Classifications

• • 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 which is intended in particular for installation in drinking water pipes and which has a flow housing which contains a feed and discharge line, a spring-loaded feed valve accommodated therein and a spring-loaded drain valve and a means arranged between the two valves is provided, which is to be connected to the outside atmosphere via a drain valve which ensures the maintenance of a minimum differential pressure between the supply line and the central chamber and in particular is acted upon by a valve spring, the valve body of which is connected to a control membrane 5, one side of which acts on the supply line and the other Acting side is in hydraulic connection with the middle chamber.
• Backflow preventers of the above type are known. They ensure that the liquid pressure prevailing in the middle chamber is always lower than the liquid pressure present in the feed line, so that even if the feed valve is defective or has a leakage, the backflow of the feed valve Liquid from the middle chamber or discharge into the supply line is prevented.
• the inlet and outlet valves are provided with valve flaps closing the supply line or middle chamber, which are acted upon by articulated toggle levers and valve springs engaging them and arranged perpendicular to the flow direction. This requires a space-saving housing design.
• both known backflow preventers have a comparatively large flow resistance for the liquid, which tends to swirl as it flows through it and thereby also causes disturbing noise.
• the invention is therefore based on the object of providing a backflow preventer of the type in question which does not have the aforementioned disadvantages, is rather of a narrow, compact design and an improved liquid flow rate with a greatly reduced flow rate
• the flow-through housing is cylindrical in shape, the inlet and outlet valves accommodated therein, including their actuation springs, are arranged coaxially and that
• Drain valve, its valve body and the control membrane are outside the flow housing tube.
• the middle chamber with the sole exception of the inlet valve is free of internals and also has no housing chamber niches in which fluid swirling can occur.
• the liquid flowing through finds only a low flow resistance.
• Another contributing factor is that the drain valve spring is only very weak compared to the feed valve spring.
• control valve body is provided with two control membranes separated from one another by an intermediate space connected to the outside atmosphere, the control valve membrane of which faces the discharge valve body and the discharge valve spring surrounding the latter can be acted upon by the liquid pressure prevailing in the central chamber, while the other control membrane is always under the liquid pressure prevailing in the feed line.
• the control membrane of which faces the discharge valve body and the discharge valve spring surrounding the latter can be acted upon by the liquid pressure prevailing in the central chamber, while the other control membrane is always under the liquid pressure prevailing in the feed line.
• the effective loading cross section of the control membrane connected to the feed line is smaller than the effective loading cross section of the chamber connected other control membrane, and expediently just by a dimension corresponding to the cross section of the discharge valve body piston. This ensures that the response minimum pressure difference between the supply line and the middle chamber can be kept constant regardless of the liquid pressure prevailing in the supply line.
• the illustrated backflow preventer essentially consists of the flow housing tube 3, which is connected to an inlet pipe socket 1 and an outlet pipe socket 2 in a liquid-tight manner, in which an inlet valve 4, which allows the inlet line 1 "to be shut off, and an outlet valve 5 and an outlet valve between the two valves Mittel ⁇ chamber 6 are arranged, which can be connected to the outside atmosphere via the drain valve generally designated 7.
• Manometer can be attached to the threaded connecting piece _. '' ' And 3 ".
• 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 strongly dimensioned inlet valve spring 11 is accommodated, which tries to press the valve body 8 with its end face bearing a seal 8 'against the valve seat 1' ', which protrudes from the recessed shoulder of the inlet tube projecting into the flow housing tube 3 or pipe connection piece 1 is formed.
• the drain valve 5 has a mushroom-shaped valve body 12, which with its shaft 12 'is in a guide tion 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 frusto-conical valve head 12 ′′ interacts with the conical valve seat surface 16 ′, which is located in a plug-in sleeve 16 inserted into the rear of the flow housing tube 3.
• 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 one another via screws 19. Between the middle part 18 ′′ and the end parts 18 ′ of the housing on the one hand and 18 ′′ ′′ on the other hand, a control membrane 20, 20 'is firmly clamped around the periphery of 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 space 26 present between the two membranes 20, 20 'is connected to the outside atmosphere via the ventilation openings 27.
• the drain valve body 25 is together with the drain valve spring 28 surrounding it in the on the housing part 18 '' '
• This tube extension 18 is provided on the bottom side with a drain opening 29 leading into the open and with a lateral connecting piece 30 which connects via line 31 to the
• Middle chamber 6 is connected. Above the outside
• a seal 32 is provided in the tube extension 18, on which the valve body 25 can sit with its end face 25 '.
• 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 control chamber 33 facing the lower diaphragm 20 ' is connected to the central chamber 6 via the line 31, while the control chamber 34 located adjacent to the other control diaphragm 20 is connected to the connecting piece _ via the pipe connection 35.
• ⁇ ⁇ ⁇ the feed line 1 ' is connected to conduct liquid.
• the cross section of the control chamber 34 is kept smaller than that of the control chamber 33, so that the control diaphragm 20 has a smaller effective cross section than the control diaphragm 20 '.
• the degree of the reduction in cross section corresponds to the cross section of the drain valve body piston 25.
• the relief valve spring 28 which is set to a pressure relief of, for example, 0.5 bar, is therefore unable to lift the relief 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, what 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, according to which the discharge valve body 25 would reach its open position and would thus lead to a corresponding reduction in pressure in the middle chamber 6. It is thus ensured that there is always a minimum pressure drop between supply line 1 'and central chamber 6, which prevents the process water from flowing back into supply line 1'. It is also of particular advantage that this backflow preventer is independent of the installation position, ie it can be used in any position.

Landscapes

• 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)
• Safety Valves (AREA)
• Fluid-Driven Valves (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6342484

Family Applications (1)

Country Status (6)

Families Citing this family (5)

Citations (6)

• 1987
  • 1987-12-12 DE DE19873742207 patent/DE3742207A1/de not_active Withdrawn
• 1988
  • 1988-11-30 WO PCT/EP1988/001087 patent/WO1989005382A1/de active IP Right Grant
  • 1988-11-30 ES ES89900218T patent/ES2030596T3/es not_active Expired - Lifetime
  • 1988-11-30 EP EP19890900218 patent/EP0353266B1/de not_active Expired - Lifetime
  • 1988-11-30 EP EP88119971A patent/EP0320700A1/de active Pending
  • 1988-11-30 DE DE8989900218T patent/DE3868925D1/de not_active Expired - Fee Related
• 1989
  • 1989-08-01 FI FI893642A patent/FI893642A0/fi not_active Application Discontinuation
  • 1989-08-11 DK DK396489A patent/DK396489A/da not_active Application Discontinuation

Patent Citations (6)

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