EP0353266B1 - Nonreturn valve, in particular for incorporation in drinking water pipes - Google Patents

Nonreturn valve, in particular for incorporation in drinking water pipes Download PDF

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Publication number
EP0353266B1
EP0353266B1 EP19890900218 EP89900218A EP0353266B1 EP 0353266 B1 EP0353266 B1 EP 0353266B1 EP 19890900218 EP19890900218 EP 19890900218 EP 89900218 A EP89900218 A EP 89900218A EP 0353266 B1 EP0353266 B1 EP 0353266B1
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EP
European Patent Office
Prior art keywords
valve
valve body
drain valve
spring
drain
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EP19890900218
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German (de)
French (fr)
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EP0353266A1 (en
Inventor
Walter Evers
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Waletzko Armaturen GmbH
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Waletzko Armaturen GmbH
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    • E—FIXED CONSTRUCTIONS
    • E03—WATER SUPPLY; SEWERAGE
    • E03C—DOMESTIC PLUMBING INSTALLATIONS FOR FRESH WATER OR WASTE WATER; SINKS
    • E03C1/00—Domestic plumbing installations for fresh water or waste water; Sinks
    • E03C1/02—Plumbing installations for fresh water
    • E03C1/10—Devices for preventing contamination of drinking-water pipes, e.g. means for aerating self-closing flushing valves
    • E03C1/106—Devices for preventing contamination of drinking-water pipes, e.g. means for aerating self-closing flushing valves using two or more check valves
    • E—FIXED CONSTRUCTIONS
    • E03—WATER SUPPLY; SEWERAGE
    • E03C—DOMESTIC PLUMBING INSTALLATIONS FOR FRESH WATER OR WASTE WATER; SINKS
    • E03C1/00—Domestic plumbing installations for fresh water or waste water; Sinks
    • E03C1/02—Plumbing installations for fresh water
    • E03C1/10—Devices for preventing contamination of drinking-water pipes, e.g. means for aerating self-closing flushing valves
    • E03C1/108—Devices for preventing contamination of drinking-water pipes, e.g. means for aerating self-closing flushing valves having an aerating valve

Definitions

  • the invention relates to a backflow preventer, in particular intended for installation in drinking water pipes, with a flow-through housing formed with a feed and discharge line, a spring-loaded inlet valve accommodated therein and a spring-loaded outlet valve as well as a central chamber arranged between the two coaxially arranged valves, which communicate with the outside atmosphere
  • a drain valve which maintains a minimum differential pressure between the feed line and the middle chamber is to be connected, the valve body of which is connected to a control membrane, one side of which is in hydraulic connection with the feed line and the other side of which is in hydraulic connection with the middle chamber, the drain valve, its valve body and the Control diaphragm is outside the flow tube.
  • Backflow preventers of the above type are known from DE-A-29 30 819 and in a slightly modified manner, namely with a flow housing designed instead of a cylindrical tubular venturi nozzle, through US-A-25 03 424. They ensure that the liquid pressure in the middle chamber is always lower than the liquid pressure in the supply line, whereby a backflow of the liquid from the central chamber or discharge into the supply line is prevented even in the case of a defective or leak-prone supply valve.
  • the drain valve each having two valve seats, is provided with a single control membrane and with a valve spring or with a load weight, which seek to keep the valve body in its position lifted from its two valve seats, that is to say in the open position.
  • control membrane If the control membrane is damaged or leaky, contaminated water can still get from the central chamber into the supply chamber via the control membrane chamber. Even if the valve spring becomes damaged or breaks, the desired backflow prevention option is not achieved because the hydraulic pressure in the central chamber can then reach the same level as the hydraulic pressure in the inflow chamber without the drain valve then already opening.
  • the invention is therefore based on the object to provide a backflow preventer of the type in question, which does not have the aforementioned disadvantages, but rather offers an even greater security against any backflow.
  • this object is achieved in that two control membranes separated from one another by a space connected to the outside atmosphere are connected to the drain valve body, the control membrane facing the drain valve body being acted upon by the liquid pressure prevailing in the central chamber, whereas the other control membrane is affected by the liquid pressure prevailing in the feed line is acted upon and wherein the effective pressurizing cross section of the control diaphragm connected to the supply line is smaller by more than the cross-sectional dimension of the drain valve body piston than the effective pressurizing cross section of the other control diaphragm pressurized connected to the central chamber.
  • the presence of two control membranes with their space connected to the outside atmosphere ensures that in the event of defective or The one control membrane leaks the other control membrane still ensures a perfect separation of the inlet and intermediate chamber.
  • the inventive dimensioning of the different effective pressurization cross-sections of the two control membranes and the drain valve body piston ensures that the drain valve opens in any case even if the drain valve spring does not exist or breaks, before the hydraulic pressure in the middle chamber reaches or reaches that of the feed chamber comes close.
  • This shut-off and ventilation device is available in a non-generic pipe separator, where the drain valve body in question does not allow the middle chamber between the inlet and outlet valve to be connected to the outside atmosphere, but is installed in the supply line leading to the pressurization chamber of a piston valve-shaped inlet valve, depending on the situation after the water pressure in the discharge line, connect the above-mentioned pressurization chamber either to the liquid supply line or to the outside atmosphere, so that the inlet valve piston can return to its separation position which is relieved of the application pressure.
  • the two control membranes acting on the common drain valve body are here, on the one hand, under the liquid pressure prevailing in the supply line and, on the other hand, under the liquid pressure prevailing in the discharge line. In addition, both control membranes have the same area of application.
  • the drain valve has a single valve seat surface and its valve body is acted upon by a valve spring which tries to lift it off.
  • a single valve seat on the drain valve body teaches that the known backflow preventer existing drain valves with two valve seats each have the advantage of simple design and better sealing.
  • the presence of a special drain valve spring is advantageous because it enables the opening of the drain valve to be predetermined or achieved exactly when the hydraulic pressure difference between the inlet and middle chambers reaches a certain minimum value.
  • the illustrated backflow preventer consists essentially of the flow housing pipe 3, which is connected in a liquid-tight manner to a supply pipe socket 1 and a discharge pipe socket 2, in which a supply valve 4 and a drain valve 5 and a central chamber 6 present between the two valves are arranged to shut off the supply line 1 , which can be connected to the outside atmosphere via the drain valve generally designated 7.
  • a supply valve 4 and a drain valve 5 and a central chamber 6 present between the two valves are arranged to shut off the supply line 1 , which can be connected to the outside atmosphere via the drain valve generally designated 7.
  • the drain valve generally designated 7.
  • the inlet valve 4 has a valve body 8 which is axially displaceably mounted on an axially arranged guide tube 10 held in the flow-through housing tube 3 via connecting webs 9.
  • the comparatively large inlet valve spring 11 is accommodated, which seeks to press the valve body 8 with its seal 8 'bearing end face against the valve seat 1', which is formed by the recessed shoulder of the inlet tube or tube connection piece 1 projecting into the flow housing tube 3 becomes.
  • the drain valve 5 has a mushroom-shaped valve body 12, with its shaft 12 'in a guide bore 13 is guided axially displaceably, which is located in the housing web 14. Between the head 12 ⁇ of the valve body and the housing web 14, the drain valve spring 15 is supported, which is kept much weaker than the inlet valve spring 11.
  • the frustoconical valve head 12 'cooperates with the tapered valve seat surface 16', which is located in a plug-in sleeve 16 inserted into the flow housing tube 3 at the rear.
  • the valve seat surface 16 ' is provided with a correspondingly designed seal 17.
  • the drain valve 7 has a drain valve housing 18, which consists of three housing parts 18 ', 18 ⁇ , 18' '', which are firmly connected to each other via screws 19. Between the housing middle part 18 Gebirus and the housing end parts 18 'on the one hand and 18' '' on the other hand, a control membrane 20, 20 'is clamped firmly around the edge. Both membranes 20, 20 'are firmly connected to the piston-like valve body 25 via the disks 21, 22, 23 and the connecting screw 24. The between the two membranes 20, 20 'existing space 26 is connected via the ventilation openings 27 with the outside atmosphere.
  • the Ablrawventilkorper 25 is housed together with the surrounding drain valve spring 28 in the housing part 18 '''existing tube extension 18 IV axially displaceable.
  • This tube extension 18 IV is provided on the bottom side with a drain opening 29 leading into the open and with a lateral connecting piece 30 which is connected to the central chamber 6 via the line 31.
  • a seal 32 is provided in the tube extension 18 IV , on which the valve body 25 with its end face 25 'can sit.
  • the drain valve spring 28 is also supported on this seal 32 while it engages with its other end on rib-like projections 25 ⁇ of the valve body 25.
  • the lower diaphragm 20 'facing control chamber 33 is connected via line 31 to the middle chamber 6, while the other control diaphragm 20 adjacent control chamber 34 is connected via the pipe connection 35 to the connecting piece 1' '' of the feed line 1 ' .
  • the control chamber 34 is kept smaller in cross section than the control chamber 33, so that there is a smaller effective cross section for the control diaphragm 20 than for the control diaphragm 20 '.
  • the extent of the reduction in cross section corresponds to the cross section of the drain valve body piston 25.
  • valves 4, 5 get into their in the Drawing shown open position, since the water withdrawal causes a corresponding pressure drop not only in the discharge line 2 'but also after opening the drain valve 5 in the middle chamber 6, so that the pressure in the supply line 1' of, for example, 5 bar is designed to be, for example, 4 bar the inlet valve spring 11 overcomes.
  • the pressure in the central chamber 6 of, for example, 4 bar also prevails in the control chamber 33.
  • the relief valve spring 28 set for a pressure relief of, for example, 0.5 bar is therefore unable to lift the drain valve body 25 from its closed position into the open position.
  • the drain valve spring 28 can even be omitted because even then the desired minimum pressure difference between the central chamber 6 and the feed line 1' would be achieved .

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Hydrology & Water Resources (AREA)
  • Public Health (AREA)
  • Water Supply & Treatment (AREA)
  • Check Valves (AREA)
  • Fluid-Driven Valves (AREA)
  • Safety Valves (AREA)

Abstract

A nonreturn valve comprises a flow housing (3) containing an inlet and an outlet pipe (1', 2') in which are lodged a spring-loaded inlet valve (4), an outlet valve (5) and an intermediate central chamber (6). The latter is connected to the outside atmosphere by a drain valve (7), the valve body (25) of which is connected to a control membrane (20, 20'). One side of said membrane is in hydraulic communication with the inlet pipe (1') and the other side is in hydraulic communication with the central chamber (6). In addition, the membrane (20, 20') is controlled by a drain valve spring (28) which maintains a minimal pressure differential between the inlet pipe (1') and the central chamber (6). In order to achieve a compact structure with negligible flow resistance, the flow housing (3) is cylindrical, the inlet and outlet valves (4 and 5) together with their control springs (11, 15) are lodged axially in said housing and the drain valve (7), its valve body (25) and the control membrane (20, 20') are located outside the tubular housing (3). The drain valve body (25) is advantageously provided with two control membranes (20, 20') separated from each other by an intermediate space (26) in communication with the outside atmosphere. The control membrane (20') facing the drain valve body (25) can be actuated by the liquid pressure prevailing in the central chamber (6), while the other control membrane (20) is actuated by the liquid pressure prevailing in the inlet pipe (1').

Description

Die Erfindung bezieht sich auf einen insbesondere zum Einbau in Trinkwasserleitungen bestimmten Rückflußverhinderer mit einem eine Zu- und Ableitung enthaltenden, zylinderrohrförmig ausgebildeten Durchflußgehäuse, einem darin untergebrachten federbelasteten Zulaufventil und einem federbelasteten Ablaufventil sowie einer zwischen beiden koaxial angeordneten Ventilen angeordneten Mittelkammer, die mit der Außenatmosphäre über ein für die Aufrechterhaltung eines Mindestdifferenzdrucks zwischen Zuleitung und Mittelkammer sorgendes Ablaßventil zu verbinden ist, dessen Ventilkörper mit einer Steuermembran verbunden ist, deren eine Beaufschlagungsseite mit der Zuleitung und deren andere Beaufschlagungsseite mit der Mittelkammer in hydraulischer Verbindung steht, wobei das Ablaßventil, sein Ventilkörper und die Steuermembran außerhalb des Durchflußgehäuserohres liegen.The invention relates to a backflow preventer, in particular intended for installation in drinking water pipes, with a flow-through housing formed with a feed and discharge line, a spring-loaded inlet valve accommodated therein and a spring-loaded outlet valve as well as a central chamber arranged between the two coaxially arranged valves, which communicate with the outside atmosphere A drain valve which maintains a minimum differential pressure between the feed line and the middle chamber is to be connected, the valve body of which is connected to a control membrane, one side of which is in hydraulic connection with the feed line and the other side of which is in hydraulic connection with the middle chamber, the drain valve, its valve body and the Control diaphragm is outside the flow tube.

Rückflußverhinderer obiger Art sind durch die DE-A-29 30 819 sowie in leicht abgewandelter Art, nämlich mit einem statt zylinderrohrförmig venturidüsenartig ausgebildeten Durchflußgehäuse versehen, durch die US-A-25 03 424 bekannt. Sie sorgen dafür, daß der in der Mittelkammer herrschende Flüssigkeitsdruck stets niedriger als der in der Zuleitung vorhandene Flüssigkeitsdruck ist, wodurch auch bei etwa schadhaftem oder leckagebehaftetem Zulaufventil ein Rückfluß der Flüssigkeit aus der Mittelkammer oder Ableitung in die Zuleitung verhindert wird. Bei diesen vorbekannten Rückflußverhinderern ist das jeweils zwei Ventilsitze besitzende Ablaßventil mit einer einzigen Steuermembran und mit einer Ventilfeder bzw. mit einem Belastungsgewicht versehen, die den Ventilkörper in seiner von seinen beiden Ventilsitzen abgehobenen Stellung, also in Offenstellung zu halten suchen. Bei schadhafter bzw. undichter Steuermembran kann hier aber dennoch verunreinigtes Wasser aus der Mittelkammer über die Steuermembrankammer in die Zuleitungskammer gelangen. Auch bei Schadhaftwerden bzw. Bruch der Ventilfeder wird die angestrebte Rückflußverhinderungsmöglichkeit nicht erreicht, weil dann der hydraulische Druck in der Mittelkammer die gleiche Höhe wie der hydraulische Druck in der Zuflußkammer erreichen kann, ohne daß das Ablaßventil dann bereits öffnen würde.Backflow preventers of the above type are known from DE-A-29 30 819 and in a slightly modified manner, namely with a flow housing designed instead of a cylindrical tubular venturi nozzle, through US-A-25 03 424. They ensure that the liquid pressure in the middle chamber is always lower than the liquid pressure in the supply line, whereby a backflow of the liquid from the central chamber or discharge into the supply line is prevented even in the case of a defective or leak-prone supply valve. In these known backflow preventer, the drain valve, each having two valve seats, is provided with a single control membrane and with a valve spring or with a load weight, which seek to keep the valve body in its position lifted from its two valve seats, that is to say in the open position. If the control membrane is damaged or leaky, contaminated water can still get from the central chamber into the supply chamber via the control membrane chamber. Even if the valve spring becomes damaged or breaks, the desired backflow prevention option is not achieved because the hydraulic pressure in the central chamber can then reach the same level as the hydraulic pressure in the inflow chamber without the drain valve then already opening.

Der Erfindung liegt daher die Aufgabe zugrunde, einen Rückflußverhinderer der in Rede stehenden Gattung zu schaffen, der die vorerwähnten Nachteile nicht aufweist, vielmehr eine noch größere Sicherheit gegen etwaigen Rückfluß bietet. Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß mit dem Ablaßventilkörper zwei durch einen mit der Außenatmosphäre verbundenen Zwischenraum voneinander getrennte Steuermembranen verbunden sind, deren dem Ablaßventilkörper zugewandt liegende Steuermembran vom in der Mittelkammer herrschenden Flüssigkeitsdruck beaufschlagt ist, wohingegen die andere Steuermembran vom in der Zulaufleitung herrschenden Flüssigkeitsdruck beaufschlagt ist und wobei der wirksame Beaufschlagungsquerschnitt der mit der Zuleitung druckbeaufschlagungsmäßig verbundenen Steuermembran um mehr als das Querschnittsmaß des Ablaßventilkörperkolbens kleiner als der wirksame Beaufschlagungsquerschnitt der mit der Mittelkammer druckbeaufschlagungsmäßig verbunden anderen Steuermembran ist.The invention is therefore based on the object to provide a backflow preventer of the type in question, which does not have the aforementioned disadvantages, but rather offers an even greater security against any backflow. According to the invention, this object is achieved in that two control membranes separated from one another by a space connected to the outside atmosphere are connected to the drain valve body, the control membrane facing the drain valve body being acted upon by the liquid pressure prevailing in the central chamber, whereas the other control membrane is affected by the liquid pressure prevailing in the feed line is acted upon and wherein the effective pressurizing cross section of the control diaphragm connected to the supply line is smaller by more than the cross-sectional dimension of the drain valve body piston than the effective pressurizing cross section of the other control diaphragm pressurized connected to the central chamber.

Auf diese Weise wird eine zusätzliche doppelte Sicherheit gegen Rückfluß erreicht. So wird durch das Vorhandensein zweier Steuermembranen mit ihrem an die Außenatmosphäre verbundenen Zwischenraum sichergestellt, daß bei Schadhaft-bzw. Undichtwerden der einen Steuermembran die andere Steuermembran immer noch für eine einwandfreie Trennung von Zulauf- und Zwischenkammer sorgt. Weiterhin wird durch die erfindungsgemäße Bemessung der unterschiedlichen wirksamen Beaufschlagungsquerschnitte der beiden Steuermembranen sowie des Ablaßventilkörperkolbens erreicht, daß bereits bei Nichtvorhandensein oder aber Zubruchgehen der Ablaßventilfeder das Ablaßventil in jedem Falle öffnet, bevor noch der hydraulische Druck in der Mittelkammer etwa den der Zulaufkammer erreicht bzw. ihm nahekommt.In this way an additional double security against backflow is achieved. Thus, the presence of two control membranes with their space connected to the outside atmosphere ensures that in the event of defective or The one control membrane leaks the other control membrane still ensures a perfect separation of the inlet and intermediate chamber. Furthermore, the inventive dimensioning of the different effective pressurization cross-sections of the two control membranes and the drain valve body piston ensures that the drain valve opens in any case even if the drain valve spring does not exist or breaks, before the hydraulic pressure in the middle chamber reaches or reaches that of the feed chamber comes close.

An dieser Stelle sei bemerkt, daß es bei einer durch die DE-C-35 37 484 bekannten Absperr- und Belüftungsvorrichtung für Trinkwasseranlagen bereits bekannt ist, einen Ablaßventilkörper mit zwei durch einen mit der Außenatmosphäre verbundenen Zwischenraum voneinander getrennten Steuermembranen zu verbinden, die außen von unterschiedlichen Flüssigkeitsdrücken beaufschlagt werden. Diese Absperr- und Belüftungsvorrichtung ist aber bei einem gattungsfremden Rohrtrenner vorhanden, wo der betreffende Ablaßventilkörper nicht die zwischen Zu- und Ablaufventil vorhandene Mittelkammer mit der Außenatmosphäre zu verbinden erlaubt, sondern in die zur Druckbeaufschlagungskammer eines kolbenrohrartig ausgebildeten Zulaufventils führende Zuleitung eingebaut ist, um hier je nach dem in der Ableitung vorhandenen Wasserdruck die vorerwähnte Druckbeaufschlagungskammer entweder mit der Flüssigkeitszuleitung oder mit der Außenatmosphäre zu verbinden, damit der Zulaufventilkolben in seine vom Beaufschlagungsdruck entlastete Trennstellung zurückfahren kann. Die beiden auf den gemainsamen Ablaßventilkörper wirkenden Steuermembranen stehen hier einerseits unter dem in der Zuleitung und andererseits unter dem in der Ableitung herrschenden Flüssigkeitsdruck. Darüber hinaus besitzen beide Steuermembranen den gleichen Beaufschlagungsquerschnitt.At this point it should be noted that in a shut-off and ventilation device for drinking water systems known from DE-C-35 37 484, it is already known to connect a drain valve body to two control membranes separated from one another by a space connected to the outside atmosphere, the outside of which different liquid pressures are applied. This shut-off and ventilation device is available in a non-generic pipe separator, where the drain valve body in question does not allow the middle chamber between the inlet and outlet valve to be connected to the outside atmosphere, but is installed in the supply line leading to the pressurization chamber of a piston valve-shaped inlet valve, depending on the situation after the water pressure in the discharge line, connect the above-mentioned pressurization chamber either to the liquid supply line or to the outside atmosphere, so that the inlet valve piston can return to its separation position which is relieved of the application pressure. The two control membranes acting on the common drain valve body are here, on the one hand, under the liquid pressure prevailing in the supply line and, on the other hand, under the liquid pressure prevailing in the discharge line. In addition, both control membranes have the same area of application.

Nach einem weiteren Merkmal der Erfindung besitzt das Ablaßventil eine einzige Ventilsitzfläche und sein Ventilkörper ist durch eine ihn davon abzuheben suchende Ventilfeder beaufschlagt. Das Vorhandensein einer einzigen Ventilsitzfläche beim Ablaßventilkörper bringt gegenüber den bei den vorbekannten Rückflußverhinderern vorhandenen Ablaßventilen mit je zwei Ventilsitzflächen den Vorteil einfacher Bauart sowie besserer Abdichtung. Das Vorhandensein einer besonderen Ablaßventilfeder ist vorteilhaft, weil dadurch das Öffnen des Ablaßventils exakt vorausbestimmt bzw. erreicht werden kann, wenn die hydraulische Druckdifferenz zwischen Zulauf- und Mittelkammer einen bestimmten Mindestwert erreicht.According to a further feature of the invention, the drain valve has a single valve seat surface and its valve body is acted upon by a valve spring which tries to lift it off. The presence of a single valve seat on the drain valve body teaches that the known backflow preventer existing drain valves with two valve seats each have the advantage of simple design and better sealing. The presence of a special drain valve spring is advantageous because it enables the opening of the drain valve to be predetermined or achieved exactly when the hydraulic pressure difference between the inlet and middle chambers reaches a certain minimum value.

Weitere Merkmale der Erfindung sind in den Ansprüchen 3 bis 6 gekennzeichnet.Further features of the invention are characterized in claims 3 to 6.

In der Zeichnung ist ein vorteilhaftes Ausführungsbeispiel eines nach der Erfindung gestalteten Rückflußverhinderers im Schnitt dargestellt.In the drawing, an advantageous embodiment of a check valve designed according to the invention is shown in section.

Der abgebildete Rückflußverhinderer besteht im wesentlichen aus dem mit einem Zuleitungs-Rohrstutzen 1 und einem Ablauf-Rohrstutzen 2 flüssigkeitsdicht verbundenen Durchflußgehäuserohr 3, in welchem ein die Zuleitung 1′ abzusperren erlaubendes Zulaufventil 4 und ein Ablaufventil 5 sowie eine zwischen beiden Ventilen vorhandene Mittelkammer 6 angeordnet sind, die über das generell mit 7 bezeichnete Ablaßventil mit der Außenatmosphäre verbunden werden kann. An den Gewindeanschlußstutzen 1′′′ und 3′ können Manometer angebracht werden.The illustrated backflow preventer consists essentially of the flow housing pipe 3, which is connected in a liquid-tight manner to a supply pipe socket 1 and a discharge pipe socket 2, in which a supply valve 4 and a drain valve 5 and a central chamber 6 present between the two valves are arranged to shut off the supply line 1 , which can be connected to the outside atmosphere via the drain valve generally designated 7. At the threaded connection piece 1 '' 'and 3' manometers can be attached.

Das Zulaufventil 4 besitzt einen Ventilkörper 8, der auf einem im Durchflußgehäuserohr 3 über Verbindungsstege 9 gehaltenen, axial angeordneten Führungsrohr 10 axial verschieblich gelagert ist. Im Führungsrohr 10 ist die vergleichsweise stark bemessene Zulaufventilfeder 11 untergebracht, die den Ventilkörper 8 mit seiner eine Dichtung 8′ tragenden Stirnfläche gegen den Ventilsitz 1˝ zu drücken sucht, der von der zurückspringenden Schulter des in das Durchflußgehäuserohr 3 hineinagenden Zulaufrohres bzw.rohranschlußstutzens 1 gebildet wird.The inlet valve 4 has a valve body 8 which is axially displaceably mounted on an axially arranged guide tube 10 held in the flow-through housing tube 3 via connecting webs 9. In the guide tube 10, the comparatively large inlet valve spring 11 is accommodated, which seeks to press the valve body 8 with its seal 8 'bearing end face against the valve seat 1', which is formed by the recessed shoulder of the inlet tube or tube connection piece 1 projecting into the flow housing tube 3 becomes.

Das Ablaufventil 5 besitzt einen pilzförmigen Ventilkörper 12, der mit seinem Schaft 12′ in einer Führungsbohrung 13 axial verschieblich geführt ist, die sich in dem Gehäusesteg 14 befindet. Zwischen dem Kopf 12˝ des Ventilkörpers und dem Gehäusesteg 14 stützt sich die Ablaufventilfeder 15 ab, die sehr viel schwächer als die Zulaufventilfeder 11 gehalten ist. Der stumpfkegelig ausgebildete Ventilkopf 12˝ wirkt mit der kegeligen Ventilsitzfläche 16′ zusammen, die sich in einer in das Durchflußgehäuserohr 3 rückwärtig eingesetzten Einsteckbüchse 16 befindet. Deren Ventilsitzfläche 16′ ist mit einer entsprechend gestalteten Dichtung 17 versehen.The drain valve 5 has a mushroom-shaped valve body 12, with its shaft 12 'in a guide bore 13 is guided axially displaceably, which is located in the housing web 14. Between the head 12˝ of the valve body and the housing web 14, the drain valve spring 15 is supported, which is kept much weaker than the inlet valve spring 11. The frustoconical valve head 12 'cooperates with the tapered valve seat surface 16', which is located in a plug-in sleeve 16 inserted into the flow housing tube 3 at the rear. The valve seat surface 16 'is provided with a correspondingly designed seal 17.

Das Ablaßventil 7 besitzt ein Ablaßventilgehäuse 18, das aus drei Gehäuseteilen 18′, 18˝, 18′′′ besteht, die miteinander über Schrauben 19 fest miteinander verbunden sind. Zwischen dem Gehäusemittelteil 18˝ und den Gehäuseendteilen 18′ einerseits und 18′′′ andererseits ist je eine Steuermembran 20, 20′ randumfangsmäßig fest eingespannt. Beide Membranen 20, 20′ sind über die Scheiben 21, 22, 23 und die Verbindungsschraube 24 fest mit dem kolbenartig ausgebildeten Ventilkörper 25 verbunden. Der zwischen den beiden Membranen 20, 20′ vorhandene Zwischenraum 26 steht über die Belüftungsöffnungen 27 mit der Außenatmosphäre in Verbindung.The drain valve 7 has a drain valve housing 18, which consists of three housing parts 18 ', 18˝, 18' '', which are firmly connected to each other via screws 19. Between the housing middle part 18 Gehäus and the housing end parts 18 'on the one hand and 18' '' on the other hand, a control membrane 20, 20 'is clamped firmly around the edge. Both membranes 20, 20 'are firmly connected to the piston-like valve body 25 via the disks 21, 22, 23 and the connecting screw 24. The between the two membranes 20, 20 'existing space 26 is connected via the ventilation openings 27 with the outside atmosphere.

Der Ablaßventilkorper 25 ist zusammen mit der ihn umgebenden Ablaßventilfeder 28 in dem am Gehäuseteil 18′′′ vorhandenen Rohransatz 18IV axial verschieblich untergebracht. Dieser Rohransatz 18IV ist bodenseitig mit einer ins Freie führenden Ablaßöffnung 29 sowie mit einem seitlichen Anschlußstutzen 30 versehen, der über die Leitung 31 mit der Mittelkammer 6 in Verbindung steht. Oberhalb der ins Freie führenden Ablaßöffnung 29 ist im Rohransatz 18IV eine Dichtung 32 vorgesehen, auf der der Ventilkörper 25 mit seiner Stirnfläche 25′ aufzusitzen vermag. Die Ablaßventilfeder 28 stützt sich gleichfalls auf dieser Dichtung 32 ab, während sie mit ihrem anderen Ende an rippenartigen Vorsprüngen 25˝ des Ventilkörpers 25 angreift.The Ablaßventilkorper 25 is housed together with the surrounding drain valve spring 28 in the housing part 18 '''existing tube extension 18 IV axially displaceable. This tube extension 18 IV is provided on the bottom side with a drain opening 29 leading into the open and with a lateral connecting piece 30 which is connected to the central chamber 6 via the line 31. Above the discharge opening 29 leading into the open, a seal 32 is provided in the tube extension 18 IV , on which the valve body 25 with its end face 25 'can sit. The drain valve spring 28 is also supported on this seal 32 while it engages with its other end on rib-like projections 25˝ of the valve body 25.

Die der unteren Membran 20′ zugewandt liegende Steuerkammer 33 steht über die Leitung 31 mit der Mittelkammer 6 in Verbindung, während die der anderen Steuermembran 20 benachbart liegende Steuerkammer 34 über den Rohrverbindungsanschluß 35 mit dem Anschlußstutzen 1′′′ der Zuleitung 1′ flüssigkeitsleitend verbunden ist. Die Steuerkammer 34 ist in ihrem Querschnitt kleiner gehalten als die Steuerkammer 33, so daß sich für die Steuermembran 20 ein kleinerer wirksamer Beaufschlagungsquerschnitt als für die Steuermembran 20′ ergibt. Das Maß der Querschnittsverringerung entspricht dem Querschnitt des Ablaßventilkörperkolbens 25. Hierdurch kann unabhängig von dem in der Zuleitung 1′ herrschenden Flüssigkeitsdruck bei geschlossenem Zulaufventil 4 stets ein bestimmter Mindestdifferenzdruck zwischen der Zuleitung 1′ und der Mittelkammer 6 aufrechterhalten werden.The lower diaphragm 20 'facing control chamber 33 is connected via line 31 to the middle chamber 6, while the other control diaphragm 20 adjacent control chamber 34 is connected via the pipe connection 35 to the connecting piece 1' '' of the feed line 1 ' . The control chamber 34 is kept smaller in cross section than the control chamber 33, so that there is a smaller effective cross section for the control diaphragm 20 than for the control diaphragm 20 '. The extent of the reduction in cross section corresponds to the cross section of the drain valve body piston 25. As a result, a certain minimum differential pressure between the feed line 1 'and the central chamber 6 can always be maintained regardless of the liquid pressure prevailing in the feed line 1' when the feed valve 4 is closed.

Erfolgt auf der Ableitungsseite 2′ keine Wasserentnahme, so befinden sich alle Ventile 4, 5 und 7 in der Schließstellung. Dabei stellt das Ablaufventil 7 sicher, daß in der Mittelkammer 6 der Flüssigkeitsdruck stets um so viel unter dem in der Zuleitung 1′ herrschenden Druck liegt, wie das durch die Stärke der Ablaßventilfeder 28 gegeben ist. Sollte dabei aus irgend einem Grund in der Mittelkammer 6 der Flüssigkeitsdruck steigen, etwa durch eine plötzliche Druckerhöhung auf der Ablaufseite 2′ bei schadhaftem Ablaufventil 5, so würde das zu einer entsprechenden Druckerhöhung in der Steuerkammer 33 und damit zu einem Anheben des Ablaßventilkörpers 25 führen, der dadurch von der dichtenden Ventilsitzfläche 32 abheben würde, was zu einer sofortigen Druckabnahme in der Leitung 31 und damit auch in der Mittelkammer 6 führen würde. Wird ablaufseitig Wasser entnommen, so gelangen die Ventile 4, 5 in ihre in der Zeichnung dargestellte Offenstellung, da die Wasserentnahme einen entsprechenden Druckabfall nicht nur in der Ableitung 2′ sondern nach Öffnen des Ablaufventils 5 auch in der Mittelkammer 6 hervorruft, wodurch der in der Zuleitung 1′ vorhandene Druck von beispielsweise 5 bar den auf beispielsweise 4 bar ausgelegten Druck der Zulaufventilfeder 11 überwindet. Der in der Mittelkammer 6 vorhandene Druck von beispielsweise 4 bar herrscht auch in der Steuerkammer 33. Die auf einen Druckablaß von beispielsweise 0,5 bar eingestellte Ablaßventilfeder 28 vermag daher den Ablaßventilkörper 25 nicht aus seiner Schließstellung in die Offenstellung anzuheben. Das wäre erst dann möglich, wenn es etwa auf der Ablaufseite wieder zu einer Druckerhöhung oder aber, was grundsätzlich auch möglich wäre, auf der Zulaufseite 1′ zu einem plötzlichen Druckabfall käme. Für diesen Falle würde ein entsprechender Druckabfall auch in der Steuerkammer 34 eintreten, demzufolge der Ablaßventilkörper 25 in seine Offenstellung gelangen und dadurch zu einer entsprechenden Druckerniedrigung in der Mittelkammer 6 führen würde. Somit ist also sichergestellt, daß zwischen Zuleitung 1′ und der Mittelkammer 6 stets ein Mindestdruckgefälle besteht, das einen Rückfluß des Brauchwassers in die Zuleitung 1′ verhindert. Von besonderem Vorteil ist auch, daß dieser Rückflußverhinderer einbaulageunabhängig ist, also in beliebiger Position verwendet werden kann.If there is no water withdrawal on the discharge side 2 ', all valves 4, 5 and 7 are in the closed position. The drain valve 7 ensures that in the central chamber 6 the liquid pressure is always so much below the pressure prevailing in the feed line 1 'as is given by the strength of the drain valve spring 28. If the liquid pressure in the middle chamber 6 should rise for any reason, for example due to a sudden pressure increase on the outlet side 2 'with a defective drain valve 5, this would lead to a corresponding pressure increase in the control chamber 33 and thus to a rise in the drain valve body 25, which would thereby lift off the sealing valve seat surface 32, which would lead to an immediate decrease in pressure in the line 31 and thus also in the middle chamber 6. If water is removed on the outlet side, the valves 4, 5 get into their in the Drawing shown open position, since the water withdrawal causes a corresponding pressure drop not only in the discharge line 2 'but also after opening the drain valve 5 in the middle chamber 6, so that the pressure in the supply line 1' of, for example, 5 bar is designed to be, for example, 4 bar the inlet valve spring 11 overcomes. The pressure in the central chamber 6 of, for example, 4 bar also prevails in the control chamber 33. The relief valve spring 28 set for a pressure relief of, for example, 0.5 bar is therefore unable to lift the drain valve body 25 from its closed position into the open position. That would only be possible if there was a pressure increase again on the discharge side or, which would also be possible in principle, a sudden pressure drop on the inlet side 1 '. In this case, a corresponding pressure drop would also occur in the control chamber 34, as a result of which the drain valve body 25 would reach its open position and thereby lead to a corresponding pressure reduction in the middle chamber 6. Thus, it is ensured that there is always a minimum pressure drop between supply line 1 'and the central chamber 6, which prevents the process water from flowing back into the supply line 1'. It is also particularly advantageous that this backflow preventer is independent of the installation position, ie it can be used in any position.

Im Rahmen der vorliegenden Erfindung sind mancherlei Abwandlungen möglich. So kann beispielsweise beinoch stärkerer Querschnittsverengung der Steuerkammer 34, also entsprechend weitergehender Reduzierung des wirksamen Beaufschlagungsquerschnitts der Steuermembran 20 im Vergleich zu dem der Steuermembran 20′, die Ablaßventilfeder 28 sogar entfallen, weil selbst dann die angestrebte Mindestdruckdifferenz zwischen Mittelkammer 6 und Zuleitung 1′ erreicht würde.Various modifications are possible within the scope of the present invention. For example, even greater cross-sectional constriction of the control chamber 34, that is to say a corresponding further reduction in the effective loading cross section of the control membrane 20 in comparison to that of the control membrane 20 ', the drain valve spring 28 can even be omitted because even then the desired minimum pressure difference between the central chamber 6 and the feed line 1' would be achieved .

Claims (6)

1. Non-return valve, in particular for incorporation in drinking water pipes, comprising a cylindrical tubular flow housing (3) having an inlet pipe (1′) and an outlet pipe (2′), a spring-loaded inlet valve (4) mounted therein and a spring-loaded outlet valve (5) as well as a middle chamber (6) arranged between the two coaxially arranged valves (4,5), said middle chamber being connected to the ambient atmosphere by means of a drain valve (7) which ensures the maintenance of a minimum pressure difference between inlet pipe (1′) and middle chamber (6), wherein the drain valve has a valve body (25) connected to a control membrane (20, 20′), one pressure side of which is in hydraulic communication with the inlet pipe (1′) and the other pressure side of which is in hydraulic communication with the middle chamber (6), and wherein the drain valve (7), its valve body (25) and the control membrane (20, 20′) lie outside the flow housing tube (3), characterised in that two control membranes (20, 20′) are connected to the drain valve body (25) and are separated from each other by an intermediate chamber (26) connected to the ambient atmosphere, the control membrane (20′) which faces the drain valve body (25) is subject to the fluid pressure prevailing in the middle chamber (6), the other control membrane (20) is subject to the fluid pressure prevailing in the inlet pipe (1′), and wherein the effective cross-sectional resistance of the control membrane (20) which is in hydraulic pressure communication with the inlet pipe (1′) is less than the effective cross-sectional resistance of the other control membrane (20′) which is in hydraulic pressure communication with the middle chamber (6) by more than the cross-sectional dimension of the drain valve body piston (25).
2. Non-return valve according to claim 1, characterised in that the drain valve (7) has a single valve seat surface (32) and its valve body (25) is subject to the action of a valve spring (28) which attempts to lift the valve body from said surface.
3. Non-return valve according to claim 2, characterised in that the two control membranes (20, 20′) and the drain valve body (25) connected to them, including the drain valve spring (28) encompassing the valve body, are mounted in a three-part drain valve housing (18), wherein the one end part (18′) of the housing is connected to the inlet pipe (1′) and defines a control chamber (34) bounding the one control membrane (20), while the other end part (18′′′) contains the control chamber (33) which cooperates with the other control membrane (20′) and includes a tubular socket (18IV) containing the piston-like drain valve body (25) as well as the drain valve spring (28) which surrounds the latter, and wherein a connecting pipe (31) branches laterally from the tubular socket and leads to the middle chamber (6), the tubular socket having at its bottom end a drain hole (29) leading to the ambient atmosphere and which is arranged to be sealingly closed by the end of the valve body piston (25).
4. Non-return valve according to claim 2, characterised in that the inlet valve spring (11) is stronger than the drain valve spring (28) and the outlet valve spring (15) is weaker than the drain valve spring (28).
5. Non-return valve according to claim 4, characterised in that the inlet valve (4) comprises a valve body (8) which is displaceably seated on a guide tube (10) which is arranged axially in the flow housing tube (3) and which contains the inlet valve spring (11), and wherein the valve body (8) cooperates with a valve seat (1˝) formed by the resilient shoulder of the inlet tube (1) which projects into the flow housing tube (3).
6. Non-return valve according to claim 4, characterised in that the outlet valve (5) comprises a mushroom-shaped valve body (12) which has its stem (12′) axially displaceably guided in a guide bore (13) arranged in a housing web (14), and which has its frusto-conical valve head (12˝) which is seated at the rearward side against the weak outlet valve spring (15) arranged to cooperate with a tapering valve seating surface (16′) which is provided on a sleeve insert (16) which is fitted rearwardly into the flow housing tube (3).
EP19890900218 1987-12-12 1988-11-30 Nonreturn valve, in particular for incorporation in drinking water pipes Expired - Lifetime EP0353266B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3742207 1987-12-12
DE19873742207 DE3742207A1 (en) 1987-12-12 1987-12-12 BACKFLOW PREVENTORS, ESPECIALLY FOR INSTALLATION IN DRINKING WATER PIPES

Publications (2)

Publication Number Publication Date
EP0353266A1 EP0353266A1 (en) 1990-02-07
EP0353266B1 true EP0353266B1 (en) 1992-03-04

Family

ID=6342484

Family Applications (2)

Application Number Title Priority Date Filing Date
EP19890900218 Expired - Lifetime EP0353266B1 (en) 1987-12-12 1988-11-30 Nonreturn valve, in particular for incorporation in drinking water pipes
EP88119971A Pending EP0320700A1 (en) 1987-12-12 1988-11-30 Backflow preventer, especially for installation in drinking-water conduits

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP88119971A Pending EP0320700A1 (en) 1987-12-12 1988-11-30 Backflow preventer, especially for installation in drinking-water conduits

Country Status (6)

Country Link
EP (2) EP0353266B1 (en)
DE (2) DE3742207A1 (en)
DK (1) DK396489D0 (en)
ES (1) ES2030596T3 (en)
FI (1) FI893642A0 (en)
WO (1) WO1989005382A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4204386C2 (en) * 1992-02-14 1994-01-20 Honeywell Braukmann Gmbh System separator
DE4217334C2 (en) * 1992-05-26 1994-06-09 Heinrich W Kiesewetter System separation valve
ES2178915B1 (en) * 2000-03-07 2004-04-16 Plasticos Mondragon, S.A. PERFECTED MEMBRANE HYDRAULIC VALVE, FOR FLUID FLOW REGULATION.
CN102486237A (en) * 2010-12-01 2012-06-06 刘永 Backflow preventer with built-in filter screen and no external piping
CN102322541B (en) * 2011-09-02 2013-08-28 陈银周 Low-resistance backflow preventer

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2503424A (en) * 1945-01-15 1950-04-11 Leonard L Snyder Backflow preventer
US3083723A (en) * 1959-11-04 1963-04-02 Paul J Duchin Vacuum breaker
IL45802A (en) * 1973-10-26 1977-05-31 Griswold Controls Check valve useful in backflow prevention apparatus
DE2650934A1 (en) * 1976-11-08 1978-05-11 Waletzko Alfred Apparatebau Back flow preventer between drinking and washing water pipework - has guide rings fitted between valve and guide rod
DE2930819C2 (en) * 1979-07-30 1985-04-11 Amtrol Inc., West Warwick, R.I. Device for preventing the backflow of water in a supply line
DE3537484C1 (en) * 1985-10-22 1987-03-05 Baelz Juergen Controls Shut-off and aeration device, in particular for drinking-water systems

Also Published As

Publication number Publication date
DE3742207A1 (en) 1989-06-22
EP0353266A1 (en) 1990-02-07
DK396489A (en) 1989-08-11
FI893642A0 (en) 1989-08-01
DK396489D0 (en) 1989-08-11
DE3868925D1 (en) 1992-04-09
EP0320700A1 (en) 1989-06-21
WO1989005382A1 (en) 1989-06-15
ES2030596T3 (en) 1992-11-01

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