection (14'), to a flow position in which the first block valve (11) and the second block valve (12) are open to connect the inlet (110) via the connection (14') to the outlet (120) and the bleed valve (13) to block the bleed outlet (130), and is designed to be adjustable back, wherein the safety valve (10) is designed as a directional control valve, wherein the piston (25) is a hollow piston (250), wherein the hollow piston (250) has a cavity (14) as a connection (14'), wherein the safety valve (10) has a valve body (20) of a 5 / 2-way valve with the hollow piston (250), characterized in that the inlet (110) in the block position is connected to an additional port (140), wherein the additional port (140) is narrowed by a nozzle, wherein an outlet cross-section of the nozzle is significantly smaller than a cross-section of the additional port (140).

Description

[0001] The invention relates to a safety valve according to the preamble of claim 1.

[0002] These types of safety valves are also known as block-bleed-block valves and are used in cleaning systems for milking parlors, particularly for the automatic milking of dairy animals such as cows, sheep, and goats. The automatic milking process can be carried out using so-called milking robots. The safety valve is required to introduce a dipping fluid onto the teat of a dairy animal.

[0003] Relevant national regulations and guidelines, e.g., the American FDA guidelines, which apply to cleaning devices for milking systems and milking equipment that come into contact with milk, must be observed and followed.

[0004] The safety valve comprises two block valves and a bleed valve and switches between a first position, hereinafter referred to as the block position, and a second position, hereinafter referred to as the open position. In the block position, the block valves must be closed and the bleed valve open simultaneously, while in the open position, the block valves are open and the bleed valve is closed.

[0005] Document US 2012 / 0017836 A1 describes a safety valve for a cleaning device for an automatic milking system used to milk dairy cows. The safety valve comprises a first block valve with one inlet, a second block valve with one outlet, a bleed valve with one bleed outlet, a piston, and an actuator. The safety valve is adjustable from a closed position, in which the first and second block valves are closed to block the inlet and outlet and the bleed valve is open to connect the bleed outlet to a connection, to a flow-through position, in which the first and second block valves are open to connect the inlet to the outlet via the connection and the bleed valve is closed to block the bleed outlet, and back again.

[0006] Furthermore, the description of the function and structure of a cleaning device is given in the document WO 2010 / 053577 A1.

[0007] Due to the ever-increasing demands, especially for high throughput rates and continuous, low-maintenance operation or long maintenance intervals for today's cleaning devices for milking systems or milking robots, which are complex and costly, there is a need for an improved safety valve.

[0008] The solutions proposed so far have an excessively large footprint, excessively high costs, and low to insufficient resistance to the media used.

[0009] Against this background, the object of the invention is to create an improved safety valve.

[0010] This problem is solved by a safety valve having the features of claim 1.

[0011] A safety valve according to the invention for a cleaning device for a milking system for milking dairy animals comprises a first block valve with an inlet, a second block valve with an outlet, a bleed valve with a bleed outlet, a piston, and an actuation unit. The safety valve is adjustable from a closed position, in which the first and second block valves are closed to block the inlet and outlet and the bleed valve is open to connect the bleed outlet to a connection, to a flow-through position, in which the first and second block valves are open to connect the inlet to the outlet via the connection and the bleed valve is closed to block the bleed outlet, and back again. The safety valve is designed as a directional control valve, wherein the piston is a hollow piston.

[0012] This advantageously allows the use of a standard, cost-effective, high-quality directional control valve as a base. The piston is formed by a hollow piston.

[0013] In a preferred embodiment, the hollow piston has a cavity as a connection. This enables a particularly economical, space-saving design.

[0014] The hollow space is designed to extend along the longitudinal axis of the hollow piston. This facilitates simple manufacturing. The hollow piston is preferably made of stainless steel resistant to the media used. In particular, a longer service life can be achieved with respect to iodine and iodine compounds that may be present in the media.

[0015] In a further development of the design, the cavity comprises a first opening and a second opening. This allows for a simple design of the valves.

[0016] In another embodiment, in the closed position, the first and second block valves are closed to block the inlet and outlet via the hollow piston, and the bleed valve connects the bleed outlet to the hollow piston cavity. This is advantageously possible with the hollow piston. Further advantages arise from the fact that, in the event of any leaks, it is easily ensured that no medium can flow uncontrollably from the inlet to the outlet.

[0017] In another embodiment, in the open-circuit position, the first block valve communicates with the hollow piston cavity via the first opening, and the second block valve communicates with the hollow piston cavity via the second opening, connecting the inlet to the outlet. The bleed valve is closed by the hollow piston to block the bleed outlet. In this way, several functions are advantageously combined in the hollow piston without additional components. Only the hollow piston is required. Seals and spacers from a conventional directional control valve can be used. Their material simply needs to have suitable media resistance.

[0018] In a further embodiment, the hollow piston is connected to a drive element for adjusting the hollow piston from the closed position to the open position of the safety valve and back. This can advantageously be a pneumatic and / or electric drive.

[0019] In another embodiment, the safety valve features a pre-tensioned energy storage element that pre-tensions the hollow piston into the closed position and holds it there. This allows the closed position to be used simply as a basic and safety position.

[0020] In a further embodiment, the safety valve has a sensor unit for detecting the closed position and / or the open position. If this sensor unit interacts with the hollow piston directly and / or indirectly via a drive element, particularly advantageous monitoring of the safety valve is possible, since the current position of the hollow piston can be detected regardless of whether the drive unit is activated or not.

[0021] For example, the sensor unit can interact with a magnetic element attached to the hollow piston and / or the drive element. This enables a compact design with high reliability.

[0022] In one version, the safety valve features a valve body of a 3 / 2-way valve with a hollow piston. Such a valve body, including its seals, is readily available on the market in high quality and at low cost. A modular design, in particular, allows for a wide range of applications.

[0023] In the preferred embodiment, the safety valve can have a valve body of a 5 / 2-way valve with a hollow piston. This allows for special protection of the energy storage element (e.g., a compression spring) due to the longer creepage paths of the medium in the event of leaks, and also due to additional connections.

[0024] In the preferred embodiment, the inlet in the block position is connected to an auxiliary port, wherein the auxiliary port is constricted by a nozzle, the nozzle's outlet cross-section being significantly smaller than the auxiliary port's cross-section. This achieves the advantage of venting the inlet to allow a flow rate that prevents unwanted milk flow into the dip tube or the dip medium line. A further advantage is that the so-called headspace volume at the teat end can be reduced.

[0025] In one variant, the hollow piston cavity in the closed position is connected to the bleed outlet via a first opening and to an additional port via a second opening. This allows for particularly convenient venting, flushing, and / or cleaning of the cavity, e.g., with one or more media.

[0026] The safety valve, with the exception of the hollow piston and sensor unit, can be made entirely of plastic. The screws and fasteners for the covers, actuator, and sensor unit can also be made of plastic. This results in a low weight and a compact design.

[0027] Several safety valves can be easily connected to each other and used compactly as a safety valve arrangement due to the standard valve body.

[0028] Further advantages and details will become apparent from the exemplary embodiment shown in the figures of the drawing. These show: Fig. 1 a schematic representation of an exemplary application of a safety valve according to the invention together with a safety valve device; Fig. 2 safety valves according to the invention in a pre-dip / post-dip device in a schematic block diagram; Fig. 3-3c Schematic sectional views and circuit diagrams of a typical directional control valve in different switching positions; Fig. 4-4c schematic sectional views and circuit diagrams of another common safety valve in different switching positions; Fig. 5 a schematic perspective view of a typical piston; Fig. 6 a schematic perspective view of a hollow piston; Fig. 7 a schematic sectional view of a first embodiment of the safety valve according to the invention; Fig. 8-8a Schematic sectional views of a variant of the first embodiment according to Fig. 7 in different switch positions; and Fig. 9-9a Schematic perspective views of the variant of the first embodiment according to Fig. 8-8a.

[0029] In the figures, identical or similar functional elements and components are provided with the same reference symbols.

[0030] The terms "top", "bottom", "left", and "right" refer to the respective arrangement in the figures. This does not restrict installation positions, e.g., upside down, sideways, or in any other orientation.

[0031] In Fig. Figure 1 shows a schematic representation of an exemplary use case of a safety valve 10 according to the invention together with a safety valve device 1. Fig. Figure 2 shows safety valves 10 according to the invention in a pre-dip / post-dip device in a schematic block representation.

[0032] Two safety valve devices 1 of a milking system for milking dairy animals, e.g., cows, are shown. Two safety valve devices 1 are provided for each teat of a dairy animal's udder. The milking system is not described further. A teat cup 8 is shown schematically as a representative of a milking unit of the milking system. One of the safety valve devices 1 is connected to it via a line 5. The teat cup 8 is also connected via another output line 9 to a cleaning device (so-called pre-dip / post-dip devices). This cleaning device is shown here only schematically with one of several safety valves 10 and supply units (pre-dip supply 170 and post-dip supply 170'). At least one safety valve 10 is provided for each teat or teat cup 8.

[0033] A detailed description of the cleaning device and the safety valve devices can be found in documents US 2012 / 0017836 A1 and WO 2010 / 053577 A1.

[0034] The safety valve devices 1 serve to prevent the accidental suction of unwanted media from a “bad milk” line (here e.g. a line 5b) or a “cleaning line” (here e.g. line 5) into a “good milk” line (here e.g. a line 5a, 5c).

[0035] The safety valve assembly 1 comprises three individual valves 2, 3, and 4. The first valve 2 and the second valve 3 are also called "block valves." Depending on the flow direction of the medium, the first valve 2 is referred to as the inlet valve and the second valve 3 as the outlet valve, or vice versa. The third valve 4 is usually called the "bleed valve." These three valves 2, 3, and 4 are connected to each other such that the first valve 2 and the second valve 3 are connected in series, with the third valve 4 being connected to a connection between the first valve 2 and the second valve 3. This forms the safety valve assembly 1, which is also called the "block-bleed-block valve."

[0036] The first valve 2 of the first safety valve assembly 1 is connected via a first connection 2a and line 5b to a bad milk container 6. An outlet of the first valve 2 is connected to an inlet of the second valve 3 via the third valve 4. The third valve has a connection 4a through which the connection of the first valve 2 to the third valve 4 can be connected to the atmosphere. The second valve 3 is connected via its connection 3a to both line 5 to the teat cup and line 5a to the second safety valve assembly 1. The second safety valve assembly 1 is constructed like the first and is connected via line 5c to a good milk container 7.

[0037] The safety valve devices 1 are subjected to a vacuum for the suction of milk from the teat cup 8 by a vacuum unit not described in detail.

[0038] The safety valve 10 is shown schematically here and has two block valves 11 and 12 as well as a bleed valve 13. The first block valve 11 is connected via an inlet 110 and a line 16 to the pre-dip supply 170 and post-dip supply 170', respectively. Furthermore, an outlet of the first block valve 11 is connected via a connection 14' to an inlet of the second block valve 12. An outlet of the second block valve 12 is connected via an outlet 120 to the outlet line 9 on the teat cup 8.

[0039] The connection 14' also communicates with an inlet of the bleed valve 13, which is connected with its outlet to a bleed outlet 130 of the safety valve 10.

[0040] This safety valve 10 also functions as a block-bleed-block valve. When block valves 11 and 12 are open, bleed valve 13 is closed. This position is hereinafter referred to as the open position. In a so-called block position, block valves 11 and 12 are closed, while bleed valve 13 is open and connects the bleed outlet 130 to connection 14'. Thus, in the block position, it is ensured that, on the one hand, the first block valve 11 completely blocks the flow of medium from the pre-dip supply 170 or post-dip supply 170', and on the other hand, the second block valve 12 blocks the connection to the teat cup 8 via the outlet line 9.

[0041] The open position is used during cleaning processes (pre-dip, post-dip), while the closed position is used during milking processes. Additionally, the closed position is always used as a safety position when the actuator of safety valve 10 is not activated.

[0042] In the block position, it is also ensured that in the event of a possible leakage of the first block valve 11 (e.g. due to wear), medium from the pre-dip supply 170 or post-dip supply 170' cannot enter the suction line 5 of the safety valve device 1, since the connection 14' is connected to the bleed outlet 130 (e.g. to the atmosphere or to a suitable collecting vessel) via the open bleed valve 13.

[0043] If the second block valve 12 leaks in the block position, no medium can be drawn in from the pre-dip supply 170 or post-dip supply 170' via the outlet line 9 due to the open bleed valve 13.

[0044] Safety valve 10 is described in detail below.

[0045] A possible arrangement of these safety valves in connection with pre-dip / post-dip supplies 170, 170' is shown in Fig. 2 shown in a schematic block diagram.

[0046] Four teat cups 8 are each connected via outlet lines 9 and 9a, and check valves RV, to a first safety valve assembly 10A with four safety valves 10. This assembly is connected to a post-dip supply 170' via inlet lines 16a and 16b. A second safety valve assembly 10B, also consisting of four safety valves 10, is connected via further outlet lines 9b to the outlet lines 9 leading to the teat cups 8 via check valves RV. The second safety valve assembly 10B is part of the pre-dip supply 170' via inlet lines 16a, 16b, and 16e. The check valves RV ensure a directed flow of the media into the outlet lines 9 while preventing backflow.

[0047] The pre-dip supply delivers a pre-dip medium from a pre-dip medium source 17 through inlet lines 16e. Additionally, filtered purge air from a purge air source 19 is provided in inlet lines 16b.

[0048] In the post-dip supply, the post-dip medium is supplied from a post-dip medium source 17' via inlet lines 16d. Water from a water source 18 is supplied via inlet lines 16c. A purge air source 19 for filtered purge air is also available, which is supplied via inlet lines 16b.

[0049] This includes, for example, iodine, hexidine compounds, or similar substances. For instance, 150 ml of pre-dip or post-dip medium is required per teat.

[0050] All sources 17, 17', 18, and 19 supply the media they provide under a specific pressure. Therefore, the safety valves 10 are subjected to this pressure, but not to negative pressure or vacuum. Furthermore, the safety valves 10 do not perform any metering functions.

[0051] In the Fig. Figures 3-3c show schematic sectional views and circuit diagrams of a typical directional control valve 100 in different switching positions. Fig. Figure 5 shows a schematic perspective view of a typical piston 25.

[0052] This shows Fig. 3 the directional control valve 100 in a first switching position, wherein Fig. 3a shows the corresponding circuit diagram. A further, second switching position of the directional control valve 100 is shown in Fig. 3b with the corresponding circuit diagram in Fig. 3c is shown.

[0053] The directional control valve 100 is a so-called 3 / 2-way valve with a valve body 20. The valve body 20 has a continuous circular cylindrical inner bore 20a into which two vertically spaced bores extend from above. The left bore forms a port 101, the right one another port 102. A third bore is formed from below through the valve body 20 into the inner bore 20a and forms a third port 103.

[0054] The following components are arranged in the inner bore 20a of the valve body 20 (from left to right in the drawing): a retaining flange 21, a seal 22, a spacer 23, another seal 22, a spacer 23b, a seal 22a, a spacer 23a, a seal 22a, and another retaining flange 21. The seals 22-22a seal simultaneously with their outer diameter against the wall of the inner bore 20a (statically) and with their inner diameter against sections of a piston 25. The piston 25 is linearly displaceable along its longitudinal axis 25a. It has two circular cylindrical body sections 25b, 25c, between which an annular recess with a connecting section 25d is arranged and connected to the body sections 25b, 25c.

[0055] Spacer 23 is located in the area of ​​the first connection 101, spacer 23a in the area of ​​the second connection 102, and spacer 23b in the area of ​​the third connection 103. Spacers 23, 23a, and 23b can be one-piece or multi-piece. Variants are also possible in which, instead of double seals 22-22a, one seal is provided for the wall of the inner bore 20a and one seal for the piston 25 (e.g., O-rings).

[0056] A space 24 is defined between the seals 22 with the spacer 23 between them. In the case of seals 22a with spacer 23a, a space 24a is also defined. A third space 24b is formed by the opposing seals 22 and 22a with the spacer 24b between them.

[0057] By means of a linear adjustment of the piston 25 by means of a drive not shown but easily imaginable, the position of its annular recess 25d in the first switching position is determined according to Fig. 3 the second terminal 102 with the third terminal 103 and in the second switching position after Fig. 3b the first terminal 101 is connected to the third terminal 103. The respective connection via the annular recess 25d is shown in the corresponding circuit diagram. Fig. 3a and Fig. 3c is specified as connection 26.

[0058] In the first switching position after Fig. In this way, chambers 24a and 24b communicate via the annular recess 25d of piston 25. Chamber 24 is closed due to the body section 25b of piston 25, thus closing the connection 101. In the second switching position after Fig. 3b now communicate between spaces 24 and 24b via the annular recess 25d of the piston 25. Here, space 24a is closed due to the body section 25c of the piston 25, thus closing the connection 102.

[0059] The other standard safety valve 10 is now used in connection with the Fig. 4-4c and 5 described.

[0060] Fig. Figures 4-4c show schematic sectional views and circuit diagrams of another common safety valve 10 in different switching positions. Fig. Figure 6 is a schematic perspective view of a hollow piston 250.

[0061] In this first embodiment, the other conventional safety valve 10 comprises the valve body 20 of a conventional 3 / 2-way valve 100 with the circular cylindrical inner bore 20a.

[0062] In contrast to the usual 3 / 2-way valve 100, the other usual safety valve 10 is equipped with a hollow piston 250, which is explained in detail below, and thus the function of the three bores is also different. The upper left bore in the drawing forms the inlet 110 of the first block valve 11, the upper right bore the outlet 120 of the second block valve 12, and the lower bore the bleed outlet 130 of the bleed valve 13.

[0063] In the closed position of the safety valve 10, the inlet 110 and the outlet 120 are both closed simultaneously by the closure of the respective block valves 11 and 12 by the hollow piston 250. Furthermore, the bleed outlet 130 communicates with the corresponding bleed valve 13 via the cavity 14 of the hollow piston 250 due to the position of the hollow piston 250. This will be explained in more detail below.

[0064] In the through position of the safety valve 10 according to Fig. 4b, Fig. 4c The inlet 110 of the first block valve 11 and the outlet 120 of the second block valve 12 communicate with each other via the cavity 14 of the hollow piston 250, so that a pressurized medium can flow from the inlet 110 through the cavity 14 of the hollow piston 250 to the outlet (or vice versa, depending on the connection). In other words, the block valves 11 and 12 are opened and connected by the position of the hollow piston 250 and its cavity 14. Simultaneously, the bleed outlet 130 of the bleed valve 13 is closed by the position of the hollow piston 250. This position is described in detail below.

[0065] The following components are arranged in the inner bore 20a of the valve body 20 (from left to right in the drawing): a retaining flange 21, a seal 22, a spacer 23, another seal 22, a spacer 23b, a seal 22a, a spacer 23a, and another seal 22a. Additionally, a further spacer 23c and another seal 22b are provided in front of the further retaining flange 21. The seals 22-22a seal simultaneously with their outer diameter against the wall of the inner bore 20a (statically) and with their inner diameter sections of the hollow piston 250.

[0066] Between the seals 22 with the spacer 23 between them, a space 24 is defined; the seals 22a with the spacer 23a define space 24a. The third space 24b is formed by the opposing seals 22 and 22a with the spacer 24b between them. Furthermore, a fourth space 24c is formed by the opposing seals 22a and 22b with the spacer 23c between them. In this way, space 24 can be assigned to the first block valve 11 with inlet 110, space 24a to the second block valve 12 with outlet 120, and space 24b to the bleed valve 13 with bleed outlet 130.

[0067] The hollow piston 250 is arranged to be longitudinally displaceable in the inner bore 20a of the valve body 20 and has a body 250a with a surface 250b. The right-hand end of the hollow piston 250, as shown in the drawing, is designated as the drive end 250c and is connected to a drive element 280, which will be described in more detail below. The drive end 250c is guided to be longitudinally displaceable in the right-hand retaining flange 21. The other, left-hand end of the hollow piston 250 has an end section 250d with a cylindrical recess that extends approximately one-quarter of the way along a longitudinal axis 251 of the piston and forms a receptacle for a power storage element 27, which will be explained in more detail below. The end section 250d of the hollow piston 250 is guided to be longitudinally displaceable in the left-hand retaining flange 21.

[0068] Furthermore, the hollow piston is provided with a cavity 14, which extends from the drive end 250b to a wall 250f in the direction of the piston's longitudinal axis 251. The wall 250f forms a partition between the receptacle for the energy storage element 27 and the cavity 14. The cavity 14 has two openings 14a and 14b, each extending radially and each opening into an intermediate section 250e. These intermediate sections 250e are spaced apart in the direction of the piston's longitudinal axis 251 and are formed into the surface 250b of the hollow piston 250. This is shown in Fig. 6 clearly visible.

[0069] The first opening 14a (arranged on the left in the figures) is assigned to the first block valve 11, and the other opening 14b is assigned to the second block valve 12.

[0070] The cavity 14 is tightly sealed from the drive end 250c by a section of the drive element 280, for which purpose a seal 281, e.g., an O-ring, is provided between this section and the inner wall of the cavity 14. The drive element 280 is a type of circular cylindrical body which has a drive piston 280a at its end facing away from the hollow piston 250. The drive piston 280a is guided longitudinally displaceable in a circular cylindrical displacement 28a of a drive unit 28 in the direction of the longitudinal axis 251 of the hollow piston 250. The drive unit 28 is mounted on the right end face of the valve body 20 of the safety valve 10 and encompasses an outer flange of the retaining flange 21. The displacement 28a can be supplied with a drive medium, e.g. compressed air, via a drive connection 28b to the right in front of the drive piston 280a.

[0071] A cover 29, overlapping the outer flange of the retaining flange 21, is attached to the other, left end face of the valve body 20. The cover 29 has an opening 29a for ventilation during movement of the hollow piston 250 and forms a counter-bearing for the energy storage element 27, which here is a compression spring. The spring is inserted under preload between the inside of the cover 29 and the receptacle in the end section 250d of the hollow piston 250. Due to the preload of the energy storage element 27, which acts in the direction of the piston's longitudinal axis 251 towards the drive unit 28, the hollow piston 250 is drawn into the Fig. 4 shown in the blocked position of the safety valve 10. In this position, the right end of the drive element 280 can form a stop for the hollow piston 250 in the blocked position with the inner face of the displacement chamber 28a of the drive unit 28.

[0072] Activation of the drive unit 28 by pressurizing the displacement 28a to the right of the drive piston 280a causes the hollow piston 250 to move to the left against the preload force of the energy storage element 27 into the open position of the safety valve 10, which in Fig. 4b and Fig. 4c is shown. The left end of the end section 250d of the hollow piston 250, together with the inside of the cover 29, acts as a stop to the movement of the hollow piston 250 in the open position.

[0073] In the Fig. In the block position shown in Figure 4, the end section 250d of the hollow piston 250, with its continuous surface 250b, is located in the area of ​​the inlet 110 and seals the chamber 24. That is, the seals 22 seal the inner bore 20a and the area of ​​the end section 250d. Thus, the chamber 24 is closed, which is equivalent to the first block valve 11 and therefore the inlet 110 being closed. The same condition exists for the second block valve 12. Here, the surface 250b of the body 250a of the hollow piston 250, together with the associated seals 22a, seals the chamber 24a. Thus, the second block valve 12 and the inlet 120 are closed.

[0074] The first opening 14a of the cavity 14 of the hollow piston 250 communicates in the Fig. Figure 4 shows the closed position with chamber 24b, which is sealed by seals 22 and 22a. The second opening 14b is connected to chamber 24c between seals 22a and 22b. Simultaneously, chamber 24b, as part of the bleed valve 13, communicates with the bleed outlet 130. In other words, the bleed outlet 130 is connected to cavity 14 and chamber 24c via chamber 24b and opening 14b. Thus, the bleed valve 13 is open in the closed position of the safety valve 10. In the event of a leak in the first closed valve 11, the escaping medium is diverted on the right side via chamber 24b into the bleed valve 13 and cannot reach the closed outlet 12. On the left side of the first block valve 11, the medium from the inlet 110 would enter the area of ​​the energy storage element 27 and be able to exit through the opening 29a. Both sides of the block valve 12, i.e.Rooms 24b and 24c are connected to the open bleed valve 13 and the bleed outlet 130 as described above.

[0075] The circuit diagram in Fig. Figure 4a shows the cavity 14 symbolically in the block position connected to the bleed outlet 130. Inlet 110 and outlet 120 are closed.

[0076] In the Fig. In the open position shown in Figure 4b, the central section of the body 250a of the hollow piston 250, with its continuous surface 250b, is located in the area of ​​the bleed outlet 130 and seals the chamber 24b together with the seals 22 and 22a. That is, the chamber 24b is closed, which is equivalent to the fact that the bleed valve 13 and the bleed outlet 130 are closed in the open position of the safety valve 10.

[0077] The first opening 14a of the cavity 14 of the hollow piston 250 communicates in the Fig. The passage position shown in Figure 4b connects to chamber 24, which is sealed by seals 22. The second opening 14b is connected to chamber 24a between seals 22a. In other words, inlet 110 is connected via chamber 24 through the first opening 14a to the cavity 14 of the hollow piston 250. Simultaneously, the second opening 14b communicates with the cavity 14 of the hollow piston 250, and chamber 24a communicates with outlet 120. In this way, block valves 11 and 12 are open, and inlet 110 and outlet 120 are connected.

[0078] The passage position is in Fig. 4c is illustrated by a circuit diagram, where the cavity 14 is connected to the input 110 via the first opening 14a and to the output 120 via the second opening 14b. The bleed output 130 is closed.

[0079] Fig. Figure 7 shows a schematic sectional view of a first embodiment of a safety valve 10 according to the invention.

[0080] Unlike the one in Fig. In the safety valve 10 shown in Figure 4-4c, the housing of a conventional 5 / 2-way valve is used, also featuring a hollow piston 250 with a cavity 14. The hollow piston 250 is extended on the left side in its longitudinal direction 251 and has a constriction 250g.

[0081] The body 250a of the hollow piston 250 is guided longitudinally displaceable in the right retaining flange 21 in the direction of the piston longitudinal axis 251 and is sealed against the retaining flange 21 with a seal 283.

[0082] In the recess of the end section 250d, a holder 27a is arranged, which extends to the left into a space in the cover 29 and forms a support for the energy storage element 27, which is also supported against an inner surface of the cover 29. The cover 29 is attached to the left side of the valve body 20 by fastening elements 29b, e.g., screws.

[0083] The following components are arranged in the inner bore 20a of the valve body 20 (from left to right in the drawing): a retaining flange 21, a seal 22c, a spacer 23d, a seal 22c, a spacer 23c, a seal 22, a spacer 23, another seal 22, a spacer 23b, a seal 22a, a spacer 23a, and a seal 22a. Seals 22-22b and associated spaces 24-24b of the valves 11, 12, and 13 are arranged as in the first embodiment above. Fig. 4-4c described.

[0084] A first auxiliary connection 140 is located at the bottom left next to the outlet 130, and a second auxiliary connection 150 is provided at the top left next to the inlet 110. This second auxiliary connection 150 is completely closed with a sealing element. The first auxiliary connection 140 is provided with a sealing element 141, which has a small opening.

[0085] The in Fig. The block position shown in Figure 7 with regard to valves 11, 12, 13 has already been explained in the first embodiment and is not repeated here.

[0086] The first auxiliary port 140, in the closed position, is connected to the inlet 110 via the constriction 250g of the hollow piston 250, thus enabling ventilation of the inlet 110. This allows a flow rate to prevent unwanted milk flow into the dip tube or the outlet line 9 of the dip medium. A further advantage is that the so-called headspace volume at the teat head can be reduced. In the open-circuit position (not shown, but imaginable), the first auxiliary port 140 is connected to the closed second auxiliary port 150 via the constriction 250g of the hollow piston 250.

[0087] In this first embodiment, it is shown that the drive element 280 comprises the drive piston 280a with a seal 282, which seals the drive piston 280a against the displacement chamber 28a. The drive element 280 is tightly inserted into the drive end 250c of the hollow piston 250 with the seal 281 and seals the cavity 14. The drive connection 28b is arranged radially.

[0088] Furthermore, the safety valve 10 has a sensor unit 30, which comprises a sensor element 30a with a sensor cable 30d, a sensor mounting 30b (e.g., a screw), and a sensor holder 30c. The sensor holder 30c is attached to the right side end of the drive unit 28 such that the sensor element 30a is located in the area of ​​the right end of the drive element 280. The sensor element 30a interacts, for example, with a magnetic element 31, which is fixed to the right end of the drive element 280 by a locking element 31a. The sensor element 30a can be, for example, a Hall effect sensor. Of course, other sensor types, such as ultrasonic, infrared, etc., can also be used.

[0089] With the sensor unit 30, it is possible to detect the linear position of the hollow piston 250 in its longitudinal axis 251. Thus, the in Fig. The block position shown here can be scanned without contact, thus enabling error detection.

[0090] The valve body 20 has several mounting openings 20b which extend perpendicularly through the valve body 20 to the plane of the drawing.

[0091] Fig. 8 and Fig. Figure 8a shows schematic sectional views of a variant of the second embodiment according to Fig. 7 in different switch positions. This shows Fig. 8 the block position of the safety valve 10, and Fig. 8a represents the passage position.

[0092] The design of this variant is similar to that of the second embodiment. Only the differences will be explained.

[0093] In this case, inlet 110 and outlet 120 are located on the top of the valve body 20, with the bleed outlet 130 situated between them on the underside. To the right of the bleed outlet 130, towards the actuator side, the first auxiliary port 140 with a valve 14 is provided. To the left of the bleed outlet 130 is the second auxiliary port 150.

[0094] In this variant, the following components are arranged in the inner bore 20a of the valve body 20 (from left to right in the drawing): a retaining flange 21, a seal 22c, a spacer 23c, a seal 22, a spacer 23, another seal 22, a spacer 23b, a seal 22a, a spacer 23a, a seal 22a, a spacer 23b, and a seal 22b. Seals 22-22b and associated spaces 24-24b of the valves 11, 12, and 13 are arranged as in the first embodiment above. Fig. 4-4c described.

[0095] The cavity 14 of the hollow piston 250 is located in the Fig. In the block position shown in Figure 8, the first opening 14a of the cavity 14 of the hollow piston 250 is connected to the valve 13 and the bleed outlet 130. Additionally, the second opening 14b of the cavity 14 of the hollow piston 250 is connected to the valve 14 and the first auxiliary port 140. This allows the cavity 14 to be flushed with a cleaning medium (including air).

[0096] In the Fig. In the flow position shown in Figure 8a, the auxiliary ports 140 and 150 are closed, as can be easily seen. In the event of a leak at the inlet 110, the second auxiliary port 150 can protect the energy storage element 27 from the ingress of medium, thus preventing corrosion of the energy storage element 27.

[0097] The safety valve 10 can be made of plastic, provided the seals are resistant to the media used. For this purpose, a fluoroelastomer material (e.g., Viton) can be used. The hollow piston 250 is made of stainless steel.

[0098] Fig. 9 and Fig. Figure 9a illustrates schematic perspective views of the variant of the second embodiment according to Fig. 8-8a.

[0099] In Fig. Figure 9 shows a top view of the safety valve 10, where Fig.Figure 9a shows the underside. The safety valve 10 is extremely narrow and occupies very little installation space. Using the mounting openings 20b, several safety valves 10 can easily be combined to form a safety valve assembly 10A, 10B. The sensor unit 30 is also visible. Standard sensor elements 30a can be easily inserted into the sensor holder 30c, adjusted within it, and secured using the sensor mounting 30b.

[0100] The hollow piston 250 is manufactured from a material that is resistant to the media it comes into contact with. This material can be, for example, stainless steel and / or plastic. Combinations of different materials are also possible.

[0101] The embodiments described above do not limit the invention. The invention is modifiable within the scope of the appended claims.

[0102] For example, the recordings can show the respective [information / details].

[0103] It is also conceivable that the spacers 23-23d with the associated seals 22-22c are manufactured as two-component injection molded parts.

[0104] The closure element 141 of the auxiliary port 140 can be a nozzle or be equipped with a nozzle, wherein the outlet cross-section of the nozzle is significantly smaller than the cross-section of the auxiliary port 140. Reference sign 1 Valve device 2 First valve 2a First connection 3 Second valve 3a Second connection 4 Third valve 4a Third connection 5-5c line 6 bad milk containers 7 good milk containers 8 teat cups 9, 9a, 9b Exit line 10 safety valve 10A, 10B Safety valve arrangement 11 First block valve 12 Second block valve 13 Bleed valve 14' connection 14 Cavity 14a, 14b Opening 15 connection 16, 16a-e Entrance line 17 Pre-dip medium source 17' Post-dip medium source 18 Water source 19 Purge air source 20 valve bodies 20a Internal bore 20b Mounting opening 21 Mounting flange 22, 22a-c Seal 23, 23a-c spacers 24, 24a-c Section 25 pistons 25a Piston longitudinal axis 25b, 25c Body section 25d connecting section 26 connection 27 Energy storage element 27a Holder 28 Drive unit 28a Engine capacity 28b Drive connection 29 lids 29a Opening 29b Fastener 30 sensor units 30a Sensor element 30b Sensor mounting 30c Sensor Holder 30d sensor cable 31 Magnetic element 31a Safety element 100-way valve 101, 102, 103 connection 110, 110' Entrance 120 Exit 130 Bleed output 140, 150 additional connection 141, 151 Locking element 170 Pre-Dip Supply 170' Post-Dip Supply 250 hollow pistons 250a Body 250b surface 250c drive end 250d End section 250e Intermediate section 250f wall 250g constriction 251 Piston longitudinal axis 280 drive element 280a Drive piston 281, 282, 283 Seal RV check valve

Claims

[1] Safety valve (10) for a cleaning device for a milking system for milking dairy animals, comprising a first block valve (11) with an inlet (110), a second block valve (12) with an outlet (120), a bleed valve (13) with a bleed outlet (130), a piston (25) and an actuator (28), wherein the safety valve (10) can be moved from a blocked position in which the first block valve (11) and the second block valve (12) are closed to block the inlet (110) and the outlet (120) and the bleed valve (13) is open to connect the bleed outlet (130) to a connection (14'), to a flow position in which the first block valve (11) and the second block valve (12) are open to connect the inlet (110) via the connection (14') to the outlet (120) and the bleed valve (13) is closed to block the bleed outlet (130) and is designed to be adjustable back, wherein the safety valve (10) is designed as a directional control valve, wherein the piston (25) is a hollow piston (250), wherein the hollow piston (250) has a cavity (14) as a connection (14'), wherein the safety valve (10) has a valve body (20) of a 5 / 2-way valve with the hollow piston (250), characterized by , that the inlet (110) in the block position is connected to an additional port (140), wherein the additional port (140) is narrowed by a nozzle, wherein an outlet cross-section of the nozzle is significantly smaller than a cross-section of the additional port (140). [2] Safety valve (10) according to claim 1, characterized by , that the cavity (14) extends in the direction of a piston longitudinal axis (251) of the hollow piston (250). [3] Safety valve (10) according to claim 2, characterized by that the cavity (14) comprises a first opening (14a) and a second opening (14b). [4] Safety valve (10) according to claim 3, characterized by , that in the block position the first block valve (11) and the second block valve (12) are closed to block the inlet (110) and outlet (120) through the hollow piston (250) and the bleed valve (13) connects the bleed outlet (130) to the cavity (14) of the hollow piston (250). [5] Safety valve (10) according to claim 3 or 4, characterized by , that in the open position the first block valve (11) communicates via the first opening (14a) with the cavity (14) of the hollow piston (250) and the second block valve (12) communicates via the second opening (14b) with the cavity (14) of the hollow piston (250) to connect the inlet (110) with the outlet (120), and that the bleed valve (13) is closed to block the bleed outlet (130) through the hollow piston (250). [6] Safety valve (10) according to claim 5, characterized by, that the hollow piston (250) is connected to a drive element (280) for adjusting the hollow piston (250) from the block position to the open position of the safety valve (10) and back. [7] Safety valve (10) according to claim 6, characterized by , that the safety valve (10) has a pre-tensioned energy storage element (27) which pre-tensions the hollow piston (250) into the blocked position and holds it in the blocked position. [8] Safety valve (10) according to any one of the preceding claims, characterized by , that the safety valve (10) has a sensor unit (30) for detecting the block position and / or the flow position. [9] Safety valve (10) according to claim 8, characterized by that the sensor unit (30) interacts directly or / and indirectly with the hollow piston (250) via a drive element (280). [10] Safety valve (10) according to claim 9, characterized by, that the sensor unit (30) interacts with a magnetic element (31) which is attached to the hollow piston (250) and / or the drive element (280).

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