GB2488395A

GB2488395A - Assembly for controlling the temperature of a drinking water heater

Info

Publication number: GB2488395A
Application number: GB1200408.1A
Authority: GB
Inventors: Willi Hecking
Original assignee: Hans Sasserath GmbH and Co KG
Current assignee: Hans Sasserath GmbH and Co KG
Priority date: 2011-02-22
Filing date: 2012-01-10
Publication date: 2012-08-29
Anticipated expiration: 2032-01-10
Also published as: GB201200408D0; GB2488395B; DE202012100069U1; GB201120998D0

Abstract

An assembly for controlling the temperature in a boiler of a drinking water heater comprises a cold water inlet 12, a cold water outlet 14, a release outlet 46 and a control valve 64, 66, 76. The cold water outlet is connected to the boiler for refilling the boiler. The release outlet is provided for draining hot water from the boiler. A connection 16, 72, 62 is situated between the cold water inlet and the release outlet. The control valve is provided in the range of the connection between the cold water inlet and the release outlet for controlling the inward flow of cold water into the release outlet according to the temperature in the boiler. The control valve comprises a spring biased piston 64 axially movably guided in a cylindrical space 62, 72, where the piston cooperates with a first valve seat 68 for the control of the hot water flow from the boiler, which is provided between the cylindrical space 62 and the boiler, and the piston cooperates on the other side with a second valve seat 80 for the control of the cold water flow, which is provided between the cold water inlet and the release outlet.

Description

Assembly for controllingteteperature of a ikig water heater

Technical field

The invention relates an assembly for controlling the temperature in a heatable boiler of a drinking water beater, comprising: (a) acoidwaterinlet; (b) a cold water outlet connected to the boiler for refilling the boiler with cold water; (c) a release outlet for draining hot water from the boiler; (d) a connection between the cold water inlet and the release outlet; and (e) a control valve in the range of the connection between the cold water inlet and the release outlet for controlling the inward flow of cold water into the release outlet according to the temperature in the boiler.

Drinking water heaters serve to provide hot water in buildings. They comprise a container (boiler) heating an amount of drinking water depending on the requirements and providing for use. If hot water is tapped at a tap fresh, cold drinking water is fed to the boiler and heated therein. In order to secure the closed boiler a pressure-and a temperature control is provided. If the pressure increases beyond a set threshold water is released. Thereby, the pressure decreases.

The temperature in such a boiler can rise up to close to the evaporation temperature at 100°C. This is dangerous due to the developing pressure. If the temperature increases beyond a set threshold hot water is released through a release outlet and cold water is fed to the boiler. By feeding cold water the temperature is reduced.

In some countries pipes of non-temperature resistant plastic material are used. If hot water is released through such pipes there is a risk that the plastic material melts.

Therefore, it is desirable to cool hot water before it is released. In a very simple case cold water is added to the hot water. Depending on the temperature in the boiler there is more beyond a set threshold hot water is released through a release outlet and cold water is fed to the boiler. By feeding cold water the temperature is reduced.

in some countries pipes of non-temperature resistant plastic material are used. If hot S water is released through such pipes there is a risk that the plastic material melts.

Therefore, it is desirable to cool hot water before it is released. In a very simple case cold water is added to the hot water. Depending on the temperature in the boiler there is more or less water necessary to cool the released water. The control can be effected by a suitable, temperature controlled valve.

Disclosure of the invention

It is an object of the invention to provide an assembly of the above mentioned kind which is simple and which is highly reliable. is

According to the present invention this object is achieved in that (f) the control valve comprises a spring biased piston axially movably guided in a cylindrical space, wherein (g) the piston cooperates with a first valve seat for the control of the hot water flow from the boiler, which is provided between the cylindrical space and the boiler, and (h) the piston cooperates on the other side with a second valve seat for the control of the cold water flow, which is provided between the cold water inlet and the release outlet.

The double seat cooperating with the piston causes the hot water flow and the cold water flow to be controlled simultaneously, but separately from each other. Cold water will be fed only if hot water flows through the control valve. Both portions of the control valve open and close simultaneously together with the movement of the piston in the cylindrical space.

The temperature control of the control valve can be effected by means of a wax probe.

The wax probe forms an elongated stick. The stick extends well into the boiler. If the temperature in the boiler increases the wax probe expands. The wax probe extends into the assembly through an opening in the boiler. It is connected to the piston therein. Upon expansion of the wax probe the piston is moved accordingly. The hot water source of the assembly is connected to the opening in the boiler. The hot water feed channel provided for this purpose is closed by the piston. If the piston moves it opens towards the release outlet. Hot water is released. Simultaneously, the piston opens the cold water inlet.

Thereby, cold water is added to the hot water.

Preferably, a hot water feed channel is provided for the connection with the boiler, wherein the hot water feed channel is aligned with the cylindrical space and has a smaller diameter, and wherein the second valve seat is formed by an annular shoulder formed thereby. A particularly compact assembly is achieved if the longitudinal axis of the hot water feed channel and of the cylindrical space aligned therewith extends perpendicular to the longitudinal axis of a continuous cold water channel between the cold water inlet and the cold water outlet.

The longitudinal axis of the release outlet may extend perpendicular to the longitudinal axis of the hot water feed channel and parallel to the longitudinal axis of the cold water channel.

The piston is preferably provided with an annular sealing at each of the opposite end ranges, an annular space formed therebetween around the piston which establishes a connection between the cold water inlet and/or the cylindrical space and the release outlet when the control valve is open.

The cold water passes the cold water side sealing and flows into the cylindrical space when the control valve is open. It is then added to the hot water and flows out through the release outlet.

In a particularly preferred modification of the invention the end faces of the piston effective for the water pressure have the same surface areas. In this case the forces effective on the end faces of the piston is always the same independent of the pressure and depends only on the temperature of the water in the boiler.

Preferably, a backflow preventer is provided in the range of the cold water inlet which opens in the flow direction, The backflow preventer prevents a backflow of water from the drinking water heater into the drinking water supply.

In a ftirther modification of the invention a connection is provided for art expansion vessel connected to the cylindrical space. When the temperature increases expansion water can be received by the expansion vessel at first.

Preferably, a pressure reducer is provided for controlling the inlet pressure at the cold water inlet. A desired pressure of the supplied cold water can be set and maintained with such a pressure reducer. The pressure reducer can be installed in the form of an insert into a socket provided for this purpose. The assembly may then be used either with or without a pressure reducer without having to change the housing in the manufacturing process.

Preferably, a safety valve is provided in the range of the cold water outlet opening a connection between the cold water outlet and the release outlet upon excess pressure. The safety valve controls the pressure in the boiler. Such safety valves are well known in the art. If the pressure in the boiler increases beyond a threshold, the valve opens and water is released through the release outlet until the pressure decreases again under the threshold. in particular, the same release outlet may be provided for the safety valve and the temperature control valve.

In a particularly preferred embodiment of the invention a venting valve is provided for venting the boiler. A connection can be established between the boiler and the release outlet through the venting valve even f the piston is in a closed position. The venting valve can be formed by a valve spindle shftably guided in a housing socket, the valve spindle having a valve sealing cooperating with a valve seat integrated on the inside of the housing socket. The range above the valve seat has a passage connected to the annular space in the range of the piston. The housing socket is positioned in such a way that it is connected to the hot water feed channel. If the venting valve is opened entrained air can be released through the hot water feed channel through the venting valve and through the passage into the annular space around the piston. The annular space is connected to the release outlet. In such a way entrained air can be released even if the piston closes the cold water inlet.

Further modifications of the invention are subject matter of the subclaims. Embodiments are described below in greater detail with reference to the accompanying drawings.

Brief description of the drawings

Fig. 1 is a perspective outside view of an assembly for the control of pressure and temperature in a boiler of a drinking water heater with a pressure reducer and an additional cold water connection.

Fig.2 is a top view of the assembly of Fig. 1. is

Fig.3 is a cross section A-A along a vertical cross sectional plane through the assembly of Figure 1.

Fig.4 is a cross section along the cross sectional plane F-F in Figure 3.

Fig.5 is a cross section along the cross sectional plane D-D in Figure 5.

Fig.6 is an enlarged representation of the temperature control valve.

Fig.7 is a cross section along the cross sectional plane B-B in Figure 5.

Fig.8 is a cross section along the cross sectional plane E-E in Figure 3.

Fig.9 shows the piston of Figure 6 in greater detail with opened temperature control valve.

Fig. 10. is a perspective outer view of an assembly for controlling the pressure and the temperature in a boiler of a drinking water heater without a pressure reducer and without an additional cold water connection.

Fig.1l is a longitudinal cross section through the assembly of Figure 10 along a vertical cross sectional plane.

Fig.12 is a cross section through the assembly of Figure 10 along a horizontal cross-sectional plane.

Fig. 13 shows the range around the piston in Figure 11 in greater detail.

Fig.14 shows the range around the piston in Figure 12 in greater detail.

IS Fig. 15 is a cross section through an assembly according to a third embodiment with an alternative venting assembly.

Fig. 16 shows the venting assembly of Figure 15 in a closed position in greater detail.

Fig 17 shows the venting assembly of Figure 15 in an open position in greater detail.

Fig. 18 is a cross section through the individual and separated components of the venting assembly of Figure 15.

Fig 19 is a perspective representation of the individual and separated components of the venting assembly of Figure 15.

Description of the embodiments

1. Embodiment Figure 1 and 2 show an assembly for controlling the pressure and the temperature in a boiler of a drinking water heater (not shown) generally denoted with numeral 10. The assembly is provided with a cold water inlet 12 for cold drinking water. The cold water inlet 12 is connected to a drinking water supply (not shown).

The cold water inlet 12 is connected to a cold water outlet 14 by a cold water channel 16.

The cold water inlet 12 is aligned with the cold water outlet 14. The cold water outlet 14 is connected to the boiler of a drinking water container.

The assembly 10 is provided with a pressure reducer 18 and a safety valve 20 which is aligned therewith on the opposite side of the assembly. An additional low pressure cold water connection 22 is provided for providing cold water. A temperature probe 24 extends into the inside of the boiler through an opening in the boiler. An expansion vessel is aligned with the temperature probe 24 on the opposite side of the assembly at a connection 26. In the present embodiment the connection 26 is closed with a plug 28.

Figure 3 is a cross section of the assembly where the pressure reducer 18 and the safety valve 20 can be well seen. The assembly 10 has a housing 30. A pipe portion 32 is inserted into a socket 34 of the housing 30, which forms the cold water inlet 12. The drinking water from the drinking water supply enters an annular space 38 in the assembly in the direction of the arrows 42 through the cold water inlet 12. A pressure reducer 18 is inserted into the housing 30 from the left side in Figure 3. If the water pressure drops behind the pressure reducer valve 36 the pressure reducer valve 36 opens and fresh drinking water flows from the annular space 38 through the open pressure reducer valve.

Such pressure reducers are generally well known and must, therefore, not be described here in greater detail.

A backflow preventer 40 is arranged behind the pressure reducer valve 36 which blocks the water flow in the direction of the pressure reducer and thereby in the direction of the drinking water supply. The backflow preventer 40 is a simple, spring biased valve which is inserted into a bore hole in the housing 30 in the form of a cartridge. With the backflow preventer 40 it is according to many regulations avoided that water from the boiler can flow back to the drinking water supply.

A safety valve 20 is provided in alignment with the opening direction of the pressure reducer valve. The safety valve 20 is inserted as a whole into a socket 44 of the housing.

The safety valve 20 is connected to the boiler of the drinking water heater through the cold water channel 16 and the cold water outlet 14. lIthe pressure in the boiler increases beyond a given threshold the safety valve 20 opens. Water is then released into a release outlet 46. The release outlet 46 can be particularly well seen in the sectional view E-E in Figure 8. Safety valves are also well known, The presently used safety valve 20 must, therefore, not be described here in greater detail. With the safety valve 20 the pressure in the boiler is limited to a desired value.

On the opposite lower end of the cold water inlet 12 a pipe portion 48 is inserted into the housing 30. The pipe portion 48 forms the cold water inlet 14. it can be seen, that the pressure at the cold water outlet 48 and thereby inside the boiler is limited by the pressure reducer 18 to the lower end and by the safety valve 20 to the upper end.

In Figure 4 the assembly 10 is shown along the cross sectional plane F-F. It can be seen that a socket 50 is integrated into the housing 30 in the flow path between the pressure reducer 18 and the backflow preventer 40. The longitudinal axis of the socket 50 extends perpendicular to the longitudinal axis of the cold water channel 16 and perpendicular to the opening direction of the pressure reducer valve. A pipe portion 52 is inserted into the socket 50. The pipe portion 52 forms the low pressure cold water connection 22 providing cold water with a controlled pressure.

A socket 26 can be seen parallelly to the longitudinal axis of the low pressure cold water connection 22 and on the right side therebelow in Figure 4, which can be optionally used for an expansion vessel. In the present embodiment the socket is closed. A temperature control valve is aligned with the socket 26 which is generally denoted with numeral 54.

The temperature control valve 54 can be well seen in Figures 5 to 7. It comprises a temperature probe 24. The temperature probe 24 is essentially an elongated stick of wax material. The temperature probe 24 is arranged inside the hot water feed channel 56. The hot water feed channel 56 is formed by a portion 58 which is set onto a socket 60 of the housing 30 and sealed with scalings. The hot water feed channel 56 ends in the inside of the boiler. The temperature probe 24 extends into the inside of the boiler. The temperature probe 24 expands with increasing water temperature.

A piston 64 is movably guided in a coaxial bore 62 in the housing 30. The piston 64 is biased by the spring power of a spring 70 in the direction of the temperature probe 24.

The bore 62 is connected to the release outlet 46. The piston 64 is shown in Figure 6 again in greater detail. The piston 64 has an essentially H-shaped cross section. An annular sealing 66 is provided in a circumferential groove at the end of the piston 64 facing the temperature probe 24. Thereby the inside of the bore 62 and the release outlet 46 is sealed against the hot water feed channel 56.

The bore 62 has a slightly larger diameter than the hot water feed channel 56. Thereby an annular shoulder 68 is formed. The annular shoulder 68 limits the piston movement of the piston 64 to the left side in Figures 5 to 7 and forms a first valve seat.

On the side opposite to the temperature probe 24 the bore 62 is enlarged to a cylindrical space 72 with a slightly larger diameter. Thereby, an annular shoulder 78 is formed. The annular shoulder 78 is provided with an annular, pointed edge 80 projecting in the direction of the sealing 76. The spring 70 is arranged in the space 72. The spring 70 pushes against the spring side end of the piston 64. The piston 64 ends with a diameter at the spring side end which is larger than the diameter of the bore 62. Thereby an annular projection 74 is formed. An annular sealing 76 with rectangular cross section is inserted into an annular groove abutting the annular projection 74.

The spring 70 pushes the piston 64 with the sealing 76 on the edge 80. Thereby the space 72 is closed against the bore 62 and the release outlet 46. The edge 80 is a second valve seat forming the second portion of the temperature control valve together with the piston 64 at the sealing 76.

S

If the temperature probe 24 expands it pushes on the piston 64 with a pin 82 and moves it against the spring power of the spring 70 in an opening direction to the right side in the representations. Thereby the two portions of the control valve are opened. The end of the piston 64 facing the temperature probe ends in the range of the release outlet 46. Hot water from the boiler can flow through the hot water feed channel 56 into the release outlet 46.

With the movement of the piston 64 in an opening direction the second portion of the control valve also opens. Thereby, a connection between the cylindrical space 72 and the IS bore 62 is established which is, furthermore, connected to the release outlet 46. As can be seen in Figure 7, the cold water channel 16 is guided along the cylindrical space 72. The cylindrical space is, therefore, continuously filled with cold water. If the valve formed by the valve seat 80 and the piston with the sealing 76 is opened cold water will flow into the range of the bore 62. This is shown in Figure 9. The piston 64 has a small diameter in the range between the sealings 66 and 76. Thereby, an annular space 84 is formed. Cold water can easily flow into the release outlet 46 passing the piston 64. This is illustrated by arrows 90. It will then cool hot water which flows from the hot water feed channel 56 into the release outlet 46. This is illustrated by arrows 92.

Figure 8 illustrates how the release outlet 46 is used for the expansion water of the safety valve 20 as well as for the hot-and cold water for the temperature control.

It can be seen in the enlarged view of Figure 6 that the pressure-effective end faces of the piston 64 have the same area. Boiler pressure acts on the end face on the left side in Figure 6 through the hot water feed channel 56. On the right end face in Figure 6 the boiler pressure acts through the cold water channel 16. Thereby it is ensured that independently of the boiler pressure there is a compensation at all times and the ii movement of the piston is effected exclusively upon a change of temperature and not upon a change of the pressure in the boiler.

2. Embodiment Figures 10 to 14 show an assembly for controlling the pressure and the temperature in a boiler of a drinking water heater (not shown) generally denoted with numeral 110. The assembly is provided with a cold water inlet 112 for cold drinking water. The cold water inlet 112 is connected to a drinking water supply (not shown).

The cold water inlet 112 is connected to a cold water outlet 114 by a cold water channel 116. The cold water inlet 112 is aligned with the cold water outlet 114. The cold water outlet 114 is connected to the boiler of a drinking water container.

The assembly 110 is provided with a safety valve 120. A temperature probe 124 extends into the inside of the boiler through an opening in the boiler. A release outlet 146 with an outlet hopper 122 extends in a downward direction.

Figure II is a cross section of the assembly where the safety valve 120, the release outlet 146 and the temperature probe 124 can be well seen. The assembly 110 has a housing 130. Figure 12 is a horizontal cross section through the assembly where the cold water inlet 112, the cold water outlet 114, the safety valve 120 and the temperature probe 124 can be well seen. A backflow preventer 140 is arranged in a socket 134 of the housing which blocks the water flow in the direction of the drinking water supply. The backflow preventer 140 is a simple, spring biased valve which is inserted into a bore hole in the socket 134 of the housing 130 in the form of a cartridge. With the backifow preventer 140 it is according to many regulations avoided that water from the boiler can flow back to the drinking water supply.

The drinking water enters a space 138 of the assembly 110 in the direction of the arrows 142 from the drinking water supply through the cold water inlet 112. A safety valve 120 is provided at the space 138. The safety valve 120 is inserted as a whole into a socket 144 of the housing. The safety valve 120 is connected to the boiler of the drinking water heater through the cold water channel 116 and the cold water outlet 114. If the pressure in the boiler increases beyond a given threshold the safety valve 120 opens. Water is then released into the release outlet 146. The release outlet 146 can be particularly well seen in the sectional view in Figure 11. Safety valves are also well known. The presently used safety valve 120 must, therefore, not be described here in greater detail. With the safety valve 120 the pressure in the boiler is limited to a desired value.

On the opposite end of the cold water inlet 112 a socket 148 is integrated into the housing 130. The socket 148 forms the cold water outlet 114. It can be seen, that the pressure at the cold water outlet 148 and thereby inside the boiler is limited by the safety valve 120.

A temperature control valve generally denoted with numeral 154 is aligned with the longitudinal axis of the safety valve.

The temperature control valve 154 is shown again in Figures 13 and 14 in greater detail.

It comprises a temperature probe 124. The temperature probe 124 is essentially an elongated stick of wax material. The temperature probe 124 is arranged inside the hot water feed channel 156. The hot water feed channel 156 ends in a portion 158 which is set onto a socket 160 of the housing 130 and sealed with sealings. The hot water feed channel 156 ends on the outside in the boiler. The temperature probe 124 extends into the inside of the boiler. The temperature probe 124 expands with increasing water temperature.

A piston 164 is movably guided in a coaxial bore 162 in the housing 130. The piston 164 is biased by the spring power of a spring 170 in the direction of the temperature probe 124. The bore 162 is connected to the release outlet 146. This is shown in Figure 14. The piston 164 has an essentially cylindrical shape. An annular sealing 166 is provided in a circumferential groove at the end of the piston 164 facing the temperature probe 124.

Thereby, the inside of the bore 162 and the release outlet 146 is sealed against the hot water feed channel 156.

The bore 162 has an annular shoulder 168 on the side of the space 138. The piston 164 is provided there with an annular projection 169. The annular shoulder 168 thereby limits the piston movement of the piston 164 to the left side in Figure 13. An annular groove with a sealing 172 is provided behind the annular shoulder 169. The bore 162 is slightly widened in the range between the sealings 166 and 172, thereby forming an annular space 176 around thepiston 164. The annular space 176 is connected to the release outlet 146. This can be seen in Figure 14. The sealings 166 and 172 each form a valve seat cooperating with the inner wall of the bore 162.

The piston 164 forms a space 173 which is open towards the right side in Figure 13. A spring 170 is arranged in the space 173. The spring 170 pushes against the inside of the end face 171 of the piston 164. On the other side the spring 170 pushes against a plate-shaped spring abutment 180. the spring abutment 180 is fixed to the housing. The spring abutment 180 is connected to a valve seat portion 181 by webs 183. The valve seat portion 181 is an insert portion forming the valve seat of the safety valve 120. It can be inserted from the right side in Figure 13 into the socket 185 provided at the housing 130 for the safety valve 120.

The spring 170 pushes the piston 164 with the annular projection 169 against the annular shoulder. Thereby the space 138 is closed against the bore 162 and the release outlet 146.

The hot water channel 156 is also closed against the bore 162 and the release outlet 146.

If the temperature probe 124 expands it pushes on the piston 164 with a pin 182 and moves it against the spring power of the spring 170 in an opening direction to the right side in the representations. Thereby, the two portions of the control valve are opened.

The end of the piston 164 facing the temperature probe ends in the range of the release outlet 146. Hot water from the boiler can flow through the hot water feed channel 156 into the release outlet 146.

With the movement of the piston 164 in an opening direction the second portion of the control valve also opens. Thereby, a connection between the space 138 and the bore 162 is established which is, furthermore, connected to the release outlet 146 through the annular space 176. As can be seen in Figure 12, the cold water channel 116 is guided along the space 138. The space 138 is, therefore, continuously filled with cold water. If the valve formed by the piston with the sealing 172 is opened cold water will flow into the range of the bore 162. The bore 162 has an enlarged diameter in the range between the sealings 166 and 172. thereby the annular space 176 is formed. Cold water can easily flow into the release outlet 146 passing the piston 164. Tt will there cool hot water which flows from the hot water feed channel 156 into the release outlet 46 passing the sealing 166 in the same piston position.

Figure Ii illustrates how the release outlet 146 is used for the expansion water of the safety valve 120 as well as for the hot-and cold water for the temperature control. For this purpose an annular channel 196 is provided establishing a connection between the safety valve 120 and the release outlet 146.

It can be seen in the enlarged view of Figure 13 and 14 that the pressure-effective end faces of the piston 164 have the same area. Boiler pressure acts on the end face on the left side in the representations through the hot water feed channel 156. On the right end face the boiler pressure acts through the cold water channel 116. Thereby, it is ensured that independently of the boiler pressure there is a compensation at all times and the movement of the piston is effected exclusively upon a change of temperature and not upon a change of the pressure in the boiler.

With some applications it is provided that the double-piston is air released according to some standards. This is particularly useful, if an air cushion is used in the boiler instead of an expansion vessel. For the air release a manually operated handle 195 is provided which is connected to a lever 199 through a spindle 197. The lever has an eccentric pull.

The lever moves the piston 164 towards the right in the representation by rotation of the handle by about 90° and thereby opens the piston.

3. Embodiment This embodiment essentially corresponds to the second embodiment and must, therefore, not be described again in detaiL The venting assembly, however, is different to the one of the second embodiment. With an eccentric pull the piston is moved for venting the system and the cold water side and the hot water side are opened Water will always be released at least from the cold water side. Therefore, it will be djfjIcult to recognize the end of the venting procedure. With the invention according to the third embodiment only the hot water side is opened This is shown in Figures 15 to 19.

The venting assembly generally denoted with numeral 210 is positioned in a socket 212 integrated in the housing 214 of the assembly. The socket 212 is positioied above the temperature probe 216 and above the piston 218. The inside of the socket 212 is connected to the hot water feed channel 220 and the bore 222 with the movably guided piston 218.

Figure 16 and Figur 17 shwo the venting assembly 210 again in greater detaiL A valve spindle 224 is arranged in the socket 212. The shape of the valve spindle 224 can be well seen in Figure 19. The upper end of the valve spindle 224 is rotatably connected to a handle 226. A pin 228 is provided for this purpose. The pin 228 forms a rotational axis for the handle 226. The valve spindle 224 is moved upwards or downwards, respectively upon rotation of the handle 226.

The valve spindle 224 is movably guided in a guiding body 230. The guiding body 230 is immobile and screwed into the socket 2/2. It has a sealing 232. The guiding body 230 forms an annular space 234 which open at its lower end. A spring 236 is accomodated in the annular space 234. The guiding body 230 forms a spring abutment for the spring 236 at its upper closed end of the annular space 234. The lower end of the spring 236 pushes on an annular projecti on 238 at the lower end of the valve spindle 224. In such a way the spring pushes the valve spindle 224 downwards.

The valve spindle 224 is provided with a valve sealing 240 which is coaxially arranged below the annular projection 238 around the valve spindle. The valve seat 242 is integrated in the inside of the housing socket 2)2 at the housing. A connection between the hot water feed channel 220 and the release outlet 246 is established through the venting valve. The venting valve opens the connection between the hot water fled channel 220 and a passage 244 which is connected to the annular space 248 around the piston. In other words: f the venting valve is opened air and/or water can be released into the passage 244 from the hot water fred channel 220 through the venting valve.

From there it flows into the annular space 248 and finally into the release outlet 246.

The piston 218 is not moved The connection between the cold water supply and the release outlet 246 remains closed Figure 17 shows the venting valve in an open state. It can be recognized that the right end of the handle 226 in Figure 17 is moved upwards. The handle is rotated about pin 228 and pulls the valve spindle 224 upwards against the spring power of the spring 236 Thereby, the venting valve is opened A control bore 250 is provided inside the valve spindle 224 in a longitudinal direction.

The control bore 250 connects the hot water feed channel 220 with a lateral bore 252.

The lateral bore 252 is positioned between annular sealing rings 254 and 256 between the valve spindle 224 and the guiding body 230. Therefore. boiler pressure is present above the annular sealing ring 256. The annular sealing ring 256 has the same pressure effective cross section as the valve sealing 240 of the venting valve. Boiler pressure acts from below on the valve sealing 240. As the pressure effective cross sections are the same the boiler pressure effective on the valve spindle 224 is completely compensated.

Only the spring power and possibly the lever power of the handle 226 are effective.

Therefore, the assembly is independent of the boiler pressure and can be used with high pressures, also.

Claims

Claims 1. Assembly for controlling the temperature in a beatable boiler of a drinking water heater, comprising: (a) a cold water inlet (12; 112); (b) a cold water outlet (14; 114) connected to the boiler for refilling the boiler with cold water; (c) a release outlet (46; 146) for draining hot water from the boiler; (d) a connection (16, 72, 62; 138, 162) between the cold water inlet and the release outlet (46; 146); and (e) a control valve (64, 66, 76; 164, 166, 172) in the range of the connection between the cold water inlet (12; 112) and the release outlet (46; 146) for controlling the inward flow of cold water into the release outlet (46; 146) according to the temperature in the boiler; characterized in that (1) the control valve comprises a spring biased piston (64; 164) axially movably guided in a cylindrical space (62, 72; 162), wherein (g) the piston (64; 164) cooperates with a first valve seat (66; 166) for the control of the hot water flow from the boiler, which is provided between the cylindrical space (62; 162) and the boiler, and (h) the piston (64; 164) cooperates on the other side with a second valve seat (80; 172) for the control of the cold water flow, which is provided between the cold water inlet (12; 112) and the release outlet 46; 146).
2. Assembly according to claim 1, characterized by a hot water feed channel (56) for the connection with the boiler, wherein the hot water feed channel (56) is aligned with the cylindrical space (62, 72) and has a smaller diameter, and wherein the second valve scat is formed by an annular shoulder (78) formed thereby.
3. Assembly according to claim 2, characterized in that the longitudinal axis of the hot water feed channel (56) and of the cylindrical space (62, 72) aligned therewith extends perpendicular to the longitudinal axis of a continuous cold water channel ([6) between the cold water inlet (12) and the cold water outlet (14).
4. Assembly according to claim 3, characterized in that the longitudinal axis of the release outlet (46) extends perpendicular to the longitudinal axis of the hot water feed channel (56) and parallel to the longitudinal axis of the cold water channel (16).
5. Assembly according to any of the preceding claims, characterized in that the piston (64; 164) is provided with an annular sealing (66, 76; 166, 172) at each of the opposite end ranges, an annular space (84; 176) formed therebetween around the piston which establishes a connection between the cold water inlet (12, 16; 112, 116) and/or the cylindrical space (62, 72; 162) and the release outlet (46; 146) when the control valve is open.
6. Assembly according to claim 5, characterized in that the end faces of the piston (64; 164) effective for the water pressure have the same surface areas.
7. Assembly according to any of the preceding claims, characterized by a backilow preventer (40; 140) in the range of the cold water inlet (12; 112) which opens in the flow direction.
8. Assembly according to any of the preceding claims, characterized by a connection (26) for an expansion vessel connected to the cylindrical space (62, 72).
9. Assembly according to any of the preceding claims, characterized by a pressure reducer (18) for controlling the inlet pressure at the cold water inlet.
IC. Assembly according to any of the preceding claims, characterized by a safety valve (20; 120) in the range of the cold water outlet opening a connection between the cold water outlet (14; 114) and the release outlet (46; 146) upon excess pressure.
11. Assembly according to claim 5, characterized in that a venting valve is provided for venting the boiler, the venting valve establishing a connection between the boiler and the release outlet if the piston is in a closed position.