EP0173090B1 - Pressure transducer for a pressure switch or regulator - Google Patents

Pressure transducer for a pressure switch or regulator Download PDF

Info

Publication number
EP0173090B1
EP0173090B1 EP19850109478 EP85109478A EP0173090B1 EP 0173090 B1 EP0173090 B1 EP 0173090B1 EP 19850109478 EP19850109478 EP 19850109478 EP 85109478 A EP85109478 A EP 85109478A EP 0173090 B1 EP0173090 B1 EP 0173090B1
Authority
EP
European Patent Office
Prior art keywords
pressure
bimetallic
pressure transducer
spring
transducer according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19850109478
Other languages
German (de)
French (fr)
Other versions
EP0173090A1 (en
Inventor
Peter Oliver Honegger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huba Control AG
Original Assignee
Huba Control AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huba Control AG filed Critical Huba Control AG
Publication of EP0173090A1 publication Critical patent/EP0173090A1/en
Application granted granted Critical
Publication of EP0173090B1 publication Critical patent/EP0173090B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/26—Details
    • H01H35/28—Compensation for variation of ambient pressure or temperature

Definitions

  • the invention relates to a pressure transmitter according to the preamble of claim 1.
  • Such a pressure transmitter is used either to actuate a switching contact in a pressure switch or to emit a constant output signal, which can be an electrical or a pneumatic signal. It can serve as an input signal for a continuously acting controller or a two-point controller.
  • the pressure to be measured by the pressure transmitter can be a differential pressure, a negative pressure or an excess pressure.
  • the switching point can be set within a limited range.
  • the sensor element to which pressure can be applied is usually a membrane or occasionally also a piston.
  • the switching accuracy or the scanning accuracy is influenced by fluctuations in the ambient temperature.
  • the main causes of the influence are the changing flexing forces, in particular in the case of rubber membranes, and in the case of heat-expanding housings, in particular in the case of plastic parts.
  • Circuit arrangements for compensating the ambient temperature are known in the case of electronic transmitters, but these generally relate to the fluctuations caused in the electronic components, the characteristics of which largely differ from the mechanically caused fluctuations.
  • a pressure sensor of the type specified in the preamble of claim 1 is known from CH-A 528 142.
  • This known pressure sensor has a bellows as the sensor element, which acts on a microswitch via a bimetallic disc by means of a rod.
  • the microswitch which can be pivoted about an axis, is constantly pressed against an adjusting screw by a spring designed as a hinge spring, which is supported on a fixed abutment.
  • the distance between the microswitch and the actuating rod connected to the bellows or the bimetallic disc can be adjusted by means of the adjusting screw in order to change the operating point.
  • the invention is therefore based on the object of creating a pressure transmitter which is not only largely insensitive to influences from the ambient temperature, but which also has a high switching accuracy.
  • the spring serves to determine the operating point, which is largely stabilized by the bimetallic element independently of influences from the ambient temperature. Since the spring constantly exerts a force on the sensor element, the arrangement of the bimetallic element in series with the spring results in a force-dependent temperature compensation, so that in contrast to a path-dependent temperature compensation when the working point is adjusted. Relocation of the switch contact or the transmitter is required.
  • the operating point can be easily adjusted by changing the spring pressure.
  • the solution according to the invention is characterized by its simplicity and is largely applicable to already existing constructions.
  • the bimetallic element arranged in series with the spring alters the effect of the spring without resulting in displacements of the parts determining the calibration accuracy.
  • a particularly preferred embodiment according to claim 4 enables the compensation effect of the bimetal element to be compared in a simple manner by adding or removing bimetal disks.
  • the bimetal disks are lined up alternately on a mandrel as perforated disks.
  • the alternating arrangement results in a larger stroke than a similar arrangement, since the strokes of the individual disks add up.
  • An embodiment according to claim 6 not only corresponds to a structurally favorable solution, but is also associated with the advantage that the bimetallic discs prevent the spring from turning when the pressure adjusting screw is adjusted, since they can be easily rotated relative to one another. This enables the setting accuracy to be increased because disruptive deviations in the switching point are avoided by turning the spring.
  • a chamber 10 which can be acted upon by the pressure to be measured is closed off by means of a membrane 12, which is reinforced by a disk 14 on the side opposite the pressure.
  • a plunger 16 is supported on the disk 14, the opposite end of which is centered in a guide piece 20 connected to a leaf spring 18 clamped on one side.
  • a compression spring 22 engages the guide piece 20, which loads the membrane 12 serving as a pressurizable sensor element against the pressure to be measured.
  • the leaf spring 18, which acts as an actuating element is coupled at its free end to a c-shaped snap spring 24, which engages a switching contact 28 biased against a fixed contact 26.
  • the prestress of the compression spring 22 can be adjusted on a pressure adjusting screw 34, on which the compression spring 22 is supported by means of bimetallic washers 36 of a bimetallic element 38 which are curved in the manner of a plate.
  • the bimetallic disks 36 are perforated in their center and lined up alternately on a mandrel 40 which is rigidly connected to the pressure adjusting screw 34.
  • the pressure adjusting screw 34 is screwed into a thread arranged in a housing shoulder 44.
  • a piston can be provided instead of the membrane 12, which can be acted upon by the pressure of the medium to be measured against the force of the compression spring 22.
  • a plurality of switching contacts can also be provided, which switch either simultaneously or at different pressures.
  • the switch contacts can be designed as change-over switches, openers or make contacts.
  • FIG. 2 shows a detail from FIG. 1 on a larger scale.
  • FIG. 2 shows the shape of the bimetallic disks 36, which are curved like a plate spring, and their arrangement.
  • FIG. 2 shows the bimetal disks 36 in the normal position
  • the effect of the bimetal disks 36 at an elevated ambient temperature can be seen from the right half of this figure.
  • the bimetallic disks 36 are curved more strongly.
  • bimetal disks can be added or removed. Due to the alternating arrangement of the bimetallic discs 36, the compensation stroke increases by each added bimetallic disc.
  • slightly curved, round perforated disks are preferred as bimetallic disks.
  • the bimetallic element 38 formed by the bimetallic disks 36 serves as an axially movable support for the compression spring 22.
  • FIG. 3 shows, as a variant of FIG. 1, a measuring transducer 46 which emits a continuous signal depending on the approach of a tongue 48.
  • a transmitter preferably has electronic components and can, for example, inductively, capacitively or optically sense the approach of the tongue 48.
  • the tongue 48 is arranged instead of the leaf spring 18 shown in FIG. 1 and acts in the same way as the leaf spring 18 as an actuating element.
  • bimetal perforated disks lined up on the mandrel 40 it is also possible to use bimetal disks without a hole, which must be lined up in a sleeve. It is also possible to use perforated bimetal strips instead of round bimetal discs, which are lined up on a mandrel and insured against rotation.

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Measuring Fluid Pressure (AREA)

Description

Die Erfindung betrifft einen Druckgeber nach dem Oberbegriff des Anspruchs 1.The invention relates to a pressure transmitter according to the preamble of claim 1.

Ein solcher Druckgeber dient entweder zur Betätigung eines Schaltkontaktes in einem Druckschalter oder zur Abgabe eines stetigen Ausgangssignals, welches ein elektrisches oder auch ein pneumatisches Signal sein kann. Es kann als Eingangssignal eines stetig wirkenden Reglers oder eines Zweipunktreglers dienen. Der vom Druckgeber zu messende Druck kann ein Differenzdruck, ein Unterdruck oder ein Ueberdruck sein. Bei der Verwendung in einem Druckschalter ist der Schaltpunkt in einem begrenzten Bereich einstellbar. Das vom Druck beaufschlagbare Fühlerelement ist üblicherweise eine Membran oder gelegentlich auch ein Kolben.Such a pressure transmitter is used either to actuate a switching contact in a pressure switch or to emit a constant output signal, which can be an electrical or a pneumatic signal. It can serve as an input signal for a continuously acting controller or a two-point controller. The pressure to be measured by the pressure transmitter can be a differential pressure, a negative pressure or an excess pressure. When used in a pressure switch, the switching point can be set within a limited range. The sensor element to which pressure can be applied is usually a membrane or occasionally also a piston.

Bei einem derartigen Druckgeber wird die Schaltgenauigkeit bzw. die Abtastgenauigkeit durch Schwankungen der Umgebungstemperatur beeinflusst. Hauptursachen der Beeinflussung sind die sich ändernden Walkkräfte, insbesondere bei Gummimembranen, und sich bei Wärme ausdehnende Gehäuse, insbesondere bei Kunststoffteilen. Bei elektronischen Messumformern sind zwar Schaltungsanordnungen zur Kompensation der Umgebungstemperatur bekannt, jedoch beziehen sich diese in der Regel auf die in den elektronischen Bauelementen verursachten Schwankungen, deren Charakteristik sich von den mechanisch verursachten Schwankungen weitgehend unterscheidet.In such a pressure transmitter, the switching accuracy or the scanning accuracy is influenced by fluctuations in the ambient temperature. The main causes of the influence are the changing flexing forces, in particular in the case of rubber membranes, and in the case of heat-expanding housings, in particular in the case of plastic parts. Circuit arrangements for compensating the ambient temperature are known in the case of electronic transmitters, but these generally relate to the fluctuations caused in the electronic components, the characteristics of which largely differ from the mechanically caused fluctuations.

Ein Druckgeber der im Oberbegriff des Anspruchs 1 angegebenen Art ist aus der CH-A 528 142 bekannt. Dieser bekannte Druckgeber weist als Fühlerelement einen Faltenbalg auf, der über eine Bimetallscheibe mittels einer Stange auf einen Mikroschalter einwirkt. Der um eine Achse schwenkbare Mikroschalter wird durch eine als Scharnierfeder ausgebildete Feder, die sich an einem festen Widerlager abstützt, ständig gegen eine Justierschraube gedrückt. Mittels der Justierschraube ist der Abstand des Mikroschalters von der mit dem Faltenbalg bzw. der Bimetallscheibe verbundenen Betätigungsstange zur Veränderung des Arbeitspunktes einstellbar. Bei nicht betätigtem Mikroschalter ist deshalb ein Abstand zwischen der Betätigungsstange bzw. einem mit der Betätigungsstange verbundenen Hebel und dem Stössel des Mikroschalters vorhanden. Erst bei einer ausreichenden Druckbeaufschlagung des Faltenbalges dringt die Betätigungsstange mit dem Hebel bis zum Stössel des Mikroschalters vor, um diesen zu betätigen. Bei einer Verstellung des Arbeitspunktes muss der ganze Mikroschalter verschwenkt werden. Die dafür vorgesehene Justierschraube befindet sich inmitten des Apparates, so dass sie nur schwer zugänglich ist. Ferner muss die Kraft zur Rückstellung der Betätigungsstange durch den Faltenbalg aufgebracht werden, sodass die Schaltgenauigkeit beim Zurückschalten von der Rückstellkraft des Mikroschalter-Stössels und von derjenigen des Faltenbalges abhängig ist. Beide Faktoren können die Schaltgenauigkeit nachteilig beeinflussen.A pressure sensor of the type specified in the preamble of claim 1 is known from CH-A 528 142. This known pressure sensor has a bellows as the sensor element, which acts on a microswitch via a bimetallic disc by means of a rod. The microswitch, which can be pivoted about an axis, is constantly pressed against an adjusting screw by a spring designed as a hinge spring, which is supported on a fixed abutment. The distance between the microswitch and the actuating rod connected to the bellows or the bimetallic disc can be adjusted by means of the adjusting screw in order to change the operating point. When the microswitch is not actuated, there is therefore a distance between the actuating rod or a lever connected to the actuating rod and the plunger of the microswitch. Only when the bellows is sufficiently pressurized does the actuating rod with the lever advance to the plunger of the microswitch in order to actuate it. The entire microswitch must be swiveled when the working point is adjusted. The adjustment screw provided for this is located in the middle of the device, making it difficult to access. Furthermore, the force for resetting the actuating rod must be applied by the bellows, so that the switching accuracy when switching back depends on the restoring force of the microswitch plunger and that of the bellows. Both factors can adversely affect the switching accuracy.

Der Erfindung liegt daher die Aufgabe zu Grunde, einen Druckgeber zu schaffen, der nicht nur weitgehend unempfindlich auf Einflüsse der Umgebungstemperatur ist, sondern der auch eine hohe Schaltgenauigkeit aufweist.The invention is therefore based on the object of creating a pressure transmitter which is not only largely insensitive to influences from the ambient temperature, but which also has a high switching accuracy.

Die gestellte Aufgabe wird erfindungsgemäss durch die im kennzeichnenden Teil des Anspruchs 1 angegebenen Merkmale gelöst.The object is achieved according to the invention by the features specified in the characterizing part of claim 1.

Bei der erfindungsgemässen Lösung dient die Feder zur Festlegung des Arbeitspunktes, der durch das Bimetallelement weitgehend unabhängig von Einflüssen der Umgebungstemperatur stabilisiert ist. Da die Feder ständig eine Kraft auf das Fühlerelement ausübt, ergibt sich durch die Anordnung des Bimetallelementes in Reihe mit der Feder eine kraftabhängige Temperaturkompensation, sodass im Gegensatz zu einer wegabhängigen Temperaturkompensation bei einer Verstellung des Arbeitspunktes keine. Verlagerung des Schaltkontaktes oder des Messumformers erforderlich ist. Der Arbeitspunkt lässt sich auf einfache Weise durch Veränderung des Federdruckes einstellen. Die erfindungsgemässe Lösung zeichnet sich durch ihre Einfachheit aus und ist weitgehend auch auf bereits bestehende Konstruktionen anwendbar. Durch das mit der Feder in Reihe angeordnete Bimetallelement wird die Wirkung der Feder verändert, ohne dass sich dadurch Verschiebungen der die Eichgenauigkeit bestimmenden Teile ergeben.In the solution according to the invention, the spring serves to determine the operating point, which is largely stabilized by the bimetallic element independently of influences from the ambient temperature. Since the spring constantly exerts a force on the sensor element, the arrangement of the bimetallic element in series with the spring results in a force-dependent temperature compensation, so that in contrast to a path-dependent temperature compensation when the working point is adjusted. Relocation of the switch contact or the transmitter is required. The operating point can be easily adjusted by changing the spring pressure. The solution according to the invention is characterized by its simplicity and is largely applicable to already existing constructions. The bimetallic element arranged in series with the spring alters the effect of the spring without resulting in displacements of the parts determining the calibration accuracy.

Bei bevorzugten Ausführungsformen nach den Ansprüchen 2 und 3 ist eine leichte Zugänglichkeit zum Einstellelement gewährleistet.In preferred embodiments according to claims 2 and 3, easy access to the adjusting element is ensured.

Eine besonders bevorzugte Ausführungsform nach Anspruch 4 ermöglicht auf einfache Art und Weise einen Abgleich der Kompensationswirkung des Bimetallelementes durch Hinzufügen oder Wegnehmen von Bimetallscheiben.A particularly preferred embodiment according to claim 4 enables the compensation effect of the bimetal element to be compared in a simple manner by adding or removing bimetal disks.

Bei einer weiteren bevorzugten- Ausführungsform nach Anspruch 5 sind die Bimetallscheiben als Lochscheiben wechselsinnig auf einem Dorn aufgereiht. Die wechselsinnige Anordnung ergibt einen grösseren Hub als eine gleichsinnige Anordnung, da sich die Hübe der einzelnen Scheiben addieren.In a further preferred embodiment according to claim 5, the bimetal disks are lined up alternately on a mandrel as perforated disks. The alternating arrangement results in a larger stroke than a similar arrangement, since the strokes of the individual disks add up.

Eine Ausführungsform nach Anspruch 6 entspricht nicht nur einer konstruktiv günstigen Lösung, sondern ist darüberhinaus mit dem Vorteil verbunden, dass die Bimetallscheiben das Mitdrehen der Feder beim Verstellen der Druck-Einstellschraube verhindern, da sie sich leicht gegeneinander verdrehen lassen. Dadurch lässt sich die Einstellgenauigkeit erhöhen, weil störende Abweichungen des Schaltpunktes durch das Verdrehen der Feder vermieden werden.An embodiment according to claim 6 not only corresponds to a structurally favorable solution, but is also associated with the advantage that the bimetallic discs prevent the spring from turning when the pressure adjusting screw is adjusted, since they can be easily rotated relative to one another. This enables the setting accuracy to be increased because disruptive deviations in the switching point are avoided by turning the spring.

Eine Ausführungsform nach Anspruch 7 ergibt einen besseren thermischen Wirkungsgrad, da anstelle von runden Lochscheiben Lochstreifen vorgeschlagen werden, welche jedoch gegen Verdrehung gesichert werden müssen.An embodiment according to claim 7 results in better thermal efficiency, since perforated strips are proposed instead of round perforated disks, which, however, have to be secured against rotation.

Anhand der Zeichnungen werden Ausführungsbeispiele der Erfindung näher erläutert. Es zeigt :

  • Fig. 1 einen Axialschnitt durch einen gebrochen dargestellten Druckschalter,
  • Fig. 2 ein Detail aus der Fig. 1 in einem grösseren Massstab, wobei durch den Unterschied zwischen der linken und der rechten Zeichnungshälfte die Wirkung des Bimetallelementes veranschaulicht wird,
  • Fig. 3 die Anordnung eines elektronischen Messumformers mit einer vom Druckfühler bewegbaren Zunge anstelle eines Schaltkontaktes.
Exemplary embodiments of the invention are explained in more detail with reference to the drawings. It shows :
  • 1 is an axial section through a broken pressure switch,
  • 2 shows a detail from FIG. 1 on a larger scale, the effect of the bimetallic element being illustrated by the difference between the left and right half of the drawing,
  • Fig. 3 shows the arrangement of an electronic transmitter with a tongue movable by the pressure sensor instead of a switching contact.

In der Fig. 1 ist eine von dem zu messenden Druck beaufschlagbare Kammer 10 mittels einer Membran 12 abgeschlossen, welche auf der dem Druck entgegensetzten Seite durch eine Scheibe 14 verstärkt ist. Auf der Scheibe 14 stützt sich ein Stössel 16 ab, dessen entgegensetztes Ende in einem mit einer einseitig eingespannten Blattfeder 18 verbundenen Führungsstück 20 zentriert ist. Auf der dem Stössel 16 entgegengesetzten Seite greift eine Druckfeder 22 am Führungsstück 20 an, welches die als druckbeaufschlagbares Fühlerelement dienende Membran 12 gegen den zu messende Druck belastet. Die als Betätigungselement wirkende Blattfeder 18 ist an ihrem freien Ende mit einer c-förmigen Schnappfeder 24 gekoppelt, welche an einem gegen einen feststehenden Kontakt 26 vorgespannten Schaltkontakt 28 angreift.In FIG. 1, a chamber 10 which can be acted upon by the pressure to be measured is closed off by means of a membrane 12, which is reinforced by a disk 14 on the side opposite the pressure. A plunger 16 is supported on the disk 14, the opposite end of which is centered in a guide piece 20 connected to a leaf spring 18 clamped on one side. On the side opposite the plunger 16, a compression spring 22 engages the guide piece 20, which loads the membrane 12 serving as a pressurizable sensor element against the pressure to be measured. The leaf spring 18, which acts as an actuating element, is coupled at its free end to a c-shaped snap spring 24, which engages a switching contact 28 biased against a fixed contact 26.

Wird nun die in der Ruhestellung an einem feststehenden Anschlag 30 anliegende Membran 12 gegen die Kraft der Druckfeder 22 durch den Druck des zu messenden Mediums beaufschlagt, dann bewegt sie die Blattfeder 18 gegen die Druckfeder 22. Ueberschreitet dabei die Blattfeder 18 die Ebene des Schaltkontaktes 28, dann kippt die c-förmige Schnappfeder 24 in ihre andere stabile Stellung und bewegt dabei den Schaltkontakt 28 vom feststehenden Kontakt 26 weg und auf den zweiten feststehenden Kontakt 32 zu. Nimmt der zu messende Druck des Mediums in der Kammer 10 ab, dann schaltet der Schaltkontakt 28 wieder in seine in der Fig. 1 dargestellte Ausgangsstellung zurück, sobald die Blattfeder 18 die Ebene des Schaltkontaktes 28 wieder überschreitet.If, in the rest position, a diaphragm 12 resting against a fixed stop 30 is pressed against the force of the compression spring 22 by the pressure of the medium to be measured, then it moves the leaf spring 18 against the compression spring 22. In the process, the leaf spring 18 exceeds the level of the switching contact 28 , then the c-shaped snap spring 24 tilts into its other stable position and thereby moves the switching contact 28 away from the fixed contact 26 and towards the second fixed contact 32. If the pressure of the medium to be measured in the chamber 10 decreases, then the switch contact 28 switches back to its initial position shown in FIG. 1 as soon as the leaf spring 18 again exceeds the level of the switch contact 28.

Die Vorspannung der Druckfeder 22 ist an einer Druck-Einstellschraube 34 einstellbar, an welcher sich die Druckfeder 22 mittels tellerferartig gewölber Bimetallscheiben 36 eines Bimetallelementes 38 abstützt. Die Bimetallscheiben 36 sind in ihrem Zentrum gelocht und wechselsinnig auf einem Dorn 40 aufgereiht, welcher mit der Druck-Einstellschraube 34 starr verbunden ist. Zur Zentrierung des oberen Endes der Druckfeder 22 befindet sich zwischen der untersten Bimetallscheibe 36 und der Druckfeder 22 ein zweites Führungsstück 42. Die Druck-Einstellschraube 34 ist in ein in einem Gehäuseansatz 44 angeordnetes Gewinde eingeschraubt.The prestress of the compression spring 22 can be adjusted on a pressure adjusting screw 34, on which the compression spring 22 is supported by means of bimetallic washers 36 of a bimetallic element 38 which are curved in the manner of a plate. The bimetallic disks 36 are perforated in their center and lined up alternately on a mandrel 40 which is rigidly connected to the pressure adjusting screw 34. To center the upper end of the compression spring 22, there is a second guide piece 42 between the lowermost bimetal disk 36 and the compression spring 22. The pressure adjusting screw 34 is screwed into a thread arranged in a housing shoulder 44.

In einer nicht dargestellten Ausführungsform kann anstelle der Membran 12 auch ein Kolben vorgesehen sein, welcher durch den Druck des zu messenden Mediums gegen die Kraft der Druckfeder 22 beaufschlagbar ist. Anstelle des einen dargestellten Schaltkontaktes können auch mehrere Schaltkontakte vorgesehen sein, welche entweder gleichzeitig oder bei verschiedenen Drücken schalten. Die Schaltkontakte können als Umschalter, als Oeffner oder als Schliesserausgebildet sein.In an embodiment not shown, a piston can be provided instead of the membrane 12, which can be acted upon by the pressure of the medium to be measured against the force of the compression spring 22. Instead of the switching contact shown, a plurality of switching contacts can also be provided, which switch either simultaneously or at different pressures. The switch contacts can be designed as change-over switches, openers or make contacts.

Die Fig. 2 zeigt ein Detail aus der Fig. 1 in einem grösserem Massstab. Insbesondere ist aus der Fig. 2 die Form der tellerfederartig gewölbten Bimetallscheiben 36 und deren Anordnung ersichtlich.FIG. 2 shows a detail from FIG. 1 on a larger scale. In particular, FIG. 2 shows the shape of the bimetallic disks 36, which are curved like a plate spring, and their arrangement.

Während die linke Hälfte der Fig. 2 die Bimetallscheiben 36 in der Normalstellung zeigt, ist aus der rechten Hälfte dieser Figur die Wirkung der Bimetallscheiben 36 bei einer erhöhten Umgebungstemperatur ersichtlich. In diesem Fall sind die Bimetallscheiben 36 stärker gewölbt. Zur Anpassung der durch die Bimetallscheiben bewirkten Kompensation der Umgebungstemperatur können Bimetallscheiben hinzugefügt oder entfernt werden. Durch die wechselsinnige Anordnung der Bimetallscheiben 36 erhöht sich der Kompensationshub um jede hinzugefügte Bimetallscheibe. Für den vorliegenden Verwendungszweck werden schwach gewölbte, runde Lochscheiben als Bimetallscheiben bevorzugt. Das durch die Bimetallscheiben 36 gebildete Bimetallelement 38 dient als axial bewegliche Abstützung der Druckfeder 22. Beim Verstellen der Druck-Einstellschraube 34 verhindern die Bimetallscheiben 36, dass die Druckfeder 22 mitgedreht wird, da sich die Bimetallscheiben 36 an ihren Innendurchmessern mit geringer Reigung gegeneinander verdrehen lassen.While the left half of FIG. 2 shows the bimetal disks 36 in the normal position, the effect of the bimetal disks 36 at an elevated ambient temperature can be seen from the right half of this figure. In this case, the bimetallic disks 36 are curved more strongly. To adjust the compensation of the ambient temperature caused by the bimetal disks, bimetal disks can be added or removed. Due to the alternating arrangement of the bimetallic discs 36, the compensation stroke increases by each added bimetallic disc. For the present purpose, slightly curved, round perforated disks are preferred as bimetallic disks. The bimetallic element 38 formed by the bimetallic disks 36 serves as an axially movable support for the compression spring 22. When the pressure adjusting screw 34 is adjusted, the bimetallic disks 36 prevent the compression spring 22 from being rotated as well, since the bimetallic disks 36 can be rotated with respect to one another with little inclination on their inside diameters .

Die Fig. 3 zeigt als Variante zur Fig. 1 einen Messumformer 46, welcher in Abhängigkeit von der Annäherung einer Zunge 48 ein stetiges Signal abgibt. Ein solcher Messumformer weist vorzugsweise elektronische Bauelemente auf und kann beispielsweise die Annäherung der Zunge 48 induktiv, kapazitiv oder optisch abtasten. Die Zunge 48 ist dabei anstelle der in der Fig. 1 dargestellten Blattfeder 18 angeordnet und wirkt gleich wie die Blattfeder 18 als Betätigungselement.FIG. 3 shows, as a variant of FIG. 1, a measuring transducer 46 which emits a continuous signal depending on the approach of a tongue 48. Such a transmitter preferably has electronic components and can, for example, inductively, capacitively or optically sense the approach of the tongue 48. The tongue 48 is arranged instead of the leaf spring 18 shown in FIG. 1 and acts in the same way as the leaf spring 18 as an actuating element.

Anstelle der auf dem Dorn 40 aufgereihten Bimetall-Lochscheiben ist es auch möglich, Bimetallscheiben ohne Loch zu verwenden, welche in einer Hülse aufgereiht sein müssen. Ferner ist es möglich, anstelle von runden Bimetallscheiben gelochte Bimetallstreifen zu verwenden, welche auf einem Dorn aufgereiht und gegen Verdrehung versichert sind.Instead of the bimetal perforated disks lined up on the mandrel 40, it is also possible to use bimetal disks without a hole, which must be lined up in a sleeve. It is also possible to use perforated bimetal strips instead of round bimetal discs, which are lined up on a mandrel and insured against rotation.

Es ist auch möglich, die Kompensation durch einen Einzelnen, einseitig eingespannten Bimetallstreifen zu erzielen, der eine Kraftkorrektur direkt oder mittels einer Feder auf die Membran ausübt.It is also possible to achieve the compensation by means of a single bimetal strip clamped on one side, which exerts a force correction on the membrane directly or by means of a spring.

Claims (7)

1. A pressure transducer for a pressure switch or a regulator, comprising a pressure-loadable sensing element (12), which is coupled under the influence of a bimetallic element (38) to an actuating member (18, 48) for actuating at least one switching contact (28) or to a measuring transducer (46) for the delivery of a constant output signal, characterized in that the sensing element (12) is loaded by a spring (22), which is arranged in series with the bimetallic element (38)..
2. A pressure transducer according to claim 1, characterized in that the spring (22) constructed as a compression spring is supported with its opposite end from the sensing element (12) on the bimetallic element (38).
3. A pressure transducer according to claim 2, characterized in that the bimetallic element (38) is in turn supported on an adjusting member (34).
4. A pressure transducer according to any one of claims 1 to 3, characterized in that the bimetallic element (38) comprises bimetallic disks (36) arranged in series and curved in the manner of disk springs.
5. A pressure transducer according to claim 4, characterized in that the bimetallic disks (36) have holes at their centres and are lined up in alternate directions on a shaft (40).
6. A pressure transducer according to claim 3 and claim 5, characterized in that the shaft (40) is connected with a pressure adjusting screw (34) serving as an adjusting member.
7. A pressure transducer according to any one of claims 1 to 3, characterized in that the bimetallic element (38) comprises curved perforated strips arranged in series in alternate directions.
EP19850109478 1984-08-15 1985-07-27 Pressure transducer for a pressure switch or regulator Expired EP0173090B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3913/84 1984-08-15
CH391384A CH664220A5 (en) 1984-08-15 1984-08-15 PRESSURE SENSOR FOR A PRESSURE SWITCH OR REGULATOR.

Publications (2)

Publication Number Publication Date
EP0173090A1 EP0173090A1 (en) 1986-03-05
EP0173090B1 true EP0173090B1 (en) 1988-05-25

Family

ID=4266191

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850109478 Expired EP0173090B1 (en) 1984-08-15 1985-07-27 Pressure transducer for a pressure switch or regulator

Country Status (3)

Country Link
EP (1) EP0173090B1 (en)
CH (1) CH664220A5 (en)
DE (1) DE3562961D1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3934415A1 (en) * 1989-10-14 1991-04-18 Wabco Westinghouse Fahrzeug DEVICE FOR MONITORING THE TIGHTNESS OF A GAS-FILLED CHAMBER
CN110391110B (en) * 2019-09-04 2024-04-26 济南迈克阀门科技有限公司 Double-output type pressure-adjustable pressure switch for fire control
CN112652503A (en) * 2019-10-10 2021-04-13 侯耀淞 Differential pressure switch
CN114659698B (en) * 2022-03-06 2024-04-09 淮安市格洋浩瑞电子科技有限公司 Impact-resistant high-stability flat membrane type pressure sensor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2514881A (en) * 1947-05-23 1950-07-11 United Electric Controls Co Thermostatic switch
US2635157A (en) * 1949-05-03 1953-04-14 Rheostatic Co Ltd Thermostatic control switch
CH315978A (en) * 1952-08-04 1956-09-15 Buerkert Christian Electrothermally operated, continuously working adjustment device
FR1357961A (en) * 1962-06-02 1964-04-10 Danfoss As Improvements made to \ thermostatic devices
CH528142A (en) * 1971-02-24 1972-09-15 Bbc Brown Boveri & Cie Pressure dependent temperature compensated switch
DE2407205B2 (en) * 1974-02-15 1977-12-22 Vdo Adolf Schindling Ag, 6000 Frankfurt PRESSURE-ACTUATED SWITCHING DEVICE

Also Published As

Publication number Publication date
CH664220A5 (en) 1988-02-15
DE3562961D1 (en) 1988-06-30
EP0173090A1 (en) 1986-03-05

Similar Documents

Publication Publication Date Title
DE60017328T2 (en) Altimeter with coupled double slide
DE2510410A1 (en) CONTROL DEVICE FOR A DEFLECTION ROLLER
EP0173090B1 (en) Pressure transducer for a pressure switch or regulator
DE2214750C3 (en) Compensation converter for the pressure of a pressure medium into an electrical output signal
DE4220083A1 (en) Reference force or pressure generator for calibration of meters - has pressure transmitting opening above liquid which surrounds heater-cooler, which acts as setting element of control loop, to enable use of dependency of vapour pressure of liquid on temp..
EP0178551B1 (en) Pressure-responsive transducer
DE4312771A1 (en) Two-stage push button (key)
EP0792446B1 (en) Pressure sensor
DE2401914A1 (en) ELECTRICAL SWITCHING DEVICE ACTUATABLE DEPENDING ON A PRESSURE
EP0279390A1 (en) Pressure-operated membrane switch
DE3406942A1 (en) PRESSURE SENSOR
DE2746627C2 (en) Pressure-dependently operated electrical switches, in particular evaporator thermostats for refrigerators
EP0094446B1 (en) Pressure detector with a membrane and an overload stopper
EP0126172A1 (en) Damping means for force tranducers
EP0728513B1 (en) Apparatus for indicating the subatmospheric pressure
EP0361518A2 (en) Platform balance
DE2424275C3 (en) Device for sensing and displaying a parameter, preferably for use in barometric altimeters
DE2843419A1 (en) DEVICE FOR THE OPTIONAL MEASUREMENT OF A LIQUID FLOW OR A LIQUID PRESSURE
DE3201262A1 (en) Pressure sensor
EP0423462A1 (en) Apparatus to monitor the airtightness of a vehicle tyre
DE102019135841B3 (en) Mechanical pressure switch, set of parts for building the same and a set of such pressure switches
DE1954947C3 (en) Pneumatic control device
DE1515595C3 (en) Electric snap switch
DE2208678A1 (en) DIAPHRAGM PRESSURE SWITCH
DE2512384C2 (en) Fine focusing device for the objective of an optical instrument

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19860319

17Q First examination report despatched

Effective date: 19861215

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB NL

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
REF Corresponds to:

Ref document number: 3562961

Country of ref document: DE

Date of ref document: 19880630

ET Fr: translation filed
PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: G. KROMSCHROEDER AKTIENGESELLSCHAFT

Effective date: 19880901

NLR1 Nl: opposition has been filed with the epo

Opponent name: G. KROMSCHROEDER AKTIENGESELLSCHAFT

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19890510

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19890516

Year of fee payment: 5

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19890630

Year of fee payment: 5

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19900201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19900727

GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19910329

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19910403

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

RDAG Patent revoked

Free format text: ORIGINAL CODE: 0009271

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: PATENT REVOKED

27W Patent revoked

Effective date: 19920202