CH535898A

CH535898A - Electro-hydraulic converter

Info

Publication number: CH535898A
Application number: CH459371A
Authority: CH
Inventors: Jaroslav Cyphelly Ivan
Original assignee: Cyphelly Ivan J
Priority date: 1970-05-06
Filing date: 1971-03-30
Publication date: 1973-04-15
Also published as: DE2119957A1; US3805843A; GB1347317A; NL7106109A; SE371258B; NO138260B; BE766726A; DE2119957B2; FR2088372A1; NO138260C; JPS5426731B1; FR2088372B1

Description

  

  
 



   Das Hauptpatent betrifft einen elektro-hydraulischen Wandler, der gemäss Patentanspruch I eine elektrisch heizbare, laminare Drosselstelle aufweist. Eine Ausführungsform des Wandlers besteht gemäss Unteranspruch 1 des Hauptpatentes darin, dass die Drosselstelle ein Rohr ist, dessen Wände zugleich als elektrischer Widerstand ausgebildet sind.



   Solche Wandler können zweckmässig anstelle der bekannten elektro-magnetisch betätigten Wandler eingesetzt werden, solange der elektrische Strom im Verhältnis zum beeinflussten Strom des Hydraulikmediums nicht dermassen gross wird, dass das Rohr durch Überhitzung zerstört wird.



   Die Erfindung betrifft eine weitere Ausführungsform des elektro-hydraulischen Wandlers nach dem Hauptpatent und bezweckt, den Wandler gegenüber elektrischer   tssberlast    durch eine Vorrichtung zu schützen, die bei einer gegebenen Temperatur des elektrisch heizbaren Rohrs den elektrischen Steuerstrom unterbricht oder begrenzt.



   Erfindungsgemäss wird dies dadurch erreicht, dass eine Vorrichtung zur optischen oder mechanischen Abtastung der zur Temperatur des elektrisch heizbaren Rohres proportionalen Längenausdehnung des Rohres vorgesehen ist, welche Vorrichtung ein Tastsignal erzeugt, das zur Begrenzung oder Unterbrechung eines heizenden Steuersignales dient, um den Wandler vor Überhitzung zu schützen.



   Um ein sicheres Abtasten zu gewährleisten, kann die Längenausdehnung des Rohrs stark verstärkt werden. Durch festes Einspannen der Rohrenden wird bei Erwärmung des Rohrs eine Ausknickung des Rohres erzwungen, wobei die Ausknikkung in der Rohrmitte ein Vielfaches der effektiven Längenausdehnung des Rohres beträgt. Dadurch wird infolge grosser Schaltwege der   Überiastschutz    weitgehend von Störeffekten unabhängig, insbesondere wenn zusätzlich Vorkehrungen getroffen werden, um den Rohrhalter frei von thermischen Einflüssen zu halten.



   Nachstehend wird ein Ausführungsbeispiel des Erfindungsgegenstandes anhand der Zeichnung näher erläutert. Es zeigen:
Fig. 1 im Aufriss entlang der Linie II der Fig. 2 ein eingespanntes Heizrohr mit Lichtschrankenabtastung,
Fig. 2 im Seitenriss entlang der Linie I das eingespannte Heizrohr mit Lichtschrankenabtastung.



   Fig. 3 eine schematische Anordnung eines Überlastschutzes mit mechanischer Abtastung,
Fig. 4 einen vergrösserten Ausschnitt der Fig. 1 am niederdruckseitigen Lötpunkt des Heizrohres, wobei eine thermische Isolierung zwischen einem Halter und dem Rohr dargestellt ist.



   Das Heizrohr 1 der Fig. 1 und 2 ist niederdruckseitig in einem Halter 2 und druckseitig in der   dse    3 eingelötet. Die Öse 3 ist über ein elektrisch isolierendes Blättchen 4 mit dem Halter 2 fest verbunden. Die Steuerstromeinspeisung erfolgt über einen Draht 5. Das Rohr 1 ist leicht vorgeknickt eingelötet; somit ist eine Ausknickrichtung vorgegeben. Bei Erwärmung nimmt die Ausknickung infolge Längenausdehnung zu, bis das Heizrohr in der Lage 1' einen auf ein Photoelement 8 gerichteten Lichtstrahl 6 einer Lichtquelle 7 unterbricht. Das Signal des Photoelements 8 beeinflusst das heizende Steuersignal entweder durch Betätigen eines Relais, das die Verbindung zwischen einem Servoverstärker und der Ose 3 unterbricht, oder dadurch, dass durch das Signal eine Gegenkupplung vor der Leistungsstufe des Servoverstärkers eingefügt wird.

  Gemäss Fig. 1 ist der Halter 2 durch Schrauben 9 an ein zu steuerndes Ventil 10 angeschraubt.



   Fig. 3 stellt schematisch den gleichen Überlastschutz als mechanische Vorrichtung dar. Das heizende Steuersignal des Servoverstärkers 11 wird bei einer gewissen Ausknickung des geheizten Rohres 1 durch einen isolierten Taster 12 über einen Kontakt 13 unterbrochen. An sich weisen aber mechanische Kontakte den Nachteil auf, dass sie weniger betriebssicher sind, so dass die in Fig. 1 und 2 dargestellte Bauart mit einer Lichtschranke vorzuziehen ist.



   Um ein gutes Funktionieren des Überlastschutzes zu sichern, muss die Referenzlänge der Rohreinspannung konstant bleiben, d.h. der Halter 2 muss dem thermischen Einfluss des heizbaren Rohres 1 und des austretenden warmen Hydraulikmediums an der Niederdruckseite entzogen werden.



  Die direkte Beheizung durch das Rohr 1 kann vermieden werden, indem man das gemäss Fig. 4 elektrisch geheizte Rohr 1 an seinen Enden mit einer hauchdünnen, elektrisch sehr gut leitenden Schicht 14 beaufschlagt, wodurch die Heizzone des Rohres um eine Distanz a vom Halter 2 ferngehalten wird. Die Beheizung durch das heisse Hydraulikmedium kann nur durch einen thermischen Kurzschluss zwischen Lötstelle des Rohrs 1 am Halter 2 (Fig. 1) und dem Ventil 10 begrenzt werden; dies erfordert ein Haltermaterial mit sehr grosser Wärmeleitfähigkeit,   z,B.    Aluminium oder Kupfer.



   PATENTANSPRUCH



   Elektro-hydraulischer Wandler nach dem Patentanspruch I und dem Unteranspruch 1 des Hauptpatentes, dadurch gekennzeichnet, dass eine Vorrichtung (7, 8; 12, 13) zur optischen oder mechanischen Abtastung der zur Temperatur des elektrisch heizbaren Rohres (1) proportionalen Längenausdehnung des Rohres vorgesehen ist, welche Vorrichtung ein Tastsignal erzeugt, das zur Begrenzung oder Unterbrechung eines heizenden Steuersignales dient, um den Wandler vor Überhitzung zu schützen.



   UNTERANSPRÜCHE
1. Elektro-hydraulischer Wandler nach Patentanspruch, dadurch gekennzeichnet, dass das elektrisch   heizbare    Rohr (1) an seinen beiden Enden mittels eines Halters (2) fest eingespannt ist und dass die genannte Vorrichtung zur Abtastung der bei der Längenausdehnung des Rohres auftretenden Rohrausknickung angeordnet ist.

 

   2. Elektro-hydraulischer Wandler nach Patentanspruch und Unteranspruch 1, dadurch gekennzeichnet, dass eine Lichtquelle (7) und ein Photoelement (8) vorgesehen sind, die derart angeordnet sind, dass der auf das Photoelement gerichtete Lichtstrahl (6) bei einer bestimmten Ausknickung des elektrisch heizbaren Rohrs (1) unterbrochen wird.



   3. Elektro-hydraulischer Wandler nach Patentanspruch und Unteranspruch 1 oder 2, dadurch gekennzeichnet, dass zwecks Vermeidung eines direkten thermischen Einflusses des elektrisch heizbaren Rohrs (1) auf den Halter (2) das Rohr an seinen beiden Enden mit einer elektrisch leitenden Schicht (14) versehen ist, derart, dass die elektrisch   heizbare    Zone des Rohrs verkürzt ist.

**WARNUNG** Ende DESC Feld konnte Anfang CLMS uberlappen**.



   



  
 



   The main patent relates to an electro-hydraulic converter which, according to claim I, has an electrically heatable, laminar throttle point. According to dependent claim 1 of the main patent, one embodiment of the converter consists in that the throttle point is a tube, the walls of which are also designed as an electrical resistor.



   Such converters can expediently be used instead of the known electro-magnetically actuated converters, as long as the electrical current in relation to the influenced flow of the hydraulic medium does not become so great that the pipe is destroyed by overheating.



   The invention relates to a further embodiment of the electro-hydraulic converter according to the main patent and aims to protect the converter against electrical overload by means of a device which interrupts or limits the electrical control current at a given temperature of the electrically heatable pipe.



   According to the invention, this is achieved in that a device for optical or mechanical scanning of the length of the pipe proportional to the temperature of the electrically heatable pipe is provided, which device generates a key signal which is used to limit or interrupt a heating control signal in order to prevent the converter from overheating protect.



   To ensure reliable scanning, the length expansion of the pipe can be greatly increased. By firmly clamping the pipe ends, a kink of the pipe is forced when the pipe is heated, the kink in the center of the pipe being a multiple of the effective length expansion of the pipe. As a result, as a result of the large switching paths, the overload protection is largely independent of interference effects, in particular if additional precautions are taken to keep the pipe holder free from thermal influences.



   An exemplary embodiment of the subject matter of the invention is explained in more detail below with reference to the drawing. Show it:
Fig. 1 in elevation along the line II of Fig. 2, a clamped heating tube with light barrier scanning,
2 shows the clamped heating tube with light barrier scanning in a side elevation along line I.



   3 shows a schematic arrangement of an overload protection with mechanical scanning,
4 shows an enlarged section of FIG. 1 at the soldering point on the low-pressure side of the heating pipe, with thermal insulation being shown between a holder and the pipe.



   The heating tube 1 of FIGS. 1 and 2 is soldered into a holder 2 on the low-pressure side and in the nozzle 3 on the pressure side. The eyelet 3 is firmly connected to the holder 2 via an electrically insulating leaf 4. The control current is fed in via a wire 5. The tube 1 is soldered in slightly pre-bent; thus a buckling direction is specified. When heated, the buckling increases as a result of longitudinal expansion until the heating tube in position 1 ′ interrupts a light beam 6 from a light source 7 directed onto a photo element 8. The signal from the photo element 8 influences the heating control signal either by activating a relay that interrupts the connection between a servo amplifier and the Ose 3, or by inserting a counter-coupling upstream of the servo amplifier's power stage.

  According to FIG. 1, the holder 2 is screwed to a valve 10 to be controlled by screws 9.



   3 shows schematically the same overload protection as a mechanical device. The heating control signal of the servo amplifier 11 is interrupted by an insulated button 12 via a contact 13 when the heated tube 1 kinks. However, mechanical contacts per se have the disadvantage that they are less reliable in operation, so that the type of construction with a light barrier shown in FIGS. 1 and 2 is to be preferred.



   To ensure that the overload protection works properly, the reference length of the pipe restraint must remain constant, i.e. the holder 2 must be withdrawn from the thermal influence of the heatable pipe 1 and the emerging warm hydraulic medium on the low-pressure side.



  Direct heating through the pipe 1 can be avoided by applying a very thin, electrically very conductive layer 14 to the ends of the pipe 1, which is electrically heated according to FIG. 4, whereby the heating zone of the pipe is kept away from the holder 2 by a distance a becomes. The heating by the hot hydraulic medium can only be limited by a thermal short circuit between the soldering point of the pipe 1 on the holder 2 (FIG. 1) and the valve 10; this requires a holder material with very high thermal conductivity, e.g. Aluminum or copper.



   PATENT CLAIM



   Electro-hydraulic converter according to claim 1 and dependent claim 1 of the main patent, characterized in that a device (7, 8; 12, 13) is provided for optical or mechanical scanning of the length of the pipe proportional to the temperature of the electrically heatable pipe (1) is which device generates a key signal that is used to limit or interrupt a heating control signal in order to protect the converter from overheating.



   SUBCLAIMS
1. Electro-hydraulic converter according to claim, characterized in that the electrically heatable pipe (1) is firmly clamped at its two ends by means of a holder (2) and that said device is arranged for scanning the kinking of the pipe occurring during the longitudinal expansion of the pipe .

 

   2. Electro-hydraulic converter according to claim and dependent claim 1, characterized in that a light source (7) and a photo element (8) are provided, which are arranged such that the light beam (6) directed onto the photo element at a certain buckling of the electrically heatable pipe (1) is interrupted.



   3. Electro-hydraulic converter according to claim and dependent claim 1 or 2, characterized in that in order to avoid a direct thermal influence of the electrically heatable tube (1) on the holder (2), the tube is provided with an electrically conductive layer (14 ) is provided in such a way that the electrically heatable zone of the pipe is shortened.

** WARNING ** End of DESC field could overlap beginning of CLMS **.

Claims

** WARNING ** Beginning of CLMS field could overlap end of DESC **.

The main patent relates to an electro-hydraulic converter which, according to claim I, has an electrically heatable, laminar throttle point. According to dependent claim 1 of the main patent, one embodiment of the converter consists in that the throttle point is a tube, the walls of which are also designed as an electrical resistor.

Such converters can expediently be used instead of the known electro-magnetically actuated converters, as long as the electrical current in relation to the influenced flow of the hydraulic medium does not become so great that the pipe is destroyed by overheating.

The invention relates to a further embodiment of the electro-hydraulic converter according to the main patent and aims to protect the converter against electrical overload by means of a device which interrupts or limits the electrical control current at a given temperature of the electrically heatable pipe.

According to the invention, this is achieved in that a device for optical or mechanical scanning of the length of the pipe proportional to the temperature of the electrically heatable pipe is provided, which device generates a key signal which is used to limit or interrupt a heating control signal in order to prevent the converter from overheating protect.

To ensure reliable scanning, the length expansion of the pipe can be greatly increased. By firmly clamping the pipe ends, a kink of the pipe is forced when the pipe is heated, the kink in the center of the pipe being a multiple of the effective length expansion of the pipe. As a result, as a result of the large switching paths, the overload protection is largely independent of interference effects, in particular if additional precautions are taken to keep the pipe holder free from thermal influences.

An exemplary embodiment of the subject matter of the invention is explained in more detail below with reference to the drawing. Show it: Fig. 1 in elevation along the line II of Fig. 2, a clamped heating tube with light barrier scanning, 2 shows the clamped heating tube with light barrier scanning in a side elevation along line I.

3 shows a schematic arrangement of an overload protection with mechanical scanning, 4 shows an enlarged section of FIG. 1 at the soldering point on the low-pressure side of the heating pipe, with thermal insulation being shown between a holder and the pipe.

The heating tube 1 of FIGS. 1 and 2 is soldered into a holder 2 on the low-pressure side and in the nozzle 3 on the pressure side. The eyelet 3 is firmly connected to the holder 2 via an electrically insulating leaf 4. The control current is fed in via a wire 5. The tube 1 is soldered in slightly pre-bent; thus a buckling direction is specified. When heated, the buckling increases as a result of longitudinal expansion until the heating tube in position 1 ′ interrupts a light beam 6 from a light source 7 directed onto a photo element 8. The signal from the photo element 8 influences the heating control signal either by activating a relay that interrupts the connection between a servo amplifier and the Ose 3, or by inserting a counter-coupling upstream of the servo amplifier's power stage.

According to FIG. 1, the holder 2 is screwed to a valve 10 to be controlled by screws 9.

3 shows schematically the same overload protection as a mechanical device. The heating control signal of the servo amplifier 11 is interrupted by an insulated button 12 via a contact 13 when the heated tube 1 kinks. However, mechanical contacts per se have the disadvantage that they are less reliable in operation, so that the type of construction with a light barrier shown in FIGS. 1 and 2 is to be preferred.

To ensure that the overload protection works properly, the reference length of the pipe restraint must remain constant, i.e. the holder 2 must be withdrawn from the thermal influence of the heatable pipe 1 and the emerging warm hydraulic medium on the low-pressure side.

Direct heating through the pipe 1 can be avoided by applying a very thin, electrically very conductive layer 14 to the ends of the pipe 1, which is electrically heated according to FIG. 4, whereby the heating zone of the pipe is kept away from the holder 2 by a distance a becomes. The heating by the hot hydraulic medium can only be limited by a thermal short circuit between the soldering point of the pipe 1 on the holder 2 (FIG. 1) and the valve 10; this requires a holder material with very high thermal conductivity, e.g. Aluminum or copper.

PATENT CLAIM

Electro-hydraulic converter according to claim 1 and dependent claim 1 of the main patent, characterized in that a device (7, 8; 12, 13) is provided for optical or mechanical scanning of the length of the pipe proportional to the temperature of the electrically heatable pipe (1) is which device generates a key signal that is used to limit or interrupt a heating control signal in order to protect the converter from overheating.

SUBCLAIMS 1. Electro-hydraulic converter according to claim, characterized in that the electrically heatable pipe (1) is firmly clamped at its two ends by means of a holder (2) and that said device is arranged for scanning the kinking of the pipe that occurs during the longitudinal expansion of the pipe .

2. Electro-hydraulic converter according to claim and dependent claim 1, characterized in that a light source (7) and a photo element (8) are provided, which are arranged such that the light beam (6) directed onto the photo element at a certain buckling of the electrically heatable pipe (1) is interrupted.

3. Electro-hydraulic converter according to claim and dependent claim 1 or 2, characterized in that in order to avoid a direct thermal influence of the electrically heatable tube (1) on the holder (2), the tube is provided with an electrically conductive layer (14 ) is provided in such a way that the electrically heatable zone of the pipe is shortened.