GB1581724A

GB1581724A - Injector shower attachment

Info

Publication number: GB1581724A
Application number: GB4434976A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-10-26
Filing date: 1977-10-26
Publication date: 1980-12-17

Description

(54) INJECTOR SHOWER ATTACHMENT (71) I, PETER WILSON, a British subject of 49 Gainsborough Drive, Leeds LS16 7PE, do hereby declare the invention, for which I pray that a Patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to showers and to shower attachments.

A simple conventional form of portable hand-held shower unit comprises tubes adapted to be secured, releasably, to the hot and cold water taps of a domestic bath, the tubes leading to a common outlet tube which in turn supplies the mixed hot and cold flows of water to the shower head. The temperature of the outflow from the shower head is set by regulating the hot and cold supply taps, and since the throughput of the shower is also dependent directly on the regulation of these taps it follows that the throughput and the temperature of the outflow vary simultaneously so that the one cannot be set without affecting the other.

To use this kind of shower successfully, a positive pressure head on the hot water supply is needed. Once the desired outflow temperature has been set, the shower rose must be kept at a constant height if the temperature is not to vary. This, together with the need to balance outflow temperature and throughput simultaneously, is a drawback of these simple showers. A much more serious drawback is the possibility of a sudden increase in outflow temperature if the pressure on the cold water inlet is affected by, for example, other taps being turned on in other parts of the house in which the shower is being used.

A shower unit embodying the present invention is characterised by two primary design features. Firstly, an injector device fitted in the cold water supply line utilises the excess pressure of the cold water system to draw hot water from the hot water tap. The combined mixed outflow from the shower head can thus have its throughput altered, without altering its temperature appreciably (for substantially zero hot-water pressure head), by simply regulating the cold input.

More importantly, if the pressure of the cold water input is inadvertently reduced, the throughput will automatically be reduced instead of the temperature suddenly rising.

Secondly, because the injector fitment causes a back-pressure to build up at the cold supply tap, the fitting which, in use, secures the supply tube to that tap, incorporates a releasable mechanical clamp to reduce the risk of the fitting being "blown-off" the tap by the accumulated back-pressure of the cold supply.

The shower unit will normally incorporate flexible supply and output tubes joined by a relatively rigid T-piece. The injector nozzle is fitted in this T-piece. Alternatively the T-piece is connected to the fitting by a short rigid tube integral with the fitting which, in use, secures the cold supply tube to the supply tap. If the fitting and the unit are combined in this way, a particularly advantageous design results, since an existing and otherwise conventional shower can be modified smply.

The invention therefore includes within its scope a fitting in which the injector and the fitting having releasable clamp are combined.

Increased performance can in some cases be obtained by sending the mixed hot and cold outflow through a pressure recovery tube in the form of a divergent nozzle, or a convergent-divergent nozzle. Alternatively the outflow may have its initial mixing zone along a parallel-side bore.

In the accompanying drawings: Figure 1 shows in longitudinal crosssection a first cold-water supply fitting embodying the invention; Figure 2 shows graphically the variation of shower temperature with flow rate for showers embodying the invention.

In Figure 1, a T-piece 1 of a shower is made of circular-cross-section copper tubing. Each of its extremities 2, 3, 4 Is screw-threaded externally so that a respective co-operating union - shown only at 5 in Figure 1 - can be attached to it. Each such union may be on one end of a flexible tube, the other end of which is adapted for connection to the shower rose, the hot-water supply tap and the cold-water supply tap respectively.

In conventional portable shower units, the ends of the hot-water and cold-water supply tubes can simply be stretched over the output ends of the respective supply taps. However, in all but the very lowest-pressure domestic installations, a shower unit embodying the invention will inevitably cause a fairly considerable back-pressure to build up in the cold-water supply line. The fitting connecting the cold water supply tube to its tap must therefore be designed appropriately. As Figure 1 shows, such a fitting comprises a section 6 (which may be at the end of a flexible tube or, as actually shown, at the end of a rigid tube). The section is of enlarged diameter and thickness, and is adapted to be stretched over the tap (not shown) and then to be tightly secured in place by a releasable mechanical clamp such as, for instance, a "JUBILEE" clip 7 ("JUBILEE" is a Trade Mark).

The fitting connecting the hot-water supply line to its tap could be designed similarly.

for example to make both hot and cold supply fittings identical in appearance and therefore aesthetically acceptable when in position on the two adjacent taps. The supply tubing could be reinforced, for example by coiling metallic strip about its external surface, in order to withstand the backpressures generated in the supply lines, particularly the cold supply line. Again, if a symmetrical appearance is desired for the whole unit, the supply tubing from the T-piece outlet to the shower rose could be similarly reinforced.

The T-piece of Figure 1 incorporates the shower's injector device. The injector device comprises a convergent nozzle 8, made from circular-cross-section copper tubing symmetrically flattened at one end to define the nozzle outlet. Other forms of nozzle could be moulded from suitably hard synthetic plastics material, or machined from metal or from hard plastics material.

The nozzle of Figure 1 could be welded into the end of the limb of the T-piece, but it is conceivable that a hard plastics O-ring could be moulded to fit in the end of the T-piece and to locate in a suitably machined or moulded groove around the body of the nozzle. As illustrated, the nozzle body itself incorporates a section of enlarged diameter at its inlet end, and this section seals on the end face of the T-piece. In each case, the nozzle is firmly located and held in position by the union 5 when that union is firmly screwed into position on the T-piece.

At the outlet 4 from the T-piece, a convergent-divergent nozzle 10 is fitted. The nozzle 10 in this instance is a tight fit in the bore of the outlet of the T-piece. It could again be made from metal, or from a hard plastics material. It is located in place when the union (not shown) connecting the combined-flow outlet tubing to the T-piece at 4 is screwed into place.

Figure 2 illustrates the variations of shower flow-rate with temperature obtained using two different sizes of nozzle.

Point A on the graph shows the flow-rate and temperature for a shower unit using a nozzle of 0.055 inches diameter, with the hot and cold water supply taps fully open.

When flow from the cold tap only is restricted, the locus of successive flowrate/temperature points travels along a horizontal line on the graph to point B - in other words, flow-rate is reduced but temperature remains constant.

When flow from the hot tap only is restricted, the locus travels along the line to point C - i.e. flow-rate and temperature come down progressively in unison.

A change in nozzle size to 0.065 inches diameter, and the same operations, produces similar results, shown as triangle A1 B1 C,.

The results illustrated in Figure 2 were obtained with a cold-water supply temperature of 12 degrees Centigrade and a hotwater supply temperature of 62 degrees Centigrade. with the shower rose held at the same height as the water level in the storage tank. Intermediate nozzle sizes will produce their own outlet temperature ranges, with the outlet temperature increasing approximately 1 degree Centigrade for each 0.001 inch decrease in nozzle diameter. Selection of nozzle size can therefore be made to suit a particular situation; for example, a smaller nozzle may be used in winter to compensate for a lower cold-water supply temperature.

To allow for this, a variable-size nozzle could be used: for example, a tapered needle could pass through the nozzle, with provision to set the needle at predetermined positions in the nozzle outlet. The needle could be mounted in a knurled ring which made screw-threaded engagement with the body of the nozzle, and marking on the ring and/or body could indicate the appropriate directions of rotation to raise and lower the shower outlet temperature.

Alternatively, a nozzle of soft plastics material could be mounted in a knurled adjusting ring so that rotation of the ring in one direction would squeeze the nozzle outlet into a progressively narrowing space, thus deform ing the nozzle and restricting the size of the jet.

It is envisaged that, with current commercially available shower units, the diameter of the nozzle outlet (of a purely convergent nozzle) or throat (for a convergent-divergent nozzle) might vary between 0.055 inches and 0.065 inches. A suitable pressure recovery tube would be 0.1875 inches in internal diameter and not less than 1 inch long, with a parallel bore.

It will be appreciated that further modifications could be made, or other constructions conceived, which are still within the scope of the invention. For example, multiple nozzles could be used, either in series or in parallel; and if more than two nozzles in parallel were to be used, the nozzles could be arranged in a symmetrical ring with their outputs directed towards a common point, since this is more efficient and gives a more evenly mixed outflow. Other modifications will become apparent to those skilled in this particular art.

WHAT I CLAIM IS: 1. A hot-and-cold separately-supplied combined-outflow shower unit, in which a convergent nozzle is so located in the flow path of cold water through the unit, that in use it functions as an injector and utilises the excess pressure of the cold water supply to draw the hot water into and through the unit, maintaining for a substantially zero hotwater pressure head a substantially constant combined outflow temperature irrespective of any variation in the pressure of the cold water supply; in which the hot and cold supply tubes from the unit each end in a respective fitting which in use secures the tube releasably to a supply tap; and in which the cold supply fitting a releasable mechanical clamp to reduce the risk of the fitting being blown off the tap by the back-pressure which accumulates at the cold supply tap during use of the shower.

2. A shower according to claim 1, in which the nozzle and the mechanical clamp are both incorporated into the cold supply fitting.

3. A shower according to claim 1 or claim 2, in which the hot supply fitting is substantially identical in appearance to the cold supply fitting.

4. A fitting for use in a shower according to claim 2, or claim 3 when appendant to claim 2, the fitting comprising a T-piece or Y-piece one of whose branches incorporates a releasable mechanical clamp adapted to secure the fitting releasably to a cold-water supply tap, and the fitting also incorporating a convergent nozzle so located that, with said one branch secured to a cold water supply and one of the remaining two branches secured to a hot-water supply, the nozzle functions as set forth in claim 1.

5. A shower according to claim 2 or claim 3, or a fitting according to claim 4, in which the nozzle is located but not permanently held, within the cold supply fitting, and the fitting comprises a composite assembly of parts which can readily be dismantled to enable the nozzle to be removed and if necessary replaced with a different nozzle.

6. A shower according to any of claims 1 to 3 or claim 5, or a fitting according to claim 4 or claim 5, in which the nozzle outlet is followed by a pressure recovery tube comprising a divergent nozzle.

7. A shower according to claim 6 when appendant to claim 5, or a fitting according to claim 6 when appendant to claim 5, in which the pressure recovery tube can also be readily removed, and if necessary replaced with a different tube, when the cold supply fitting is dismantled.

8. A shower according to any of claims 1 to 3 or 5 to 7, or a fitting according to any of claims 4 to 7, in which a tapered needle is located in the throat of the nozzle, and can be axially advanced and retracted towards and away from the throat by for example an adjusting ring, to vary selectively the effective throat diameter of the nozzle.

9. A shower according to any of claims 1 to 3 or 5 to 7, or a fitting according to any of claims 4 to 7, in which the nozzle throat is made of a resiliently deformable material, and means such as an adjusting ring are provided which vary the effective throat diameter by selectively squeezing and releasing the nozzle throat.

10. A shower fitting substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

11. A shower incorporating a fitting according to claim 10.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ing the nozzle and restricting the size of the jet. It is envisaged that, with current commercially available shower units, the diameter of the nozzle outlet (of a purely convergent nozzle) or throat (for a convergent-divergent nozzle) might vary between 0.055 inches and 0.065 inches. A suitable pressure recovery tube would be 0.1875 inches in internal diameter and not less than 1 inch long, with a parallel bore. It will be appreciated that further modifications could be made, or other constructions conceived, which are still within the scope of the invention. For example, multiple nozzles could be used, either in series or in parallel; and if more than two nozzles in parallel were to be used, the nozzles could be arranged in a symmetrical ring with their outputs directed towards a common point, since this is more efficient and gives a more evenly mixed outflow. Other modifications will become apparent to those skilled in this particular art. WHAT I CLAIM IS:

1. A hot-and-cold separately-supplied combined-outflow shower unit, in which a convergent nozzle is so located in the flow path of cold water through the unit, that in use it functions as an injector and utilises the excess pressure of the cold water supply to draw the hot water into and through the unit, maintaining for a substantially zero hotwater pressure head a substantially constant combined outflow temperature irrespective of any variation in the pressure of the cold water supply; in which the hot and cold supply tubes from the unit each end in a respective fitting which in use secures the tube releasably to a supply tap; and in which the cold supply fitting a releasable mechanical clamp to reduce the risk of the fitting being blown off the tap by the back-pressure which accumulates at the cold supply tap during use of the shower.

11. A shower incorporating a fitting according to claim 10.