DE9218310U1 - Swivel drive - Google Patents

Description

P5236 - 4 -

Swivel actuator for quick-closing or quick-opening valves

The invention relates to a rotary actuator for quick-closing and quick-opening valves.

Quick-closing or quick-opening valves are usually designed as flaps or ball valves for safety-relevant tasks, as they only require a swivel path of 90° to close or open. Pneumatic piston drives are now common as drives for such valves, as they allow short actuation times. However, operation with compressed air requires a high level of mechanical equipment and piping in order to have this compressed air available at the valve installation point. The mechanical components of such drives are subject to very high wear with short actuation times. The well-known electrical valve swivel drives are too slow for such tasks. Electromagnets, on the other hand, are only suitable for this task in very limited individual cases.

The object of the present invention is to create a rotary actuator for quick-closing and quick-opening valves that can be manufactured with few components and at low cost and that works reliably.

This task is solved by a rotary actuator with a torsion bar and an electrical target-actual comparison control, which is characterized in that

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the torsion bar made of shape memory alloy, which is firmly clamped on one side to a fixed point and is connected at its output end to a connecting coupling of an apparatus to be driven, and that a heating device is provided.

The invention can be used as an electrical quick-closing or quick-opening swivel drive, which uses the spring effect of a memory material with minimal use of mechanical components and switches a valve with a 90" swivel movement from the open position to the closed position and vice versa with a very short actuation time. The torsion bar is heated by an electrical heater that is connected to the entire torsion bar, or the torsion bar, e.g. made of a nickel-containing material, acts as a heater even when current is applied. The temperature of the torsion bar can, e.g., be kept just below the jump temperature, so that only a short-term increase in temperature is required to switch over.

The rotary actuator according to the invention also has the advantage that it is stable, wear-resistant and quiet. It is also suitable for control tasks. Another advantage is that it can be designed so that it returns to the safety position in the event of a power failure. It is also suitable for 100% tight encapsulation.

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A further advantage of the invention is that the swivel drive is practically maintenance-free, since the entire swivel drive essentially consists of only a torsion bar made of metal with shape memory and an electric heater. This swivel drive is therefore particularly suitable for installation in places that are difficult to access.

The torsion bar with shape memory can be dimensioned according to the required swivel forces.

The calculation formulas can be found in the relevant technical textbooks such as Dubbels Taschenbuch für den Maschinenbau, under torsion springs.

For the selection of shape memory alloys, please refer to the following publications:

Technical Academy Wuppertal, Sem. No. 510220020 "Possible uses of shape memory alloys (memory alloys), properties, processing, applications, venue Wuppertal-Elberfeld, Hubertusallee 18, available from Technical Academy Wuppertal, 5600 Wuppertal 1, Hubertusallee 18, the content of which is hereby made the subject of the present disclosure. - A copy of the mentioned publication is attached to the present application.

Superelastic behavior of shape memory alloys", in BLECH ROHRE PROFILE 38 (1991), especially pages 782 - 785.

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According to a further development of the invention, the heating is divided into several zones over the entire length of the torsion bar, which can be controlled individually.

The individual heating zones can, for example, be activated one after the other, so that the memory effect only ever affects the individual heated zone. This makes it possible to switch the entire stroke with a delay, which can then be regulated via a controller depending on the angle of rotation. The swivel drive of this embodiment of the invention is suitable as a control drive.

The torsion bar can be made of shape memory alloy with two-way effect.

Conveniently, the two effects are two different torsion states of the torsion bar.

According to one embodiment of the present invention, the free end of the torsion bar can be twisted by 90" relative to the clamped end by heating.

The torsion bar can have a rectangular cross-section.

The torsion bar in its fixed point holder is conveniently equipped with a maximum torque safety device that disengages as soon as a maximum torque is exceeded, thus making it impossible to overload the bar.

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The heating can be controlled using known electrical controls. An external controller can be used to determine the swivel position of the torsion bar depending on this controlled variable. These controlled variables can be, for example, pressure, quantity or temperature, which are influenced by the swivel position of the drive and thus the driven valve.

According to another development of the invention, the alloy of the torsion bar is selected so that it assumes its one end position at normal ambient temperature. This allows the safety position to be predetermined in the event of a power failure.

According to another development of the invention, the alloy of the torsion bar is selected so that it assumes its other end position at an increased temperature.

The invention is described in more detail below using an embodiment and in conjunction with a figure.

The figure shows a torsion bar 1 which is firmly clamped to a fixed point 2 and whose opposite end is connected to a connecting coupling 3. The middle area of the torsion bar 1 is surrounded by a heating system which is only indicated schematically and which is divided into heating zones 4 which can be controlled individually or in combination.

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The position of the coupling-side end of the torsion bar 1 is indicated by a position sensor 5 (e.g. 4 -22OmA = 0-100% travel). A controller 6 carries out an actual value-setpoint comparison and controls the heating of the individual heating zones 4 accordingly.

At the right end of the torsion bar, a cooling system 8 is also provided, which enables a faster return of the torsion bar to its non-heated starting position.

At 9, a maximum torque protection device is provided, which disengages when a maximum torque is exceeded. This safely prevents the torsion bar from being overloaded.

The torsion bar can be quickly changed to its other state by simultaneously heating all heating zones 4 and thus quickly twisted. However, it is also possible to heat up zone by zone using the target-actual comparison control and thus to carry out a rotational path of e.g. 90° or 180° through a gradual thermoelastic martensitic transformation and to move a fitting, a flap or a tap via the connection coupling 3.

Claims (12)

REFERENCE NUMBER: P 5236 Applicant: Johannes Erhard, H. Waldenmaier Erben Süddeutsche Armaturenfabrik GmbH & Co. Meeboldstraße 22 7920 Heidenheim 1 Part-turn actuator Protection claims: 1. Rotary actuator for quick-closing or quick-opening valves with rotary actuator with a torsion bar and an electrical target-actual comparison control, characterized in that the torsion bar (1) consists of shape memory alloy, is firmly clamped on one side to a fixed point (2) and is connected at its output-side end to a connecting coupling (3) of an apparatus to be driven, and that a heating device (4) is provided. 2. Swivel drive according to one of the preceding claims, characterized in that the heater (4) is divided over the entire length of the torsion bar (1) into several zones (4) which can be controlled individually. P5236 - 2 - 3. Swivel drive according to claim 1, characterized in that the torsion bar (1) consists of shape memory alloy with two-way effect. 4. Swivel drive according to one of the preceding claims, characterized in that the two effects are two different torsional states of the torsion bar (1). 5. Swivel drive according to one of the preceding claims, characterized in that the free end (3) of the torsion bar can be twisted by 90" relative to the clamped end (2) by heating. 6. Swivel drive according to one of the preceding claims, characterized in that the torsion bar (1) has a rectangular cross-section. 7. Swivel drive according to one of the preceding claims, characterized in that the torsion bar cross-section is designed so that it transmits a predetermined torque during the rotary movement which is below its permissible material load limit. 8. Swivel drive according to one of the preceding claims, characterized in that the torsion bar (1) in its fixed point holder (2) is equipped with a maximum torque safety device (9) which disengages as soon as a maximum torque is exceeded, thus making it impossible to overload the bar. P5236 - 3 - 9. Swivel drive according to one of the preceding claims, characterized in that the heating is controlled via known electrical control. 10. Swivel drive according to one of the preceding claims, characterized in that the alloy of the torsion bar (1) is selected so that it assumes its one end position at normal ambient temperature. 11. Swivel drive according to claim 10, characterized in that the alloy of the torsion bar is selected so that it assumes its other end position at an increased temperature. 12. Swivel drive according to one of the preceding claims, characterized in that the swivel position of the torsion bar (1) is determined by setpoint values specified by an external controller.