EP0404892A1

EP0404892A1 - Controllable driving mechanism with actuator, and seal for this driving mechanism

Info

Publication number: EP0404892A1
Application number: EP19890913113
Authority: EP
Inventors: Reinhard Konig
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-11-03
Filing date: 1989-11-03
Publication date: 1991-01-02
Also published as: WO1990005260A1; JPH04500996A; AU4629889A

Abstract

Un piston (25) relié de manière fixe avec un cône de soupape (24) est agencé dans un cylindre (5, 8). Ce cône de soupape (24) coopère avec un siège de soupape (26) à l'intérieur d'une conduite (38). On peut, grâce à un relais hydraulique (70), soumettre les faces latérales (42, 43) du piston (25) soit à la pression relativement plus élevée (P1) qui règne en amont du siège de soupape (26), soit à la pression relativement plus basse (P2) qui règne en aval du siège de soupape (26). Selon la pression à laquelle il est soumis, le piston (25) se déplace vers le haut ou vers le bas. Les commandes sont transmises par des courants magnétiques à la soupape pilote. Elles se présentent sous forme d'une impulsion positive ou négative de courant continu, qui est dirigée sur un électro-aimant (1), qui à son tour produit un flux magnétique polarisé généré par l'impulsion de courant. Le courant magnétique est dirigé, en passant par un noyau (3), vers l'intérieur du système d'entraînement, où les différentes opérations de commutation sont ensuite exécutées par le déplacement d'un cône de soupape (9) et d'un élément de commutation (11). L'étanchéification du piston (25) et de la tige de piston (26) par rapport à la face interne du cylindre se fait à l'aide de membranes enroulées fermées (15, 19) dont la partie interne est reliée à la pression la plus élevée (P1) qui comprime la membrane enroulée contre les parois du cylindre.A piston (25) fixedly connected with a valve cone (24) is arranged in a cylinder (5, 8). This valve cone (24) cooperates with a valve seat (26) inside a pipe (38). It is possible, thanks to a hydraulic relay (70), to subject the lateral faces (42, 43) of the piston (25) either to the relatively higher pressure (P1) which prevails upstream of the valve seat (26), or to the relatively lower pressure (P2) prevailing downstream of the valve seat (26). Depending on the pressure to which it is subjected, the piston (25) moves up or down. The commands are transmitted by magnetic currents to the pilot valve. They are in the form of a positive or negative direct current pulse, which is directed on an electromagnet (1), which in turn produces a polarized magnetic flux generated by the current pulse. The magnetic current is directed, passing through a core (3), to the interior of the drive system, where the various switching operations are then carried out by the displacement of a valve cone (9) and a switching element (11). The sealing of the piston (25) and of the piston rod (26) with respect to the internal face of the cylinder is done using closed wound membranes (15, 19) the internal part of which is connected to the pressure higher (P1) which compresses the wound membrane against the walls of the cylinder.

Description

Controllable drive with an actuator, and seal for such a drive

The invention relates to a controllable drive with an actuator according to the preamble of independent patent claim 1. Such drives have a wide range of uses and are used, for example, in process engineering, in power plant technology or for heating mixers, etc. Many systems are equipped with a large number of such drives, which have to be controlled individually and independently of one another. These known drives have a motor supplied with external energy, for example an electric motor, with which, for example, control valves are moved. In systems with many drives, the installation effort and the energy consumption are very high. The known drives also work with a comparatively large hysteresis, which is further increased by further translation elements. Since these drives require a relatively large amount of external energy, this has the consequence that, for example, a controller a power output stage is required or higher powers have to be switched on and off via relays. If a digital system is used for regulation and control, then digital-to-analog converters must be used as matching elements in order to be able to satisfy the drive in terms of its power requirements

A drive is known from BE-A-523626 which requires little external energy. However, this requires an exit to the environment and is not suitable for a line carrying a liquid medium.

The invention has for its object - to create a drive of this type, which avoids the disadvantages mentioned above and which is functionally reliable with a simple structure and is particularly suitable for lines with a liquid medium.

The invention uses as a source of energy a media difference, such as is present for example in a valve before and after this in a line. A motor with external energy and the necessary installation is not required for the drive according to the invention. The valve can be moved in the desired direction in a simple manner, for example with digital pulses from a computer. The control command is preferably transmitted to the drive by means of magnetic currents. In particular, the tax officer

REPLACEMENT LEAF from the outside in the form of a positive or negative direct current pulse. Signaling with radio, superimposed high-frequency signals or via light guides is also possible. The drive can be moved to any position with just three pulses. Since the principle of the drive is based on an existing pressure difference and a media quantity shift that can be triggered thereby, an accuracy in the range of i / 100 and 1/1000 mm is possible. Accuracy is achieved through an exact metering of the amount of media per unit of time, which flows from one cylinder chamber to the other.

It is essential that the drive can be manufactured in a very compact manner and without external hose connections and the like and can therefore be assembled and disassembled quickly and easily. The drive can be used in a variety of ways, for example as a pressure difference controller, as a flow controller or flow meter and as a constant quantity controller. Since the drive works quietly, it is particularly suitable for a flush valve in a toilet facility. A special measuring device may not be required. With a stop in the cylinder, the drive can be designed in a simple manner so that the stroke is adjustable.

Particularly small frictional forces between the piston and cylinder housing are made possible by the development according to claim 2

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reached. The requirements for surface processing, the inside of the cylinder housing are low, so that the cylinder housing can be cast inexpensively for its manufacture. The roll membrane can be made of rubber and is reinforced with a fabric at higher pressure differences.

If, according to a further development, the switch or the hydraulic relay is arranged in the pressure chamber of the cylinder, the housing of the relay is only comparatively small. Exposed to pressure difference and can be manufactured inexpensively from plastic.

An advantageous seal is the subject of claim 10. This is particularly suitable for the drive according to the invention.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Show it:

1 shows a section through a drive according to the invention,

2 shows a section through a switching part,

Fig. 3 seen a view of the changeover part in the direction of arrow III in Fig. 2.

REPLACEMENT LEAF 4 is a partial view of the valve body of a pilot valve,

5 is a plan view of a drive,

6 shows a section through a variant of the drive,

7a and 7b views of a valve seat of the embodiment of FIG. 6, and

Fig. 8 shows a drive corresponding to Fig. 6, but with the piston in the other end position.

The drive shown in FIG. 1 has two connections 27 and 28 with which it is connected to a line 38. In the flow passage 37 of the line 38, which carries a liquid or a gas, a valve with a valve seat 26 and a valve cone 24 is attached. When viewed in the direction of flow 37, the pressure P ^* L before the valve seat 26 is greater than the pressure P2 after the valve seat.

Above the valve seat 26 there is a connection 23 which leads to a cylinder chamber which is only open to the inside of the line 38. This chamber is formed by a connecting part 18, a cylindrical housing 8 and a cover 5. These parts are screwed together and sealed against one another by means of sealing rings 6, 17 and 22. With

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a union nut 20, the cylinder housing 8 is detachably connected to the connecting part 18.

A piston 25 is arranged in the cylinder housing 8 and divides the chamber into an upper chamber 30 and a lower chamber 40. The piston 25 is on its circumference with a tubular roller membrane 15 against the inside of the

REPLACEMENT LEAF Sealed housing 8. A piston rod 16 projecting downwards is attached to the piston 25, through which a channel 33 and a channel 39 lead. The channel 33 opens in the direction of flow 37 in front of the valve seat 26 into the interior of the line 38 and here takes up the higher pressure P 1. Radial connecting bores 31 and 32 lead from the channel 33 to the rolling membrane 15 or to a rolling membrane 19 attached to the piston rod. The higher pressure P prevailing inside the rolling membranes presses the rolling membrane 15 and 19 against the inside of the cylinder housing 8 or the inner side of the connecting part 18. The closed roll membranes 15 and 19 each seal the space in front of the roll membrane against the space behind the roll membrane. The roller membranes 15 and 19 combine the advantage of the lowest and therefore the highest differential pressure sensitivity with high insensitivity to the quality and quality of the cylinder, piston and piston rod wall. In this use, their independence from absolute pressure is also advantageous. The local independence to flange connections sw is also advantageous.

The channel 33 leads from a lower mouth 29 to a connection 13 to which a flexible hose (not shown here) is connected, which leads to an input E, a hydraulic relay 70 with a valve cone 9 and

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a switching part 11 leads. The input E leads through a bore in the housing 12 to a valve seat 26 which cooperates with the cone 9a of the valve cone 9. This cone 9a is firmly connected to a control plate 9b, which is made of magnetizable but not premagnetized metal. If a control signal in the form of a current pulse is now set in a magnet 1, a magnetic field is generated and the control plate 9b is pulled upward regardless of the polarity of the magnetic field. With the control plate 9b, the valve cone 9a is also moved upward and the flow of the medium through the inlet 1 is thus released. When the valve is open, a flow occurs in a chamber 34, which flows through an outlet A. into the upper cylinder chamber 30 and builds up a pressure in this chamber which is higher than the pressure in the lower cylinder chamber 40. As a result of which the piston 25 and thus the valve cone 24 move downward. As a result of this change in position, the flow at the valve seat 26 changes accordingly. The liquid displaced from the chamber 40 flows through a flexible hose 53 which is only partially shown here and which is connected to the relay 70 at an output A ~. As can be seen from FIG. 4, the outlet A leads via a chamber 36 to an inlet E ₂ , which is connected to the channel 39 via a hose (not shown here) via the mouthpiece 14. This channel 39 is also open to line 38.

REPLACEMENT LEAF If the piston 25 is to be moved upward, the paths are switched with the switching part 11. The switching part 11 has a polarized permanent magnet 10, which is attracted or repelled depending on whether it is opposed by the north or south pole generated by the control command. In order to move the piston upward, the changeover part 11 is also moved upward into a position not shown here. In this position, input E _{1 is} connected to output A-. As already mentioned, the outlet A ₂ leads via the hose 53 into the lower chamber 40. In this case, the lower piston side 42 is thus subjected to the higher pressure P. At the same time, input E is connected to output A. The liquid displaced from the chamber 30 can thus be discharged through the channel 39 into the line 38. The position of the switchover part 11, however, determines the direction in which the drive moves. A change in direction can only be achieved by switching the switching part 11. The control command comes from the outside in the form of a positive or negative direct current pulse and goes to an electromagnet 1 attached to the outside of the drive, which in turn generates a polarized magnetic flux generated by the current pulse. Via a core 3 passing through the cover 5, the magnetic current is conducted into the hydraulic relay in the interior of the drive, where the switching functions mentioned above are then carried out. If there is no signal, this means "Step".

REPLACEMENT LEAF If a stop signal is set, the piston 25 remains exactly where it is. In addition to this stop signal, two further signals can be set, which are also magnetically transmitted by magnetic fields with defined north or south poles. These defined magnetic fields move the changeover part 11, which has a polarized permanent magnet 10, upwards or downwards accordingly. If the current pulse in the magnet 1 is interrupted, the magnetic field is reduced and the valve cone 9a is pressed into the closed position by a compression spring 7. The flow through inlet E at the hydraulic pilot valve is thus interrupted, and pressure equalization occurs in chambers 30 and 40, causing piston 25 to stop immediately. The drive can thus be moved into any position with three pulses. Depending on requirements, the drive according to the invention can also be equipped with several stages, ie with several pistons. In this embodiment, too, however, only a hydraulic relay 70 is required for the control function. Designs with the device for manual adjustment shown in FIG. 5 are also conceivable. This has a disc 65 which is rotatably mounted on the cover 5 about an axle 66. Two magnets 63 and 64 are fastened on the disk 66 at a distance from the axle journal 66 and can be displaced by rotating the disk 65 in such a way that a magnet 63 or 64 is located above the hydraulic relay 70. Depending on the display

REPLACEMENT LEAF When the disc 65 is in position, the relay 70 is exposed to a magnetic south pole, a magnetic north pole or no influencing magnetic field.

Figures 6 to 8 show a variant of the drive, which is even simpler in construction. It is also important here that in a valve body 105, before and after a constriction 130 in the valve seat 120, a higher pressure P ^ and a lower pressure P2 of the medium are used to move a piston 103. In this embodiment, an open chamber 123 is provided, which is permanently connected to the medium with the lower pressure P2 via a channel 122. A closed chamber 124 can now optionally be connected via a channel 121 to the medium area with the pressure 2 or via the channel 122 to the medium area with the pressure P --_.

This is controlled with two control valves A and B, each of which has an electrical coil 106, a magnetic core housing 108, a compression spring 12, a magnetic core 7 with a rubber seat 113 and a seat shown on a larger scale in FIGS. 7a and 7b 109 have. The two seats 109 are each firmly connected at the upper end with spring washers 115 to an upper housing part 102. With the lower end, the seats 109 engage in bores 123 and 128 of the piston 103 and are slidably sealed against the piston with O-rings 116.

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As FIGS. 7a and 7b show, the seats 109 each have a through hole 109a which is closed by the rubber seat 113 when the coil 106 is not energized and is continuous for the medium when the coil 106 is excited and the rubber seat 113 is thus lifted off. When the rubber seat 113 is lifted off, the medium can flow through the channel 121 or 122, through the bore 123 or 128 and the bore 109a and through lateral recesses 109c in the upper part of the seat 109 into the closed chamber 124.

As FIGS. 6 and 8 show, the valve body 105 is screwed to the housing body 101 via an adapter 104. The piston 103 has a shaft 124 which, with a lower opening 125 of the channel 121 in each position of the piston 103, projects through the valve seat 120 into the medium with the higher pressure P-j_.

The piston 103 is sealed with a roller membrane 110 against the housing cover 101. In contrast to the membrane of the first embodiment, the roller membrane 110 is open. The tubular membrane 110 is connected at its edges to the piston 103 and the housing body 101 by means of steel spring rings 126. The diaphragm 110 is placed on the piston 103 in a groove in which it is held pressure-tight by the built-in steel spring 126. As can be seen from FIGS. 6 and 8, the membrane 110 is open to the system break P2. It is now essential that the membrane 110 by a large

REPLACEMENT LEAF Pressure surface 110a to the wall of the housing body 101 keeps itself in position. This seal is particularly easy to attach and causes only very little resistance when the piston moves.

The mode of operation of the drive according to FIGS. 6 to 8 is explained below:

As can already be seen from the above explanations, the drive according to the invention is based on using the pressure differences in the medium before and after the constriction 130 in the valve seat 120.

In order to move the piston 103 upward from the position according to FIG. 6 and thus to open the valve, the control valve A is opened and therefore the closed chamber 124 is connected to the medium region with the lower pressure. Since the higher pressure Pi prevails in the open chamber 123, the piston 103 is moved upward against the force of a compression spring 111. By closing the control valve A, the piston 103 can be held in any intermediate position. If the control valve A remains open, the piston 103 moves into the end position shown in FIG. 8. If this end position has not yet been reached, P2 is connected to the closed chamber 124 and passes through the inner channel of the piston 103, via the bore 109a in the seat 109 and laterally past the seat 109 to the chamber 124. The end position is now this connection

REPLACEMENT LEAF interrupted by a rubber pad 117 of the piston 103. A pressure equalization now forms in the closed chamber 124 and thus protects the membrane 110 from excessively high pressure differences. This safety function protects the Membr 110 from damage caused by high pressure differences in the two chambers.

In order to move the piston 103 from the end position according to FIG. 8, the control valve B is opened when the control valve A is closed. The closed chamber 124, like the open chamber, is now in communication with the pressure * L. The same pressure therefore prevails in both chambers, so that the piston 103 is moved downward by the compression spring 111 in the view according to FIG. 8.

Despite considerable advantages of the drive according to the invention, this can be implemented with a few simple and robust components. According to the invention, a drive is thus created which not only takes account of the control requirements in an outstanding manner, but is extremely economical and versatile in use due to its low energy consumption in operation.

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Claims

P a t e n t a n s r u c h e

Controllable drive with an actuator (24, 26, 114, 120) which can be connected to a line (38) carrying a medium, with a cylinder (5, 8, 101) a piston (25, 103) which can be displaced in a cylinder and which can be connected to the actuator (24, 26, 114, 120) is operatively connected and divides the cylinder space into a first cylinder chamber (30, 124) and a second cylinder chamber (40, 113), characterized in that two channels (33, 39, 121, 122) are provided with which different pressures (P ^* L, P2) in the area of the actuator (24, 26, 114, 120) before and after a constriction (130) can be transferred into the chambers (30, 124; 40, 123).

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2. Drive according to claim 1, characterized in that the piston (25) with roller membranes (15, 19) is sealed against the cylinder housing, the roller membranes (15, 19) on the piston (25) or on the cylinder housing (8) be¬ are consolidated and each enclose an annular space that can be filled with the medium.

3. Drive according to claim 2, characterized in that the piston (25) has connecting channels (31, 32) via which the inner surfaces of the rolling membranes (15, 19) with the higher media pressure (P,) can be acted upon.

4. Drive according to one of claims 1 to 3, characterized gekenn¬ characterized in that the switch (70) has a Ventilkegeϊ (9) which can be switched with an external control command by means of an electromagnet (1).

5. Drive according to claim 4, characterized in that the control command occurs in the form of a positive or negative direct current pulse or pulsating direct current pulse and that a switching part (11) is provided which has a polarized permanent magnet (10) which, depending on whether it is a through faces the control command generated north or south pole, is attracted or repelled.

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6. Drive according to claim 4 or 5, characterized in that the switch (1-12, A ,, A ₂ , E .., E ₂ ) is located in the Druck¬ space of the cylinder.

7. Drive according to claim 5, characterized in that the switching part (11) has two positions, an input (E,) being connected to an output (A,) in a first position and the input (A,) in a second position. E,) is connected to a second output (A ₂ ), that a second input (E ₂ ) is provided, which switches in exactly the opposite way to the first input (E,), so that whenever the first input (E ,) is connected to the second output (A ₂ ), the second input '(E ₂ ) is connected to the first output (A ₁ ) and the first input (E.) is connected to the first output (A ..) ver ¬ connected, the second input (E ~) is connected in parallel to the second output (A_), the first input (E,) with the one channel (33) and the second input (E_) with are connected to the other channel (39) and the first outlet (A,) is connected to one cylinder chamber (30) and the second outlet (A ₂ ) to the other cylinder chamber (40) ,

8. Drive according to one of claims 1 to 7, characterized gekenn¬ characterized in that it is a hydraulic drive and the switch is a hydraulic relay.

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9. Drive according to claim 1, characterized by an open chamber (123) which is permanently connected via a channel (122) to the lower pressure range of the medium and a closed chamber (124) via channels (122, 121) and control valves (A , B) can optionally be connected to the lower or the higher pressure range of the medium.

10. Rolling membrane, in particular for a drive according to claim 1, characterized in that it is open and has a pressure surface which is pressed against a wall of the cylinder housing or the piston by a permanently higher pressure.

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