WO2002081978A1

WO2002081978A1 - Device for a hot water tank of the pressure heater type and a fitting for a hot water tank of the pressure heater type

Info

Publication number: WO2002081978A1
Application number: PCT/NO2002/000118
Authority: WO
Inventors: Thor Frølich BRAATHEN
Original assignee: Braathen Thor F
Priority date: 2001-03-26
Filing date: 2002-03-21
Publication date: 2002-10-17
Also published as: WO2002081978A8; NO20011535D0; NO314102B1; NO20011535L

Abstract

Devices for a hot water tank of the pressure heater type are shown and described, wherein a cold water inlet pipe (5'; 23) and a hot water outlet pipe (6'; 24) are arranged concentrically within each other in the tank (4'; 22) and are connected to a fitting housing (1'; 21) which has two ducts (7', 8'; 25, 26) for cold water and hot water respectively, and where there is a cross connection for the mixing of cold water into the outflowing hot water. The cross connection is in the form of one or more through holes (20; 27) in the wall of the inner one of the two concentric pipes (5', 6'; 23, 24). A fitting for connection in a cold water inlet pipe and a hot water outlet pipe in a hot water tank of the pressure heater type is also shown and described, wherein the cold water inlet pipe and the hot water outlet pipe are arranged concentrically within each other, which fitting has two ducts for cold water and hot water respectively, which fitting comprises a fitting housing having a first duct (45) in the form of a graduated bore having a smaller (46) and a larger bore portion (47), a second duct (49) which intersects the said first duct (45) in the area of the smaller bore portion, and a third duct which intersects the said first duct in the area of the larger bore portion (47).

Description

Device for a hot water tank of the pressure heater type and a fitting for a hot water tank of the pressure heater type.

The invention relates to a device for a hot water tank of the pressure heater type where a cold water inlet pipe and a hot water outlet pipe are arranged concentrically within each other in the tank and are connected to a fitting housing which has two ducts for cold water and hot water respectively, and where there is a cross connection for the mixing of cold water into the outflowing hot water.

The invention also relates to a fitting for a pressure heater.

Firstly, reference will be made to NO-PS 157153, which describes a fitting which can be used to control the temperature of the outflowing water from a water heater, so that this water maintains a temperature of, for example, 70°C or lower, whilst the operating temperature of the water heater is maintained at 90°C. By mixing the outflowing hot water with inflowing cold water with the aid of the thermostat-controlled mixing valve in the fitting, it is possible to obtain an increase in the capacity of the water heater, whilst observing regulations relating to the temperature of the outflowing hot water.

Reference will also be made to NO-PS 164863, which describes a fitting having a cross connection for cold mixing water, which thus is mixed with the outflowing hot water.

The fittings known today, such as those described in the two aforementioned patent documents, comprise a thermostat-controlled mixing valve, with a thermostat arranged in the hot water duct which has a valve body that is spring-biased against a valve seat in a cross connection in the fitting. For reasons of safety, the thermostat valve should be set at a hot water temperature which is below the scalding limit. The relevant authorities in a number of countries consider it to be a disadvantage that the thermostat valve can be adjusted, thus producing a source of danger in that, for example, children may set the thermostat valve at an undesirably high scalding temperature. To avoid such undesirable adjustment of the thermostat valve, it has been suggested that it should be lead-sealed. Of course, in terms of costs it is disadvantageous to use an expensive fitting with a thermostat-controlled mixing valve which must be sealed. On the other hand, it is a major advantage and a requirement that cold water is mixed into the outflowing hot water, for the very purpose of preventing excessively high temperatures of the hot water. It is an object of the present invention to provide a simpler solution for the supply of cold mixing water to the outflowing hot water.

It is also an object of the invention to provide new, advantageous fittings.

According to the invention, therefore, a device of the type mentioned above is proposed, which device is characterised in that the cross connection is in the form of one or more through holes in the wall of the inner one of the two concentric pipes.

This allows the use of a simpler fitting, without the thermostat-controlled mixing valve. The cross connection in the form of one or more holes must, of course, be adapted/dimensioned according to certain criteria in order to obtain the desired effect, namely that the outflowing hot water is not above scalding temperature, for example, 55°C. However, tests have shown that it is very easy to dimension the new cross connection on the basis of knowledge of pipe dimensions and water pressure.

In its preferred form, the cross connection is constant, but it would be possible to have an adjustable cross connection. An adjustable cross connection of this kind can be obtained by providing a face abutting the perforated pipe wall and which encircles the pipe wall and has a bevel edge end in the area of a hole in the pipe wall. The turning of the pipe will cause, for example, a large hole in the pipe wall to be covered more or less by the encircling face at the bevel edge end, thus making it possible to adjust the size of the hole by turning the pipe, which in practice is done by tightening, to a greater or lesser extent, the threaded connection which is used to mount the pipe in the fitting.

Additional features of the invention are disclosed in the dependent patent claims.

An especially preferred fitting with which the invention can be realised, but which is also considered to have independent inventive value, is a fitting (valve) for connection in a cold water inlet pipe and a hot water outlet pipe in a hot water tank of the pressure heater type, where the cold water inlet pipe and the hot water outlet pipe are arranged concentrically within one another, which fitting has two ducts for cold water and hot water respectively, and what characterises the new fitting is that it comprises a fitting housing having a first duct in the form of a graduated bore having a smaller and a larger bore portion, and a second duct which intersects the first duct in the area of the smaller bore portion, and a third duct which intersects the said first duct in the area of the larger bore portion. Two concentric pipes arranged within each other can be mounted in a fitting of this kind, the inner one of the two pipes being fixed in the smaller bore portion and the outer one of the two pipes being fixed in fluid communication with the larger bore portion.

When the cross connection (the perforation) according to the invention is to be realised in a fitting of this kind, the inner one of the two pipes is provided with holes in the pipe section which is in the larger bore portion.

The said graduated bore is preferably a blind bore.

An especially preferred embodiment of the new fitting is one where the fitting housing comprises a substantially cylindrical body having a longitudinal axis, with the said graduated bore concentric with the longitudinal axis, a first extended housing portion on the substantially cylindrical body, with the said second duct, and a second extended housing portion on the substantially cylindrical body, with the said third duct.

A fitting of this kind is compact and can be made in a simple manner by impact forging a fitting body, especially in brass, and subsequently boring the graduated blind bore and the said ducts including necessary valve seats etc.

Additional features are disclosed in the dependent patent claims related to the fitting claim.

The invention will now be explained in more detail with reference to the drawings, wherein:

Fig. 1 is a sectional view of a known hot water tank equipped with a fitting housing, taken from the aforementioned Norwegian Patent Specification 164863; Fig. 2 shows a section of a pressure heater equipped with a device according to the invention, in a bottom mounting;

Fig. 3 shows a section like that in Fig. 2, but with a top-mounted fitting;

Fig. 4 shows a section like that in Fig. 2, but with an adjustable cross connection;

Fig. 5 shows a section like that in Fig. 3, but with an adjustable cross connection; Fig. 6 shows a fitting with a cold water inlet pipe and a hot water outlet pipe, for bottom mounting; Fig. 7 shows a fitting with a cold water inlet pipe and a hot water outlet pipe, for top mounting;

Fig. 8 is a cutaway view of the fitting in Fig. 7;

Fig. 9 is a cutaway view of the fitting in Fig. 7, where the section is made somewhat differently than the section in Fig. 8;

Figs. 10 and 11 are sectional views through the fitting in Fig. 7; and

Fig. 12 shows a test curve in a water temperature/volume flow rate diagram.

The fitting shown in Fig. 1 comprises a fitting housing 1 equipped with a thermostat- controlled mixing valve 2 and a combined non-return/shut-off valve 3 intended for connection in a cold water inlet pipe 5 and a hot water outlet pipe 6 in a hot water tank 4 of the pressure heater type. The hot water outlet pipe 6 is arranged concentrically within the cold water inlet pipe 5. The fitting housing 1 has two ducts 7, 8 for cold water and hot water respectively, and a cross connection 9 for cold mixing water between these two ducts. Arranged in the hot water duct 8 is a thermostat 2a having a valve body 2b which is spring-biased against a valve seat 2c in the cross connection 9. A stem 10 is connected to an operating means 11 for screwing the stem 10 and thus the thermostat 2a against the biasing force of a spring disposed between the thermostat 2a valve body 2b and the interior of a closing plug 12 for the bore 8a. The thermostat is held in place by the spring 14, and the thermostat body/valve body 2b can be adjusted towards and from the valve seat 2c in the cross connection 9 in order to set the desired temperature of the outflowing mixing water. The hot water duct 8 is positioned in close connection with the thermostat 2a thermostat valve body 2b, so that hot water flowing therethrough actuates the thermostat body simultaneously with cold water running from the cold water inlet 7 via the cross connection 9 and flushing over the thermostat valve body 2, 3 at the same time as the hot water for actuating the thermostat so as to obtain the desired and preset temperature of the resulting mixing water, which runs out of the hot water duct 8 bore 8a via an outlet spigot 8b arranged in a side wall of the bore 8a for connection to a hot water pipe in a water pipe network.

Cold water flows in as indicated by the arrow KN and flows out into the tank 4 as indicated by the arrows. Thus, hot water is forced in at the top of the pipe 6 and down through this pipe and then out through the outlet 8b. Cold water is mixed with the outflowing hot water through the cross connection 9.

Fig. 2 shows an embodiment of the new device according to the invention. As in the known solution in Fig. 1, here too a cold water pipe 5' surrounding a concentric hot water pipe 6' is welded in the bottom of the hot water tank 4'. These two concentric pipes 5', 6' are connected to a fitting 1' which has a simpler design than the fitting 1 in Fig. 1 , as it does not have the known thermostat-controlled mixing valve and is only provided with a safety valve S. The cold water inlet of the fitting 1' is indicated by the reference numeral 7'. The hot water outlet is indicated by 8'.

A particular advantage of the fitting in Fig. 2 is its low installation height, which, for example, permits the fitting to be built into a box right beneath the water heater.

The hot water outlet pipe 6' is perforated, i.e., through holes 20 are made in the hot water outlet pipe 6'. Cold water from the cold water inlet pipe 5' can flow through these holes into the hot water outlet pipe 6', as indicated by the arrows, and become mixed with the cold water that exits at 8'.

Fig. 3 shows a top-mounted fitting 21 , i.e., that water inlet and water outlet take place at the top of the pressure heater water tank 22. Cold water is led into the water tank through a cold water inlet pipe 23, whilst hot water flows out through the surrounding hot water outlet pipe 24. Both pipes 23, 24 are connected to the fitting 21 whose cold water supply is indicated by means of the reference numeral 25 and whose hot water outlet is indicated by the reference numeral 26. The cold water inlet pipe 23 is perforated in this embodiment, i.e., provided with a plurality of through holes 27 in the pipe wall, so that the inflowing cold water can run out through the holes and become mixed with the outflowing hot water in the pipe 24.

Of course, the total cross-section of the holes 27 must be such that the desired mixing of cold water into the outflowing hot water is obtained, in order to avoid an excessively high temperature (scalding temperature) in the outflowing hot water. Determining parameters here are the pipe dimensions and the water pressure.

When there is standard domestic water pressure of 2-8 ato and the cold water inlet pipe 5' in Fig. 2 has an internal diameter of 19 mm, a total of four holes, each having a diameter of 3 mm, will give the desired mix of cold water with the hot water, so as to ensure that the outflowing hot water does not exceed a scalding temperature of about 55°C.

The same applies to Fig. 3 where a cold water inlet pipe 23 internal diameter of 14 mm requires six holes 27, each having a diameter of 3 mm. It should be noted that a top mounting like that in Fig. 3 requires a larger total hole cross-section than a bottom mounting under otherwise identical conditions.

The pipe 6', 23, provided with holes 20, 27 may advantageously be in the form of a pipe which has a threaded portion 33, 35, 34, 36 at both ends, as shown in Figs. 2 and 3. The plumber or person setting up the heater may then choose an embodiment with temperature reduction, i.e., that the hole or holes are at the fitting end, as is shown in Figs. 2 and 3, or an embodiment with the means for full temperature, i.e., that the holes are inside the tank, close to the pipe end that projects into the body of water in the tank.

With the embodiment in Figs. 3 and 5 a favourable installation height is obtained, with the two ducts for cold and hot water spaced apart in the vertical direction, which is favourable for connecting or adjusting to a hot water pipe and cold water pipe. The heater may be placed by a wall, which is the standard installation, and the pipes are then passed vertically downwards or upwards along the wall, and very often horizontally. No matter how the pipes run, the fitting will be easily connected to the pipes. A favourable situation arises in particular when the piping is horizontal, because the pipes run parallel, one above the other.

An adjustable embodiment of the cross connection according to the invention is shown in Fig. 4, which shows a section through a fitting like the one in Fig. 2. From the section in Fig. 4, it can be seen that inside the fitting there is a bevel edge end 28 in the interior space in the fitting 1'. The bevel edge 28 extends around the hot water outlet pipe 6" in the area of, in this case, a single opening or a single hole 29 in the wall of the hot water outlet pipe 6". The pipe 6" has a threaded portion 33 by which it is screwed into the fitting 1'. By screwing the pipe 6" a half turn in the fitting housing V, the hole 29 can be brought from a full opening to a stepless smaller opening, because the surrounding wall, whose bevel edge is indicated by the reference numeral 28, covers the hole according to the turning position. Thus, in this way it is quite easy to reduce the flow cross-section of the hole 29 steplessly from a full opening to a closed opening.

A similar embodiment is shown in Fig. 5 for a top mounting of the kind shown in Fig. 3. In this case too, there is a continuous bevel edge 31 inside the fitting 21' which can be made to cover a hole 32 in the cold water inlet pipe 23' to a greater or lesser degree by turning the pipe 23' more or less (a half turn) into the corresponding threaded portion in the fitting 21'. Tests have shown that the new device according to the invention controls the mixing ratio between hot and cold water in a stable manner, so that the mixed water fed into the hot water pipes has the desired temperature level. The device can thus replace the conventional, complex and costly control valves. The adjustable embodiment, with bevelled edge, can easily be set by a plumber during installation.

Fig. 12 shows a test curve in a water temperature/volume flow rate diagram for an embodiment as mentioned above. A 200-litre pressure water heater was served by a fitting like the one in Fig. 2 with a water pressure of 4 ato and a cold water inlet pipe 5' internal diameter of 19 mm and with four holes 20, each having a diameter of 3 mm. The heater had a water temperature of 75°C. The inflowing cold water, from a household tap, had a temperature of 10°C.

When a small amount of less than 2 litres per minute was drawn off, the outgoing hot water had a fairly low temperature, as shown in the diagram, but the temperature then quickly reached an almost constant and desiredlevel, between 55°C and 58°C.

Fig. 6 shows a fitting 35 with connected cold water inlet pipe 36 and a hot water outlet pipe 37 arranged concentrically therein. The cold water inlet pipe 36 has holes 38 (only one hole is shown) for the outflow of cold water into the surrounding pressure heater (not shown). The illustrated fitting 35 is for bottom mounting, and reference is made to Fig. 2. The fitting 35 and the pipes 36, 37 thus replace the fitting 1' and the pipes 5', 6' in Fig. 2.

' Fig. 7 shows a fitting 40 with cold water inlet pipe 41 and hot water outlet pipe 42 for top mounting, as in Fig. 3.

The fitting 40 has a special new and favourable design, which is shown in more detail in Figs. 8 and 9, which show the fitting 40 in two different cutaway views.

From Figs. 7-11 it can be seen that the fitting 40 is made having a central, substantially . cylindrical body 43. From the connection end for the pipe 42, which is connected by means of a clamping nut 44, the body 43 is bored out with a graduated blind bore 45, which has an inner or upper smaller bore portion 46 and a larger bore portion 47, passing from the connection end in (up) towards the smaller bore portion 46. This is shown in particular in Figs. 10 and 11. The section in Fig. 10 has been taken along the centre line X-X in Fig. 11, and the section in Fig. 11 goes through the body 43.

The fitting has a first extended portion 48 on the central body 43. This extended portion 48 has a duct (second duct) 49 which intersects the smaller bore portion 46 of the blind bore 45, thereby providing fluid communication between the bore portion 46 and the duct 49 (see in particular Fig. 11).

Furthermore, the fitting has a second extended portion 50 on the central body 43. This second extended portion 50 has a duct (third duct) 51 which intersects the larger bore portion 47 of the blind bore 45, thereby providing fluid communication between the larger bore portion 47 and the duct 51 (see in particular Figs. 10 and 11).

A threaded portion 52 is provided in the smaller bore portion 46 for the insertion of the cold water inlet pipe 41 (not shown in Fig. 11). The hot water outlet pipe 42 is secured in the body 43 by means of the clamping nut 44, in a known way. As shown in Fig. 8, the cold water inlet pipe 41 has a plurality of holes 53, which form a cross connection between cold water and hot water, whereby the outgoing hot water is mixed with cold water so that the temperature of the outgoing hot water is lowered to below scalding temperature.

The duct 49 is the cold water duct in the fitting. (See Figs. 8 and 9.) A cold water pipe (not shown) is connected to the duct 49 by means of the clamping nut 54, with inserted clamping ring 55 . The duct 49 is made having a valve seat 56 which cooperates with a valve body 57. The valve body 57 is a part of a known valve embodiment, having shut- off and non-return functions.

The valve body 57 is closed or blocked by the operating wheel 58.

The duct 51 is the hot water duct in the fitting. As mentioned, the duct 51 is in open fluid communication with the larger blind bore portion 47 which forms an annular space under the pipe 41 and is in fluid communication with the pipe 42.

When the cold water valve 56, 57 is opened (see Figs. 8 and 9), cold water will flow into and down through the pipe 41, as explained in connection with Fig. 3, and hot water from the heater will be forced up through the pipe 42 and into the annular space 47 and out into the hot water pipe (not shown) that is connected to the duct 51 by means of the clamping nut 59 with associated clamping ring 60. Cold water will be mixed into the outflowing hot water through the holes 53 in the pipe 41.

The fitting has a safety valve 61. In this case, the safety valve 61 is of a type that is known (NO 161281). The safety valve 61 comprises a diaphragm 62 (see Fig. 9) which cooperates with a valve seat 63 in the duct 51 (see also Fig. 10). When the pressure on the diaphragm 62 exceeds a given value, the diaphragm will be lifted up from the seat 63 and allow water out via the overflow 64, which has fluid communication 65 with the duct 51 behind the seat 63, i.e., with the part of the duct 51 which is on the side of the valve seat 63 facing the diaphragm 62. The overflow 64 is connected to an overflow pipe (not shown). It will be appreciated that the fitting in Fig. 6 is in principle made like the fitting 40 in Figs. 7-11. The fitting 40 can be "turned around", i.e., that the duct 49 can be used as hot water duct whilst the duct 51 is used as cold water duct, the fitting 40 then being capable of use as a bottom-mounted fitting, like the fitting in Fig. 6.

Claims

P a t e n t c l a i m s

1.

A device for a hot water tank of the pressure heater type, where a cold water inlet pipe (5'; 23) and a hot water outlet pipe (6'; 24) are arranged concentrically within each other in the tank (4'; 22) and are connected to a fitting housing (T; 21) which has two ducts (7', 8'; 25, 26) for cold water and hot water respectively, and where there is a cross connection for the mixing of cold water into the outflowing hot water, characterised in that the cross connection is in the form of one or more through holes (20; 27) in the wall of the inner one of the two concentric pipes (5', 6'; 23, 24).

2.

A device according to claim 1 , characterised in that the pipe (6; 23) provided with the hole or holes (20; 27) is a pipe having a threaded portion (33, 35; 34, 36) at both ends.

3.

A device according to claim 1 , characterised by a face abutting the perforated pipe wall which encircles the pipe wall and has a bevel edge (28; 31) in the area of a hole (29; 32) in the pipe wall.

4.

A fitting for connection in a cold water inlet pipe and a hot water outlet pipe in a hot water tank of the pressure heater type, where the cold water inlet pipe and the hot water outlet pipe are arranged concentrically within each other, which fitting has two ducts for cold water and hot water respectively, characterised in that the fitting comprises a fitting housing having a first duct (45) in the form of a graduated bore having a smaller (46) and a larger bore portion (47), a second duct (49) which intersects the said first duct (45) in the area of the smaller bore portion, and a third duct which intersects the said first duct in the area of the larger bore portion (47).

5.

A fitting according to claim 4, characterised in that the fitting housing comprises a substantially cylindrical body having a longitudinal axis, with the said graduated bore (45) concentric with the longitudinal axis, a first extended housing portion on the substantially cylindrical body with the said second duct (49), and a second extended housing portion on the substantially cylindrical body, with the said third duct (51).

6. A fitting according to claim 4 or 5, characterised in that the said graduated bore (45) is a blind bore.

7.

A fitting according to claim 4, 5 or 6, characterised in that the said second duct (49) is through-going and is made having a valve seat (56) in front of the intersection of the first duct (46) seen in the direction of flow.

8.

A fitting according to one of claims 4-7, characterised in that the said third duct (51) is though-going and is made having a valve seat (63) between the ends.

9.

A fitting according to claim 7 or 8, characterised by a combined non-return and shut-off valve assembly (58) having a valve body (57) intended for cooperation with the valve seat (56) in the said second duct (49).

10.

A fitting according to claim 8 or 9, characterised by a pressure relief valve assembly (61) having a diaphragm body (62) intended for cooperation with the valve seat (63) in the said third duct (51).