EP2644788B1 - Pipe splitting device - Google Patents

Description

Technical area

1. (a) ein Gehäuse mit einem Einlass und einem Auslass,
2. (b) einen in dem Gehäuse angeordneten, stromaufwärtigen Rückflussverhinderer,
3. (c) einen stromabwärtigen Rückflussverhinderer,
4. (d) ein von einer Belastungsfeder beaufschlagtes Ablassventil mit einer Sitzdichtung und einem mit der Sitzdichtung zusammenwirkenden, Ventilsitz, und
5. (e) einen an dem Gehäuse vorgesehenen Gehäusestutzen zum Ablassen von Flüssigkeit, welche durch das Ablassventil aus dem Gehäuse austritt, wobei
6. (f) stromaufwärts von dem stromaufwärtigen Rückflussverhinderer ein Eingangsdruck des stromaufwärtigen Flüssigkeitssystems,
7. (g) zwischen den Rückflussverhinderern ein Mitteldruck in einer Mitteldruckkammer, und
8. (h) stromabwärts von dem stromabwärtigen Rückflussverhinderer ein Ausgangsdruck des stromabwärtigen Flüssigkeitssystems herrscht, und wobei
9. (i) der bewegliche Teil des Ablassventils mit einem in dem Gehäuse beweglichen, federbeaufschlagten Kolben verbunden ist, und der Kolben einerseits gegen die Federwirkung der Belastungsfeder mit Eingangsdruck und andererseits mit Mitteldruck beaufschlagt ist,
10. (j) der Kolben senkrecht zu der in der Mitteldruckkammer herrschenden Strömungsrichtung beweglich ist, und
11. (k) der Kolben in dem Gehäusestutzen außerhalb einer in der Mitteldruckkammer erzeugbaren Strömung beweglich geführt ist.

The invention relates to a pipe separator arrangement for physically separating an upstream liquid system from a downstream liquid system by means of a drain valve

1. (a) a housing having an inlet and an outlet,
2. (b) an upstream backflow preventer disposed in the housing,
3. (c) a downstream non-return valve,
4. (D) a loaded by a loading spring discharge valve with a seat seal and a cooperating with the seat seal, valve seat, and
5. (E) a housing provided on the housing for discharging liquid, which exits through the drain valve from the housing, wherein
6. (f) upstream of the upstream non-return valve, an input pressure of the upstream liquid system,
7. (g) between the backflow preventer a mean pressure in a medium pressure chamber, and
8. (h) downstream of the downstream non-return valve, there is an outlet pressure of the downstream fluid system, and wherein
9. (i) the movable part of the drain valve is connected to a spring-loaded piston movable in the housing, and the piston is acted on the one hand against the spring action of the loading spring with inlet pressure and on the other hand with medium pressure,
10. (J) the piston is movable perpendicular to the prevailing in the medium pressure chamber flow direction, and
11. (K) the piston is movably guided in the housing stub outside a flow which can be generated in the medium-pressure chamber.

Pipe separators or system separators serve to reliably prevent backflow of liquid from a downstream liquid system into an upstream liquid system. The upstream fluid system can be a drinking water system be. The downstream fluid system may be, for example, a heating system. It is essential to prevent contaminated water from the heating system from flowing back into the drinking water system when the heating system is being refilled or refilled, for example by the pressure in the drinking water system collapsing for some reason.

There are so-called backflow preventer. These are spring loaded valves which allow fluid flow in only one direction, namely from the upstream to the downstream system. Such backflow preventers can be leaking. Therefore, e.g. For drinking water and heating water a separation of the liquid systems alone by backflow preventer not allowed. There must be a physical separation of the fluid systems so that in case of failure between the systems a connection to a drain and to the atmosphere is made.

System or pipe dividers include an upstream backflow preventer connected to the upstream liquid system and a downstream backflow preventer connected to the downstream system. In prior art pipe breakers, a pressure controlled bleed valve is provided between the non-return valves to provide passage from the upstream liquid system to the downstream liquid system when there is a sufficient pressure differential between the two liquid systems so that the liquid can safely flow only from the upstream to the downstream liquid system. If this pressure drop does not exist, the drain valve establishes a connection of the space between the backflow preventers with the atmosphere and a drain.

State of the art

In known pipe separators, such as in the DE 102 14 747 or DE 10 2005 031 422 discloses the drain valve is a displaceable in a valve body piston. This piston has a central passage and at its downstream end face an annular valve seat, which comes to a valve-tight ring seal axially to the plant. The passage then sets one to the atmosphere closed connection between upstream and downstream fluid system ago. The upstream backflow preventer sits in the passage. As a result, acts on the piston against an effective spring in the opening direction, the pressure difference between the inlet pressure in the upstream fluid system and a medium pressure, which is established in a medium-pressure space between the piston and the downstream non-return valve. For a flow to the downstream system can take place, even this pressure difference must exceed a predetermined, determined by the spring force measure. The drain valve body is arranged coaxially with the non-return valve.

If, for example, a low-pressure heating system from a drinking water system is to be filled via the system separator, the inlet pressure in the drinking water system initially forces the piston of the discharge valve against the action of the spring acting on it into its operating position in which it connects to the drinking water system Atmosphere and interrupts the process and establishes a connection between drinking water system and heating system. Then, the upstream and downstream backflow preventers are pressed. It flows drinking water to the heating system and fills it up or down.

The heating system is then filled to an outlet pressure that is below the inlet pressure. In normal operation, the difference between inlet pressure and outlet pressure is determined by the pressure drop at the backflow preventer, that is by the strength of the springs of the non-return valve. The intermediate pressure is in accordance with the pressure drop across the upstream backflow preventer and the pressure drop across the upstream backflow preventer. The pressure difference between the inlet pressure and the mean pressure must be greater than a limit determined by the loading spring of the valve body of the drain valve.

DE 10 2007 030 654 A1 discloses a pipe separator arrangement in which the valve seat of the drain valve is connected to a spring-loaded piston. The stroke direction of the piston runs perpendicular to the center axis of the pipeline and the opening direction of the non-return valve. The piston is acted upon by the action of a spring force from the inlet pressure.

All known pipe separators use a fixed funnel connected to the fitting. Returning water drains downwards via the drain funnel. Accordingly, the orientation of the pipe separator is specified. The drain funnel must always point downwards. Depending on the orientation of the pipe in which the pipe separator is to be installed, i. horizontal or vertical, the pipeline must be rebuilt. That's expensive. For different flow directions different pipe separator are required.

DE 20 2009 001 957 U1 discloses a module assembly having a fitting housing to which one or more fitting modules can be flanged. Among other things, a pipe separator is listed as a valve module. The same fitting housing, which is installed in the pipeline, is a connection fitting, which has no other functionalities except two shut-off valves.

DE 42 17 334 A1 discloses a two-piece pipe separator in which a drain valve in a second housing part is flanged to a first housing part. The second housing part is rotatable so that the drain is always down. The known arrangement comprises a piston which is acted upon on the one hand via a connection channel leading past the upstream backflow preventer with inlet pressure and on the other hand with medium pressure. The piston is connected to a movable valve plate.

US 4,945,940 discloses a pipe separator with two backflow preventers upstream and downstream of a medium pressure chamber. The medium-pressure chamber has at the lower end an opening which is closed by a valve disk. The valve disk is connected via a valve spindle with a spring-loaded piston. The piston is guided in a separate housing, which is connected via a outside of the separate housing passed over pipe connection with the input portion of the pipe separator.

US 3,478,778 discloses an arrangement with two series-connected non-return valve in a housing and an interposed drain valve.

Disclosure of the invention

It is an object of the invention to provide a Rohrtrenneranordnung, which is compact and has very good flow conditions. According to the invention, the object is achieved by a first connecting channel between the region in the housing neck above the piston and the region upstream of the upstream non-return valve and a second connecting channel between the region in the housing neck below the piston and the medium-pressure chamber. The piston always has an open position when the mean pressure is greater than the inlet pressure. But he is no longer in the flow path within the medium-pressure chamber. Accordingly, the flow conditions are better. The piston causes virtually no pressure drop. Since the piston is no longer between the non-return valve, they can be arranged closer to each other. As a result, the arrangement is particularly compact.

A particularly compact arrangement is achieved when the backflow preventer are arranged coaxially. In this case, the backflow preventer can be arranged coaxially within an elongate housing coaxial with a pipeline. But they can also be arranged coaxially within a flange pipe separator, in which the pipe separator is flanged to a connection fitting in the pipeline. In this case, a first housing part, for example in the form of a connection fitting, a planar connection surface, with which it can be flanged to a corresponding connection surface on the second housing part, wherein the output channel in the region of the connection is an annular channel, which is arranged around a central inlet channel. Such flange connections with coaxial arrangements of an annular channel around a central inlet channel are known from the prior art. They are also suitable for connecting a pipe separator in different angular positions.

In such arrangements, the inlet is connected to a central channel and the outlet to an annular channel connected to the central channel. The backflow preventer can be arranged coaxially in the central channel.

Alternatively, the downstream non-return valve can be arranged in the outlet of the first housing part and does not need to be arranged in the annular channel. Even then, a conventional backflow preventer cartridge can be used. For maintenance or replacement of the backflow preventer the housing parts are separated. The backflow preventers are then open and easily accessible.

In an alternative embodiment of the invention, a first housing part also has a flat connection surface with which it can be flanged to a corresponding connection surface on the second housing part. In the alternative, however, the input channel in the region of the connection is an annular channel, which is arranged around a central output channel. In this alternative, a higher flow area and lower flow resistance is achieved.

In one embodiment of the invention, the housing neck comprises a detachable, housing-fixed adapter to which a drain funnel is attached. Alternatively, the discharge funnel is molded onto the adapter. However, the housing neck can also be completely formed on the housing. A detachable adapter has the advantage that it can be made of less expensive material, such as plastic, instead of expensive brass, since there is no increased pressure. Furthermore, the production of complex geometries by means of injection molding is made possible.

In one embodiment of the invention, the drain valve comprises a valve seat part connected to the piston, which cooperates with a housing-fixed valve disk. The valve plate may be connected to the discharge funnel or to the housing-fixed adapter. When the piston moves at high input pressure against the force of the loading spring and against the medium pressure downwards in the direction of the valve disk, the valve closes. Then water can flow through the fitting to the outlet. At low inlet pressure by the spring force of the piston and thus the Valve seat part moved upwards. Then the drain valve is open. There is no water flow back to the inlet.

The adapter may have an upper edge forming a spring abutment for the loading spring of the piston.

• (g) das Gehäuse zweiteilig ausgebaut ist, wobei
• (h) ein erster Gehäuseteil als Anschlussarmatur ausgebildet ist, welche mit einem Einlass und einem koaxial zum Einlass angeordneten Auslass in einer Rohrleitung installierbar ist;
• (i) ein zweiter Gehäuseteil das Ablassventil aufnimmt; und
• (j) der zweite Gehäuseteil in mehreren verschiedenen Positionen an dem ersten Gehäuseteil anschließbar sind, welche um eine horizontale Verbindungsachse winkelversetzt sind.

In a particularly preferred embodiment of the invention, it is provided that

• (G) the housing is constructed in two parts, wherein
• (H) a first housing part is formed as a connection fitting, which is installable with an inlet and a coaxially arranged to the inlet outlet in a pipeline;
• (i) a second housing part receives the drain valve; and
• (J) the second housing part can be connected in several different positions on the first housing part, which are angularly offset about a horizontal connecting axis.

With such a pipe separator arrangement, the second housing part can always be fastened to the first housing part such that the opening of the drain valve and the outlet funnel points downwards. The flow direction can be taken into account accordingly. Preferably, four angular positions are provided, in which the second housing part can be fastened to the first housing part. Thus, the most common cases of vertical and horizontal pipe run in both flow directions can be considered. The pipe must not be broken when changing the valve. A fitting can be used for all cases without special measures. Only the angular position during assembly must be adapted to local conditions.

In a further embodiment of the invention, a pressure reducer behind the downstream backflow preventer is provided. This will reduce the pressure in the Downstream system, for example, when filling a heating system controlled.

A particularly compact arrangement and simple assembly is achieved when the first housing part has an input-side and an output-side stopcock. The shut-off valves then no longer have to be installed separately.

In a particularly inexpensive variant of the invention, some components, in particular piston and valve seat of the drain valve are made of plastic. As a result, the valve can be made more economical.

In a particularly preferred embodiment of the invention, the valve seat has a smaller diameter than the piston. The input pressure acting on the piston thus generates a larger force in the closing direction of the drain valve than would be the case with the valve seat due to the larger diameter. The sealing force of the drain valve is correspondingly better.

Embodiments of the invention are the subject of the dependent claims. An embodiment is explained below with reference to the accompanying drawings.

Brief description of the drawings

Fig.1

is a perspective view of a pipe separator assembly with two housing parts with central inlet channel and an outlet channel designed as an annular channel.

Fig.2

is a side view of the arrangement FIG. 1 ,

Figure 3

is a cross section through the pipe separator assembly FIG. 2 along the vertical section plane AA.

Figure 4

is a cross section through the pipe separator assembly FIG. 2 along the vertical sectional plane BB.

Figure 5

is a cross section through the pipe separator assembly FIG. 1 along a horizontal sectional plane DD through the backflow preventer.

Figure 6

is a cross section through the pipe separator assembly FIG. 1 along a horizontal sectional plane EE through the Prüfstutzen.

Figure 7

is a perspective view of a compensation piston for the arrangement of Figure 1 to 6 in detail.

Figure 8

is an exploded view of the horizontal housing bore of the arrangement FIG. 1 provided components.

Figure 9

is a perspective view of the piston of the drain valve in detail.

Figure 10

is a perspective view of a pipe separator assembly with two housing parts with pressure reducer with central inlet channel and an annular channel as an outlet channel.

Fig. 11

is a side view of the arrangement FIG. 10 ,

Fig. 12

is a cross section through the pipe separator assembly FIG. 11 along the vertical section plane AA.

Fig. 13

is a cross section through the pipe separator assembly FIG. 10 along the vertical sectional plane BB.

Fig. 14

is a cross section through the pipe separator assembly FIG. 1 along a horizontal sectional plane DD through the backflow preventer.

Fig. 15

is a perspective view of a pipe separator arrangement with an annular channel formed as an inlet channel.

Figure 16

is a side view of the arrangement FIG. 15 ,

Fig. 17

is a side view of the arrangement FIG. 15 from one opposite FIG. 16 90 degree perspective.

Fig. 18

is a plan view of the arrangement FIG. 15 ,

Fig. 19

is a cross section of the arrangement FIG. 15 along a vertical sectional plane FF.

fig.20

is a cross section of the arrangement FIG. 15 along a vertical sectional plane PP.

Figure 21

is a cross section of the arrangement FIG. 15 along a horizontal sectional plane CC.

Fig. 22

is an exploded view of the arrangement FIG. 15 ,

Figure 23

is a perspective view of a piston for controlling the exhaust valve for the pipe separator FIG. 15 ,

Figure 24

is a side view of the piston FIG. 23 ,

Figure 25

is a vertical cross section through the piston FIG. 23 ,

Figure 26

is an exploded view of the arrangement FIG. 23 ,

Fig.27

is a perspective view of a functional unit with two backflow preventer for the pipe separator FIG. 15 ,

Figure 28

is a side view of the unit FIG. 27 ,

Figure 29

is a cross section through the unit FIG. 27 ,

Fig.30

is an exploded view of the unit FIG. 27 ,

Fig. 31

is a perspective view of a pipe separator arrangement with an annular channel formed as an inlet channel, which is connected to an existing faucet and having a hose connection.

fig.32

is a side view of the arrangement FIG. 31 ,

fig.33

is a side view of the arrangement of Figure from one opposite FIG. 31 90 degree perspective.

Fig.34

is a plan view of the arrangement FIG. 31 ,

Fig.35

is a cross section of the arrangement FIG. 31 along a vertical cutting plane GG.

Fig.36

is a cross section of the arrangement FIG. 31 along a vertical sectional plane HH.

Fig.37

is a cross section of the arrangement FIG. 31 along a horizontal sectional plane II.

Fig.38

is an exploded view of the arrangement FIG. 31 ,

Fig. 39

is a perspective view of a pipe separator arrangement with an annular channel formed as an inlet channel, which is connectable to a barrier in a pipeline and having a hose connection.

Fig.40

is a side view of the arrangement FIG. 39 ,

Fig.41

is a side view of the arrangement FIG. 39 from one opposite FIG. 40 90 degree perspective.

Fig.42

is a plan view of the arrangement FIG. 39 ,

FIGURE 43

is a cross section of the arrangement FIG. 39 along a vertical section plane JJ.

Fig.44

is a cross section of the arrangement FIG. 39 along a vertical sectional plane KK.

Fig.45

is a cross section of the arrangement FIG. 39 along a horizontal sectional plane LL.

Fig.46

is an exploded view of the arrangement FIG. 39 ,

Fig. 47

is a perspective view of a pipe separator assembly with an annular channel formed as an inlet channel, which is connectable to a pipeline and having a pressure reducer.

Fig.48

is a side view of the arrangement FIG. 47 ,

Fig.49

is a side view of the arrangement FIG. 47 from one opposite FIG. 48 90 degree perspective.

Fig.50

is a plan view of the arrangement FIG. 47 ,

Fig.51

is a cross section of the arrangement FIG. 47 along a vertical sectional plane MM.

Fig.52

is a cross section of the arrangement FIG. 47 along a vertical sectional plane NN.

Fig.53

is a cross section of the arrangement FIG. 47 along a horizontal sectional plane OO.

Fig.54

is an exploded view of the arrangement FIG. 47 ,

Fig.55

is an overview of the various modules with which pipe separators can be adapted to the requirements.

Fig. 56

is a detailed view of the drain valve of the embodiments 3 to 6.

Fig.57

shows an embodiment of the drain valve for one of in FIG. 55 illustrated modules as a sectional view.

Fig. 58

is an exploded view of the arrangement Figure 57 ,

Fig. 59

shows a detail Figure 57 ,

Fig.60

is a cross-section through an alternative arrangement with one-piece housing and obliquely arranged between the inlet and outlet backflow preventer.

Description of the embodiments Exemplary embodiment 1 (FIGS. 1-9): Flanged pipe separator with central inlet channel

In Fig.1 is a generally designated 10 fitting in the form of a pipe separator arrangement shown. The pipe separator arrangement 10 comprises a housing with a first housing part 12 and a second housing part 13. The first housing part 12 forms a connection fitting with an inlet designed as inlet connection 14 and an outlet connection 16 arranged coaxially therewith as an outlet. The pipe separator assembly 10 is in a pipeline (not shown) for Example between a supply side arranged drinking water supply in front of a heating system arranged on the outlet side (not shown) installed. The water thus flows from the drinking water supply through the inlet 14 into the fitting and from there out of the outlet 16. Ball valves (not shown) on both sides are used to shut off the inlet 14 and outlet 16. In the inlet 14, a sieve 11 is inserted. This is in FIG. 5 to recognize.

The second housing part 13 is flanged to the first housing part 12 via a flange connection. This is in FIG. 1 . 3 . 4 . 5 and 6 clearly visible. The figures show the flange on the first housing part with a flat surface 27. The flange is fixed by means of screws in openings 19. The inlet 14 is connected to a central inlet channel 21. This is in FIG. 3 clearly visible. The outlet 16 is connected to an annular channel 23. The water thus flows from the inlet 14 through the central inlet channel 21 into the second housing part and through the annular channel 23 out again to the outlet 16.

Between the inlet and outlet, an upstream backflow preventer 18 and a downstream backflow preventer 20 are provided.

These are in FIGS. 3 to 5 to recognize. The upstream backflow preventer 18 is seated in the central inlet channel 21 on the side of the second housing part immediately behind the flange connection. This is good in FIG. 3 recognizable. FIG. 8 shows an exploded view of the backflow preventer and the other components, which are arranged in a common, horizontal housing bore in the second housing part 13.

The backflow preventer 18 and 20 open in the flow path in the direction of the outlet. The non-return valve 18 is seated in a non-return valve cartridge 25. The non-return valve cartridge 25 forms a spring abutment for the spring 27 of the non-return valve 18. The non-return valve cartridge 25 is located inside a coaxial compensation piston 29. The compensation piston 29 is internally provided with a peripheral edge 31 with a ring seal. The edge 31 forms the valve seat of the non-return valve 18. This is in FIG. 3 clearly visible.

The downstream backflow preventer 20 is seated in a conventional backflow preventer cartridge 22. The backflow preventer cartridge 22 is disposed in an insert 33 and sealed against it with a ring seal.

In the present embodiment, the compensation piston 29 is displaceably guided with a seal in a housing-fixed sleeve 35. The sleeve 35 is seated in the horizontal housing bore in extension of the inlet channel 21 in the second housing part 13. The insert 33 has on the downstream side an outwardly extending, circumferential edge 37. With the edge 37, the inserted into the sleeve 35 insert 33 closes the Sleeve 35 on the downstream side.

The edge 37 forms a spring abutment for a weak compensation spring 39. The other end of the compensation spring 39 presses on the downstream end of the compensation piston 29. The sleeve 35 has inside a shoulder 41 in the region of the downstream end of the compensation piston 29. The shoulder 41 forms a stop for an axial movement of the compensation piston 29 against the spring force of the compensation spring 39. On the upstream side, the movement of the compensation piston 29 at the connection plane 27 between the housing parts 12 and 13 is limited.

Between the backflow preventers 18 and 20, a medium-pressure chamber 43 is formed. With the compensation piston 29, the volume of the medium-pressure chamber 43 can be changed. As a result, slight pressure fluctuations of the inlet pressure can be compensated without the drain valve opens. The exact operation of such a compensation piston is already out of the DE 10 2005 031 422 known and therefore need not be further described here.

On the side of the housing, a test connection 32 and 34, which is closed with a plug 28 or 30, is provided in each case. The test port 32 is connected to the inlet 14 via a channel 47 and the central inlet channel 21. This is in FIG. 6 to recognize.

The test port 34 is connected via a channel 45 with the medium-pressure chamber 43 between the backflow preventers 18 and 20. This is in FIG. 4 to recognize. A provided at the upper end of the housing test port 36 with plug 38 is connected via the annular channel 23 to the outlet 16. In this way, for example, by means of a manometer of the input, middle and output pressure can be determined.

The second housing part 13 has a housing stub 40 with a downwardly directed opening. The housing stub 40 extends in the vertical direction, perpendicular to the flow direction through the upstream backflow preventer 18 and to the connection axis of the flange connection.

In the housing stub 40 is screwed at the lower end of a generally designated 44 adapter made of plastic and sealed with a seal 45. The adapter 44 is substantially cylindrical and has an external thread 48. With the thread 48 of the adapter 44 is screwed into the housing neck. An inwardly projecting rim 50 in the upper region of the adapter forms a spring abutment for a loading spring 52. The vertical part of the rim 50 forms a cylindrical guide for a valve seat part 54 to be described. A substantially conventional discharge funnel 56 made of plastic is provided with a thread 58 screwed into the adapter 44.

The valve seat part 54 is connected to a piston 60 at the upper end. The piston 60 is movably guided in a vertical bore 66 within the housing wall with a seal 62 in the vertical direction. A downwardly projecting pin 64 is provided on the bore 66 upwardly bounding the housing wall. To the pin 64 engages an annular projection 68 at the top of the piston 60. The pin 64 also serves as a guide for the piston 60 and the valve seat member 54 formed element. The annular projection 68 is provided off-center on the top of the piston 60. Accordingly, the piston 60 is guided against rotation in the bore 66.

The outlet funnel 56 has radial ribs 70 below the nozzle 44. The ribs 70 extend inwardly and hold a valve seal 72 in a valve core 74. The valve seal 72 is secured to a valve disk 76 which fits into the valve core 74 is screwed. The lower end 78 of the axially movable valve seat portion 54 forms with the valve seal 72, a drain valve.

The valve seat part 54 is guided with a seal 80 in the edge 50 of the adapter 44. Above the seal 80, the valve seat part 54 in the region of the spring 52 has ribs which connect the lower end 78 with the piston 60. The region 82 below the piston 60 is thus connected to the interior 84 of the valve seat part 54. The region 82 is further connected via the connecting channel 45 with the medium-pressure chamber 43. This is in FIG. 4 to recognize. That is, below the piston there is medium pressure.

The bore 66 is connected via a channel 86 to the central input channel 21. The channel 86 passes through the housing of the housing part 13 and recesses 88 in the sleeve 35 and recesses 90 in the compensation piston 29. These are in FIG. 7 and in FIG. 8 clearly visible. Above the piston 60 therefore prevails inlet pressure.

The spring 52 is supported on the one hand on the underside of the piston 60. On the other hand, the spring 52 is supported on the upper side of the rim 50 on the adapter 44. The spring 52 tries the piston 60 up in FIG. 3 to press and thus to hold the valve seat 54 connected to the piston 76 in an open position of the drain valve.

At low inlet pressure in the inlet 14, the backflow preventer 18 and 20 are closed. The piston 60 is in an upper position. The valve seat 78 of the drain valve is in an upper, open position. Now, when the downstream backflow preventer 20 is leaking, the water flows down into the medium pressure chamber and down through the drain valve into the atmosphere.

To fill the heating system or the like, the barriers at the inlet and the outlet are opened. Then there is an increased inlet pressure in the inlet 14. The piston 60 is always acted on the channel 86 against the spring action of the loading spring 52 with input pressure. When the inlet pressure is increased, the piston 60 is pressed down. Then open the backflow preventer 18 and 20. Then there is a differential pressure between the medium pressure chamber and the inlet pressure. The Water flows through the upstream backflow preventer 18 into the medium pressure chamber and from there through the downstream backflow preventer 20 to the outlet 16. The force of the inlet pressure acting on the piston is greater than the spring force and the force acting from below on the piston medium pressure. The drain valve is thereby closed. When the inlet pressure drops, the drain valve opens.

In the present embodiment, the backflow preventer are arranged directly behind each other. As a result, the flow is only slightly affected. Fig.1 shows the arrangement in perspective view. It can be seen that the arrangement is particularly compact. The overall length is low compared to known arrangements. The diameters are also small. Since all internal components are made of plastic, the material consumption for metal is low.

It can be seen that the effective piston area 82 is greater than the seat diameter of the seat 74. As a result, the force exerted on the piston at each pressure is greater than the force exerted on the valve.

The present embodiment allows installation of the assembly in virtually any orientation. In FIG. 1 It can be seen that the flange connection between the housing parts 12 and 13 is identical in four orientations. The second housing part can thus be installed in four different orientations. Thus, if the pipe runs, for example, in the vertical direction, the second housing part 13 is rotated by 90 ° about the connecting axis. Then the drain funnel 56 also projects downwardly as required.

In the reverse flow direction, the connection fitting 12 can be completely rotated by 180 ° about the connection axis of the flange connection. There is also the possibility of rotation through 180 ° about the tube axis, so that the flange "back" in FIG. 2 is arranged

Exemplary embodiment 2 (FIGS. 10-14): Flanged pipe separator with central inlet channel and pressure reducer

Embodiment 2 generally corresponds to the embodiment 1. Again, a central input channel and an annular channel is provided as an output channel. Furthermore, a pressure reducer 100 is provided. This is in the FIGS. 10 to 14 shown. The pressure reducer 100 is inserted into a nozzle 102 in the region of the outlet 116 behind the downstream non-return valve 20. The nozzle 102 is formed in the present embodiment in the first housing part 112. The pressure reducer 100 regulates the output pressure to a desired value.

Exemplary embodiment 3 (FIGS. 15-30): Flanged pipe separator with annular channel as input channel

In Fig.15 to 30 is also a generally designated 210 fitting in the form of a Rohrtrenneranordnung shown. The pipe separator arrangement 210 comprises a housing with a first housing part 212 and a second housing part 213. The first housing part 212 forms a connection fitting with an inlet formed as inlet port 214 and a coaxially arranged outlet nozzle 216 as an outlet. The pipe separator arrangement 210 is installed in a pipeline (not shown), for example, between a drinking water supply arranged on the inlet side in front of a heating system (not shown) arranged on the outlet side. The water thus flows from the drinking water supply through the inlet 214 into the fitting and from there out of the outlet 216. Ball valves (not shown) on both sides are used to shut off the inlet 214 and outlet 216. In this respect, the present fitting 210 does not differ from the fitting 10 of the first embodiment.

The second housing part 213 is flanged to the first housing part 212 via a flange connection. This is in FIGS. 15 to 22 clearly visible. The figures show the flange on the first housing part with a flat surface analogous to the surface 27 of the first embodiment. The flange connection is made by means of screws 211 in openings 219 (FIG. Figure 22 ) fixed. Unlike the above two embodiments, the inlet 214 is not connected to a central input port but to an annular port 221. This is in FIG. 21 clearly visible. The outlet 216 is thus connected to a central outlet channel 223 instead of an annular channel. The water flows from the inlet 214 through the annular channel 221 into the second housing part 213 and back through the central outlet channel 223 to the outlet 216.

Between the inlet and outlet, an upstream backflow preventer 218 and a downstream backflow preventer 220 are provided. These are in FIG. 20 and 21 to recognize. It can be seen that, unlike the above embodiments, the backflow preventers 218 and 220 flow through from right to left in the illustration.

The downstream backflow preventer 220 is seated in the central exit passage 223 on the side of the second housing part just behind the flange connection. This is good in FIG. 20 and 21 recognizable. FIGS. 27 to 30 show the backflow preventer 218 and 220, and the other components which are arranged in a common, horizontal housing bore in the first and second housing part.

The backflow preventers 218 and 220 open in the flow path in the direction of the outlet, ie to the left in FIG. 20 and 21 , FIG. 29 and 30 show the arrangement of the backflow preventer in detail. The backflow preventer 220 is seated in a backflow preventer cartridge 225. The backflow preventer cartridge 225 forms a spring abutment for the spring of the backflow preventer 220. The spring urges a valve disk 229 of the backflow preventer 220 against a valve seat formed by a valve seat portion 231 and a seal 202. This is in FIG. 29 clearly visible.

The valve seat part 231 has an annular groove on the outside. In the annular groove sits a ring seal 208. The valve seat part 231 is sealingly inserted into an insert 206. The valve seat part 231 bears against an inwardly projecting edge 201 of the insert 206. The insert 206 has an annular groove on the outside. In the annular groove, a ring seal 203 is arranged. The insert member 206 is inserted with the ring seal 203 in the downstream region of a housing-fixed sleeve 235.

The sleeve 235 is provided with a downstream annular groove with a ring seal 205. The sleeve 235 is further provided with an upstream annular groove having a Ring seal 207 provided. The sleeve 235 is seated in a horizontal housing bore in extension of the outlet channel 221 in the first and second housing part. The sleeve 235 is sealed with the ring seal 205 against the first housing part and with the ring seal 207 against the second housing part.

In the area between the ring seals 205 and 207, the sleeve 235 has an open area with ribs 209. These are in FIG. 27 . 28 and 30 clearly visible. The insert 206 is connected to a radially outwardly projecting edge portion 237. The edge portion is externally adjacent to the downstream end of the sleeve 235 and holds the insert in place. This is in FIG. 29 to recognize.

The upstream backflow preventer 218 includes a valve plate 239 which cooperates with a seal 204 in a valve seat portion 233. The valve seat part 233 is fixed to the housing and sleeve-shaped. The sleeve 235 has an inwardly projecting edge at the upstream end. The valve seat portion 233 of the upstream non-return valve 218 is inserted to the edge of the sleeve 235 and sealed with the seal 204 against this. The valve seat portion 233 forms a collar 200 at the inner end. The collar 200 forms a spring abutment for the spring 241 of the non-return valve. The spring 241 presses the valve plate 239 of the non-return valve 218 against the seal 204.

Unlike in the embodiments 1 and 2 of FIGS. 1 to 14 No compensating piston is required here. The compensation of small pressure fluctuations of the inlet pressure without opening the drain valve takes place in the manner described below.

Between the backflow preventers 218 and 220 and between the annular seals 205 and 207, an intermediate pressure chamber 243 is formed. At the top of the housing, in each case, a test connection 232 and 234 sealed with a plug 228 or 230 is provided. The test port 232 is connected to the inlet 214 via the annular channel 221. There prevails inlet pressure. This is in FIG. 20 to recognize. The test port 234 is connected to the central outlet 216 via a channel 247. There is initial pressure.

On the side of the housing, a test port 236 is provided with a plug 238. This one is in FIG. 19 good to see. The test port 236 is connected via a channel 245 to the medium pressure chamber 243 between the backflow preventers 218 and 220. There is medium pressure. In this way, for example, by means of pressure gauges at the test ports of the input, middle and output pressure can be determined.

The second housing part 213 has a housing neck 240 with a downwardly directed opening. The housing stub 240 extends in the vertical direction, perpendicular to the flow direction through the upstream backflow preventer 218 and to the connection axis of the flange connection.

On the housing neck 240, funnel 256 made of plastic is screwed at the lower end and sealed with a seal 245. For this purpose, the housing socket 240 is provided with an external thread 258.

In the housing stub 240 is a generally designated 244 piston assembly is arranged, which will be described below with reference to FIGS. 23 to 26 is described. The piston assembly includes an axially movable piston 260. The piston 260 is urged upward by the spring force of a loading spring 252. The piston 260 is sealingly guided in a housing-fixed guide sleeve 248 with a seal 254. The guide sleeve 248 has an upper sleeve part 268 and a lower sleeve part 269 formed thereon. The lower sleeve portion 269 is concentric with the housing neck 240. The upper sleeve portion 268 is formed off-axis to the lower sleeve portion 269. The lower sleeve part 269 is sealed with a arranged in an outer annular groove seal 242 relative to the housing neck 240. The upper sleeve part 268 has an outer circumferential annular groove with a seal 246.

The second housing part 213 has an inner housing neck 250, which is arranged with a smaller diameter off-axis within the housing neck 240. The upper sleeve part 268 is sealed with the seal 246 opposite the inner housing neck 250. This is in FIG. 25 to recognize. The piston 260 is with the seal 254 axially displaceably guided within the upper sleeve part. Thus, no water can get past the piston 260 down.

The guide sleeve 248 is provided between the upper and lower sleeve members 268 and 269 with an inwardly projecting rim 258. The rim 258 extends inwardly and holds a tubular inner guide member 262. The inner guide member 262 is coaxial with the upper sleeve member 268. On the top of the rim 258, the loading spring 252 is supported. The edge 258 thus forms a spring abutment. The upper end of the loading spring 252 presses on the underside of the piston 260.

The piston 260 has at the lower end a threaded ring 264 which is connected via ribs 266 to the underside of the upper piston surface. The threaded ring 264 is provided with an external thread. On the external thread a substantially tubular valve closing body 267 is screwed.

The valve closing body 267 together with a valve seal 272 forms a drain valve. The valve seal 272 is fastened with a screw 270 on a valve seat 274 serving as a valve seat. The plate 274 is held by means of radial ribs 276 off-axis in a ring 278. The ring 278 is supported on an edge extending inwardly from the discharge throat. It can be seen that the valve seal 272, the screw 270 and the plate 274 are formed fixed to the housing. The piston 260 with the valve closing body 267, however, are axially movable.

The medium-pressure space 243 is connected to the area below the upper piston surface and the interior of the valve closing body 267 via the intermediate space 280 formed between the housing stub 240 and the inner housing stub 250. Here is therefore medium pressure. When the valve closing body 267 pushes with its lower edge on the valve seal 272, the drain valve is closed. It can not leak water.

The region 282 upstream of the backflow preventers, and thus the inlet, is connected via a channel 284 to the region above the upper piston surface of the piston 260. Here, therefore, there is inlet pressure. The spring 252 tries the Piston 260 up in FIG. 20 to press and so to hold the connected to the piston 260 valve closing body 267 in an open position of the drain valve. When the input pressure decreases, the piston 260 is moved upward. Then the drain valve opens. Water flows out of the medium pressure chamber until the pressure is again lower than the inlet pressure.

At low inlet pressure in the inlet 214, the backflow preventer 218 and 220 are closed. The piston 260 is in an upper position. The valve closing body 269 of the drain valve is in an upper, open position. Now, when the downstream backflow preventer 20 is leaking, the water flows down into the medium pressure chamber 243 and down through the drain valve into the atmosphere.

To fill the heating system or the like, the barriers at the inlet and the outlet are opened. Then there is an increased inlet pressure in the inlet 214. The piston 260 is always acted upon via the channel 284 against the spring action of the loading spring 252 with inlet pressure. With increased inlet pressure, the piston 260 is first pressed down. Then open the backflow preventer 218 and 220. Then there is a differential pressure between the pressure in the medium pressure chamber and the inlet pressure. The water flows through the upstream backflow preventer 218 into the medium pressure chamber 243 and from there through the downstream backflow preventer 220 to the outlet 216. The force of the inlet pressure acting on the piston is greater than the spring force and that acting from below on the piston Force of medium pressure. The drain valve is thereby closed. When the inlet pressure drops, the drain valve opens and the backflow preventer closes.

In the present embodiment, the backflow preventer are arranged directly behind each other. As a result, the flow is only slightly affected. It can be seen that the arrangement is particularly compact. The overall length is low compared to known arrangements. The diameters are also small. Since all internal components are made of plastic, the material consumption for metal is low.

It can be seen that the effective piston area of the piston 260 is greater than the seat diameter of the piston-closing body 267. As a result, the force exerted on the piston at each pressure is greater than the force exerted on the valve.

If, as often happens, the inlet pressure fluctuates slightly and - as here - no compensating piston is provided, a conventional drain valve would open constantly. The present embodiment therefore uses a valve seal 272, which has a peripheral lip 600 at the edge. The lip 600 extends upward in FIG FIG. 25 and something inside. As a result, the lip 600 abuts the outside slightly above the lower edge of the valve closing body 267. This is in FIG. 56 to recognize. The valve closing body must make a small stroke before the drain valve opens. This hub is indicated by an arrow 604 in FIG FIG. 56 illustrated. The last end 602 of the lower edge of the valve closing body 267 passes over the lip 600. During this stroke, the drain valve remains closed. This means that the drain valve does not open at small pressure fluctuations of the inlet pressure. As long as the pressure fluctuations do not trigger a stroke of the valve closing body, in which the lower edge leaves the valve seal 272, a drop is avoided.

If the inlet pressure continues to drop, the mean pressure is greater than the inlet pressure. The piston 260 moves upward. Thereby, the valve closing body 267 is moved upward. The drain valve opens. Water from the medium pressure space flows. The spring 252 holds the drain valve in the open state until the inlet pressure rises again. If, on the other hand, the outlet pressure rises and, at the same time, the downstream non-return valve should be defective, this increased outlet pressure also prevails in the medium-pressure chamber. Then the mean pressure is greater than the inlet pressure. The piston is also moved up here and the drain valve opens. Heating water is drained.

As in the above embodiment, the present embodiment enables the assembly to be installed in virtually any orientation. In this case, the arrangement according to this embodiment has an even lower flow resistance than the arrangement with a central inlet channel. All parts requiring maintenance, in particular the backflow preventer are provided on the second housing part 213. It will allows to easily exchange the second housing part 213 and to wait in the factory. The installer involved in maintenance only needs to loosen the screws and does not need to know the device any further. This reduces the training required and the risk of incorrect installation and maintenance.

Exemplary embodiment 4 (FIGS. 31-38): Flanged pipe separator with annular channel as input channel and hose connection

FIGS. 31 to 38 show a variant of the third embodiment. In this variant, the pipe separator is not installed in a pipeline, but screwed to an existing, lockable faucet (not shown). The generally designated 310 pipe separator consists of a first housing part 312 and a second housing part 313. The second housing part 313 and all its components and functions installed therein are identical to the housing part 213 of the third embodiment and therefore need not be further explained here.

The first housing part 312 has a flange 327, with which the second housing part 313 is flanged to the first housing part 312 as in the third embodiment. Between the housing parts 312 and 313, a seal 315 is arranged. This is in Figure 38 clearly visible.

In FIG. 36 It can be clearly seen that the inlet 314 is connected to an annular channel 321. The outlet 316 is connected to a central outlet channel 323. This is further connected to a plugged with test port 330. At the test port 330, the output pressure can be determined.

This arrangement makes it possible to integrate a pipe separator in an existing heating system without having to break a pipe. The assembly 310 is bolted to the inlet 314 at an existing water connection. The outlet 316 is designed as a hose connection. An attached hose can be firmly connected to the heating system, which would not be standard without a pipe separator.

Of course, the hose can also be removed and water at the outlet 316 tapped.

Exemplary embodiment 5 (FIGS. 39-46): Flanged pipe separator with annular channel as input channel, hose connection and stopcock.

FIGS. 39 to 46 show a further variant of the third embodiment. In this variant, the pipe separator is not integrated into a pipe, but connected to the end of a pipe (not shown). The generally designated 410 pipe separator consists of a first housing part 412 and a second housing part 413. The second housing part 413 and all its components and functions installed therein are identical to the housing part 213 of the third embodiment and therefore need not be further explained here.

The first housing part 412 has a flange 427, with which the second housing part 413 is flanged to the first housing part 412 with a seal 415, as in the third embodiment.

In the present embodiment, the first housing portion 412 includes a tubular inlet 414. The tubular inlet 414 rests on a post having a downwardly extending neck 486. The nozzle 486 is plugged onto the test port 434 without plugs, which serves in the embodiments 3 and 4 as a test port for checking the inlet pressure. As a result, the comparatively long, tubular inlet 414 is supported and held in its position. This is in FIG. 46 to recognize.

The tubular inlet 414 forms at its device-side end (on the right in FIG FIG. 44 ) a shoulder 487. The shoulder 487 serves as a valve seat for a manually operated shut-off valve. The shut-off valve comprises a control handle 488, a spindle 489 and a valve head 490 which can be adjusted by means of the control handle. Turning the control handle 488, the valve can be closed and thus the inlet 414 shut off. In the area behind the shut-off valve, a test connection 491 closed with a stopper is molded onto the first housing part 412. This replaces that in the exemplary embodiments 3 and 4 test port provided on the housing part 413, which is used to check the input pressure.

Behind the shut-off valve, a channel 492 is further provided, which is connected to an annular channel 421. The annular channel 421 is connected as an inlet as described above with the annular channel in the second housing part 413. The outlet 416 is connected behind the two backflow preventers with the central channel in the second housing part 413. The outlet 416 has the form of a hose connection as in the above embodiment.

In this embodiment, the arrangement 410 can be used on the one hand as a pipe separator for filling, for example, heating systems. At the same time, however, the arrangement also offers the possibility of tapping water at the outlet 416. For this purpose, only the control handle 488 must be actuated.

Exemplary embodiment 6 (FIGS. 47-54): Flanged pipe separator with annular channel as input channel, pressure reducer and pressure gauge

FIGS. 47 to 54 show a further variant of the third embodiment. In this variant, the pipe separator is integrated into a pipeline. The generally designated 510 pipe separator consists of a first housing part 512 and a second housing part 513. The second housing part 513 and all its components and functions installed therein are identical to the housing part 513 of the third embodiment and therefore need not be further explained here.

The first housing part 512 has a flange 527, with which the second housing part 513 is flanged to the first housing part 512 with a seal 515 as in the third embodiment.

In addition to the components already described with reference to the embodiments described above, this sixth embodiment has a pressure reducer 580 and a pressure gauge 582. In FIG. 52 It can be seen that the pressure reducer 580 as a pressure reducer insert into a housing stub 584 in the first Housing part 512 is formed. The pressure reducer insert is already known from numerous publications and patents of the applicant and therefore need not be described in detail here. The housing stub 584 is disposed with the outlet and the central portion 586 downstream of the backflow preventers. In this way, the pressure at the outlet 516 is regulated. The pressure gauge 582 is seated in a housing neck, which is integrally formed with the area behind the pressure reducer 580 to the first housing part 512. This is in FIG. 54 to recognize.

FIG. 55 illustrates how the components of the pipe separator assemblies described above form a modular kit from which various pipe separators can be formed. The present exemplary embodiments integrate the different components in the first housing parts 212, 312, 412 and 512, respectively. All of these first housing parts can be connected to a housing part 213 that is identical for all assemblies. This has the advantage that the production and storage costs can be significantly reduced. In addition, only the second housing part 213 needs to be removed and maintained or replaced for maintenance and renewal of the pipe separator. The handling is made easier for the installer and the training effort is reduced.

Exemplary embodiment 7 (FIGS. 57-59): Flanged pipe separator with alternative drain valve

FIG. 56 illustrates a drain valve in which, as described above, a drop can be prevented with slightly fluctuating input pressure without using a separate compensation piston. FIGS. 57 to 59 show an alternative embodiment of such a drain valve. Again, a piston 660 is connected to a valve closing body 667. The valve closing body 667 cooperates with a valve seat portion 631 and an O-ring 632 as a gasket.

The valve closing body 667 is, as in the above embodiments 3-6 formed by a cylindrical hollow body. This is good in FIG. 58 to recognize. The valve seat portion 631 includes an upper ring 633 from which two webs 634 extend downwardly. With the ring 633, the valve seat part 631 is a tubular, inner guide member 662 written down, which is fixed to the housing with the sleeve already described above and immovably connected.

Between the webs 634, a valve plate 639 is held. The valve plate 639 extends upwardly to form a substantially vertical transition region 636. In the transition region 636, an annular groove is provided for the O-ring 632 as a valve seal. When the valve closing body 667 is closed in its lower position and the drain valve is closed, the O-ring 632 abuts inside the valve closing body 667. In the lowest position of the valve closing body 667, the O-ring 632 abuts slightly above the lower edge 637. When the inlet pressure drops slightly, the piston makes a lift upwards. The valve closing body 667 must sweep the seal 632 by a small stroke before the drain valve opens. Similar to the embodiment already described FIG. 56 In this case, a drop of the drain valve is avoided with fluctuating input pressure.

Exemplary embodiment 8 (FIG. 60): Pipe separator with off-axis arranged non-return valves

FIG. 60 shows a generally designated 710 fitting in the form of a pipe separator assembly. The pipe separator assembly 710 includes a one-piece housing 712. The housing 712 has a first flange 713 with an inlet 714 and a coaxially arranged flange 715 with an outlet 716.

The pipe separator arrangement 710 is installed in a pipeline (not shown), for example, between a drinking water supply arranged on the inlet side in front of a heating system (not shown) arranged on the outlet side. The design of inlet 714 and outlet 716 allow installation in conventional flange fittings, which are manufactured for example by the applicant. In this case, other functionalities, such as water treatment or pressure reducer in the valve can be realized. The water flows through the inlet 714 into the fitting and from there out of the outlet 716.

The housing 712 forms in the interior obliquely extending walls 701 and 702 with openings. An inlet chamber 721, a medium pressure chamber 743 and an outlet chamber 723 are formed by the walls. Backflow preventers 718 and 720 form valves which control the flow through the openings in the walls 701 and 702. The backflow preventer 718 and 720 sit in also obliquely upwardly extending housing stub 722 and 724. It can be seen that in this way large flow cross sections for applications with special pressure and flow conditions can be realized.

At the bottom of the housing 712, a housing stub 740 is formed. A channel 745 connects the upper portion 782 within the housing stub with the inlet chamber 721. A piston 760 is guided in the housing stub 740. A channel 747 connects the interior of the housing stub 740 with the medium-pressure chamber 743. With the piston 760, a drain valve is controlled in the manner described above. The mode of operation need therefore not be described further here.

Claims (14)

1. A backflow preventer assembly (10; 210; 310; 410; 510) for physical separation of an upstream liquid system from a downstream fluid system by means of a discharge valve comprising

   (a) a housing (12; 212; 312; 412) with an inlet (14; 214; 314; 414) and an outlet (16;216;316;416),

   (b) an upstream backflow preventer (18; 218) provided in the housing (12; 212; 312; 412),

   (c) a downstream backflow preventer (20; 220),

   (d) a discharge valve pressurised by a loading spring (52; 252) with a seat sealing and a valve seat (54) which cooperates with the seat seal, and

   (e) a housing socket (40; 240) provided at the housing (13; 213; 313; 413) for discharging of liquid which exits through the discharge valve from the housing (13;213; 313; 413), whereby

   (f) upstream of the upstream backflow preventer (18, 20, 218, 220) an inlet pressure of the upstream liquid system,

   (g) between the backflow preventers (18, 20, 218, 220), a medium pressure in a medium pressure chamber (43; 243), and

   (h) downstream of the downstream backflow preventer (20; 220) an outlet pressure of the downstream liquid system can be generated, and whereby

   (i) the movable part of the discharge valve is connected to a movable, spring-loaded piston (60; 260) in the housing (12; 212; 312; 412), and the piston is adapted to be pressurised on the one side against the spring effect of the loading spring (60; 260) with inlet pressure and on the other side exposed to medium pressure,

   (j) the piston (60; 260) is movable perpendicularly to the flow direction in the medium pressure chamber (43; 243), and

   (k) the piston (60; 260) in the housing socket (40; 240) is movably guided outside the flow generated in the medium pressure chamber (43; 243),
   characterised by

   (l) a first connection passage (86) between the range in the housing socket (40; 240) above the piston (60; 260) and the range upstream of the upstream backflow preventer (18; 218) and a second connection passage (45; 245) between the range in the housing socket (40) underneath the piston (60; 260) and the medium pressure chamber (43; 243).
2. Backflow preventer assembly according to claim 1, characterised in that the backflow preventers (18, 20, 218, 220) are assembled coaxially.
3. Backflow preventer assembly according to one of the preceding claims, characterised in that the housing socket (40; 240) comprises a detachable, housing fixed socket part, to which a discharge hopper (56; 256) is fixed.
4. Backflow preventer assembly according to any of the preceding claims, characterised in that the discharge valve comprises a valve seat part (54) connected to the piston (60), which interacts with a housing-fixed valve plate (76).
5. Backflow preventer according to claims 3 and 4, characterised in that the valve plate (76) is connected to the discharge hopper (56) or the housing-fixed socket part.
6. Backflow preventer according to claim 3, characterised in that the socket part has an upper rim (50) forming a spring abutment for the loading spring (52) of the piston (60).
7. Backflow preventer according to any of the preceding claims, characterised in that the housing (12, 13; 212, 213) is formed by two parts, wherein a first housing part (12; 212; 313) is formed as a connection fitting, which is adapted to be installed with an inlet (14, 214) in a pipe, at a closable water tap or any other water supply; a second housing part (13; 213; 313) receives the drain valve; and the second housing part (13; 213; 313) is adapted to be connected to the first housing part (12; 212; 313) in various different positions with an angular offset about a horizontal connection axis.
8. Backflow preventer assembly according to claim 7, characterised in that the first housing part (12; 212; 312; 412) has a plane connection surface (27; 327; 427), adapted to be flanged to a corresponding connection surface on the second housing part (13; 213; 313; 413), wherein the outlet channel (23) is an annular channel in the range of the connection extending around a central inlet channel (21) or the inlet channel is an annular channel (221; 321) in the range of the connection extending around a central outlet channel (223; 323; 423).
9. Backflow preventer assembly according to claim 8, characterised in that the upstream backflow preventer (18) is provided in the second housing part (13) in the central inlet channel (21).
10. Backflow preventer assembly according to claim 9, characterised in that both backflow preventers (18, 20) in the second housing part (13) are provided in the central inlet or outlet channel (21; 223).
11. Backflow preventer assembly according to any of the preceding claims, characterised in that pressure reducer is provided downstream of the downstream backflow preventer.
12. Backflow preventer assembly according to any of the preceding claims, characterised in that a pressure gauge (582) is provided downstream of the downstream backflow preventer (20).
13. Backflow preventer assembly according to any of claims 7 to 12, characterised in that the first housing part (12) has a hose connector (316; 416).
14. Backflow preventer assembly according to any of the preceding claims, characterised in that a stop valve is provided at the inlet (14).

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