KR20130111398A - Pressure switching device with electromagnetically controllable actuating member for diagnosing the functioning of a switching element of the pressure switching device - Google Patents

Abstract

The present invention relates to a pressure switching device (1) comprising a housing (2), a pressure chamber (3) and a switching element (71), wherein the pressure chamber is connected to an operating pressure source And is limited by the movable adjusting member 5, which is implemented in a pressure sealing manner and is dependent on the applied operating pressure p. The switching element is disposed outside the pressure chamber and can be operated through the adjusting member when a predetermined minimum pressure value is reached. The pressure switching device includes a plunger coil (92) housed in the housing and capable of being electrically excited, and a solenoid (100) movably received in the housing through the plunger coil (92) And an actuator tappet 91 having a plunger 10 (solenoid plunger). According to the present invention, the actuator tappet is also an adjusting member tappet 73 which mechanically interacts with the adjusting member at the same time. The solenoid plunger was formed and arranged in relation to the plunger coil such that at least a portion of the solenoid plunger is inserted into the plunger coil beyond the maximum working distance of the adjustment member when the plunger coil is excited. The actuator tappet has a first switching element and a switching operation part (15) for directly operating the additional second switching element. When the predetermined minimum pressure value is reached, the switching operation portion and the two switching elements are turned on only when the predetermined minimum pressure value is not reached, so that no switching element among the two switching elements can be operated, So that only the switching element can be operated and only the second switching element can be operated irrespective of the operating pressure applied when the plunger coil is excited.

Description

TECHNICAL FIELD The present invention relates to a pressure switching device having an electromagnetically controllable adjusting member for diagnosing a function of a switching device of a pressure switching device. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switching device having an electromagnetically controllable adjusting member,

The present invention relates to a pressure switching device comprising a housing, a pressure chamber and a switching element, wherein the pressure chamber can be connected to an operating pressure source by means of a connection, Limited by the movable adjustment member. The switching element is disposed outside the pressure chamber and can be operated through the adjusting member when a predetermined minimum pressure value is reached. The pressure switching device includes a plunger coil accommodated in the housing and electrically excited and a solenoid plunger movably received in the housing through the plunger coil for operating the switching device Equipped actuator tappet.

DE 101 04 438 A1 discloses a safety circuit breaker with dual safety shut-off function driven by various physical parameters. A pressure sensitive area is formed by the connecting flange and the membrane contained within the connecting flange, and the compressive force is transmitted to the pressure pin in the pressure sensitive area. A fixing bolt is disposed in the same axial direction as the pressure pin, and an electromagnetic field generated in one coil acts on the fixing bolt. In the case of one fault, one slide is released through the fixing bolt by the excitation of the coil through a control device connected in front of which an arbitrary signal, preferably a temperature signal, is provided, The implemented electrical contacts are opened. Regardless, the slide is also released through the pressure pin in the event of unacceptable overpressure. The release operation of such a slide reduces the switching operating power applied to the electrical contacts in the case of normal operation.

The pressure switching device is responsive to pressure changes in the gaseous medium or liquid medium of the working pressure source, for example, as in a pipeline. In this case, the mechanical action of the medium on the membrane or piston which actuates the switching element upon pressure rise is often used. When the pressure is constant, the position of the membrane or the piston remains unchanged. Mechanically operated switching elements, such as, for example, microswitches, are used for various safety reasons, and such switching elements are also associated with wear, since they are associated with contact.

Alternatively, it is possible to use an electronic switching device which operates in a contactless manner, such as a fork light barrier, an inductive proximity switch or the like. However, in such a case, it is necessary to design an evaluation electronic device such as a method using two processors, for example.

In order to be able to "safely" stop pressure-affected pipelines, it is necessary to safely detect the pipeline pressure, ie to safely detect pressure drop conditions below the pre-provided minimum pressure value. The range of operating pressure values is preferably in the range of one bar or in the range of two bars, for example 20 bar. The minimum pressure value is preferably set to half of the operating pressure value according to the operation, for example, 10 bar.

The expression "safe" in connection with the above description means that the technical design of the elements necessary for the above purposes must meet safety technical relevant requirements. In practice, to meet the highest level of safety category, PL e according to EN ISO 1349-1 for machines in accordance with the latest Machinery Directive 2006/42 / EG; It is necessary to comply with SIL 3 according to EN 61508 or 62061. In this case, devices capable of diagnosing the function are also needed.

In order to meet such safety technical requirements, various redundancy principles are currently applied. This principle implies that for reasons of redundancy, two pressure switching devices can be used for pressure monitoring, so that if one pressure switching device fails, another additional pressure switching device is used . On the other hand, in order to avoid a systematic simultaneous failure in two pressure switching devices, the pressure switching devices must be manufactured by different manufacturers. At this time, it is considered that the probability of a double failure is very small when the configuration, structure, design and manufacturing are different.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pressure switching device with improved diagnostic capability.

This problem is solved by the objects of the independent claim. Preferred embodiments of the invention are described in the dependent claims.

According to the present invention, the actuator tappet is also an adjusting member tappet which mechanically interacts with the adjusting member at the same time. The solenoid plunger was formed and arranged in relation to the plunger coil such that at least a portion of the solenoid plunger is inserted into the plunger coil beyond the maximum working distance of the adjustment member when the plunger coil is excited. The actuator tappet includes a first switching element in addition to the solenoid plunger and a switching operation portion for directly operating the additional second switching element. When the predetermined minimum pressure value is reached, the switching operation portion and the two switching elements are turned on only when the predetermined minimum pressure value is not reached, so that no switching element among the two switching elements can be operated, So that only the switching element can be operated and only the second switching element can be operated irrespective of the operating pressure applied when the plunger coil is excited.

The observed switching elements are, in particular, switching elements which can be mechanically actuated and associated with a contact, for example a microswitch.

The combination of a plunger coil and a solenoid plunger may also be referred to as a plunger coil magnet, a plunger magnet, a tensioning magnet, or a lifting magnet. The solenoid plunger is configured such that at least a portion of the solenoid plunger is inserted into the plunger coil to actuate the second switching device when the plunger coil is electrically excited by use.

The essence of the present invention is that it is possible to reliably inspect the elements of the pressure switching device which are mostly exposed to abrasion, that is to say the (first) mechanical switching elements, under certain practical conditions to some extent, It also meets the safety regulations and safety standards mentioned.

In the present invention, it is possible to inspect the (first) switching element for normal switching operation not only when the operating pressure source is in the no-pressure state but also under the influence of the pressure. This possibility is achieved by moving the common adjusting member and the actuator tappet further beyond the adjusting or operating distance that can be maximized by the adjusting member. The confirmation message for the next executed diagnosis is available through the second switching element. The failure of the first switching element is detected when the switching state of the first switching element does not normally change when the plunger coil is electrically triggered.

This content is associated with the great advantage that the interconnection design associated with the safety of the second pressure switching device and the second pressure switching device can be omitted.

It is also advantageous that one plunger magnet, which can be electrically triggered, can be simply integrated within the pressure switching device. The solenoid plunger is preferably disposed approximately at the center with respect to the longitudinal direction of the actuator tappet. The solenoid plunger was made from a magnetizable fabrication material, preferably iron or steel. The solenoid plunger is also matched to the dimensions of the plunger coil so that the solenoid plunger can also move in the operating direction of the adjusting member, even in the structural dimension. In addition, the entire magnetic circuit of the plunger magnet, which can be electrically excited, is designed such that this magnetic circuit can overcome the relatively small contact spring power of the second switching element.

According to one embodiment of the present invention, the adjustment member can be subjected to compressive stress by the spring power, so that the first switching element can be operated after a predetermined minimum pressure value is reached. Preferably, the compressive stress by the spring element is caused, for example, by a cylinder spring or a disk spring. The pressure switching device may also be provided with means for adjusting the minimum pressure value, for example an adjusting screw for adjusting the compressive stress distance in the spring element.

According to a further embodiment of the present invention, in order to operate one switching element among the two switching elements, switching operating power may be provided simultaneously to the actuator tappet and the adjustment member tappet, respectively. The expression "operation" of one switching element in connection with the above description means that the switching operating power for opening or closing the electrical contact of the one switching element must be actively provided against the contact spring power of the switching element .

According to a further embodiment of the present invention, the switching element has a pair of switching contacts that are electrically closed when switching operating power is provided. Switching elements of this type are also referred to as closures.

According to a further embodiment of the present invention, the switching element has a pair of switching contacts which are electrically opened when switching operating power is provided. Switching elements of this type are also referred to as openers. The switching elements described above may be a combination of a closure and an opener. Thus, one switching element may have multiple switching contact pairs, for example two or three. The reliability of the switching element is enhanced by the corresponding serial or parallel connection. Alternatively or in addition, the pressure switching device may comprise two or more switching elements, for example two micro switches, which are connected in series or in parallel to increase switching reliability.

The expression "normal" change of the switching state associated with the above content means that, when subjected to pressure, and thus if a permanent actuation of the first switching element has already been made, during the subsequent triggering period of the plunger magnet, 1 < / RTI > switching element must also be replaced, i. E., That the first switching element should no longer be operated. When the triggering operation of the plunger magnet is terminated again to terminate the diagnostic process, the same contents as above are applied in reverse chronological order. Thereby, in other cases, the defective switching characteristic of the first switching element can be clearly detected.

Alternatively, if the plunger magnet is triggered in the absence of pressure and thereby resulting in a permanent non-actuation of the first switching element, the switching state of the first switching element can only be changed for a short time. Therefore, a signal sequence of "non-operation-operation-inactivation" must be detected in the first switching element until after the operation of the second switching element is detected even later. When the triggering operation of the plunger magnet is terminated again to terminate the diagnostic process, the same contents as above are applied in reverse chronological order. Otherwise, the defective switching characteristic of the first switching element can be clearly detected even in this case as in the case described above.

The reason why such a result may be caused is that the switching contacts of the first switching element can be bonded or welded when the switching element is formed as a closure. Alternatively, if the switching element is formed as an opener, one cause may be that the contact may be contaminated by a high-impedance transition process, for example, even though the switching contact is "closed." In this case, the non-operating state of the second switching element, which is subsequently performed when the operating state of the second switching element and the triggering process of the plunger magnet is terminated, indicates that the first switching element has its normal switching characteristic And that it has been tested against. Therefore, the diagnosis could be effectively carried out.

Such a type of pressure switching device can be used for the purpose of particularly safely detecting a state in which the pressure has dropped below the minimum pressure value of the working pressure source which can preferably be determined in advance. The pressure switching device can be used particularly for the purpose of detecting a pressure drop state occurring in an operating pressure source formed as a pipeline.

The present invention is described in detail with reference to an embodiment:
1 to 3 show one embodiment of the pressure switching device according to the invention in different operating states.

Fig. 1 shows one embodiment of a pressure switching device 1 according to the present invention in a pressureless operating condition. The membrane is used as the adjusting member 5. [ Alternatively, a piston or other suitable means, not shown in the figures, can also be used as the adjusting member 5. Most of the elements of the pressure switching device-except for the switching elements-and the pressure switching device 1 are preferably formed substantially rotationally symmetrically about the main axis indicated by the dotted line.

A connecting part formed as part of the housing 2 of the pressure switching device 1 for connection to an operating pressure source is denoted by the reference numeral 21. By means of a movable adjusting element 5, which is implemented in a pressure-sealing manner and which depends on the applied operating pressure p, the pressure chamber limited in the form of a membrane in this figure is denoted by reference numeral 3. The inner space of the housing 2, which is separated from the pressure chamber 3 in accordance with the pressure and is actually in a pressure-free state, is indicated by reference numeral 4.

The pressure switching device 1 also comprises a first switching element 71 and an additional (second) switching element 72, which are arranged on the circuit carrier 30, outside the pressure chamber 3 And can be operated through the adjusting member 5. In this embodiment, the membrane 5 is adjacent to the adjusting member tappet 73, so that the adjusting operation of the membrane 5 is indirectly transmitted to the first switching element 71 upon the change of pressure in the operating direction. It becomes possible. The switching elements 71 and 72 shown in the figure are, for example, micro switches. The micro switch is also subjected to compressive stress by the spring element 8 to provide a spring compressive stress F. Thereby, the minimum pressure value at which the first switching element 71 is actuated can be set.

In the unpressurized state of the working pressure source shown in the drawing, that is, in the state in which the pressure p of the working pressure source has a pressure value exceeding a predetermined or predetermined minimum pressure value of the pressure switching device 1 The adjusting member 5 is in the left position by the inherent compressive stress of the membrane 5 shown in the figure and in particular by the compressive stress F of the spring element 8. [ Therefore, the first switching element 71 is also not operated.

According to the present invention, the actuator tappet 91 is also an adjusting member tappet 73 which already co-operates mechanically with the adjusting member 5 at the same time. In this embodiment the actuator tappet 91 and the adjusting member tappet 73 form one component unit, in particular an integral component unit. The two parts 73, 91 may be separate parts arranged in succession inside the housing 2 so as to be movable in the pressure actuation direction. Thus, the adjustment member tappet 73 can have, for example, an end section 11 on the side of the adjustment member, a middle section 12 of the cylindrical shape, and an adjacent additional section not shown in the figure. At this time, the actuator tappet 91 has a solenoid plunger 13, an intermediate portion 14 and a switching operation portion 15.

In this case, the actuator tappet 91 is a portion of a plunger magnet 9 formed of a plunger coil magnet. The plunger magnet has a plunger coil 92 and an actuator tappet 91 housed in the housing 2 of the pressure switching device 1 and the actuator tappet 91 is movably received within the housing 2 And passes through the plunger coil 92. The plunger coil 92 consists of one coil body 93 or one insulator 94 surrounding one coil and its surroundings. The actuator tappet 91 has a solenoid plunger 10 and a switching actuator 15 for actuating the first switching element 71 and the further second switching element 72. The switching operation part 15 may be integrated within the actuator tappet 91. [ The solenoid plunger 10 is also configured such that when the plunger coil 92 is electrically excited, at least a portion of the solenoid plunger 10 is in contact with the plunger coil 92 beyond the maximum working distance of the adjusting member 5, And the plunger coil 92 is inserted and inserted into the plunger coil. As a magnetic core for inducing a magnetic field, a housing part, which is embodied in two parts and is denoted by reference numeral 22, is used. The housing portion 22 is made from a magnetizable material, particularly iron or magnetic steel. A magnetic yoke extending radially inward is denoted by the reference numeral 23 as part of the housing part 22. The magnetic yoke can be used to guide the magnetic field generated by the plunger coil 92 toward the solenoid plunger 10 so that the magnetic field can be closed through the solenoid plunger 10 as a result.

In the unpressurized state shown in the drawing, the common adjusting member- and actuator tappet 73, 91 are moved to the left by the spring compressive stress F. Accordingly, similarly, the switching operation part 15 moving together does not engage with the switching button 50 of the two switching elements 71 and 72. [ As a result, the two switching elements 71 and 72 are not operated. At this time, when the predetermined minimum pressure is not reached, the switching operation part 15 and the two switching elements 71 and 72 are turned off so that no switching element can operate in the two switching elements 71 and 72 Respectively.

2 shows a pressure switching device 1 according to the present invention in the case where the pressure p of the working pressure source has a pressure value exceeding a predetermined or predetermined minimum pressure value of the pressure switching device 1 Giving. The common adjusting member and actuator tappet 73, 91 are moved to the right in the actuating direction by an adjusting power S acting on the adjusting member 5 and greater than the spring compressive stress F. [ At this time, for example, the first cam 16 provided on the side of the switching operation portion 15 deflects the switching button 70 of the first switching element 71 to the switching operation. The second switching element 72 remains unactuated and in this case the switching operation part 15 and the two switching elements 71 and 72 reach the minimum pressure The first switching elements 71 are mutually disposed so that only the first switching elements 71 can be operated. This arrangement can be achieved by changing the position of the second switching element 72 in the example of FIG. 4 with respect to the first switching element 71, so that the switching button 72 of the second switching element 72 (Not yet deflected) by the second cam 17 of the switching actuating part 15. [0050] In this embodiment, the switching actuating part 15 has one cam 16, 17 which is common to the two switching buttons 70. Alternatively, the switching actuating part 15 may have two cams 16, 17 displaced in the actuating direction. At this time, the switching buttons 70 of the two switching elements 71 and 72 may be disposed at the same position in the axial direction with respect to the main axis.

Further, the pressure switching device 1 is formed such that the maximum working distance can not be exceeded by the adjusting member 5. [ Thus, the maximum operating-or adjustment distance has been limited. Such a restriction is made in the example of FIG. 4 by a stopper inside the housing part 21, which stops the movement of the adjusting member 5 or the membrane 5 to the right. At this time, the adjoining adjustment members and the actuator tappets 73 and 91 remain in the positions shown in the figure even when the operating pressure value further rises. The adjusting member side end section of the common adjusting member- and actuator tappet 73, 91 is denoted by the reference numeral 11, which is coupled inside the housing part 21 through a recess, Adjacent the membrane (5) to deliver the distance.

Fig. 3 shows a pressure switching device 1 according to the present invention in a diagnostic situation. Regardless of whether the operating pressure p is applied or not, when the plunge coil 92 is electrically excited, at least one portion of the solenoid plunger 10 is moved beyond the maximum working distance of the adjusting member 5 And is inserted into the plunge coil 92. Thereby, the second switching element 72 is operated by the second cam 17, while the first switching element 71 is not operated. When the excitation of the actuator 9 is made from the pressureless operating state, the first switching element 71 starts to move from the non-operating state to the first cam 16 after a short period of operation, It does not work anymore by the passing action. If the excitation of the plunger magnet 9 is made from the operating state under the influence of the pressure, the first switching element 71 starts from the operating state while the plunger magnet 9 is being excited, .

During current excitation of the plunger magnet 9, the middle portion 13 of the solenoid plunger 10 is inserted into the plunger coil 92 in the actuation direction of the adjusting member 5. This mechanical motion is such that the magnetic field passes through the left magnetic yoke 23, further through the cylindrical magnetic flow portion 12, through the middle portion 13, and further into the right truncated right magnetic flow portion ( 14) and conversely through the right magnetic yoke 23, as long as it can be closed by much less magnetoresistance. Finally, the switching actuating member 15 also has a pack hole for receiving the spring element 8.

1: pressure switching device 2: housing
3: pressure chamber 4: internal space, pressureless space
5: adjusting member, membrane 6: sealing means, O-ring
8: Spring element, cylinder spring, compression spring
9: actuator, plunger magnet, plunger coil magnet
10: Solenoid plunger, adjusting member tappet
11: adjusting member side end section, bolt end
12, 14: magnetic flow guide portion
13: Middle part, solenoid plunger part
15: switching actuator 16, 17: cam, switching operation cam
21: housing part, connection part 22: housing part, magnetic core
23: magnetic yoke 30: circuit carrier, circuit board
70: Switching button
71: first switching element, micro switch
72: second switching element, microswitch
73: Adjustable member tappet, separate tappet
91: actuator tappet 92: plunger coil
93: coil body, coil 94: insulator
A: Actuator power F: Spring compressive stress
p: pressure, working pressure S: adjustment power

Claims (5)

A pressure switching device (1) comprising:
A pressure chamber 3 and a switching element 71. The pressure chamber 3 can be connected to an operating pressure source by means of a connection 21 and can be implemented in a pressure- Is limited by the movable adjustment member 5 depending on the pressure p and the switching element 71 is arranged outside the pressure chamber 3 and when the predetermined minimum pressure value is reached, And the pressure switching device can be operated through a plunger coil 92 which can be received and electrically excited in the housing 2 and through the plunger coil 92 through the housing And an actuator tappet (91) movably housed within the housing (2) and having a solenoid plunger (10) for actuating the switching element (71)
The actuator tappet 91 is also an adjusting member tappet 73 which mechanically interacts with the adjusting member at the same time,
The solenoid plunger 10 is configured such that at least a portion of the solenoid plunger 10 is inserted into the plunger coil 92 beyond the maximum working distance of the adjusting member 5 when the plunger coil 92 is excited, And is formed and arranged with respect to the plunger coil 92,
The actuator tappet 91 has a switching operation part 15 for directly operating the first switching device 71 and the further second switching device 72,
- the switching operation part (15) and the two switching elements (71, 72)
- when no predetermined minimum pressure value has been reached, no switching element of the two switching elements (71, 72)
Only the first switching element 71 can be activated when a predetermined minimum pressure value is reached, and
- when the plunger coil (92) is excited, only the second switching element (72) can be actuated independently of the applied operating pressure (p)
Pressure switching device. The method of claim 1,
Characterized in that the adjusting member 5 is subjected to compressive stress by the spring power F, as a result, the first spring element 71 can be operated after reaching a predetermined minimum pressure value,
Pressure switching device. 3. The method according to claim 1 or 2,
Characterized in that a switching operating power can be provided to the actuator tappet (91) and the adjustment member tappet (73), respectively, in order to actuate one switching element of the two switching elements (71, 72)
Pressure switching device. The method of claim 3, wherein
Characterized in that the switching elements (71, 72) comprise a pair of switching contacts, the pair of switching contacts being electrically closed when switching operating power is provided,
Pressure switching device. The method according to claim 3 or 4,
Characterized in that the switching elements (71, 72) comprise a pair of switching contacts, the pair of switching contacts being electrically opened when switching operating power is provided,
Pressure switching device.

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