EP0576415B1 - Suction control valve - Google Patents

Suction control valve Download PDF

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Publication number
EP0576415B1
EP0576415B1 EP19930890096 EP93890096A EP0576415B1 EP 0576415 B1 EP0576415 B1 EP 0576415B1 EP 19930890096 EP19930890096 EP 19930890096 EP 93890096 A EP93890096 A EP 93890096A EP 0576415 B1 EP0576415 B1 EP 0576415B1
Authority
EP
European Patent Office
Prior art keywords
suction
seat
control valve
valve
closure body
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 - Lifetime
Application number
EP19930890096
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German (de)
French (fr)
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EP0576415A1 (en
Inventor
Friedrich Dr. Dipl.-Ing. Bauer
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.)
Hoerbiger Ventilwerke GmbH and Co KG
Original Assignee
Hoerbiger Ventilwerke GmbH and Co KG
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Publication of EP0576415A1 publication Critical patent/EP0576415A1/en
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Publication of EP0576415B1 publication Critical patent/EP0576415B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/24—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S137/00—Fluid handling
    • Y10S137/907—Vacuum-actuated valves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7762—Fluid pressure type
    • Y10T137/7769—Single acting fluid servo
    • Y10T137/777—Spring biased

Definitions

  • the invention relates to an intake control valve for a screw compressor, in particular for a screw compressor with oil injection, which is installed in the intake line of the screw compressor and has a closure body which alternately releases or closes the intake line and with an actuating piston or an actuating diaphragm which can be displaced in a cylinder, which is pressurized with a pressure medium is in the opening direction of the intake line in drive connection, the intake control valve designed as a double seat valve being provided with an intake seat which the closure body closes in the intake direction and a backflow seat which the closure body closes against the intake direction.
  • Intake control valves for compressors are known in various designs.
  • the simple designs for screw compressors are "normally open", i.e. When the screw compressor is depressurized, the intake control valve releases the passage cross section of the intake line.
  • the screw compressor starts up with the intake control valve open, which means that the drive motor is immediately loaded by the full compression work. Only when a sufficient operating pressure has been built up can the intake control valve be closed completely or partially to reduce the delivery rate.
  • This embodiment thus has the disadvantage that the drive motor is heavily loaded and is also overloaded when the vehicle is started frequently in the time unit.
  • the spring force holding this closed must be overcome in this known embodiment to open the intake control valve, which is usually done by a differential piston.
  • the piston area of the differential piston must be correspondingly large, because the force exerted by it must overcome on the one hand the spring force acting on the intake control valve and on the other hand the gas pressure acting on the intake control valve due to the built-up operating pressure in the closing direction, in addition to this also the increase in spring force due to the spring stiffness .
  • a suction control device of this type is known from DE-OS 29 44 053.
  • the pressure that builds up overcomes the spring force and opens the suction line.
  • the change in the flow cross-section for regulating the delivery rate is carried out with the aid of a further control piston which is acted upon by a control pressure, for example the network pressure, and loads the closure body in the direction of the spring force, so that the operating pressure present on the opposite side of the closure body is overcome.
  • a control pressure for example the network pressure
  • An intake control valve of the type mentioned at the outset which is expressly an intake valve intended for vacuum compressors, is known from EP-A-0 391 064.
  • the intake control valve is designed as a double-seat valve and a closure body is provided which alternately opens and closes the two valve seats.
  • the closure body is mounted at one end on a rod which can be displaced in both axial directions so far by a membrane piston provided at its other end that the closure body lies sealingly against a valve seat.
  • the closure body assumes a floating position between the two valve seats, which depends on the respective pressurization of the actuating membrane.
  • US-A-4 826 134 describes an inlet valve for air compressors, which consists of a valve housing with a valve seat and a closure body controlling it. This is attached to one end of a shaft, which is guided with its other end by a piston in a cylinder slidably against the valve seat.
  • the actuating cylinder is fixed in the axis of the valve housing and flows around the pumped medium. It is a simple arrangement of the actuating cylinder, which is aligned with the valve seat and enables a straight flow through the valve.
  • the invention has for its object to simplify the structure of the known intake control valves and still improve them so that they can be operated with little effort without impairing the function.
  • the closure body has an intermediate position defined by an end position of the actuating piston or the actuating diaphragm between the two seats, in which at least approximately the largest flow cross-section is released through the intake control valve and from which it acts as a check valve against the backflow seat is freely adjustable.
  • the design of the intake control valve which is designed as a double-seat valve, with a fixedly defined intermediate position, achieves a surprisingly simple construction and also an advantageous actuation.
  • the suction control valve according to the invention is closed by the suction-side vacuum when the screw compressor starts up and, after an operating pressure has been built up, is opened up to the intermediate position between the two seats by the pressure medium acting on the control piston or the control membrane.
  • the closure body of the intake control valve is raised to about half the stroke between its two seats and releases the full intake cross-section in this position.
  • the actuating piston or the actuating diaphragm only has to overcome the weak spring force of its retraction spring and the suction force.
  • the closing body of the intake control valve which then acts as a check valve, is pressed by the pressure medium onto the backflow seat, which it closes, regardless of the position of the control piston or the control membrane.
  • the vacuum sucks the closure body over its entire stroke onto the intake seat and closes it, so that the intake control valve then performs the "normally closed” function. This prevents the drive motor from being overloaded.
  • FIG. 1 and 2 each show a longitudinal section through an embodiment of an intake control valve according to the invention.
  • Both embodiments consist of a hollow valve housing 1 or. 1 ', which is connected with a connection opening 2 to the inlet of a screw compressor, not shown.
  • a flange 3 with fastening bores 4 for flange screws is provided for this purpose.
  • the valve housing 1 has a flow channel 5, to which the suction line 6 connects at the other end of the housing.
  • a backflow seat 7 is formed and at some distance from it the valve housing 1 has an inwardly projecting collar 8, which forms a suction seat 9 opposite the backflow seat 7.
  • an actuating cylinder 10 is arranged inside the valve housing 1, which can be designed as a cast part, in which an actuating piston 11 can be displaced against the force of a return spring 12.
  • the open end of the actuating cylinder 10 is closed by a screw cap 13, via which a control connection 14 opens into the actuating cylinder 10.
  • the actuating piston 11 is guided out of the actuating cylinder 10 with a rod 15, on the free end of which an extension 16 provided with a bore a plate-shaped closure body 17 is slidably mounted.
  • a weak helical spring 18 is supported on the housing of the actuating cylinder 10 and loads the closure body 17 against the backflow seat 7.
  • the closure body 17 has a seal 19 which effects a tight seal of the backflow seat 7.
  • a channel 20 is provided in the collar 8, which bypasses the suction seat 9 of the suction control valve and thus represents a leak in the suction seat 9.
  • the intake control valve is designed as a corner valve and an actuating membrane, which is designated 11 ′, is provided for the adjustment of the closure body 17.
  • the housing 1 ' is connected at one end to the suction line 6 as in the embodiment according to FIG. 1, but the flow channel 5 opens out on the side of the housing 1' and is connected there in a manner not shown to the inlet of a screw compressor.
  • the membrane 11 ' is clamped in a pressure chamber 10', which is provided with a control connection 14, and acts on a membrane plate 11 "which is loaded by the return spring 12.
  • the rod 15 is fastened to the membrane plate 11", on which the hollow extension 16 of the closure body 17 is placed.
  • the closure body 17 can thus also be largely freely displaced relative to the actuating membrane 11 ', with only a driving connection between the rod 15 and the closure body 17 in the opening direction of the suction seat 9, etc. to an intermediate position between the suction seat 9 and the backflow seat 7.
  • this intermediate position which is caused by the stop of a part of the actuating piston 11 on the actuating cylinder 10 (FIG. 1) or the diaphragm plate 11 "on the valve housing 1 '(FIG. 2) is defined, the flow cross-section through the intake control valve is fully open and largest.
  • the rod 15 is designed in coordination with the piston 11 or the membrane 11 'that adjusts it so that it can only adjust the closure body 17 to the intermediate position between the suction seat 9 and the backflow seat 7.
  • the closure body 17 can therefore not be pressed against the backflow seat 7 even at high operating pressure by the actuating piston 11 or the actuating membrane 11 '. This is closed by the closure body 17 only as a freely adjustable check valve as soon as the delivery of the screw compressor stops, etc. by the force exerted on it by the compressed medium with the support of the spring 18.
  • the medium delivered by the screw compressor, not shown, is drawn in in the direction of arrow 21 through the flow channel 5 of the intake control valve.
  • the closure body 17 of the intake control valve is in the intermediate position shown in both drawing figures approximately in the middle between the return flow seat 7 and the intake seat 9, whereby it releases the full flow cross-section through the flow-through channel 5.
  • the helical spring 18 immediately presses the closure body 17 against the backflow seat 7, which is completely sealed by means of the seal 19. As a result, backflow of compressed medium into the intake line 6 and in particular the escape of oil injected to lubricate the compressor is avoided.
  • the coil spring 18 also causes the backflow seat 7 to remain closed even if the screw compressor is later depressurized.
  • the actuating piston 11 or the actuating membrane 11 ' is under the action of the return spring 12 in the lower end position, in which the rod 15 is retracted as far as possible into the actuating cylinder 10 or into the pressure chamber 10'.
  • the resulting negative pressure causes the closure body 17 to be detached from the backflow seat 7 and to be moved until it contacts the suction seat 9. This movement is not hindered by the relatively short rod 15 drawn back into the interior of the actuating cylinder 10 or the pressure chamber 10 '.
  • the intake control valve performs its "normally closed" function.
  • the medium conveyed by the screw compressor is sucked in through the small channel 20, which can be calibrated so that the compressor is brought to the operating pressure in the desired slow manner, for example by pumping up a pressure container connected to the screw compressor.
  • the control connection 14 is pressurized via a two-point controller and thus the actuating piston 11 or the actuating diaphragm 11 'is pressurized, whereupon the rod 15 lifts the closure body 17 from the suction seat 9 and brings it into the intermediate position shown in the drawing.
  • the size of the pressure of the medium supplied through the control connection 14 it is also possible to lift the closure body 17 more or less from the suction seat 9 and thus to continuously regulate the amount of medium sucked in by the screw compressor.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Compressor (AREA)

Description

Die Erfindung bezieht sich auf ein Ansaugregelventil für einen Schraubenverdichter, insbesondere für einen Schraubenverdichter mit Öleinspritzung, das in die Ansaugleitung des Schraubenverdichters eingebaut ist und einen Verschlußkörper aufweist, der die Ansaugleitung abwechselnd freigibt oder verschließt und mit einem in einem Zylinder verschiebbaren Stellkolben oder einer Stellmembran, der oder die mit einem Druckmittel beaufschlagbar ist, in Öffnungsrichtung der Ansaugleitung in Antriebsverbindung steht, wobei das als Doppelsitzventil ausgebildete Ansaugregelventil mit einem Ansaugsitz, den der Verschlußkörper in Ansaugrichtung verschließt, und einem Rückströmsitz, den der Verschlußkörper gegen die Ansaugrichtung verschließt, versehen ist.The invention relates to an intake control valve for a screw compressor, in particular for a screw compressor with oil injection, which is installed in the intake line of the screw compressor and has a closure body which alternately releases or closes the intake line and with an actuating piston or an actuating diaphragm which can be displaced in a cylinder, which is pressurized with a pressure medium is in the opening direction of the intake line in drive connection, the intake control valve designed as a double seat valve being provided with an intake seat which the closure body closes in the intake direction and a backflow seat which the closure body closes against the intake direction.

Ansaugregelventile für Verdichter sind in verschiedenen Ausführungen bekannt. Die einfachen Bauarten für Schraubenverdichter sind "normal offen", d.h. in drucklosem Zustand des Schraubenverdichters gibt das Ansaugregelventil den Durchgangsquerschnitt der Ansaugleitung frei. Der Schraubenverdichter fährt also mit offenem Ansaugregelventil an, wodurch der Antriebsmotor sofort durch die volle Verdichtungsarbeit belastet wird. Erst wenn ein ausreichender Betriebsdruck aufgebaut ist, kann das Ansaugregelventil zur Verringerung der Fördermenge ganz oder teilweise geschlossen werden. Diese Ausführung hat somit den Nachteil, daß der Antriebsmotor stark belastet und bei häufigem Anfahren in der Zeiteinheit auch überlastet wird.Intake control valves for compressors are known in various designs. The simple designs for screw compressors are "normally open", i.e. When the screw compressor is depressurized, the intake control valve releases the passage cross section of the intake line. The screw compressor starts up with the intake control valve open, which means that the drive motor is immediately loaded by the full compression work. Only when a sufficient operating pressure has been built up can the intake control valve be closed completely or partially to reduce the delivery rate. This embodiment thus has the disadvantage that the drive motor is heavily loaded and is also overloaded when the vehicle is started frequently in the time unit.

Durch die weiterhin bekannten Ansaugregelventile der Bauart "normal geschlossen" wird eine Überlastung des Antriebsmotors beim Anlaufen vermieden. Bei dieser bekannten Ausführung wird das Ansaugregelventil durch Federkraft verschlossen gehalten. Nach dem Anlaufen des Schraubenverdichters erfolgt ein wesentlich langsamerer Druckaufbau mit entsprechend geringerer Belastung des Antriebsmotors. Um den Druckaufbau zu beschleunigen, ist es auch schon bekannt, das geschlossene Ansaugregelventil undicht auszubilden, z.B. durch eine Bohrung oder einen das Ventil umgehenden Kanal.Due to the still known intake control valves of the "normally closed" type, overloading of the drive motor when starting is avoided. In this known embodiment, the intake control valve is kept closed by spring force. After starting the screw compressor there is a much slower pressure build-up with a correspondingly lower load on the drive motor. In order to accelerate the pressure build-up, it is also known to make the closed suction control valve leaky, for example through a bore or a channel bypassing the valve.

Sobald ein bestimmter Betriebsdruck erreicht ist, muß bei dieser bekannten Ausführung zum Öffnen des Ansaugregelventils die dieses verschlossen haltende Federkraft überwunden werden, was meist durch einen Differentialkolben erfolgt. Die Kolbenfläche des Differentialkolbens muß entsprechend groß sein, denn die von diesem ausgeübte Kraft muß einerseits die auf das Ansaugregelventil wirkende Federkraft und anderseits den durch den aufgebauten Betriebsdruck in Schließrichtung auf das Ansaugregelventil wirkenden Gasdruck überwinden, zusätzlich dazu auch noch die Zunahme der Federkraft zufolge der Federsteife. Es handelt sich dabei um verhältnismäßige große Kräfte, weil zur Gewährleistung einer einwandfreien Funktion die Federkraft mit Sicherheit größer sein muß als die Ansaugkraft des Schraubenverdichters und der Gasdruck mit Sicherheit größer sein muß als die Federkraft.As soon as a certain operating pressure is reached, the spring force holding this closed must be overcome in this known embodiment to open the intake control valve, which is usually done by a differential piston. The piston area of the differential piston must be correspondingly large, because the force exerted by it must overcome on the one hand the spring force acting on the intake control valve and on the other hand the gas pressure acting on the intake control valve due to the built-up operating pressure in the closing direction, in addition to this also the increase in spring force due to the spring stiffness . These are relatively large forces because, in order to ensure proper functioning, the spring force must surely be greater than the suction force of the screw compressor and the gas pressure must surely be greater than the spring force.

Eine Ansaugregelvorrichtung dieser Art ist aus der DE-OS 29 44 053 bekannt. Dort ist ein verhältnismäßig komplizierter, die Ansaugleitung steuernder Verschlußkörper vorgesehen, der in Schließrichtung von einer Feder und in Öffnungsrichtung von dem vom Schraubenverdichter erzeugten Druck beaufschlagt ist. Beim Anlaufen des Schraubenverdichters wird durch den sich aufbauenden Druck die Federkraft überwunden und die Ansaugleitung geöffnet. Die Veränderung des Durchströmquerschnittes zur Regelung der Fördermenge erfolgt mit Hilfe eines weiteren Steuerkolbens, der von einem Steuerdruck, z.B. dem Netzdruck beaufschlagt wird und den Verschlußkörper in Richtung der Federkraft belastet, so daß der auf der gegenüberliegenden Seite des Verschlußkörpers anliegende Betriebsdruck überwunden wird.A suction control device of this type is known from DE-OS 29 44 053. There is a relatively complicated closure body controlling the suction line, which is acted upon in the closing direction by a spring and in the opening direction by the pressure generated by the screw compressor. When the screw compressor starts up, the pressure that builds up overcomes the spring force and opens the suction line. The change in the flow cross-section for regulating the delivery rate is carried out with the aid of a further control piston which is acted upon by a control pressure, for example the network pressure, and loads the closure body in the direction of the spring force, so that the operating pressure present on the opposite side of the closure body is overcome.

Ein Ansaugregelventil der eingangs angeführten Bauart, bei dem es sich ausdrücklich um ein für Vakuum-Kompressoren bestimmtes Einlaßventil handelt, ist aus der EP-A-0 391 064 bekannt. Auch bei dieser Ausführung ist das Ansaugregelventil als Doppelsitzventil ausgebildet und ein Verschlußkörper vorgesehen, der die beiden Ventilsitze abwechselnd öffnet und schließt. Der Verschlußkörper ist an einem Ende auf einer Stange montiert, die durch einen an ihrem anderen Ende vorgesehenen Membrankolben in beiden Achsrichtungen so weit verschoben werden kann, daß sich der Verschlußkörper jeweils an einen Ventilsitz dichtend anlegt. Bei normalem Vollastbetrieb des Verdichters, bei dem beide Ventile geöffnet sein müssen, nimmt der Verschlußkörper eine schwebende Stellung zwischen den beiden Ventilsitzen ein, die von der jeweiligen Druckbeaufschlagung der Stellmembran abhängt. Dies hat den Nachteil, daß sich bei einer unbeabsichtigten Verstellung des Verschlußkörpers auch der Durchgangsquerschnitt durch das Regelventil ändert, was zu einer Beeinträchtigung der Förderleistung des Verdichters und zu nachteiligen Schwingungen in der ganzen Verdichteranlage führen kann.An intake control valve of the type mentioned at the outset, which is expressly an intake valve intended for vacuum compressors, is known from EP-A-0 391 064. In this embodiment too, the intake control valve is designed as a double-seat valve and a closure body is provided which alternately opens and closes the two valve seats. The closure body is mounted at one end on a rod which can be displaced in both axial directions so far by a membrane piston provided at its other end that the closure body lies sealingly against a valve seat. During normal full-load operation of the compressor, in which both valves must be open, the closure body assumes a floating position between the two valve seats, which depends on the respective pressurization of the actuating membrane. This has the disadvantage that in the event of an unintentional adjustment of the closure body, the passage cross section through the control valve also changes, which can lead to an impairment of the delivery capacity of the compressor and to disadvantageous vibrations in the entire compressor system.

Die US-A-4 826 134 beschreibt schließlich ein Einlaßventil für Luftkompressoren, das aus einem Ventilgehäuse mit einem Ventilsitz und einem diesen steuernden Verschlußkörper besteht. Dieser ist an einem Ende eines Schachtes befestigt, der mit seinem anderen Ende durch einen Kolben in einem Zylinder gegen den Ventilsitz verschiebbar geführt ist. Der Stellzylinder ist in der Achse des Ventilgehäuses befestigt und vom geförderten Medium umströmt. Es handelt sich dabei um eine einfache Anordnung des Stellzylinders, der mit dem Ventilsitz fluchtet und eine geradlinige Durchströmung des Ventils ermöglicht.Finally, US-A-4 826 134 describes an inlet valve for air compressors, which consists of a valve housing with a valve seat and a closure body controlling it. This is attached to one end of a shaft, which is guided with its other end by a piston in a cylinder slidably against the valve seat. The actuating cylinder is fixed in the axis of the valve housing and flows around the pumped medium. It is a simple arrangement of the actuating cylinder, which is aligned with the valve seat and enables a straight flow through the valve.

Der Erfindung liegt die Aufgabe zugrunde, die bekannten Ansaugregelventile in ihrem Aufbau zu vereinfachen und dennoch so zu verbessern, daß sie ohne Beeinträchtigung der Funktion mit geringem Kraftaufwand betätigt werden können.The invention has for its object to simplify the structure of the known intake control valves and still improve them so that they can be operated with little effort without impairing the function.

Mit der Erfindung wird diese Aufgabe dadurch gelöst, daß der Verschlußkörper eine durch eine Endlage des Stellkolbens oder der Stellmembran definierte Zwischenstellung zwischen den beiden Sitzen aufweist, in der wenigstens annähernd der größte Durchströmquerschnitt durch das Ansaugregelventil freigegeben ist und von der er als Rückschlagventil gegen den Rückströmsitz frei verstellbar ist. Durch die Ausbildung des als Doppelsitzventil ausgeführten Ansaugregelventils mit fest definierter Zwischenstellung wird ein überraschend einfacher Aufbau und außerdem eine vorteilhafte Betätigung erreicht. Das erfindungsgemäße Ansaugregelventil wird beim Anlaufen des Schraubenverdichters durch den saugseitigen Unterdruck geschlossen und nach Aufbau eines Betriebsdruckes durch das auf den Stellkolben oder die Stellmembran wirkende Druckmedium bis in die Zwischenstellung zwischen den beiden Sitzen geöffnet.With the invention, this object is achieved in that the closure body has an intermediate position defined by an end position of the actuating piston or the actuating diaphragm between the two seats, in which at least approximately the largest flow cross-section is released through the intake control valve and from which it acts as a check valve against the backflow seat is freely adjustable. The design of the intake control valve, which is designed as a double-seat valve, with a fixedly defined intermediate position, achieves a surprisingly simple construction and also an advantageous actuation. The suction control valve according to the invention is closed by the suction-side vacuum when the screw compressor starts up and, after an operating pressure has been built up, is opened up to the intermediate position between the two seats by the pressure medium acting on the control piston or the control membrane.

Der Verschlußkörper des Ansaugregelventils wird etwa auf den halben Hub zwischen seinen beiden Sitzen angehoben und gibt in dieser Stellung den vollen Ansaugquerschnitt frei. Der Stellkolben oder die Stellmembran hat dabei nur die schwache Federkraft seiner bzw. ihrer Rückzugfeder sowie die Ansaugkraft zu überwinden. Wenn der Verdichter abgestellt wird, wird der Verschlußkörper des dann als Rückschlagventil wirkenden Ansaugregelventils unabhängig von der Lage des Stellkolbens oder der Stellmembran durch das Druckmedium auf den Rückströmsitz gedrückt, den er verschließt. Sofort nach neuerlichem Anlaufen des Schraubenverdichters saugt der Unterdruck den Verschlußkörper über seinen ganzen Hub auf den Ansaugsitz und verschließt diesen, so daß das Ansaugregelventil dann die "normal geschlossene" Funktion wahrnimmt. Eine Überlastung des Antriebsmotors wird damit verhindert.The closure body of the intake control valve is raised to about half the stroke between its two seats and releases the full intake cross-section in this position. The actuating piston or the actuating diaphragm only has to overcome the weak spring force of its retraction spring and the suction force. When the compressor is switched off, the closing body of the intake control valve, which then acts as a check valve, is pressed by the pressure medium onto the backflow seat, which it closes, regardless of the position of the control piston or the control membrane. Immediately after restarting the screw compressor, the vacuum sucks the closure body over its entire stroke onto the intake seat and closes it, so that the intake control valve then performs the "normally closed" function. This prevents the drive motor from being overloaded.

Weitere Einzelheiten und Vorteile der Erfindung ergeben sich aus der nachfolgenden Beschreibung von Ausführungsbeispielen, die in der Zeichnung dargestellt sind. Die Fig. 1 und Fig. 2 zeigen je einen Längsschnitt durch ein Ausführungsbeispiel eines erfindungsgemäßen Ansaugregelventils.Further details and advantages of the invention result from the following description of exemplary embodiments, which are shown in the drawing. 1 and 2 each show a longitudinal section through an embodiment of an intake control valve according to the invention.

Beide Ausführungsbeispiele bestehen aus einem hohlen Ventilgehäuse 1 bwz. 1', das mit einer Anschlußöffnung 2 an den Einlaß eines nicht dargestellten Schraubenverdichters angeschlossen ist. Im Ausführungsbeispiel nach Fig. 1 ist zu diesem Zweck ein Flansch 3 mit Befestigungsbohrungen 4 für Flanschschrauben vorgesehen. Das Ventilgehäuse 1 weist einen Durchströmkanal 5 auf, an den am anderen Gehäuseende die Saugleitung 6 anschließt. Am Ende der Saugleitung 6 ist ein Rückströmsitz 7 gebildet und in einigem Abstand von diesem weist das Ventilgehäuse 1 einen nach innen vorspringenden Bund 8 auf, der einen dem Rückströmsitz 7 gegenüberliegenden Ansaugsitz 9 bildet.Both embodiments consist of a hollow valve housing 1 or. 1 ', which is connected with a connection opening 2 to the inlet of a screw compressor, not shown. In the exemplary embodiment according to FIG. 1, a flange 3 with fastening bores 4 for flange screws is provided for this purpose. The valve housing 1 has a flow channel 5, to which the suction line 6 connects at the other end of the housing. At the end of the suction line 6, a backflow seat 7 is formed and at some distance from it the valve housing 1 has an inwardly projecting collar 8, which forms a suction seat 9 opposite the backflow seat 7.

Im Inneren des Ventilgehäuses 1, das als Gußteil ausgeführt sein kann, ist im Ausführungsbeispiel nach Fig. 1 ein Stellzylinder 10 angeordnet, in dem ein Stellkolben 11 gegen die Kraft einer Rückstellfeder 12 verschiebbar ist. Das offene Ende des Stellzylinders 10 ist durch einen Schraubdeckel 13 abgeschlossen, über dem ein Steueranschluß 14 in den Stellzylinder 10 mündet. Der Stellkolben 11 ist mit einer Stange 15 aus dem Stellzylinder 10 herausgeführt, auf deren freies Ende ein mit einer Bohrung versehener Fortsatz 16 eines tellerförmigen Verschlußkörpers 17 verschiebbar aufgesetzt ist. Am Gehäuse des Stellzylinders 10 stützt sich eine schwache Schraubenfeder 18 ab, die den Verschlußkörper 17 gegen den Rückströmsitz 7 belastet. Der Verschlußkörper 17 weist eine Dichtung 19 auf, die einen dichten Abschluß des Rückströmsitzes 7 bewirkt. Im Bund 8 ist dagegen ein Kanal 20 vorgesehen, der den Ansaugsitz 9 des Ansaugregelventils umgeht und damit eine Undichtheit des Ansaugsitzes 9 darstellt.In the exemplary embodiment according to FIG. 1, an actuating cylinder 10 is arranged inside the valve housing 1, which can be designed as a cast part, in which an actuating piston 11 can be displaced against the force of a return spring 12. The open end of the actuating cylinder 10 is closed by a screw cap 13, via which a control connection 14 opens into the actuating cylinder 10. The actuating piston 11 is guided out of the actuating cylinder 10 with a rod 15, on the free end of which an extension 16 provided with a bore a plate-shaped closure body 17 is slidably mounted. A weak helical spring 18 is supported on the housing of the actuating cylinder 10 and loads the closure body 17 against the backflow seat 7. The closure body 17 has a seal 19 which effects a tight seal of the backflow seat 7. In contrast, a channel 20 is provided in the collar 8, which bypasses the suction seat 9 of the suction control valve and thus represents a leak in the suction seat 9.

Im Ausführungsbeispiel nach Fig. 2 ist das Ansaugregelventil als Eckventil ausgebildet und für die Verstellung des Verschlußkörpers 17 eine Stellmembran vorgesehen, die mit 11' bezeichnet ist. Das Gehäuse 1' ist wie bei der Ausführung nach Fig. 1 an einem Ende mit der Ansaugleitung 6 verbunden, der Durchströmkanal 5 mündet jedoch an der Seite des Gehäuses 1' und ist dort in nicht näher dargestellter Weise an den Einlaß eines Schraubenverdichters angeschlossen.In the exemplary embodiment according to FIG. 2, the intake control valve is designed as a corner valve and an actuating membrane, which is designated 11 ′, is provided for the adjustment of the closure body 17. The housing 1 'is connected at one end to the suction line 6 as in the embodiment according to FIG. 1, but the flow channel 5 opens out on the side of the housing 1' and is connected there in a manner not shown to the inlet of a screw compressor.

Die Membran 11' ist in einem Druckraum 10', der mit einem Steueranschluß 14 versehen ist, eingespannt und wirkt auf einen Membranteller 11", der von der Rückstellfeder 12 belastet ist. Außerdem ist am Membranteller 11" die Stange 15 befestigt, auf die der hohle Fortsatz 16 des Verschlußkörpers 17 aufgesetzt ist. Der Verschlußkörper 17 ist also auch hier relativ zur Stellmembran 11' weitgehend frei verschiebbar, wobei lediglich eine Mitnahmeverbindung zwischen der Stange 15 und dem Verschlußkörper 17 in öffnungsrichtung des Ansaugsitzes 9 besteht, u.zw. bis in eine Zwischenstellung zwischen dem Ansaugsitz 9 und dem Rückströmsitz 7. In dieser Zwischenstellung, die durch den Anschlag eines Teils des Stellkolbens 11 am Stellzylinder 10 (Fig. 1) bzw. des Membrantellers 11" am Ventilgehäuse 1' (Fig. 2) genau definiert ist, ist der Durchströmquerschnitt durch das Ansaugregelventil ganz geöffnet und am größten.The membrane 11 'is clamped in a pressure chamber 10', which is provided with a control connection 14, and acts on a membrane plate 11 "which is loaded by the return spring 12. In addition, the rod 15 is fastened to the membrane plate 11", on which the hollow extension 16 of the closure body 17 is placed. The closure body 17 can thus also be largely freely displaced relative to the actuating membrane 11 ', with only a driving connection between the rod 15 and the closure body 17 in the opening direction of the suction seat 9, etc. to an intermediate position between the suction seat 9 and the backflow seat 7. In this intermediate position, which is caused by the stop of a part of the actuating piston 11 on the actuating cylinder 10 (FIG. 1) or the diaphragm plate 11 "on the valve housing 1 '(FIG. 2) is defined, the flow cross-section through the intake control valve is fully open and largest.

Die Stange 15 ist in beiden Ausführungsbeispielen in Abstimmung mit dem sie verstellenden Kolben 11 oder der Membran 11' so ausgebildet, daß sie den Verschlußkörper 17 nur bis in die Zwischenstellung zwischen dem Ansaugsitz 9 und dem Rückströmsitz 7 verstellen kann. Der Verschlußkörper 17 kann also auch bei hohem Betriebsdruck durch den Stellkolben 11 oder die Stellmembran 11' nicht an den Rückströmsitz 7 angepreßt werden. Dieser wird durch den Verschlußkörper 17 nur als frei verstellbares Rückschlagventil verschlossen, sobald die Förderung des Schraubenverdichters aufhört, u.zw. durch die vom verdichteten Medium auf ihn ausgeübte Kraft mit Unterstützung durch die Feder 18.In both exemplary embodiments, the rod 15 is designed in coordination with the piston 11 or the membrane 11 'that adjusts it so that it can only adjust the closure body 17 to the intermediate position between the suction seat 9 and the backflow seat 7. The closure body 17 can therefore not be pressed against the backflow seat 7 even at high operating pressure by the actuating piston 11 or the actuating membrane 11 '. This is closed by the closure body 17 only as a freely adjustable check valve as soon as the delivery of the screw compressor stops, etc. by the force exerted on it by the compressed medium with the support of the spring 18.

Das vom nicht dargestellten Schraubenverdichter geförderte Medium wird in Richtung des Pfeiles 21 durch den Durchströmkanal 5 des Ansaugregelventils hindurch angesaugt. Beim Betrieb des Schraubenverdichters befindet sich der Verschlußkörper 17 des Ansaugregelventils in der in beiden Zeichnungsfiguren dargestellten Zwischenstellung etwa in der Mitte zwischen dem Rückströmsitz 7 und dem Ansaugsitz 9, wobei er den vollen Durchströmquerschnitt durch den Durchströmkanal 5 freigibt. Wenn der Verdichter abgestellt wird, drückt die Schraubenfeder 18 den Verschlußkörper 17 unverzüglich gegen den Rückströmsitz 7, der mit Hilfe der Dichtung 19 vollständig abgedichtet wird. Dadurch wird ein Rückströmen von verdichtetem Medium in die Ansaugleitung 6 und insbesondere das Austreten von zum Schmieren des Verdichters eingespritztem Öl in diese vermieden.The medium delivered by the screw compressor, not shown, is drawn in in the direction of arrow 21 through the flow channel 5 of the intake control valve. When the screw compressor is in operation, the closure body 17 of the intake control valve is in the intermediate position shown in both drawing figures approximately in the middle between the return flow seat 7 and the intake seat 9, whereby it releases the full flow cross-section through the flow-through channel 5. When the compressor is switched off, the helical spring 18 immediately presses the closure body 17 against the backflow seat 7, which is completely sealed by means of the seal 19. As a result, backflow of compressed medium into the intake line 6 and in particular the escape of oil injected to lubricate the compressor is avoided.

Die Schraubenfeder 18 bewirkt außerdem, daß der Rückströmsitz 7 auch dann verschlossen bleibt, wenn später der Schraubenverdichter drucklos wird. Bei drucklosem Schraubenverdichter befindet sich der Stellkolben 11 oder die Stellmembran 11' unter Einwirkung der Rückstellfeder 12 in der unteren Endlage, in welcher die Stange 15 möglichst weit in den Stellzylinder 10 oder in den Druckraum 10' zurückgezogen ist.The coil spring 18 also causes the backflow seat 7 to remain closed even if the screw compressor is later depressurized. When the screw compressor is depressurized, the actuating piston 11 or the actuating membrane 11 'is under the action of the return spring 12 in the lower end position, in which the rod 15 is retracted as far as possible into the actuating cylinder 10 or into the pressure chamber 10'.

Wenn der Schraubenverdichter anschließend angefahren wird, bewirkt der dabei entstehende Unterdruck, daß der Verschlußkörper 17 vom Rückströmsitz 7 abgelöst und bis zur Anlage am Ansaugsitz 9 verschoben wird. Diese Bewegung wird durch die in das Innere des Stellzylinders 10 oder des Druckraumes 10' zurückgezogene und relativ kurze Stange 15 nicht behindert. In dieser Stellung nimmt das Ansaugregelventil seine "normal geschlossene" Funktion wahr. Das Ansaugen des vom Schraubenverdichter geförderten Mediums erfolgt in dieser Phase durch den kleinen Kanal 20, der kalibriert sein kann, so daß der Verdichter in der erwünscht langsamen Weise auf den Betriebsdruck gebracht, beispielsweise ein an den Schraubenverdichter angeschlossener Druckbehälter aufgepumpt wird.When the screw compressor is subsequently started up, the resulting negative pressure causes the closure body 17 to be detached from the backflow seat 7 and to be moved until it contacts the suction seat 9. This movement is not hindered by the relatively short rod 15 drawn back into the interior of the actuating cylinder 10 or the pressure chamber 10 '. In this position, the intake control valve performs its "normally closed" function. In this phase, the medium conveyed by the screw compressor is sucked in through the small channel 20, which can be calibrated so that the compressor is brought to the operating pressure in the desired slow manner, for example by pumping up a pressure container connected to the screw compressor.

Sobald der gewünschte Druck erreicht ist, wird z.B. über einen Zweipunktregler der Steueranschluß 14 unter Druck gesetzt und damit der Stellkolben 11 oder die Stellmembran 11' mit Druckmittel beaufschlagt, worauf die Stange 15 den Verschlußkörper 17 vom Ansaugsitz 9 abhebt und in die in der Zeichnung dargestellte Zwischenstellung bringt. Durch Wahl der Größe des Druckes des durch den Steueranschluß 14 zugeführten Mediums ist es auch möglich, den Verschlußkörper 17 mehr oder weniger vom Ansaugsitz 9 abzuheben und so die vom Schraubenverdichter angesaugte Mediumsmenge stufenlos zu regeln.As soon as the desired pressure is reached, e.g. The control connection 14 is pressurized via a two-point controller and thus the actuating piston 11 or the actuating diaphragm 11 'is pressurized, whereupon the rod 15 lifts the closure body 17 from the suction seat 9 and brings it into the intermediate position shown in the drawing. By selecting the size of the pressure of the medium supplied through the control connection 14, it is also possible to lift the closure body 17 more or less from the suction seat 9 and thus to continuously regulate the amount of medium sucked in by the screw compressor.

Claims (1)

  1. A suction control valve for a screw-type compressor, in particular for a screw-type compressor with oil injection, which is fitted in the suction line of the screw-type compressor and comprises a closure member (17) alternately releasing or closing the suction line (6) and operatively connected in the opening direction of the suction line (6) to a displacement piston (11) or diaphragm which is displaceable in a cylinder (10) and which can be acted upon with a pressure fluid, wherein the suction control valve constructed in the form of a double-seat valve is provided with a suction seat (9) closed by the closure member (17) in the suction direction (21) and a return-flow seat (7) closed contrary to the suction direction (21) by the closure member (17), characterized in that the closure member (17) has an intermediate position - between the two seats (7, 9) - which is precisely defined by an end position by means of a stop of the displacement piston (11) on the displacement cylinder (10) or the displacement diaphragm (11') on the valve housing (1') and in which at least approximately the greatest throughflow cross-section is released by the suction control valve and from which it is freely displaceable as a return valve against the return-flow seat (7).
EP19930890096 1992-06-02 1993-05-12 Suction control valve Expired - Lifetime EP0576415B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT0113792A AT402542B (en) 1992-06-02 1992-06-02 INTAKE CONTROL VALVE
AT1137/92 1992-06-02

Publications (2)

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EP0576415A1 EP0576415A1 (en) 1993-12-29
EP0576415B1 true EP0576415B1 (en) 1996-03-13

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EP19930890096 Expired - Lifetime EP0576415B1 (en) 1992-06-02 1993-05-12 Suction control valve

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US (1) US5411375A (en)
EP (1) EP0576415B1 (en)
AT (1) AT402542B (en)
DE (1) DE59301852D1 (en)
FI (1) FI105413B (en)

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Also Published As

Publication number Publication date
DE59301852D1 (en) 1996-04-18
EP0576415A1 (en) 1993-12-29
US5411375A (en) 1995-05-02
FI932498A0 (en) 1993-06-01
FI932498A (en) 1993-12-03
FI105413B (en) 2000-08-15
AT402542B (en) 1997-06-25
ATA113792A (en) 1996-10-15

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