EP0182004B1 - Protecting device for drinking-water conduit pipes - Google Patents

Abstract

1. Device for the protection of drinking-water ducts (1) leading to positions of use against back-flowing used water, with a tubular separator (3) located in the drinking-water duct behind a supply valve (2) and including an axially-movable piston separator tube (26) in a cylinder provided with a supply line, which, with the supply valve (2) open, moves against spring action into a discharge connection (7) provided with a non-return valve (8) and is then traversed by water and, in contrast, with the supply valve (2) closed, moves into its separating position remote from the discharge connection (7), as well as with a pressure-control cylinder (2') containing the pressure-control piston (22) controlling the supply valve (2) having operating chambers disposed on both sides of the pressure-control piston (22) which are to be connected via a servo-control valve (4) provided with a servo-control piston (35) with a water supply and a discharge duct, wherein the servo-control piston (35) is operable by the water pressure on the one hand in the water duct and on the other hand in the used water duct, characterised in that the servo-control valve (4) is provided on the used water duct with a holding valve (6), which is located in a by-pass duct (9) parallel to the discharge connection (7) of the separator (3) and bridging over the non-return valve (8) and contains a valve piston (48) arranged to move under the flow water pressure prevailling there, which in its shifted position bridges the connection (10) between the servo-control valve (4) and the used water duct (5).

Description

The invention relates to a device for protecting drinking water pipes leading to consumer points against returning domestic water, with a pipe separator installed in the drinking water pipe behind an inlet valve, which has a piston separating pipe which is axially displaceably guided in a cylinder provided with an inlet connector and which counteracts spring action when the inlet valve is open retracts into a discharge nozzle provided with a check valve and then flows through the water, on the other hand, when the inlet valve is closed, reaches its separation position away from the discharge nozzle, a pressure control cylinder containing a pressure control piston controlling the inlet valve being further provided, the working chambers of which are located on both sides of the pressure control piston via a working chamber with a Pilot valve provided pilot valve are to be connected alternately with the water supply line and a relief line, and the pilot piston on the one hand from the in the Water supply and on the other hand can be acted upon by the water pressure prevailing in the service water line.

In a device of the above type known from DE-A-2 806 310 and DE-A-2 849 825, the pilot piston which controls the pressure control piston of the supply valve also allows only small amounts of water to be drawn from the service water line without the switching vibrations of the piston separating tube being disruptive comes in the pipe separator. This is prevented by the fact that the pilot spool is more or less freely displaced by the water pressure that occurs in the service water line and is dependent on the water withdrawal, without bringing the pressure control spool out of its switching position holding the inlet valve in the open position, in which the working chamber facing away from the inlet valve in Pressure control cylinder is connected to the relief line. Only when so little water is removed that there is a correspondingly high water pressure in the service water line, which corresponds to the pressure on the inlet side, is the pilot spool shifted to such an extent that it switches the aforementioned working chamber in the pressure control cylinder from the relief line to the service water line while the other Working chamber in the pressure control cylinder is relieved at the same time and thereby the inlet valve moves into its closed position, which in turn has the consequence that the piston separating pipe in the pipe separator reaches its separating position which is retracted into its cylinder. In this separating position, any backflow of process water into the drinking water supply line is prevented, since even if the check valve in the discharge nozzle leaks, the process water that passes through it can flow into a discharge line branching off between the discharge nozzle and the cylinder of the pipe separator. Although the known device, thanks to its pilot valve, normally also enables reliable removal of small amounts of water when the piston separating tube remains in the flow position, switching difficulties do occur when there are major changes in water pressure in the supply system, which can only be effectively countered by changing the pressure springs acting on the pilot piston. But this is quite cumbersome and requires a considerable amount of time and assembly.

In contrast, the invention is based on the object of improving and perfecting a device of the type mentioned at the outset in such a way that even small amounts of water can be drawn with it without disruptive switching vibrations of the piston separating tube even in the case of strongly changing water supply pressures. This object is achieved on the basis of a device of the type in question according to the invention in that a holding valve is connected upstream of the pilot valve on the service water line side, which is located in a bypass line running parallel to the outlet connection of the pipe separator and bridging its check valve and one of the flow water pressure occurring therein contains displacing valve piston, which in its displacement positions interrupts the connection between the pilot valve and the hot water pipe.

This holding valve located in the bypass to the non-return valve of the pipe separator ensures that, in the case of a correspondingly sensitive setting of its valve piston, the process water pressure at the pilot piston corresponding to the larger water withdrawals can also be maintained in the event of low and minimal water withdrawals, so that the pilot piston opens the inlet valve holding switch position remains safe due to the correspondingly large admission differential pressure and only reaches its switching position which brings the inlet valve into the closed position and thus also the piston separating pipe into the disconnected position when there is virtually no water withdrawal. It is essential that the holding valve with its valve piston lies in the bypass line to the check valve of the pipe separator, because on the one hand the holding valve responds accordingly sensitively and on the other hand the check valve can perform its backflow prevention function completely unaffected by opening only with larger water withdrawals, on the other hand, with little or no water withdrawal with sufficient closing force, lies sealingly on its valve seat.

Advantageously, a restoring spring acts on the valve piston of the holding valve and tries to keep it in the rest position against the flow water pressure, the valve piston blocking the bypass line in its area in front of the check valve in its rest position. The return spring can be dimensioned relatively weak, so that even a low flow water pressure in the bypass line is sufficient to move the valve piston out of its idle position blocking the bypass line and thereby to block the connecting line between the pilot valve and the hot water line.

Further features of the invention will be explained with reference to an advantageous embodiment shown in the drawing.

• Fig. 1 die Vorrichtung zum Schutz von Trinkwasserleitungen in schematischer Blockdarstellung, während
• Fig. 2 das Zulaufventil mit Drucksteuerzylinder,
• Fig. 3 den Rohrtrenner,
• Fig. 4 das Vorsteuerventil und
• Fig. 5 das Halteventil jeweils im Schnitt wiedergeben.

It shows:

• Fig. 1, the device for protecting drinking water pipes in a schematic block diagram, while
• 2 the inlet valve with pressure control cylinder,
• 3 the pipe separator,
• Fig. 4, the pilot valve and
• Fig. 5 each show the holding valve in section.

The device shown schematically in Fig. 1 for protecting drinking water pipes leading to consumer points against backflowing process water essentially consists of the inlet valve 2 built into the drinking water inlet pipe 1 with the associated pressure control cylinder 2 ', the pipe separator 3 connected downstream of the inlet valve 2, the pilot cylinder 4, and the between the latter and the service water pipe 5 located behind the pipe separator 3, the holding valve 6. The latter is located in a bypass line 9 which is parallel to the outlet connection 7 of the pipe separator 3 and bridges its check valve 8. The holding valve 6 is also connected via the pressure control line 10 with a built-in pressure gauge 11 connected to the one connection side of the pilot valve 4, the opposite end of which is connected to the drinking water supply line 1 via the line 12. The connection line 13 is present between the pressure control valve 4 and the pressure control cylinder 2 ', the connection line 15 between the latter and a pilot valve 14, and the T-shaped connection line 17 between the pressure control cylinder 2', the pilot valve 14 and the water flow area 16 located behind the inlet valve 2. In contrast, the lines denoted by 18, 19 and 20 are so-called relief lines, which open into the open or into a process not shown in detail.

As shown in FIG. 2, the valve body 2 ″ belonging to the inlet valve 2 is firmly connected via the piston rod 21 to the pressure control piston 22, which can be displaceably accommodated in the pressure control cylinder 2 ′. This divides the interior of the pressure control cylinder 2 ′ into two working chamber halves, of which the upper 23 is connected to the lines 13, 15, whereas the lower working chamber 23 '(see FIG. 1) is in constant communication with the T-shaped branched line 17. In the pilot valve 14, a valve piston 14' is provided, which acts on is provided at its upper end with a piston membrane 14 "clamped all around in the valve housing and at its lower end with a sealing shoulder 14"'. The compression spring 14' ^v accommodated in the pilot valve 14 tries to hold the piston 14 'in its upper switching position, in which the Piston shoulder 14 '"blocks the T-shaped connecting line 17 with respect to the relief line 19. On the other hand, the piston 14 'is displaced into its lower position by appropriate pressurization of the piston membrane 14 ", in which the line section 16 and also the lower working chamber 23' are connected to the relief line 19 via the T-shaped connecting line 17.

The pipe separator 3 shown in FIG. 3 is equipped in a known manner with a piston separating pipe 26 which is axially displaceably guided in the cylinder 25 provided with an inlet connection 24. The valve rod 27, which is fastened in a memory-like manner in the inlet connection 24 and with its valve head 28 having an annular seal 28 ′, projects into this piston separating tube 26 in a sealing manner. The piston separating tube 26 is supported on the shoulder 30 of the cylinder 25 via the compression spring 29. On the valve rod 8 ', which in turn is fastened in a spoke-like manner, sits the valve body 8 ″ which forms the actual check valve 8 and is pressed with its end face seal 8 ″ by a comparatively strong compression spring (not shown) against the valve seat surface 81v in the outlet port 7. Between the outlet nozzle 7 and the cylinder 25 there is the pipe separation point 32, which is covered at the top by a viewing window 31 and below which the relief line 29 branches off.

The pilot valve 4 shown in FIG. 4 has a valve housing 33 which is screwed together from a plurality of molded parts and which is penetrated by a continuous axial bore 34, in which the pilot piston 35 is axially displaceably mounted to a limited extent. The piston 35 is provided at both ends with piston flanges 36, 37, which are covered on the outside by piston membranes 38 and 39, the outer circumferences of which are housed and clamped in the pressurizing chambers 40 and 41 of the pilot valve 4, which are of correspondingly large diameter. In the right section 34 'of the axial bore 34, the compression spring 42 is accommodated, which acts on the control piston 35 as well as the process water line pressure present via the connecting line 10. The left working chamber 40 is connected to the drinking water supply line 1 via the opening line 12. The respective inner working chambers 40 'and 41' are connected to the outside atmosphere via ventilation bores 43, 43 ', the bores 43' furthermore ensuring that even if the piston membrane 39 is damaged, there is no process water from the line 10 into the central section of the axial bore 34 can reach, so no otherwise possible contamination of the supply water can take place.

The pilot piston 35 is also provided at its end facing the feed line 12 with its axial bore 35 ′ and a transverse bore 35 ″ attached to it, which is in the flow position of the pilot piston 35 shown in FIG. 4 at the level of the bore extension 34 ″ in the valve housing 33. Furthermore, the connections 13 'and 18' for the line 13 leading to the pressure control cylinder 2 'and to the relief line 18 are provided in the valve housing 33. Two ring seals 35 "'are provided on the pilot piston 35 at a corresponding distance from one another and the ring seals 44 are provided in the valve housing in the region of the working chambers 40', 41 '.

The holding valve shown in FIG. 5 has a valve housing consisting of the two cylindrical parts 45, 46 screwed together, which is penetrated by a continuous axial bore 47 in which the valve piston 48 is axially displaceably mounted. The storage takes place via the ends 48 'and 48 "which are tapered in diameter in the correspondingly narrowed end regions 47' and 47", respectively. the continuous axial bore 47, which is connected or incorporated into a bypass line 9 via its lower and upper connection 47 ″ or 47 ^{11. The} line 10 leading to the pilot valve opens into the area 47 ^{v of} the axial bore 47, namely via the perforated stop sleeve 50, which is sealed on both sides by sealing rings 49, which is held by the sleeve 51 located above and the nut 52 screwed to the upper housing part 45 via its external thread. The central part of the valve piston 48 is provided with a shoulder 48 "'provided that carries a slightly projecting, flexible flow flange 53 and at the same time serves to support the compression spring. This strives to press the valve piston 48 with its shoulder 48 "', which carries the sealing ring 55, against the valve seat surface 46' provided on the lower valve housing part 46. The shoulder 48"'and the flexible flow flange 53 are held in diameter in such a way that in the process water line 5 recognized in forming the water extraction in the bypass line 9 can flow past water located at the Strömungsflansch 53 to be able to then existing in the piston 48 and the transverse bore 481v axial bore 48 continue to flow ^v. The compression spring 54 is preloaded accordingly, depending on the prevailing flow water pressure, the tubular part 48 ′ of the valve piston 48 blocking the inlet 47 to the pilot line 10, as shown in FIG. 5.

If there is no water withdrawal in the service water line 5, the inlet valve 2 and its pressure control piston 22 as well as the piston separating pipe 26 and the check valve 8 in the pipe separator 3 assume the closing or separating position shown in FIGS. 2 and 3. The valve piston 48 of the holding valve 6 rests with its shoulder 48 ″ or the sealing ring 55 present thereon on the valve seat 46 ′, as a result of which the service water line part 5 faces not only via the check valve 8 in the closed position but also via the bypass line 9 of the separation point 32. Since in this locked position the valve piston 48 has connected with its tubular end portion 48 ^v the connecting line 10 to the bypass line 9 and thus the water pressure prevailing in the service water line 5 together with the compression spring 42 present in the pilot valve 4 4, the pressure control line 12 is connected via the bores 35 'and 35 "and via the bore extension 34" to the line 13' leading to the upper working chamber 23, whereby the pressure control piston 22 in 2 in the position shown also the piston 14 'present in the pilot valve 14 is pressed into the lower switching position shown in FIG. 2, in which both the pipe section 16 and the lower working chamber 23' in the pressure control cylinder 2 'are connected to the relief line 19 via the T-shaped line 17 stand.

If, on the other hand, water is withdrawn from the service water line 5, the pressure in the outlet connection 8 and in the bypass line 9 drops accordingly, as a result of which, via the line 10 still initially connected to it, also in the pilot valve 4 to a corresponding pressure drop in the pressure chamber 41 comes, whereby the pilot piston 35 comes into the flow position shown in FIG. 4, in which the upper working chamber 23 of the pressure control cylinder 2 'is separated from the pressure control line 12 and is instead connected to the relief line 18. As a result, the pressure control piston 22 moves into its upper position, in which the inlet valve 2 is opened. At the same time, the valve piston 14 'present in the pilot valve 14 has separated the pipe section 16 and the lower working chamber 23' from the relief line 19. The water flow resulting from the opening of the inlet valve 2 ensures that the piston separating pipe 26 is pressed into its flow position in the outlet port 7, the piston separating pipe 26 first being pushed off by the valve head 28 projecting into it and only then releasing the water flow while simultaneously opening the check valve 8 . Due to the flow occurring in the bypass line 9 during the removal of water, the valve piston 48 in the holding valve 6 has also reached its illustrated upper blocking position against the action of the spring 54, in which it shuts off the line 10 with respect to the bypass line 9. As a result, the comparatively low water pressure prevailing in the line 10 and also acting on the piston membrane 39 is maintained. This is still the case even when the water withdrawal becomes increasingly smaller, although the check valve 8 can then already reach its closed position shown in FIG. 3. However, a sufficient amount of flow water still flows through the bypass line 9 and thus through the holding valve 6, which holds the valve piston 48 and thus ultimately also the pilot piston 35 in the position shown in FIGS. 5 and 4, which the flow position of Inlet valve 2 and pipe separator 3 corresponds. Only when virtually no more water is removed and consequently the bypass line 9 is no longer flowed through by the water, the piston 48 reaches its lower rest position, in which the process water pressure via the bypass line 9 and the line connected to it 10 again acts on the pilot piston 35 and shifts it into the switching position opposite to FIG. 4, as a result of which the inlet valve 2 closes and the piston separating tube 26 reaches its separating position which has been moved into the cylinder 25.

Claims (5)

1. Device for the protection of drinking-water ducts (1) leading to positions of use against backflowing used water, with a tubular separator (3) located in the drinking-water duct behind a supply valve (2) and including an axially-movable piston separator tube (26) in a cylinder provided with a supply line, which, with the supply valve (2) open, moves against spring action into a discharge connection (7) provided with a non-return valve (8) and is then traversed by water and, in contrast, with the supply valve (2) closed, moves into its separating position remote from the discharge connection (7), as well as with a pressure-control cylinder (2') containing the pressure-control piston (22) controlling the supply valve (2) having operating chambers disposed on both sides of the pressure-control piston (22) which are to be connected via a servo-control valve (4) provided with a servo-control piston (35) with a water supply and a discharge duct, wherein the servo-control piston (35) is operable by the water pressure on the one hand in the water duct and on the other hand in the used water duct, characterised in that the servo-control valve (4) is provided on the used water duct with a holding valve (6), which is located in a by-pass duct (9) parallel to the discharge connection (7) of the separator (3) and bridging over the non-return valve (8) and contains a valve piston (48) arranged to move under the flow water pressure prevailing there, which in its shifted position bridges the connection (10) between the servo-control valve (4) and the used water duct (5).

2. Device according to claim 1, characterised in that a return spring (54) biassed to hold it against the flow water pressure acts upon the valve piston (48) of the holding valve (6) and the valve piston (48) in its rest position closes the by-pass duct (97 in the region lying upstream of the back-pressure valve (8).

3. Device according to claim 2, characterised in that the holding valve (6) includes a valve housing (45, 46) with an axially through-going two-sided stepped reduced-diameter axial bore (47) associated with the by-pass duct (9), as well as a transverse bore (47^v) leading to the servo-control valve (4) and discharging into the axial bore section (47') facing the by-pass duct section discharging behind the non-return valve (8), where the valve piston (48) is movably mounted at both ends in the axial bore (47), is provided in its middle region with a flow switch (48''') supporting the re-setting spring (54) surrounding it and is made tube-shaped at its end facing the transverse bore connection (47^v) as well as to close or release the transverse bore connection in a piston-like manner.

4. Device according to claim 3, characterised in that the valve piston (48) of the holding valve (6) is provided on its annular shoulder (48"' ) facing the supply side reduced-diameter axial bore section (47") with a ring seal (55) contacting the bore shoulder (46') of the valve housing (46) in the rest position of the valve piston.

5. Device according to any of claims 1 to 4, characterised in that the servo-control valve (4) has a valve housing (33) provided with an axially through bore (34) and receiving the servo-control piston (35) arranged therein, which includes two actuating chambers (40, 41) for each of the associated piston members (38, 39) located at the height of the ends of the servo-control valve (35), one (38) of which is actuable by the water supply pressure and the other (39) by the used water pressure, wherein, between the used water duct side connection of the valve housing and the servo-control piston end facing it, a compression spring (42) contacting the latter is arranged and between the two actuating chambers (40, 41) in the servo-control valve housing (33) of the duct connection (13') leading to the pressure control cylinder (2') as well as axially displaced to the latter the pressure relief duct connection (18') is arranged, controlled by the servo-control piston (35) provided with corresponding valve bores (35', 35") and ring seals (35"' ).

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