Pressure reducing valve e.g. for domestic and industrial water supplies

The invention relates to a pressure reducing valve for non-aggressive, liquid, gaseous or vaporous media with

a) a housing,

b) a membrane that is clamped in the housing and on the one hand is under spring tension and on the other hand is acted upon by the medium pressure on the secondary side - the side of the pressure-reduced extraction network and

c) a pressure-relieved slide, rigidly connected to the membrane, which cooperates with a disk seal that is rigidly attached to the housing and forms the valve seat, so that the slide opening approaches the disk seal in the two end positions of the membrane until it is completely closed or up to a maximum Passage gap removed.

The invention thus relates to a pressure reducing valve which is mainly used in domestic and industrial water supplies, but which is also generally suitable for non-aggressive liquids and gases. A typical commercial application is also compressed air nets. Pressure reducing valves have the function of reducing the higher pressure on the primary-side distribution network to an optimal pressure for the secondary-side consumer line. This increases the service life of the installation, the secondary side is supplied with a regulated, constant pressure and protected against excessive pressure. At the same time, the development of noise is kept to a minimum and the consumption of the medium is reduced. The use of pressure reducing valves in domestic water supply systems, where the distribution network in the house is operated with reduced pressure, while the outside area - e.g. for garden irrigation - the full primary pressure is applied.

A pressure reducing valve for liquid, gaseous or vaporous media with a membrane, a pressure-relieved slide and an exchangeable fine sieve, as defined in the preamble of claim 1, is concerned.

A distinction is made between seat and slide valves. With seat valves, a valve disk with a flat seal - mostly made of rubber - is moved against a valve seat - mostly made of chrome steel. The pressure relief is realized structurally by providing a piston directly connected to the sealing cone, whereby primary pressure is applied to two surfaces of at least approximately the same size and the resulting forces compensate each other. The pressure relief makes the pressure reducing valve insensitive to primary pressure fluctuations. In slide valves, a slide has the function of a moving part that is moved against a flat seal. The pressure relief of the slide results from the fact that the forces resulting from the application of pressure on the sealing edge or on the diametrical face of the slide cancel each other out, ie the surfaces effective on both sides are of the same size. Each primary pressure fluctuation compensates itself in its effect on the slide and thus does not falsify the setpoint set for the secondary side.

Such a slide valve with a simplified housing structure and a pre-assembled, easily replaceable filter unit is known from DE 24 07 223 C2. The tubular slide made of plastic has centrally tapering ribs to hold the valve spindle. The valve spindle leads through two coaxial seals arranged one behind the other into the secondary chamber and is positioned centrally on the control diaphragm. These dynamically stressed spindle seals are subject to wear.

In summary, it can be stated that all of the pressure reducing valves known to date cannot be regarded as entirely satisfactory. The invention is therefore based on the problem of creating a valve arrangement with a significantly increased service life without having to increase the structural complexity. The previous advantages of slide valves with a relatively simple housing structure with a fine filter unit that can be attached at the bottom and can be easily prefabricated should be retained. Attention should also be paid to a compact, space-saving design with excellent performance parameters and minimal noise generation.

According to the invention it is proposed in the aforementioned pressure reducing valve that

d) the rigid connection between the slide and the membrane consists of at least two spacer elements, which are connected to the slide on the secondary side, protrude through openings in a permanently installed base disk and with a die

AT 408 261 B

Membrane supporting carrier plate are connected, wherein

e) the secondary medium pressure acts on the membrane through the openings.

The basic solution of the invention is that at least two valve spindles are provided in the form of spacer elements, which are located in the low pressure area, ie on the secondary side within the pressure reducing valve. These spacer elements create a rigid connection between a membrane and a slide. At least one spring acts on the diaphragm from one side - the setpoint is adjusted via the spring - and the other side of the diaphragm is acted upon by pressure on the secondary side. When the clamped membrane is deformed, the position of the slide changes, creating a passage gap for the medium flowing in from the primary side to the secondary side, between the slide and a seal - from a zero value to a maximum opening side.

Thanks to the invention, a pressure reducing valve that requires less repair is now available, where no seal is required around a valve spindle, which has to seal the higher pressure in the supply network against the reduced pressure in the consumer network. By means of a combined spring arrangement of two coaxially nested helical springs with different characteristics for the setpoint adjustment, the overall height of the pressure reducing valve is considerably reduced, and one of three selectable pressure levels can be set by inserting only one spring. The pressure reducing valve has very good performance parameters and is also service-friendly with regard to the accessibility of the filter.

Drawings and examples

A detailed description of an exemplary embodiment of the pressure reducing valve according to the invention follows with the aid of the accompanying drawings, with possible modifications being mentioned in conclusion. Show it:

FIG. 1: a vertical section through the pressure reducing valve with the slide closed;

FIG. 2: the view according to FIG. 1 with the slide open and

FIG. 3: a two-part view according to FIGS. 1 and 2 with the left half closed and the right half open.

The following definition applies to the rest of the description. If reference numbers are included in a figure for the purpose of graphic clarity, but not explained in the directly associated descriptive text, reference is made to their mention in the preceding figure descriptions. In the interest of clarity, the repeated designation of components in the following figures is mostly dispensed with, provided that it is clearly recognizable in the drawing that these are recurring components.

Figure 1

The pressure reducing valve has a housing 1 with the horizontally attached inlet connector 10 and the opposite outlet connector 11. The filter space 12 with the screw attachment 13 extends downwards to the valve chamber 14 is formed by a vertical internally threaded bore 15 which opens up into a shoulder support 16. Coming from the inlet connector 10, the flow is directed from a wall 17 into the filter space 12. A wall 18 blocks direct access from the filter space 12 to the outlet connector 11. There is therefore no direct transition from the inlet connector 10 to the outlet connector 11; the flow must pass through the internally threaded hole 15. The housing 1 closes at the top with a screw attachment 19.

A filter cup 2 with an interposed, sealing O-ring 20 is screwed into the lower screw attachment 13. The filter 21 protruding into the filter space 12 is inserted into the filter cup 2. At the bottom, the filter cup 2 has a polygon 22 for attaching a wrench.

A socket 3 is screwed into the internally threaded bore 15. At the top, the bush 3 has a plate-shaped flange 30 with an enlarged diameter and a peripheral polygon 31 for attaching a tool. A central bore 32 with a radially circumferential groove 33 in which a sealing ring 34 is seated extends through the bush 3. In the screwed-in state, the flange 30 rests on the shoulder support 16, an O-ring 35 being inserted under the flange 30 for sealing.

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A cap 4 is screwed onto the housing 1 in the upper screw attachment 19. On the top 40 of the cap there is a safety sticker 41 which covers an opening 42. After piercing the safety sticker 41, a socket wrench is used to reach the adjusting screw 5 through the opening 42. Inside, the cap 4 has spacing ribs 43 below the top 40 of the cap and longitudinal ribs 44 provided on the side. A washer 7 inserted between the head 50 of the adjusting screw 5 and a polygonal nut 6 screwed onto the latter is supported on the spacer ribs 43. A disk-shaped spring plate 8 is also pushed onto the adjusting screw 5, in the profiled recess 80 of which the polygonal nut 6 sits and its peripherally distributed claws 81 are held between the longitudinal ribs 44 so that the spring plate 8 is secured against rotation. When the adjusting screw 5 is turned, the spring plate 8 can thus be set at a greater or lesser distance from the top 40 of the cap. A first, outer helical spring 9 is arranged under the spring plate 8, a second, inner, weaker helical spring 90 being inserted into it, which is also supported on the spring plate 8. Both springs 9, 90 sit on a pressure cover 100.

The pressure cover 100 presses on the membrane cover 200 under tension of the springs 9, 90. The assembly consists of the membrane cover 200, the nut 210, the support plate 220, the base plate 230, the plate seal 240 serving as a valve seat, the slide 250 and the spacer elements 260 and the membrane 270 together.

The slide 250 consists of a downwardly directed pipe section 251 and a disk-shaped slide flange 252 attached to the top of the pipe section 251. The mouth 253 of the pipe section 251 protrudes slightly over the top of the slide flange 252 and is tapered so that the radially circumferential inner edge of the pipe section 251 is like a cutting edge is trained. From the slide flange 252 three rod-shaped spacer elements 260, each offset by 120 °, protrude to the underside of the carrier plate 220. The spacer elements 260 are fixedly attached to both the slide flange 252 and the carrier plate 220 and thus hold both parallel and spaced apart from one another. A spacer element 260 preferably consists of a countersunk screw 261, the head 262 of which is countersunk on the upper side of the carrier plate 220 and the threaded shaft 263 of which is screwed into the slide flange 252. The distance between the slide flange 252 and the carrier plate 220 is held by an interposed sleeve 264 pushed onto the threaded shaft 263.

The base disk 230 is inserted between the slide flange 252 and the carrier plate 220 and is rigidly attached to the housing 1, that is to say to the inner wall of the upper screw attachment 19. In the base plate 230, three openings 231 complementary to the spacer elements 260 are provided, so that the spacer elements 260 can move through the openings 231 unhindered. The medium on the secondary pressure side reaches the underside of the membrane 270 through the openings. On the underside of the base disk 230, a disk seal 240 is applied, which is opposite the opening 253 and is dimensioned such that it can completely cover the opening 253, ie can close it.

The membrane is inserted between the carrier plate 220 and the membrane cover 200. A threaded pin 221 extends upward from the carrier plate 220 through a bore 201 in the membrane cover 200. The nut 210 is screwed tightly onto this threaded pin 221, so that the membrane cover 200 is pressed onto the carrier plate 220 and the membrane 270 is fixed between them. The membrane 270, with an opening 271 for the threaded pin 221 to pass through, is a molded rubber part with a bead 272 around the membrane cover 200. The outer edge 273 of the membrane 270 is bent downwards and rests on the outer edge 232 of the base disk 230 and ends therewith. Advantageously, a bead 233 of lesser height is provided on the base disk 230 below the radially circumferential bead 272, so that the membrane 270 is slipped over this bead 233 and presses the base disk 230 against a peripheral annular shoulder 190 of the housing located below. The bead 272 in the membrane 270 ensures the limited, axial mobility of the unit comprising the slide 250 and the support plate 220 and membrane cover 200 rigidly connected to it.

In the assembled state, the pipe section 251, encompassed in a sealing manner by the sealing ring 34, is inserted in the bore 32 of the socket 3. According to the momentary, completely closed position of the slide 250, this is so far extended in height

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- Top end position that the mouth 253 of the pipe section 251 attaches to the disk seal 240 and is thus completely closed. A pressure ring 280 is placed on the outer edge 273 of the membrane 270. This pressure ring 280 has an externally encircling annular shoulder 281 which is delimited by an internally encircling, raised edge 282. The lower edge 45 of the cap 3 screwed into the screw attachment 19 presses on the annular shoulder 281, so that the outer edge 232 of the base disk 230 is pressed onto the annular shoulder 190. The pressure cover 100, which is under the tension of the coil springs 9, 90, presses on the upwardly protruding threaded pin 221 or on the nut 210.

A medium flowing into the pressure reducing valve via the inlet connection 10 would reach the filter space 14 after passing through the filter 21, would flow to the pipe section 251 and finally would be present at the disk seal 240 closing the opening 253. This state occurs when the medium pressure in the secondary-side extraction network, ie also in the valve chamber 14, is above the setpoint value set on the adjusting screw 5. The medium pressure on the secondary side acts through the openings 231 in the base shell 230 on the underside of the diaphragm 270. The diaphragm 270 tries to evade the top and pulls the slide 250 connected to the diaphragm 270 up until the opening 253 on the disk seal 240 strikes. The force currently set at the helical springs 9, 90 - this corresponds to a secondary-side medium pressure with a defined setpoint - is equal to or less than the force acting on the diaphragm 270 from the secondary-side medium pressure. A vent hole 46 is provided in the cap 4.

Figure 2

According to the current position of the slide 250 shown here, it has moved downwards - in principle, the lowest end position that the mouth 253 of the pipe section 251 is maximally removed from the disk seal 240. The passage gap released for the flow of medium onto the secondary side - communicating directly with the valve chamber 14 - has thus also set itself to its maximum width. The target value given at the adjusting screw 5 has now been undershot. Under the force of the coil springs 9, 90, the membrane 270 was pressed down against the too weak pressure on the secondary side and at the same time the slide 250 was moved downwards. A maximum of medium flows through the passage gap in order to compensate for the negative pressure in the extraction network compared to the target value.

Figure 3

The sole purpose of this purely schematic representation is to illustrate the different end positions of the slide 250 in the socket 3 and of the membrane 270 with the associated components. Depending on the deviation from the nominal value, a certain gap width is established between the opening 253 and the disk seal 240 within the two end positions, in order to achieve a secondary-side approach of the pressure to the nominal value by means of subsequent flow of medium with an adequate flow rate.

Further design variations can be implemented for the pressure reducing valve described above. The following are expressly mentioned here:

The use of two different helical springs 9, 90 is not mandatory. The purpose of the coil springs 9, 90 is to keep the overall height of the pressure reducing valve low, even if a higher spring force is required for the adjustment range of the pressure reducing valve. The combined spring arrangement also enables the pressure reducing valve to be provided for a specific adjustment range during pre-assembly or installation. So is for example designed to use the smaller compression spring 90 with a required adjustment range of 0 to 2 bar, while the larger compression spring 9 corresponds to an adjustment range of up to 4 bar. Both compression springs 9, 90 together correspond to an adjustment range of up to 6 bar.

- At least two spacer elements 260 must be provided; on the other hand, four or more spacer elements can also be installed between the carrier plate 220 and the slide 250. One-piece spacer elements are also conceivable.