FI86467C - Safety valve for hot water heater with pressure tank and shock absorption device for same - Google Patents

Description

1 86467

Safety valve for pressure tank water heater and shock absorber for this

The present invention relates to a safety valve for a pressure-5 tank hot water tank, which safety valve is adapted to open in the event of an overpressure in the pressure tank and is of the type set out in the preamble of the appended independent claim 1. The invention further relates to a shock absorbing device for installation between an overflow hose / pipe and the outlet of a safety valve.

The safety valve mentioned in the introduction should open when the overpressure acts on the hot water tank, etc. when the incoming water pressure in the pressure tank rises or the pressure in the pressure tank rises from a lower to a higher temperature due to water expansion.

Safety valves are subject to various requirements that vary from country to country, such as: 1. Opening pressure 9 aty.

2. Closing pressure - 10% lower than the opening pressure, i.e. 8.1 aty.

3. The volume of water flowing out at a pressure 10% higher than the opening pressure, ie 9.9 aty, must have a maximum capacity of 6.5 l / min / kW to heat the accumulator. At a maximum power of 3 kW, the safety valve must then be able to: ** · 25 19.5 l of water flow out per minute with a pressure of 9.9 aty entering the safety valve.

::: 4. Maximum pressure in the incoming cold water line: V: for safety valve 6 aty. If the pressure is higher, a pressure relief valve must be installed.

. ·. : 30 5. The overflow hose shall be capable of being installed at the outlet of the safety valve to direct water to the drain and the minimum inside diameter of the pipe or hose shall be 12.5 mm.

: The safety valves currently in use open at a pressure of 9 aty and close at a pressure of 10% lower. It is very difficult to obtain an outflow of water at a pressure of 19.5 l / min 2 86467 at 9.9 aty and at the same time to cause the safety valve to close at a closing pressure of 8.1 aty.

For many water utilities, it is difficult to maintain the water pressure at normal pressure for 6 aty periods when water consumption is low. For example, water pressure can rise by more than 50% at night.

When an overflow hose leading to the drain is connected to the outlet from the safety valve, this gives the completely changed characteristics of the safety valve and causes the following: 10 When the inlet water pressure in the valve body exceeds 9 aty, the valve opens and fills the overflow hose with water. The normally unpressurized outflow side / overflow side now receives approximately inlet pressure, the valve closes but opens quickly again as the inlet pressure rises again. The valve opens and closes at a rate of 50 to 150 strokes per minute. These pressure shocks are so severe that the safety valve, water tank welds and pipes can be damaged. The object of the present invention is to provide a safety valve-20 brick which meets the above-mentioned requirements and by means of which the above-mentioned drawbacks are eliminated.

This is achieved according to the invention by means of the features which appear from the characterizing part of the appended independent claim 1 as well as from the other dependent claims.

The invention will be explained in more detail in the following by explaining one exemplary embodiment of the safety valve shown in the drawing and a shock absorbing device connected to the safety valve.

. ·. ; In the drawings, Fig. 1 shows a safety valve in section, Fig. 2 shows a safety valve with connected: • overflow hoses and shock absorbers connected between them, and Fig. 3 shows the same as Fig. 2 in a larger ____; on a scale and with the shock absorber cut.

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The safety valve A consists of a valve housing 1 with an inlet 2 for pressurized water and an outlet 7 for possible overflow water, and a diaphragm valve arranged between them consists of an annular seat 4 through a flow channel 21 connecting the inlet 2 and the outlet 7, made of rubber or the like , which is circumferentially locked between the annular step of the valve inlet 22 of the valve housing 1 and the end plate 6a 10 of the spring housing 6 screwed into the valve inlet. The spring housing has a spring-loaded mandrel 8 with the mandrel end 8a resiliently pressed against the upper surface of the central part 5a of the membrane 5, which at its lower surface is resiliently pressed against the seat 4. The annular chamber 20 passes around the seat 4 and is otherwise delimited by the housing 1 and the lower surface of the membrane 15 5 and provided with an opening 20a in the direction of the outlet 7 for the outflow of overflow water 3a to the annular chamber 20 20 acting on the lower surface of the membrane 5 from outside the seat 4, further lifting the membrane 5 upwards from the seat 4 and. thereby increasing the annular valve opening of the valve, increasing the outflow of the overflow water 3a. The spring-loaded spindle 8 passing through the through hole 10a in the bottom of the spring housing 6 is surrounded by a compression spring 9 and tensioned between the base 10 and the spindle base 8a projecting radially past the seat 4. The base 8a of the mandrel: 8 and the central part 5a of the diaphragm 5 preferably have cooperating fastening members in the form of a threaded central bore 8b in the mandrel 8a 30 of the mandrel 8 and a central pin 5b on the upper surface of the diaphragm 5 against the bolt 8b. a transverse buffer member 16, for example an annular rubber buffer having a spring force greater than the compression of the spring 9, 35 is fitted between the shoulder 17 of the spring housing 6 and the spindle base 8a with the desired axial clearance 19 between the buffer member 16 and the spindle base 8a respectively corresponding to the maximum pressure rise of the diaphragm 5. The butt-rail 16 has an outer surface and an inner surface of the spring-end 6 at one end, or 17 and has at its other end a clearance 18 with respect to the membrane 5 which is approximately the same as the clearance 19 between the buffer member 16 and the mandrel base 8a. The central opening 16a of the buffer member 16 tapers in the direction of the spindle base 8a and is centrally narrowed at its lower end against the lower end of the compression spring 9, which in turn is centrally against the mandrel 8. The upper end 8c of the mandrel 8 passes freely through an opening 14a in the guide knob 14, which knob has a rotatable annular shoulder 12 against the spring housing 6, which shoulder cooperates with the shoulder 6c of the spring housing 6. The shoulders 12 and 6c comprise cooperating oblique surfaces 15, possibly an oblique surface and bumps, so that when the knob 14 is rotated and thus axially moved to raise the mandrel 8 through the stop plate 15 at the mandrel end 18c and thus raise the diaphragm 5 from the seat 4 to adjust water flow for emptying from the pressure vessel.

It appears from the above that the spindle 8 is matched. be further axially displaceable against the resistance of the buffer member 16 by means 12, 14 arranged outside said spring housing 6 for emptying the pressure vessel.

The compression springs 9 on the mandrel 8 have a predetermined length and spring pressure with as uniform a spring curve as possible and are tensioned to a predetermined distance between the base 10 of the spring housing 6 and the mandrel base. The screwing of the spring housing 6 into the valve inlet 22 is limited by the spring housing 6 of the cooperating stops 6b, 11, respectively the outer end 11 of the valve inlet 22 to achieve the desired tightening force of the circumferential part of the diaphragm 5 and the desired depressing force. 35 to achieve a force on the lower surface of the membrane 5 and the seat 4 .1.1; between.

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When the safety valve is installed in the pressure vessel and is in use, the pressurized water 3 at the inlet 2 and the flow-through opening 21 acts on the central part 5a of the membrane 5 inside the seat 4. When the water pressure for some reason rises to the opening pressure 9 aty mentioned in the lead 5, the diaphragm 5 rises from the seat 4 against the spring pressure of the pressure spring 9, the spring pressure of the spring 9 of which is adapted to said water opening pressure. Water further flows out into the annular chamber 20 and further through the annular chamber outlet 20a 10 towards the outlet 7 of the safety valve, simultaneously applying pressure to the annular chamber 20 acting on the lower surface of the membrane 5 outside the seat 4, the membrane 5 rising further to release more water in that case. that the water pressure ko-15 rises above the opening pressure 9 aty and up to an overpressure of 10%, namely 9.9 aty. In the event of such additional compression of the compression spring 9, this will give in or collapse. To ensure that the diaphragm 5 does not rise too much so that an uncontrolled amount of water 20 passes through the outlet 7, a rubber buffer 16 is arranged at a suitable distance 19 above the mandrel base 8a and is due to having a higher spring force than the spring pressure 9, to prevent further depression of the film.

When the water pressure drops, the pressure spring 9 tends to press the membrane 5 through the mandrel base 8a into contact with the seat '4 and finally to press against it at the closing pressure 8.1 aty mentioned in the introduction.

The spring housing 6 has a constant distance from the base 10 to the seat 4 when the spring housing is screwed into the valve inlet 22 with its stop shoulder 6b against the outer end 11 of the valve inlet 22. Due to the fact that the compression spring 9 is made with the desired spring constant and that the tolerances of the other parts are small, the desired compressive force of the membrane 5 will be placed on the seat 4 left -____; to achieve the components during installation. Thus, there is no need to use any adjusting screw to achieve the correct spring pressure.

The annular chamber 20, which can also be called an overflow space, can be changed in volume by increasing its depth during manufacture, possibly also by simultaneously changing the outflow opening 20a.

The components of safety valve A described above and its mode of operation achieve the following:

Diaphragm 5 provides a seal for both the pressure side and the 10 overflow side. The membrane 5 will always open as the pressure increases, even if impurities and limescale formation occur, as it does not comprise any skirt or metal against the metal seat between which the lime layer could adhere.

15 A compression spring is designed for a given spring pressure and the smallest possible increase in this spring pressure in connection with additional compression, i.e. with the most uniform possible spring characteristic curve.

The spring pressure is adapted for sealing the safety valve up to a pressure of, for example, 9 aty and for a certain diameter of the flow opening 21 with the seat 4. you. For example, when the inner diameter of the seat 4 is 10 mm, this gives a pressure surface ur of the central portion 5a of the membrane 5 equal to: · ** 2 ·· 5 x 5 x 3.14 = 78.5 mm. The force of the spring is calculated from this surface area: * '25 ta and 9 aty water pressure, which is the opening pressure.

'' / · / · When the water pressure rises above the opening pressure 9 aty::: to, for example, 9.8 aty, i.e. to an overpressure of 10%, the membrane 5 rises, as mentioned, in the form of a pressure. as a result into the ring chamber 20 more from the seat 4,. as a result of which the annular valve opening of the valve • increases over the flow water 3a due to the increased outflow: · * *. This pressure in the ring folder 20 acts on the part of the membrane center portion 5a supported by the base 8a of the mandrel 8, which base is given a diameter so large that it ____ extends radially outside the seat 4. This simply means that the incoming water pressure causes a higher "piston" to rise and thus overcomes the opposite spring pressure from the compression spring 9 so that the desired opening between the seat 4 and the diaphragm 5 is reached and thus a sufficiently large outflow of water at 10% overpressure. The reason for the operation of the safety valve is that the compression spring 9 compresses when the water pressure rises above 9 aty and an unlimited amount of water enters the overflow opening or outlet 8 through the ring chamber 20 and its outlet-10 flow opening 20a. To prevent this, the movement of the spindle 8 can be limited to the maximum pitch movement, for example by means of a 0.5 mm mechanical stop. This allows a sufficient outflow of water at the permissible overpressure, for example at a pressure of 9.8 aty. When emptying the pressure vessel of the accumulator, it is desirable that there is a larger gap between the membrane 5 and the seat 4, for example 1.5 mm. For this reason, the mechanical stop is then implemented to conduct when its spring pressure is higher than that of the compression spring 9, which is achieved by means of a rubber buffer 16.

The rubber buffer 16 thus has the following functions: 1. To support the diaphragm 5 in the area between the spring housing 6 and the mandrel base 8a, so that the diaphragm does not burst in the event of impacts, regardless of the pressure generated. For example, the rubber buffer 16 has a clearance 18 of 0.5 mm with respect to the size of the film 5 and a corresponding clearance 19 between the lower end of the rubber buffer 16 and the mandrel base 8a. Thus, the buffer member 16 allows the diaphragm and the base of the mandrel 8 to rise due to an overpressure of 0.5 mm, but prevents the compression spring 9 from collapsing when supporting the diaphragm 5. However, the mandrel j 30 8 and thus the diaphragm 5 can rise a total of 1.5 mm from the seat 4 when the accumulator is emptied by the compression of the above-mentioned knob 14 and the rubber buffer 16.

• The rubber buffer 16 provides precise control of the stem 8 and thus also precise control of the membrane 5 for the correct drainage and closing of the safety valve 35.

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Instead of a rubber buffer, a compressed spring can of course be used, but this does not have the same advantageous functions as a rubber buffer 16 with respect to the centering of the compression spring 9 and supporting the upper surface of the membrane 5 as the pressure 5 rises.

The different components 8a, 19, 20 and 21 work together and can vary with each other, thus achieving the following:

For example, the diameter of the mandrel base 8a may increase to achieve a larger pitch 10 and thus to achieve a greater flow of water, or vice versa. Together with the rubber buffer 16, the mandrel base 8a provides complete support for the membrane 5.

By changing the clearance 19 between the rubber buffer 16 and the base 8a of the mandrel 15, the desired maximum water outflow at maximum overpressure can be determined. Due to the fact that the rubber buffer 16 can be further compressed by means of said knob 14, a sufficient lifting of the membrane 5 for emptying the tank of the hot water tank is achieved.

20 Thus, a set two-stage spring pressure is available.

1, between the annular lower surface 5 of the film 20 and the valve TELON solves one outflow 20a · * 'with the pressure difference, which is desirable for the pressure side and the output from the input side and thus, when a pressure chamber ** 25 chamber 20, which is necessary for the film 5 for maximum lift from the seat 4.

t :: As the diameter of the flow orifice 21 is increased: Y: the total amount of flow can be increased, but then the spring pressure of the compression spring 9 also increases due to. : 30 in this case the resulting higher central pressure surface on the membrane.

With the correct modification of the above components: · the requirements for the operation of the safety valve in each country can be met.

The structure and operation of the safety valve with the flow or outlet 7 not being connected 9 86467 to a hose or pipe leading to a drain or tank has been described above. When such a hose or pipe 33 is connected directly to the outlet 7 of the safety valve A, impact problems arise due to pressure build-up in the outlet 7 and the hose 33, which causes the membrane 5 to rise from the higher seat 4. A sufficient amount of water flows through the safety valve and the inflow pressure 3 drops. as a result of which the safety valve closes. The pressure then rises above the opening pressure and the valve 10 opens and thus pressure shocks are generated.

This happens with all types of valves. To eliminate this problem, an shock absorber B, shown in Figures 2 and 3, is arranged between the overflow hose / pipe 33 and the outlet 7 of the safety valve A.

The shock absorbing device B comprises a chamber 32 for water and air with an inlet opening 32a for connection to the outlet 7 of the safety valve A and an outlet opening 32b for connection to the overflow hose / pipe 33. The chamber 32 comprises an upper chamber part L for air at a higher level than the inlet outlets 32a and 32b and water for the lower chamber space V. As shown in the drawing, the chamber 32 is preferably spherical in shape with radially opposite inlet and outlet openings 32a, 32b. The outlet opening 32b is preferably smaller than the inlet opening 32a and said openings are in the same horizontal plane with each other in the space installed in the shock absorbing device B.

The chamber 32 has a sufficiently large volume to receive a pulsating amount of water flowing in connection with the pressure shocks from the safety valve A, which pulsation and thus the pressure shocks are damped by the amount of air trapped in the upper chamber part L. See:. * that the shock absorber operates in accordance with the "wind chamber principle".

Claims (6)

A safety valve for hot water heaters with a pressure tank, which valve is arranged to open at pressure in the pressure tank and comprises a valve housing (2) with an inlet (2) for pressure water and an outlet (7) for any overflow water, and a between these arranged valves (4, 5, 8, 9) consisting of an annular seat (4) in a passage (21) connecting the inlet (2) to the outlet 10 (7), a membrane (5) clamped with its peripheral portion between an annular staircase portion of a valve insertion opening (22) in the valve housing (1) and an end surface (6a) of a spring housing (6) screwable into the valve passage opening with a spring biasing spindle (8) with the spindle head (8a) in the spring 15 abutting abutment to the upper surface of the central portion (5a) of the diaphragm (5), which is then pressed into its resilient abutment against the seat (4), an annular chamber (20) around the seat (4) and bounded by the housing (1) and the underside of the membrane (5), and provided with an opening (20a) towards 2 The outlet (7) for outflow of overflow water (3a) where the diaphragm (5) is lifted from the seat (4) at overpressure in the pressure tank and thereby in the inlet (2) and the throughput (21) while simultaneously building up a pressure in the annulus (20) for affecting the underside of the diaphragm (5) outside the seat 25 (4) for further lifting the diaphragm (5) up above the seat (4) and increasing the annular valve gap of the valve for increased outflow of overflow water (3a), and the spindle (8) being passing through a guide opening (10a) in the bottom (10) of the spring housing (6), is surrounded by a compression spring 30 (9) which is clamped between the bottom and the spindle head (8a) extending radially leaking past the seat (4), k characterized in that the head (8a) of the spindle (8) and the central portion (5a) of the membrane (5) have cooperative fastening means (8b, 5b) and that a resilient, compressible buffer element (16) with greater spring force than the compression spring (9) is arranged between a shoulder (17) in the spring housing (6) and the spindle head (8a) with the desired axial clearance (19) between the buffer element (16) and the spindle head (8a) and the shoulder (17) respectively, corresponding to maximum pressure lifting of the diaphragm. And the spindle (8) is arranged to be further axially displaced against the spring force of the buffer element by means (12, 14) arranged outside the spring housing (6) for emptying the pressure tank. 2. A safety valve as claimed in claim 1, characterized in that the compression spring (9) has a predetermined length and a spring pressure with an equally possible suspension characteristic, and it is clamped at a predetermined distance between the bottom of the spring housing (6). (10) and the spindle head (8a), and the screwing-in of the spring housing (6) into the valve insertion opening (22) is limited by cooperating stoppers (6b, 11) on the spring housing (6) and the outer end (11) of the valve insertion opening (22), respectively. ), to obtain the desired clamping force of the peripheral portion of the membrane (5) and the desired contact force between the underside of the membrane (5) and the seat (4). Safety valve according to claim 1, characterized in that the buffing element (16) is an annular rubber buffer which, with its outer wall and one end, abuts against the inner wall and shoulder (17) of the spring housing (6), and the other end of which has one slot (18) for the membrane (5),. . approximately equal to the clearance (19) between the buffer element; ; (16) and the spindle head (8a). Safety valve according to claim 3, characterized in that the central opening (16) of the buffer element (16) converges in the direction of the spindle cap (8a) and is centered with its narrowest portion towards: the spring (9). ) lower end, which in turn is centered. * towards the spindle (8). 'Γ Safety valve according to claim 1, characterized in that the upper end (8c) of the spindle (8c) ice 8 6 4 6 7 runs freely through an opening (14a) in a control body (14). rotatably abutting against the spring housing (6) with a circular shoulder (12) which cooperates with a shoulder (6c) on the spring housing (6), which shoulder (12 and 6c) comprise cooperatively inclined surfaces, possibly an inclined plane and knobs; in order to rotate and axially displace the guide body (14), lift the spindle (8) via a stop disk (15) at the end of the spindle (18c) and thereby the diaphragm (5) from the seat (4) for control of flow through and possible emptying of the pressure tank . 10 Safety valve according to Claim 1, characterized in that the cooperating fastening means (8b, 5b) consist of a preferably threaded central bore (8b), the spindle (8) head (8a) and a membrane (5). ) top mounted central pin (5b) for screwing into the bore (8b).