Safety valve

Abstract

Safety valve (11) for a cleaning device for a milking system for milking dairy animals, comprising a first block valve (20) with an inlet port (110), a second block valve (22) with an outlet port (120), a bleed valve (21) with a bleed outlet port (130), a piston rod (37) and an actuator unit (34, 34', 34"), wherein the safety valve (11) can be moved from a blocked position in which the first block valve (20) and the second block valve (22) are closed to block the inlet port (110) and the outlet port (120) and the bleed valve (21) is open to connect the bleed outlet port (130) to a connection (23), to a flow position,in which the first block valve (20) and the second block valve (22) are open to connect the inlet port (110) via the connection (23) to the outlet port (120) and the bleed valve (21) is closed to block the bleed outlet port (130), and is designed to be adjustable back, wherein the first block valve (20), the second block valve (22) and the bleed valve (21) of the safety valve (11) are designed as poppet valves with a common piston plate (40), wherein the piston plate (40) has seat section surfaces (40a, 40b, 40c) of the poppet valves (20, 22, 21), characterized in that the safety valve (11) is provided with a venting device (25) which communicates with the outlet port (120) of the second block valve (22).

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 solution 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 DE 10 2013 114 595 A1 describes a safety valve for a cleaning device for an automatic milking system. The description of the function and construction of a cleaning device is further detailed in document WO 2010 / 053577 A1.

[0006] This safety valve is designed as a slide valve. A disadvantage of this design is that its service life is insufficient to meet the requirements of a modified process. The altered cleaning and dipping process necessitates a switching life of the valve that is 10 to 15 times longer.

[0007] From publication WO 2006 / 091710 A2, a safety valve with block and bleed valves is known, which is equipped with valve seats, i.e., is designed as a seat valve, which leads to an increased switching service life.

[0008] Against this background, the object of the invention is to create an improved safety valve for a cleaning device for a milking system for milking dairy animals with a longer service life while keeping costs as constant as possible.

[0009] This problem is solved by a safety valve having the features of claim 1.

[0010] 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 port, a second block valve with an outlet port, a bleed valve with a bleed outlet port, a piston rod and a drive unit, wherein the safety valve is adjustable from a block position, in which the first block valve and the second block valve are closed to block the inlet port and the outlet port and the bleed valve is open to connect the bleed outlet port to a connection, to a flow position, in which the first block valve and the second block valve are open to connect the inlet port via the connection to the outlet port and the bleed valve is closed to block the bleed outlet port, and back again.The first block valve, the second block valve and the bleed valve of the safety valve are designed as poppet valves with a common piston plate.

[0011] This advantageously ensures that the design of the block valves and the bleed valve as seat valves achieves the required higher switching service life of 10 years and the 15*10 occurring in the process 6 can achieve switching cycles.

[0012] The design as a seat valve also offers the advantage that the dynamic load on components can be reduced many times over due to significantly smaller adjustment ranges.

[0013] Furthermore, the piston plate features seat sections for the valves, which are designed as poppet valves. These seat sections can, for example, be manufactured together in a single production process. Additionally, the piston plate requires no seals, thus reducing the number of parts.

[0014] According to the invention, the safety valve is equipped with a ventilation device for ventilating the top of an associated teat cup of a milking system, which communicates with the outlet port of the second block valve. The advantage here is that the ventilation device can be integrated into or attached to the safety valve in a compact design. For example, a check valve can be installed at the outlet port of the second block valve.

[0015] In another embodiment, the piston plate is coupled to a first drive unit via the piston rod on one side and to a second drive unit via a drive rod on the opposite side. This results in a compact design. Furthermore, a significantly shorter adjustment stroke of 3 mm is possible compared to the prior art of 8 mm. This leads to faster switching times. Additionally, smaller quantities can be dispensed, thus reducing waste.

[0016] In this arrangement, the first drive unit can have a drive cylinder with a drive piston, and the second drive unit can have a force storage element, e.g. a compression spring, which preloads the piston plate to close the block valves in the block position and holds it in the block position.

[0017] Alternatively, the first drive unit and the second drive unit can each have a drive cylinder with a drive piston. This allows the use of identical parts.

[0018] Alternatively, the piston plate can be coupled on one side via the piston rod to a double-acting drive cylinder of the drive unit. This offers the advantage of a particularly compact design that requires very little installation space.

[0019] It is particularly advantageous if the safety valve has a valve body with a longitudinal axis, constructed in a sandwich design from various functional units comprising a block valve unit, a bleed valve unit, a connection unit, and at least one actuator unit. This results in a modular design.

[0020] In one embodiment, the connection is formed by a pressure chamber between the block valve unit and the bleed valve unit, wherein the piston plate in the pressure chamber is adjustable from the open position to the closed position and back.

[0021] Another embodiment provides that, in the closed position, the first and second block valves are closed by one side of the piston plate to block the inlet and outlet ports, respectively, and the bleed valve connects the bleed outlet port to the pressure chamber. Both block valves are opened and closed by the common piston plate. The valves require only a small number of seals, which, unlike prior art designs, are not subjected to friction by moving a spool, but only to pressure, resulting in reduced wear as a further advantage.

[0022] In the open-circuit position, the first and second block valves communicate through the pressure chamber to connect the inlet port to the outlet port, and the bleed valve is closed to block the bleed outlet port by the other side of the piston plate. Here, too, the aforementioned advantages regarding the seals and the common piston plate apply.

[0023] In a further embodiment, the block valves and the bleed valve each have a sealing bushing with a seat section, each seat section interacting with a corresponding seat surface of the piston plate. This results in a simple, cost-effective design with a small number of seals. Furthermore, the sealing bushings can be replaced, which is advantageous for adapting to different applications and for maintenance.

[0024] Another design provides for a venting device with a vent opening connected to a cone or a conically shaped bore, such as a countersink, with the vent opening being molded into the piston plate. The advantage of this design is that it prevents the risk of a check valve becoming stuck due to glycerin components in the dipping medium. Furthermore, the vent opening and the cone can be easily molded into the piston plate without the need for additional components. Instead of a cone, a stepped bore could also be used.

[0025] The ventilation device can also be adjustable, for example with adjusting screws or various inserts that have a conical ventilation bore and can be inserted into the piston plate. In a further version, this can also be automated so that the milking process can be directly and individually influenced, for example to improve the adhesion of the teat cup liner to the teat and / or to speed up milk transport during high milk flows.

[0026] In another embodiment, the piston plate and the drive piston feature a rotation lock around a piston axis. This is particularly advantageous not only in the case of a venting device in the piston plate, but also with a sensor whose hysteresis is not altered by a rotation of a sensor actuator, e.g., a magnet, thus increasing the reliability of the sensor's position detection of the safety valve.

[0027] The anti-rotation device can be formed in one design by the shape of the piston plate and / or the drive piston, e.g. oval shape, positive locking engagements, etc.

[0028] In an alternative embodiment, the anti-rotation device can be formed by the shape of a flange on the piston rod, to which the piston plate is attached, and a stationary recess communicating with it. This is particularly advantageous because a special shape of the pressure chamber and / or piston chamber is not required.

[0029] In another alternative, the anti-rotation device is formed by a pin that acts as a guide for the piston plate. This is easy to manufacture.

[0030] Another design provides that the safety valve has a sensor to detect the closed position and / or the open position. This allows for easy monitoring of a function of the safety valve, in particular the closed position safety function.

[0031] In another embodiment, the sensor is designed to interact with a sensor actuator element that is attached to or inside the drive piston. This results in a simple design.

[0032] Another design offers the advantage of contactless actuation if the sensor actuator is a magnet. In this case, the sensor can have a magnetic field-sensitive component, such as a reed contact, Hall sensor, RF coil, etc.

[0033] The safety valve, as a block-bleed-block (BBB) ​​valve, offers the advantage of a wide range of applications, and in particular, it meets relevant safety regulations, e.g., those of the FDA in the USA. Due to the actuator and design of the safety valve according to the invention, a significantly increased total number of cycles can be achieved. The number of dynamically stressed seals is reduced many times over due to considerably shorter adjustment and switching travels.

[0034] Several safety valves can be easily connected to each other and used compactly as a safety valve assembly.

[0035] 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 in an exemplary milking system; Fig. 2 a safety valve in a schematic block diagram; Fig. 2a-2b schematic circuit diagrams of the safety valve according to Fig. 2 in two different switch positions; Fig. 3-4 schematic block diagrams of the safety valve according to Fig. 2 with a ventilation device; Fig. 5 the safety valve after Fig. 4 with a ventilation device in a schematic block diagram; Fig. 5a-5b schematic circuit diagrams of the safety valve with the ventilation device according to Fig. 5 in two different switch positions; Fig. 6 an embodiment of the safety valve according to Fig. 5 in a longitudinal section view; Fig. 7-8 schematic sectional views of variants of the embodiment example according to Fig. 6; Fig. 9 a schematic sectional view of the variant according to Fig. 8 with one sensor; and Fig. 10 a schematic perspective view of the embodiment example according to Fig. 6.

[0036] In the figures, identical or similar functional elements and components are provided with the same reference symbols.

[0037] The terms "top", "bottom", "left", and "right" refer to the respective arrangement in the figures. Other installation positions not shown, e.g., upside down, sideways, or in another position, are of course possible.

[0038] Fig. Figure 1 shows a schematic representation of an exemplary application of a safety valve 11 according to the invention in an exemplary milking system 1. Fig. Figure 2 shows a safety valve 11 in a schematic block diagram. Fig. 2a and Fig. 2b. Recreate schematic circuit diagrams of safety valve 11. Fig. 2 in two different switch positions.

[0039] As a representative example of an animal to be milked, a teat 2 of the same animal is shown here. Below it is a teat cup 3 of a milking unit (e.g., a milking robot, not shown) of the milking system 1, which is attached to teat 2 during milking. An animal, e.g., a cow, typically has four teats 2, each with its own teat cup 3.

[0040] Each teat cup 3 is connected via a cup line 4 to two safety valve assemblies, one of which has four good milk valves 5 and the other four bad milk valves 7. The good milk valves 5 are connected to a good milk line 6, and the bad milk valves 7 are connected to a bad milk line 8. The continuation of these lines will not be discussed here. For details regarding their construction and function, please refer to documents US 2012 / 0017836 A1 and WO 2010 / 053577 A1.

[0041] The two safety valve devices serve to prevent the accidental suction of unwanted media from the bad milk line 8 or a “cleaning line” (here the cup line 4 during a cleaning process) into the good milk line 6.

[0042] The good milk valves 5 and the bad milk valves 7 of the safety valve devices are designed as so-called “block-bleed-block valves”, the design and function of which can be found in document US 2015 / 0173320 A1.

[0043] Furthermore, the teat cup 3 is connected via a supply line 9 to a cleaning device 10 (so-called pre-dip / post-dip devices) via a safety valve 11. At least one safety valve 11 is provided for each teat 2 or teat cup 3. The cleaning device 10 comprises the safety valve 11, a dip valve 12 with a dip medium source 13, a water valve 14 with a water source 15, and an air valve 16 with a rinsing air source 17 and connecting lines 9, 18, 18a, 19. The dip valve 12, the water valve 14, and the air valve 16 are also referred to as media valves.

[0044] For example, the maximum pressure of the media is 5 bar.

[0045] During a dipping process (e.g., post-dip), the dip valve 12 opens for a defined period. During this time, a quantity of dipping medium is dispensed from the dipping medium source 13. The air valve 16 opens, and the dipping medium, which is still in the supply line 9 that carries the media to the teat cup 3, is conveyed to the teat 2 by compressed air from the purge air source 17 and distributed through a nozzle on the teat 2.

[0046] To prevent, for example, a technical defect in the dip valve 12 from causing the dip medium to enter the teat cup 3 uncontrollably, a safety valve 11 is provided between the media valves 12, 14, 16 and the teat cup 3. The safety valve 11 is only open during the dipping process and during cleaning of the system with water (from the water source 15 via the water valve 14), i.e., it is in its open position, also known as the flow position. Otherwise, the safety valve 11 is closed, i.e., in its closed position, also known as the block position.

[0047] A detailed description of cleaning equipment 10 can be found in documents US 2012 / 0017836 A1 and WO 2010 / 053577 A1.

[0048] The safety valve 11 has an inlet port 110, an outlet port 120, and a bleed outlet port 130. The inlet port 110 is connected via an inlet line 19 to outlet lines 18 and 18a of the media valves 12, 14, and 16.

[0049] The safety valve 11 is designed as a so-called "block-bleed-block valve" and comprises two block valves, namely a first block valve 20 and a second block valve 22, and a bleed valve 21. Depending on the flow direction of the medium, the first block valve 20 is referred to as the inlet valve and the second block valve 22 as the outlet valve, or vice versa. These three valves 20, 21, and 22 are connected to each other such that the first block valve 20 and the second block valve 22 are connected in series in terms of flow direction, with the bleed valve 21 being connected to a common connection 23 of the first block valve 20 and the second block valve 22. In this way, the safety valve 11 is formed as a "block-bleed-block valve".

[0050] The two block valves 20 and 22, as well as the bleed valve 21, are actuated by a common actuator 24 such that the safety valve 11 assumes a so-called open position in one position, from which it can be moved to another position, a so-called closed position, and back again. This will be explained in more detail below.

[0051] The first block valve 20 of the safety valve 11 is connected to the inlet port 110 via an inlet 20a. Thus, the first block valve 20 of the safety valve 11 is connected to the inlet line 19 via the inlet port 110 and to the media valves 12, 14, 16 via the outlet lines 18, 18a.

[0052] Furthermore, an outlet 20b of the first block valve 20 is connected via a connecting port 23a of connection 23 and via another connecting port 23c of connection 23 to an inlet 22a of the second block valve 22. An outlet 22b of the second block valve 22 is connected to the supply line 9 and thus to the teat cup 3 via the outlet port 120.

[0053] Connection 23 also communicates via a further connection port 23b with an inlet 21a of the bleed valve 21, which is connected via its outlet 21b to the bleed outlet port 130 of the safety valve 11. The bleed outlet port 130 can communicate with a separate container and / or with the atmosphere.

[0054] The safety valve 11 functions as a block-bleed-block valve. When the block valves 20 and 22 are open, the bleed valve 21 is closed. This position is hereinafter referred to as the open position of the safety valve 11. In the so-called closed position of the safety valve 11, the block valves 20 and 22 are closed, while the bleed valve 21 is open and connects the bleed outlet port 130 to the connection 23. Thus, in the closed position, it is ensured that, on the one hand, the first block valve 20 completely blocks the flow of medium from the media sources 13, 15, 17, and, on the other hand, the second block valve 22 blocks the connection to the teat cup 3 via the supply line 9.

[0055] In Fig. Figure 2a shows a schematic circuit diagram of the safety valve 11 in the open position. The closed position of the safety valve 11 is shown in the schematic circuit diagram below. Fig. 2b.

[0056] The open position is used during cleaning processes (pre-dip, post-dip, water rinsing), while the closed position is used during milking. Additionally, the closed position is always used as a safety position when the actuator of safety valve 11 is not activated. In other words, safety valve 11 is in the closed position without any actuator.

[0057] In the block position, it is also ensured that in the event of a possible leakage of the first block valve 20 (e.g. due to wear), medium from the media sources 13, 15, 17 cannot enter the suction line of the safety valve devices with the milk valves 5, 7, which is designed as a cup line 4, since the connection 23 of the safety valve 11 is connected to the bleed outlet port 130 (e.g. to the atmosphere or to a suitable collection vessel) via the open bleed valve 21.

[0058] Even in the event of a possible leak in the second block valve 22 in the block position, no medium can be drawn in from the media sources 13, 15, 17 via the supply line 9 due to the open bleed valve 21.

[0059] Safety valve 11 is described in detail below.

[0060] In the Fig. Figures 3-4 are schematic block diagrams of the safety valve 11 according to Fig. 2 with a ventilation device 25 shown. Fig. 5 shows the safety valve 11 after Fig. 4 with the ventilation device 25 in a schematic block diagram. Fig. Figures 5a-5b show schematic circuit diagrams of the safety valve 11 with the ventilation device 25 according to Fig. 5 in the different switching positions: through position and block position.

[0061] The supply line 9, which leads from the outlet port 120 of the safety valve 11 to the head of the teat cup 3, should be vented towards the head of the teat cup 3 during the milking process. Such venting prevents liquid (milk, water, and cleaning agents) from entering the supply line 9. Fig. Figure 3 shows a ventilation device 25 which connects a ventilation line 26, which communicates with the supply line 9, to the atmosphere. In this way, an airflow 27 is generated, which is regulated by a small nozzle (cross-sectional limiter) in the ventilation device 25 so that, on the one hand, no liquid from the direction of the teat cup 3 can enter the supply line 9, and on the other hand, the vacuum in the cup line 4 and in the teat cup 3 is not reduced too much.

[0062] In the arrangement according to Fig. 3 This ventilation is ensured by a check valve of the ventilation device 25, which is installed, for example, in the ventilation line 26 between safety valve 11 and teat cup 3.

[0063] Another embodiment of a ventilation device 25 is in Fig. Figure 4 shows the ventilation device 25 integrated into the safety valve 11, with the ventilation line 26 communicating with the atmosphere from the safety valve 11.

[0064] The ventilation system according to Fig. 4 is in Fig. 5 initially shown schematically. Fig. 5 shows the safety valve 11 as the basis. Fig. 2 extended by the ventilation device 25. The ventilation device 25 is arranged in the second block valve 22 and connected to the connection 23 via the ventilation line 26.

[0065] The open position of the safety valve 11 with the ventilation device 25 according to Fig. 5 is in Fig. 5a is shown and corresponds to the flow position of the safety valve 11 according to Fig. 2a. This means that the two block valves 20 and 22 are connected in series via connection 23 and are open, with the bleed valve 21 being closed.

[0066] In the blocked position of the safety valve 11 with the ventilation device 25 according to Fig. However, 5 is, as in Fig. As can be clearly seen in Figure 5b, the closed second block valve 22 is connected via the ventilation device 25 to the connection 23 and via the open bleed valve 21 to the bleed outlet port 130. In this way, the supply line 9 connected to the outlet port 120 communicates (see Figure 5b). Fig. 5) via the ventilation line 26 with the connection 23, which in turn communicates with the atmosphere via the open bleed valve 21 and the bleed outlet port 130.

[0067] The ventilation device 25 has a ventilation opening 28 with a small, defined cross-section, as described below.

[0068] Fig. Figure 6 shows an embodiment of the safety valve 11 according to Fig. 5 in a longitudinal section view.

[0069] The safety valve 11 has a valve body 29 with a longitudinal axis 29a, which is constructed here in a sandwich-like design from various functional units. In this embodiment, the valve body 29 comprises a block valve unit 30, a bleed valve unit 31, a connection unit 32, a bleed connection unit 33, a first actuator unit 34, and a second actuator unit 34'. Furthermore, the safety valve 11 has a piston rod 37 with a piston plate 40, an actuator rod 43, and, in this embodiment, a sensor holder 36.

[0070] The block valve unit 30 is centrally located in the valve body 29. On its left side, it is connected to the bleed valve unit 31, with the connection unit 32 located on the right side of the block valve plate 30. The bleed valve unit 31 is connected on its left side to the bleed connection unit 33. The first actuator unit 34 is located on the right side of the connection unit 32, with the second connection unit 34' attached to the left side of the bleed connection unit 33. The sensor holder 36 is attached to the right side of the first actuator unit 34. All units are connected to each other in a manner not described in detail below to form the valve body 29.

[0071] The bleed valve unit 31 is provided with a pressure chamber 31a on its side facing the block valve unit 30. This pressure chamber 31a is a recess in the body of the bleed valve unit 31, extending approximately halfway along a longitudinal axis of the safety valve 31. Thus, the pressure chamber 31a is defined on the left side by a base in the bleed valve unit 31, by a circumferential wall of the bleed valve unit 31, and on the right open side by the block valve unit 30.

[0072] The block valve unit 30 and the bleed valve unit 31, together with the piston plate 40, form the first block valve 20, the second block valve 22, and the bleed valve 21. A sealing bushing 20c of the first block valve 20 and a sealing bushing 22c of the second block valve 22 are inserted in the block valve unit 30, with the longitudinal axes of the sealing bushings 20c, 22c running parallel to the longitudinal axis 29a of the safety valve 11. The sealing bushings 20c, 22c each open into the pressure chamber 31a via a seat section 20d, 22d. In this way, the pressure chamber 31a forms the connection 23 of the safety valve 11 as described above in connection with Fig. 2, Fig. 2a, Fig. 2b, Fig. 5, Fig. 5a, Fig. 5b described.

[0073] A sealing bushing 21c of the bleed valve 21 is inserted into the base of the pressure chamber 31a. A longitudinal axis of the sealing bushing 21c of the bleed valve 21 lies parallel to the longitudinal axes of the other sealing bushings 20c, 22d of the block valves 20, 22 and here runs in the longitudinal axis 29a of the safety valve 11. The sealing bushing 21c of the bleed valve 21 also opens into the pressure chamber 31a with a seat section 21d.

[0074] The first block valve 20 is formed from the seat section 20d of the sealing bushing 20c and a seat section surface 40b of the piston plate 40 opposite seat section 20d. Similarly, the second block valve 22 is formed from the seat section 22d of the sealing bushing 22c and a seat section surface 40a of the piston plate 40 opposite seat section 22d. The seat section surfaces 40a and 40b of the piston plate 40 are located on the same side of the piston plate 40, which faces the block valve unit 30.

[0075] The other side of the piston plate 40, which faces the bleed valve unit 31, is also referred to as the end face of the piston plate 40 and is provided with a further, here central, seat section surface, which together with the seat section 21d of the sealing bushing 21c of the bleed valve 21 forms this bleed valve 21.

[0076] In this way, the safety valve 11 is designed as a so-called seat valve.

[0077] Each sealing bushing 20c, 21c, 22c has a bushing flange (not shown here) which axially secures the respective sealing bushing 20c, 21c, 22c in the body of the associated functional unit 30, 31. The bushing flanges of the sealing bushings 20c, 22c of the block valves 20, 22 are arranged such that they are located on the side of the block valve unit 30 to which the connection unit 32 is attached. The bushing flange of the sealing bushing 21c of the bleed valve 21 is located on the side of the bleed valve unit 31 to which the bleed connection unit 33 is attached and projects from this side into an opening of the bleed connection unit 33 that communicates with the bushing flange, such that this engagement centers the bleed connection unit 33 with the bleed valve unit 31.

[0078] The block valve unit 30 is also connected to the connection unit 32 in a centered manner. For this purpose, the block valve unit 30 has a centering projection 30a on its side facing the connection unit 32, which is received in a sealing receptacle 32d of the connection unit 32 that communicates with the centering projection 30a.

[0079] The connection unit 32 has the inlet port 110 of the safety valve 11 on its underside. The inlet port 110 is connected to a line 32a, which is formed in the connection unit 32 such that it runs parallel to the longitudinal axis 29a of the safety valve 11, extends to the left towards the block valve unit 30, and terminates on the surface of the side of the connection unit 32 facing the block valve unit 30. The outlet port 120 is located on the top of the connection unit 32 and is connected to another line 32b, which is also formed in the connection unit 32 parallel to line 32a and terminates on the surface of the side of the connection unit 32 facing the block valve unit 30.

[0080] By means of the centering formed by the centering projection 30a and the sealing receptacle 32d, the longitudinal axes of the sealing bushings 20c and 22c of the block valves 20 and 22 are aligned with their respective associated lines 32a and 32b. In this way, the sealing bushing 20c of the first block valve 20 is connected to the inlet port 110 via the line 32a, while the sealing bushing 22c of the second block valve 22 communicates with the outlet port 120 via the further line 32b.

[0081] In the bleed connection unit 33, a bleed chamber 33a is formed coaxially with the longitudinal axis 29a of the safety valve 11 and with the longitudinal axis of the sealing bushing 21c of the bleed valve 21. The bleed chamber 33a extends approximately half the length of the bleed connection unit 33 to the left along the longitudinal axis 29a and is connected in its left third to a line 33a running downwards at a right angle to the longitudinal axis 29a. The line 33a connects the bleed chamber 33a, and thus the sealing bushing 21c of the bleed valve 21, to the bleed outlet port 130 located on the underside of the bleed connection unit 33.

[0082] The piston plate 40 is arranged in the pressure chamber 31a. The piston plate 40 is guided so as to be displaceable in the direction of the longitudinal axis 29a by means of the piston rod 37. The piston plate 40 is centrally connected to a flange 39, which is integrally formed on the left end of the piston rod 37, by means of a fastening element 41, here, for example, a screw. A seal 46 is located between the piston plate 40 and the flange 39 (see Fig. 7) ordered.

[0083] To accommodate the flange 39 in the block position, which is described below, a recess 30c corresponding to the flange 39 is formed in the block valve unit 30, which transitions to the right into a smaller through-opening 32b.

[0084] The piston rod 37 has a longitudinal axis 37a which runs in the longitudinal axis 29a of the safety valve 11 and is slidably mounted in a piston bearing 32c of the connection unit 32. The piston rod 37 extends from the flange 39 to the right, first through the through-opening 32b of the block valve unit 30 into the sealing receptacle 32d of the connection unit 32, and then passes through seals 45 (see Fig. 7) through into the piston bearing 32c of the connecting unit 32 and through it to a drive cylinder 38 of the first drive unit 34. The seals 45 are spaced apart in the longitudinal direction 29a by a sleeve 45a, as shown from Fig. 7 emerges.

[0085] A drive piston 38a is attached to the right end of the piston rod 37. This piston is displaceable in the longitudinal direction 37a of the piston rod 37 and also in the longitudinal direction 29a of the safety valve 11 within a piston chamber 34a. The piston chamber 34a has unmarked piston seals for contact with the wall of the piston chamber 34a. The piston chamber 34a is connected to a drive port 140 via a line 34b. The drive cylinder 38 is driven via the drive port 140 by a drive fluid, e.g., compressed air.

[0086] A maximum switching pressure for the drive unit 34 (also for the further units described below) can be, for example, 5 bar.

[0087] The drive by means of the first drive unit 34 is only unidirectional, as it is a single-acting drive cylinder 38 with an opposing compression spring. In other words, the pressurized drive fluid pushes the drive piston 38a, and thus the piston rod 37 with the piston plate 40, to the left along the longitudinal axis 29a against a force storage element 42a of a drive cylinder 38' of the second drive unit 34'. If the first drive unit 34 is then released, e.g., by reducing the pressure of the drive fluid, the force stored in the force storage element 42a is used to return the piston plate 40 with the piston rod 37 and the drive piston 38a to its initial position.

[0088] The second drive unit 34' has a central receptacle 35 in which a cylinder liner 42 of the drive cylinder 38' is inserted. The energy storage element 42a, in this case a compression spring, is arranged in the cylinder liner 42. The left end of the energy storage element 42a rests against a base of the cylinder liner 42. The other end of the energy storage element 42a is in contact with a flange 43a of a drive rod 43. The drive rod 43 extends to the right towards the piston plate 40 through a rod bearing 33c of the bleed connection unit 33, through the bleed chamber 33a, and through the sealing bushing 21c of the bleed valve 21. The right end of the drive rod 43 is in contact with the piston plate 40.Furthermore, the drive rod 43 passes through a seal 44, which is located at the right end of the cylinder bushing 42 and also forms a centering between the second drive unit 34' and the bleed connection unit 33 by means of a (not here described) projection that protrudes towards the bleed connection plate 33.

[0089] The cylinder bushing 42, the energy storage element 42a and the drive rod 43 of the second drive unit 34' have a central axis that lies in the longitudinal axis 29a of the safety valve 11 and in the piston axis 37a of the piston rod 37 of the first drive unit 34.

[0090] The Fig. Figure 6 shows the safety valve 11 in a transitional position between the closed position and the open position for better clarity. In this position, the piston plate 40 is located approximately in the middle of the pressure chamber 31a with respect to the longitudinal axis 29a.

[0091] In the closed position of the safety valve 11, the piston plate 40 is pressed by the second actuating unit 34', i.e., by a preload force of the energy storage element 42a, with its seat sections 40a and 40b, against the respective seat sections 20d and 22d of the closed valves 20 and 22, thereby closing them. The other seat section 40c of the bleed valve 21 is lifted from the associated seat section 21d of the sealing bushing 21c of the bleed valve 21, thus opening the bleed valve 21. The pressure chamber 31a is thus connected through the open bleed valve 21 via the bleed chamber 33a, the line 33b to the bleed outlet port 130, and then, for example, to the atmosphere.

[0092] By activating the first drive unit 34, the piston plate 40 is moved to the left against the preload force of the energy storage element 42a of the second drive unit 34' in the direction of the longitudinal axis 29a of the safety valve 11, as briefly described above, until the side of the piston plate 40 facing the bleed valve unit 31 presses with its seat section surface 40c against the seat section 21d of the sealing bushing 21c of the bleed valve 21, thus closing the bleed valve 21. The safety valve 11 is thus in the open position. The other side of the piston plate 40, with its seat section surfaces 40a and 40b, is lifted from the seat sections 20d and 22d of the block valves 20 and 22. This means that the block valves 20 and 22 are open and can communicate with each other via the pressure chamber 31a, connecting the inlet port 110 and the outlet port 120 in the through position.

[0093] In this embodiment, the stroke of the piston plate 40 when adjusting from the block position to the through position is approximately 3 mm, in contrast to the usual 5 mm.

[0094] In a further embodiment, the safety valve 11 indicates the ventilation device 25. Fig. 5, 5a-5b. For the sake of clarity, the ventilation unit 25 with its components is shown only in Fig. Reference 7 is provided, but will be described below.

[0095] In this embodiment, the venting device 25 comprises a vent opening 28 connected to a cone 28a. The vent opening 28 is a cylindrical bore with a small diameter, which here corresponds to approximately one-fifth of the dimension of the piston plate 40 in the longitudinal direction 29a. The length of the vent opening 28 corresponds here to approximately three-tenths of the dimension of the piston plate 40 in the longitudinal direction 29a. The vent opening 28 extends from the side of the piston plate 40 facing the bleed valve unit 31, parallel to the longitudinal axis 29a, towards the block valve unit 30, and then transitions into the cone 28a, which opens on the side of the piston plate 40 facing the block valve unit 30 with a diameter that corresponds approximately to the dimension of the piston plate 40 in the longitudinal direction 29a. These dimensions can, of course, also have other values.

[0096] The venting device 25 is arranged in the piston plate 40 such that the opening of the cone 28a lies within the seat section surface 40a. This means that the venting device 25, with its cone 28a, opens into the sealing bushing 22c of the second block valve 22 in the closed position. For this purpose, it is necessary that the piston plate 40 be arranged to prevent rotation about the piston axis 37a, so that the cone 28a of the venting device 25 cannot be moved. For this purpose, the piston plate 40 can, for example, be guided in a rotationally secure manner by an oval shape within the correspondingly shaped pressure chamber 31a. In another embodiment, for example, the flange 39 and the recess 30c communicating with it in the block valve unit 30 can have an oval shape or a shape other than a circular shape to prevent rotation. It is also possible that a pin is provided as a guide and anti-rotation device. For example,the piston rod 37 and / or the drive piston 38a shall have a corresponding anti-rotation device in the form of a pin guide, for example.

[0097] Such a rotation protection device for the piston plate 40 including the drive piston 38a is advantageous with respect to a sensor 47, which will be explained in more detail below.

[0098] In the Fig. 7 and Fig. 8. Schematic sectional views of variants of the exemplary embodiment are shown. Fig. 6 shown.

[0099] The variant according Fig. Figure 7 shows an embodiment with two single-acting drive cylinders 38 and 38'. The second drive cylinder 38' is constructed like the first drive cylinder 38 (the reference numerals of the components are marked with an apostrophe) and is located in a second drive unit 34', which is attached to the bleed connection unit 33 on the left side instead of the second drive unit 34' according to the embodiment. Fig. 6 is attached to the energy storage element 42a. The other assembly of the safety valve 11 corresponds to the embodiment shown in the following example. Fig. 6 and is therefore not repeated.

[0100] In the variant according to Fig. 8 the safety valve 11 is equipped with a drive unit 34" with a double-acting drive cylinder 38 and therefore has a shorter length in the longitudinal direction 29a compared to the previous embodiments.

[0101] The drive unit 34" has two drive ports 140, 140', which are arranged on opposite sides of the drive unit 34". Drive port 140 serves to supply the drive cylinder 38 with drive fluid to adjust the safety valve 11 to the open position, whereas the second drive port 140' serves to supply the drive cylinder 38 from the other side of the double-acting drive piston 38a with drive fluid to adjust the safety valve 11 to the closed position.

[0102] A bleed connection unit 33, as shown in the previous examples, is not shown here, but can be optionally fitted.

[0103] Fig. Figure 9 shows a schematic sectional view of the variant according to Fig. 8 with a sensor 47.

[0104] The sensor 47 is, for example, a magnetically actuated sensor, such as a reed contact, has an electrical connection in the form of a sensor line 47a, and is mounted in the sensor holder 36 on the right outer side of the drive unit 34". The sensor actuating element 48 required for the sensor 47 is designed here as a permanent magnet and is arranged in the drive piston 38a.

[0105] The sensor 47 is used to monitor the position of the safety valve 11, in particular to determine the closed position of the safety valve 11, which is also referred to as the safety position.

[0106] In order to maintain a constant hysteresis of the sensor 47, the anti-rotation device of the drive piston 38a, already mentioned and described above, is of particular advantage.

[0107] Finally, it shows Fig. 10 a schematic perspective view of the embodiment of the safety valve 11 according to Fig. 6. Here it can be clearly seen that the individual functional units 30, 31, 32, 33, 34 and 34' are designed in block form, but this is not absolutely necessary.

[0108] The materials used must be resistant to the dipping media and, depending on the national application, must also comply with national regulations (e.g., FDA in the USA). These materials include, among others, PA, PPSA, PA12, XF, FKM, and similar materials. In particular, resistance to the components iodine, glycerin, chlorhexidine, and H₂O₂ is required.

[0109] The embodiments described above do not limit the invention. The invention is modifiable within the scope of the appended claims.

[0110] For example, it is conceivable that the ventilation device 25 with the ventilation opening 28 and the cone 28a is designed as a separate insert and can be used in different versions. Adjustability is also possible.

[0111] It is also conceivable that the sealing bushings 20c, 22c, 21c are interchangeable. They can also be designed differently for different applications.

[0112] The pressure chamber 31a can be designed with an even smaller volume. This allows for greater precision in the dipping quantity.

[0113] The safety valve 11 can therefore also be used in applications other than as a metering valve.

[0114] The piston plate 40 can also be provided with a two-component material design in its seat section surfaces 40a, 40b, 40c.

[0115] The drive units 34, 34', 34" can of course also have other drive types besides pressurized drive fluids, such as electromagnet, electric motor, piezo drive, etc.

[0116] It is also conceivable that instead of the cone 28a a stepped bore is provided, which is designed as a circular cylinder, e.g. with the diameter that the cone 28a has at its opening in the seat section surface 40a of the piston plate 40. Reference sign 1 milking system 2 teats 3 teat cups 4 cup line 5 Good milk valve 6 Good milk line 7 Bad milk valve 8 bad milk line 9 Supply line 10 Cleaning equipment 11 Safety valve 12 dip valve 13 Dip medium source 14 Water valve 15 Water source 16 air valve 17 Purge air source 18, 18a Output line 19 Entrance line 20 First block valve 20a Admission 20b Outlet 20c sealing bushing 20d Seat section 21 Bleed valve 21a Entrance 21b Outlet 21c sealing bushing 21d Seat section 22 Second block valve 22a Entrance 22b Outlet 22c sealing bushing 22d Seat section 23 connection 23a, 23b, 23c Connection 24 actuators 25 Ventilation system 26 Ventilation line 27 Ventilation flow 28 Ventilation opening 28a Cone 29 Valve bodies 29a Longitudinal axis 30 Block valve unit 30a lead 30b Passage opening 30c Exclusion 31 Bleed valve unit 31a Pressure chamber 32 connection unit 32a, 32b Line 32c piston bearing 32d seal receptacle 33 Bleed connection unit 33a Bleed chamber 33b Line 33c rod bearing 34, 34', 34" drive unit 34a, 34'a Piston chamber 34b, 34'b line 35 recording 36 Sensor holder 37 Piston rod 37a Piston axis 38, 38' Drive cylinder 38a, 38'a Drive piston 39 flange 40 piston plate 40a, 40b, 40c Seating area 41 Fastening element 42 Cylinder bushing 42a Energy storage element 43 Drive rod 43a Flange 44, 45 Seal 45a sleeve 46 Seal 47 Sensor 47a Sensor cable 48 Sensor actuation element 110 Input connection 120 output port 130 Bleed output connector 140, 140' Drive connection

Claims

Safety valve (11) for a cleaning device for a milking system for milking dairy animals, comprising a first block valve (20) with an inlet port (110), a second block valve (22) with an outlet port (120), a bleed valve (21) with a bleed outlet port (130), a piston rod (37) and an actuator unit (34, 34', 34"), wherein the safety valve (11) can be moved from a blocked position in which the first block valve (20) and the second block valve (22) are closed to block the inlet port (110) and the outlet port (120) and the bleed valve (21) is open to connect the bleed outlet port (130) to a connection (23), to a flow position,in which the first block valve (20) and the second block valve (22) are open to connect the inlet port (110) via the connection (23) to the outlet port (120) and the bleed valve (21) is closed to block the bleed outlet port (130), and is designed to be adjustable back, wherein the first block valve (20), the second block valve (22) and the bleed valve (21) of the safety valve (11) are designed as poppet valves with a common piston plate (40), wherein the piston plate (40) has seat section surfaces (40a, 40b, 40c) of the poppet valves (20, 22, 21), characterized in that the safety valve (11) is provided with a venting device (25) which communicates with the outlet port (120) of the second block valve (22). Safety valve (11) according to claim 1, characterized in that the piston plate (40) is coupled at one side via the piston rod (37) to a first drive unit (34) and at one side opposite the first side is coupled to a second drive unit (34') by means of a drive rod (43). Safety valve (11) according to claim 2, characterized in that the first drive unit (34) has a drive cylinder (38) with a drive piston (38a), and that the second drive unit (34') has a force storage element (42a) which biases the piston plate (40) into the closed position and holds it in the closed position for closing the block valves (20, 22). Safety valve (11) according to claim 2, characterized in that the first drive unit (34) and the second drive unit (34') each have a drive cylinder (38, 38') with a drive piston (38a, 38'a). Safety valve (11) according to claim 1, characterized in that the piston plate (40) is coupled at one side via the piston rod (37) to a double-acting drive cylinder (38) of the drive unit (34"). Safety valve (11) according to one of claims 1 to 5, characterized in that the safety valve (11) has a valve body (29) with a longitudinal axis (29a) which is constructed in a sandwich design from various functional units comprising a block valve unit (30), a bleed valve unit (31), a connection unit (32) and at least one actuator unit (34). Safety valve (11) according to claim 6, characterized in that the connection (23) is formed from a pressure chamber (31a) between the block valve unit (30) and the bleed valve unit (31), wherein the piston plate (40) is arranged in the pressure chamber (31a) to be adjustable from the open position to the closed position and back. Safety valve (11) according to claim 7, characterized in that in the block position the first block valve (20) and the second block valve (22) are closed to block the inlet port (110) and the outlet port (120) by one side of the piston plate (40) and the bleed valve (21) connects the bleed outlet port (130) to the pressure chamber (31a). Safety valve (11) according to claim 8, characterized in that in the open position the first block valve (20) and the second block valve (22) communicate through the pressure chamber (31a) to connect the inlet port (110) to the outlet port (120), and that the bleed valve (21) is closed to block the bleed outlet port (130) through the other side of the piston plate (40). Safety valve (11) according to one of claims 1 to 9, characterized in that the block valves (20, 22) and the bleed valve (21) each have a sealing bushing (20c, 22c, 21c) with each a seat section (20d, 22d, 21d), wherein each seat section (20d, 22d, 21d) interacts with each associated seat section surface (40a, 40b, 40c) of the piston plate (40). Safety valve (11) according to one of claims 1 to 10, characterized in that the venting device (25) has a vent opening (28) which is connected to a cone (28a), wherein the vent opening (28) is formed into the piston plate (40). Safety valve (11) according to one of claims 1 to 11, characterized in that the piston plate (40) and the drive piston (38a) have a rotation protection device about a piston axis (37a). Safety valve (11) according to claim 12, characterized in that the anti-rotation device is formed by a shape of the piston plate (40) and / or the drive piston (38a). Safety valve (11) according to claim 12, characterized in that the anti-rotation device is formed by the shape of a flange (39) of the piston rod (37) to which the piston plate (40) is attached, and a stationary recess (30c) communicating with it. Safety valve (11) according to claim 12, characterized in that the anti-rotation device is formed by a pin which forms a guide for the piston plate (40). Safety valve (11) according to one of the preceding claims, characterized in that the safety valve (11) has a sensor (47) for detecting the blocked position and / or the open position. Safety valve (11) according to claim 16, characterized in that the sensor (47) interacts with a sensor actuating element (48) which is attached to or in the drive piston (38a). Safety valve (11) according to claim 17, characterized in that the sensor actuating element (48) is a magnet.

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