GB2170883A

GB2170883A - Valves

Info

Publication number: GB2170883A
Application number: GB08503149A
Authority: GB
Inventors: Hui Kwok Leung
Original assignee: JENFORT RESEARCH Ltd
Current assignee: JENFORT RESEARCH Ltd
Priority date: 1985-02-07
Filing date: 1985-02-07
Publication date: 1986-08-13
Also published as: GB8503149D0

Abstract

A proportioning unit 1 comprising an inlet 3 and outlet connections 4, 5 includes means for varying the relative cross-sectional areas of the outlets. As shown, the unit is inserted into the cold-water inlet line 7 to a water heater 21. Preferably the unit comprises a rectangular metallic body and four internally connected openings in four adjacent faces, namely, a cold inlet pipe connection 3, a tank feed pipe connection 4, a cold bypass pipe connection 5, and a plug shaft insertion hole (6, Fig. 4); a cold inlet pipe 7 for feeding cold water from outside the unit into an open-ended, hollow plug 19, a tank feed pipe 10 for feeding a proportion of the incoming cold water via a through hole 20 in the plug 19 to the heater 21, and a cold bypass pipe 11 for feeding the remainder of the incoming cold water via the through hole 20 to the hot outlet pipe 12 from the heater. The relative proportions of cold water leaving the unit through the tank feed pipe connection 4 and the cold bypass pipe connection 5 can be varied by rotating the plug 19. <IMAGE>

Description

SPECIFICATION Mixer unit THIS INVENTION relates to a mixer unit and, in particular, to built-in hot/cold mixers for open outlet electric thermal storage water heaters and to open outlet electric thermal storage water heaters whenever comprising such mixers.

Most previously proposed open outlet electric thermal storage waters have been provided with a specially designed external mixing battery. The hot/cold mixing is usually performed outside the heater with both hands, by mixing a certain amount of cold water with a larger amount of outgoing hot water in order to attain the desired shower temperature. This results in unnecessarily high hot water consumption and it normally takes a long time to attain the required shower temperature by trial and error (wasting energy and water).

It is an object of this invention to overcome or at least mitigate the above mentioned disadvantages.

According to the invention there is provided a mixer unit, which mixer unit comprises an inlet, first and second outlets in communication with the said inlet, and means for varying the effective relative cross-sectional areas of the first and second outlets.

This invention further relates to an openoutlet electric thermal storage water heater whenever comprising a mixer in accordance with the invention. The heater may be fed directly from the water supply mains or from a cistern.

This mixing technique is particularly suitable for use with the JENFORT storage water tank described in UK Patent No. 2036269.

The present invention enables quick, easy and effective mixing of hot and cold streams at the same or different flow rates, saves energy and water, and permits a desired mixing ratio to be preset.

For a better understanding of the present invention and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic view of a built-in hot/cold mixer in accordance with the invention, Figure 2 shows the actual hot and cold water routes for different settings of the builtin hot/cold mixer of Fig. 1, Figure 3 is a comparative view of the builtin hot/cold mixer of the invention and a conventional external mixing battery, Figure 4 is a part-sectional elevational view of a built-in hot/cold mixer in accordance with the invention, Figure 5 is a part-sectional elevational view of the built-in hot/cold mixer of Fig. 4 with a mixer shaft thereof removed, and Figure 6 is a part-sectional view of the builtin hot/cold mixer of Fig. 4 with connecting pipes in position.

Referring to the drawings, a built-in hot/cold mixer 1 of an open outlet electric thermal storage water heater comprises a rectangular copper body 2 with a square top and rectangular cross section, and four internally conneced openings in four adjacent faces, namely a threaded cold inlet pipe connection 3 on the lower right hand face, a threaded tank feed pipe connection 4 on the upper left hand face, a threaded cold bypass pipe connection 5, at the same level as the tank feed pipe connection, on the upper front face and a threaded mixer shaft insertion hole 6 on the central top face, a cold inlet pipe 7 for feeding, in use, cold water from outside the mixer 1 via a cold inlet 8 and hence via a loose jumper valve 9 from the water supply mains into a hollow bottom part 19 of the mixer shaft 14, a tank feed pipe 10 for feeding, in use, a proportion of the incoming cold water via a through hole 20 on the mixer shaft 14 to outside. the mixer 1 and hence to a storage tank 21, a cold bypass pipe 11 for feeding, in use, the remainder of the incoming cold water via the through hole 20 on the mixer shaft 14 to outside the mixer 1 and hence to a hot outlet pipe 12 where the bypass cold water mixes with the outgoing hot water before discharging through a hot outlet 13.The rotatable copper mixer shaft 14 comprises three fixed steps of increasing size, namely, a top cylindrical section 15 for linkage to a mixer control knob 22 (linkage not shown), a middle cylindrical section 16 with two separate O-ring grooves 17 for sealing and mounted within a hexagonal flanged bush 1 8 with two O-rings, and a bottom hollow cylindrical section 19 with a round through hole 20 on and perpendicular to the cylindrical surface 19. The rotatable copper mixer shaft 14 controls, in use, the proportion of the incoming cold water to be fed through the tank feed pipe 10 and cold bypass pipe 11 via the through hole 20 on the mixer shaft 14 to outside the mixer 1 and hence the percentage of hot/cold mixing at the intersection of the cold bypass pipe 11 and the hot outlet pipe 12.

The mixer can be used for both feeding directly from water supply mains or another cistern.

The built-in hot/cold mixer is particularly suitable for use with a storage water tank in accordance with UK Patent No. 2036269 and is incorporated on the cold water feeding path of an open outlet electric thermal storage water heater. The mixer is located between the storage tank and cold inlet, providing a cold water bypass facility connected to the hot water discharging path. The mixer controls the proportion of incoming cold water to be fed into the tank and, in turn, the same amount of hot water to be displaced from the tank through the hot outlet pipe, where the hot outgoing water is then mixed with the remaining portion of incoming cold water bypassed through the built-in mixer via the cold water bypass pipe.The shower temperature is effectively controlled by the percentage of hot/cold mixing or by a single control knob while the shower is switched on and off by means of a loose-jumper valve installed between the cold inlet of the water heater and the water supply mains.

The mixing route for 100% COLD, 50% MIXING and 100% HOT setting of the mixer control knob is illustrated as follows:- 100% COLD Incoming cold water goes through the cold inlet pipe, the built-in hot/cold mixer, the cold bypass pipe and then the hot outlet pipe. No hot water will be displaced or discharged from the tank into hot outlet pipe. Cold temperature is defined by the temperature of incoming cold water.

50% MIXING Incoming cold water is divided into equal streams and diverted into two different routes, one route via the built-in hot/cold mixer and the tank feed pipe, so that the same amount of hot water is displaced from the storage tank and discharged into the hot outlet pipe, and the other route via the built-in hot/cold mixer, and the cold bypass pipe to the hot outlet pipe, where outgoing hot water is mixed with by-passed cold water.

100% HOT Incoming cold water goes into the storage tank via the cold inlet pipe, the built-in hot/cold mixer and the tank feed pipe and displaces the same amount of hot water via the hot outlet pipe. No cold water is bypassed to the hot outlet pipe. Hot temperature is defined by the maximum temperature attained by the heated water within the storage tank.

Other percentages of hot/cold mixing can quickly and easily be achieved by re-adjusting the setting of the built-in hot/cold mixer control knob. Significantly, re-adjustment offered by the built-in hot/cold mixer to provide either 100% hot, 100% cold or warm outgoing water can be attained at the same flowrate and almost instantly. Also, the ratio of hot/cold mixing can be preset using a visual indicator on the control knob.

In practice, more than one third of the preheated water in a storage tank of 15 litres capacity could unavoidably be wasted during the initial mixing or re-adjustment of mixing using the conventional mixing method. Thus, hot water losses in the initial mixing or readjustment of mixing effected by the built-in hot/cold mixer of the present invention are minimised.

If the built-in hot/coid mixer is installed inside an open outlet electric thermal storage water heater having a conventional bottom feed inlet pipe and top discharge outlet pipe, the mixer will behave normally when the shower head is above the level of the mixer.

If, however, the shower head is accidentally placed below the level of the mixer, the mixer could provide a water leakage path via the short bottom feed inlet pipe, the mixer and the shower set. Consequently, the immersion heating element of the water heater would possibly be damaged or burnt out due to exposure to air within the tank. This could be completely eliminated by using the built-in hot/cold mixer with a non-return tank of the type described in UK Patent No. 2036269, which is therefore preferred for use with the mixer of the present invention.

The advantages of the built-in hot/cold mixer over the previously proposed external mixing battery can be summarised as follows: 1. User installation is simpler 2. Material costs are comparatively lower.

3. Two mixing knobs (hot and cold) are not required.

4. Mixing operation requires only one hand.

5. Mixing can be peformed at lower hot/cold flow rates.

6. Relatively lower hot water consumption.

7. It takes less time to attain the required temperature.

8. Preset mixing temperature is possible.

9. Re-adjustment of mixing for hotter shower does not cut down total outgoing flowrate.

Claims

1. A mixer unit, which mixer unit comprises an inlet, first and second outlets in communication with the said inlet, and means for varying the effective relative cross-sectional areas of the first and second outlets.

2. A mixer unit according to Claim 1, which comprises metal.

3. A mixer unit according to Claim 1 or 2, which comprises shaped plastics.

4. A mixer unit according to any one of the preceding claims, wherein the mixer unit is substantially right parallelpipedal with the inlet and the first outlet extending through opposed faces thereof and the second outlet extending through a face of the mixer unit which is perpendicular to the said opposed faces, wherein the first and second outlets lie in a common plane which is parallel to the inlet.

5. A mixer unit according to any one of the preceding claims, wherein the means for varying the effective relative cross sectional areas of the first and second outlets comprises an apertured member which is rotatable so as to vary the degree of overlap between the aperture(s) and each of the first and second outlets.

6. A mixer unit according to Claim 5, wherein the rotatable member is a hollow cylinder, the inlet being in communication with the interior of the cylinder.

7. A mixer unit according to Claims 4 and 6, wherein the axis of the cylinder extends through and perpendicular to the said common plane, means being provided, on the opposite side of the said common plane to the inlet, for effecting rotation of the cylinder.

8. A built-in hot/cold mixer comprising a rectangular body with four internally connected openings in four adjacent faces, namely, a cold inlet pipe connection on the lower right hand face, a tank feed pipe connection on the upper left hand face, a cold bypass pipe connection, at the same level as the tank feed pipe connection, on the upper front face, and a mixer shaft insertion hole on the central top face, a cold water inlet for feeding, in use, cold water into the hollow bottom part of a mixer shaft from outside the mixer, a tank feed outlet for feeding, in use, a proportion of the incoming cold water via a through hole on the mixer shaft to outside the mixer and hence to a storage tank, a cold bypass outlet for feeding, in use, the remainder of the incoming cold water via a through hole on the mixer shaft to outside the mixer and hence to a hot outlet pipe where the bypass cold water mixes with the outgoing hot water from the storage tank, and a rotatable mixer shaft for controlling, in use, the proportion of the incoming cold water to be fed through the tank feed pipe and cold bypass pipe outlets via the through hole, which through hole is disposed on and perpendicular to the cylindrical surface of the rotatable mixer shaft, to outside the mixer.

9. A water heater in combination with a mixer in accordance with any one of the preceding claims.

10. A combined water heater and mixer unit, wherein the mixer unit comprises a cold water inlet, first and second outlets in communication with the said inlet, means for varying the effective relative cross-sectional areas of the first and second outlets, means for connecting the first outlet to an inlet of the water heater, and means for mixing hot water from an outlet of the water heater with cold water from the said second outlet of the mixer unit.

11. An electric water heater comprising a built-in hot/cold mixer comprising a rectangu lar metallic body with four internally connected openings in four adjacent faces, namely, a cold inlet pipe connection on the lower right hand face, a tank feed pipe connection on the upper left hand face, a cold bypass pipe connection, at the same level as the tank feed pipe connection, on the upper front face, and a mixer shaft insertion hole on the central top face, a cold water inlet for feeding, in use, cold water into the hollow bottom part of a mixer shaft from outside the mixer, a tank feed outlet for feeding, in use a proportion of the incoming cold water via a through hole on the hollow part of the mixer shaft to outside the mixer and hence to a storage tank, a cold bypass outlet for feeding, in use, the remainder of the incoming cold water via a through hole on the hollow part of the mixer shaft to outside the mixer and hence to a hot outlet pipe where the bypass cold water mixes with the outgoing hot water from the storage tank, and a rotatable metallic mixer shaft, constituting three fixed cylindrical steps of increasing size, a top step for control knob linkage and mixing adjustment, a middle step for water sealing, and a bottom hollow step with a circular through hole on and perpendicular to the cylindrical surface thereof for dividing incoming cold water into two portions via the tank feed and cold bypass pipes to outside the mixer and hence effect hot/cold mixing at the intersection of the cold bypass pipe and the hot outlet pipe before discharging through a hot outlet.

12. A mixer unit, substantially as hereinbefore described with reference to, and as shown, in the accompanying drawings.

13. A combined water heater and mixer unit substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

14. Any novel feature or combination of features described herein.