EP0338825A1

EP0338825A1 - Improved dispensing device

Info

Publication number: EP0338825A1
Application number: EP89303921A
Authority: EP
Inventors: Roberto Giovanni Fraquelli; Geoffrey Farrell
Original assignee: Wellcome Foundation Ltd
Current assignee: Wellcome Foundation Ltd
Priority date: 1988-04-21
Filing date: 1989-04-20
Publication date: 1989-10-25
Also published as: DK193989D0; FI891885A; GB8809470D0; NO891628L; JPH0227031A; PT90331A; DK193989A; KR900016558A; NO891628D0; FI891885A0; AU3323089A; ZA892919B

Abstract

A dispensing device for adding environment-improving liquid additive from a reservoir (34) to water in a flush pipe (14) leading to a urine-receiving vessel comprises a peristaltic pump (33) powered by an electric motor (32), the motor being used to dispense a precise volume of additive on each actuation.

Description

Technical Field

This invention relates to an improved dispensing device of the kind intended to add a volume of a first fluent material to a flowing stream of a second fluent material. The invention has particular, but not exclusive, application to the addition of a small volume of liquid to the flush water of a water closet or urinal basin.

Discussion of Prior Art

It is known to provide a chamber, linked, by a float-operated valve to the flush water pipe from an upper cistern to a lower urinal basin, in such a way that the chamber fills with water during an initial period of a flushing operation and drains during the final stage of the flushing operation. Located in the chamber of a prior-art dispensing device is the sponge-filled outlet of a reservoir of liquid additive (e.g. a disinfectant/perfume/descaling compound) so that each filling/emptying of the chamber causes a volume of additive to be drawn into the flush water stream.
However, with a prior art device as described above, the volume of additive drawn into the flush water stream is variable and the variation in volume is particularly marked if the delay between successive flushes is not a fixed period of time.
Direct injection of a first fluent material into a volume of flush water using an electrically-powered pump is disclosed in EP-A-0149369 and pumping of fluent material using the deflection of a resilient deformable tube is shown in EP-A-0018648.

Summary of the Invention

This invention relates to an improved dispensing device in which a substantially constant volume of a first fluent material is dispensed into a much greater volume of a second fluent material, the volume of first fluent material being determined by means of a peristaltic pump.
Suitably the pump comprises a loop of flexible tubing made to extend substantially chordally between a plurality of tube-supporting members uniformly spaced apart around a center of rotation of the pump. Conveniently there are "n" such members (which can be rollers) mounted one on each of "n" radially-extending arms of a rotatable spider ("n" being a small integer greater than 2). Means would be provided to rotate the tube-supporting members relative to the tubing and an electric motor is preferred. Means can also be provided to determine the total angular rotation of the tube-supporting members about a centre of rotation within the loop in each dispensing operation.
Conveniently three tube-supporting members are used, the loop of flexible tubing extending in two substantially chordal runs between rollers or rods each mounted at the same distance from the centre of rotation and at 120° spacings thereraround.
The peristaltic pump is conveniently driven by an electric motor (e.g. battery powered). The timing of a dispensing operation can be by means of noting the passage of a pre-set period (e.g. using a conventional timing mechanism) but conveniently involves counting the passage of the tube-supporting members past a reference point (e.g. located within the loop).
An accurately pre-determined volume of the first fluent material is expelled from the tubing by the peristaltic action of the moving tube-supporting members isolat ing "slugs" of fluent material within the bore of the tubing of each generally chordal "run" and advancing the required number of those "slugs" out of a downstream end of the tubing. This volume can be dispensed into a mixing chamber to be diluted by the second fluent material, fed directly into a reservoir of the second fluent material (e.g. into the flush cistern of a WC system) or metered into a flowing stream of the second fluent material (e.g. into the flush pipe of a urinal basin or set of urinal basins).
Initiation of a pumping cycle can be by a range of different mechanisms such as a float switch (actuated by the second fluent material), a pressure switch, a timing device, a proximity sensor or a photoelectric cell.

Brief Description of the Drawings

Some embodiments of devices in accordance with this invention for dispensing an environment-improving additive to the flush water of a urine receptacle, will now be described, by way of example, with reference to the accompanying drawings, in which

Figure 1 is a schematic sectional view of a prior art dispensing device for use in a flush water system to a urinal or water closet basin,
Figure 2 is an exploded perspective view of the prior art unit of Figure 1,
Figure 3 is an exploded view of the components of a first embodiment of sanitizer unit,
Figures 4, 5 and 6 are views similar to Figure 3 of second, third and fourth embodiments of sanitizer unit,
Figure 7 is an exploded view of the diffusion or mixing chamber used in the devices of Figures 3, 4 and 5,
Figure 8 is an exploded view of one form of pump head for a peristaltic pump as used in the devices of each of Figures 3 to 6,
Figure 9 is a partially broken-away exploded view of a modified form of diffusion chamber, and
Figure 10 is a simplified view of a second embodiment of peristaltic pump.

Description of Preferred Embodiments

Referring to Figure 1, a water closet cistern 10 is linked to an array of urinal basins 11 by a flush pipe 12. The cistern 10 is filled at a constant rate with water from a valve-controlled inlet 13 and, by an automatic syphoning action, periodically empties flushing water through the basins 11. A spur pipe 14 connects the flush pipe 12 to a prior art additive dispensing device 15. The device 15 contains a mixing chamber 16 in which is located an inverted bottle 17 of additive liquid (e.g. a disinfectant and/or perfume and/or dye and/or basin descaling composition) closed by a porous plug 18. A closure valve 19 for the spur pipe 14 is connected to a float 20 within the chamber 16.
The device shown in Figure 1, works as follows:
When the cistern 10 flushes, the hydraulic pressure in the pipe 12 forces water up into the chamber 16 until a level 21 set by the float 20 is reached at which time the valve 19 closes. The water in the chamber 16 becomes mixed with a small volume of additive which has flowed out of the bottle 17 and/or is filling the pores of the plug 18. Thus a dilute solution of additive now fills the chamber 16.
During the final phase of the flush, the hydraulic pressure in the pipe 12 drops and eventually falls to a level at which the valve 19 can open to allow the chamber 16 to empty via the spur pipe 14 discharging the solution of additive into the basins as part of the final flush stream.
Figure 2 shows a practical embodiment of the prior art device 15 shown in Figure 1 and the same reference numerals have been used, here convenient, in the two Figures. The device 15 of Figure 2 also includes a receptacle 25 behind a slotted cover 26 and an air freshener filter (not shown) can be located in the receptacle 25 so that air expelled from the casing 24 (that defines in its lower part, the chamber 16) by the ingress of flush water will have to permeate through the filter and carry a vaporous composition (e.g. a perfume or deodorant) into the ambient air.
Figure 3 shows a first embodiment of device according to this invention in a dismantled condition for ease of understanding.
The device of Figure 3 is intended to be used with a cistern-controlled flushing arrangement of the kind shown in Figure 1 and is thus connected to a flush pipe 12 via a spur pipe 14. The spur pipe 14 is connected to a diffusion chamber 30 which, like the chamber 16, fills with flush water during the initial stage of a flushing operation. A float-operated switch 31 (e.g. a microswitch or a magnetic red switch) senses arrival of water into the chamber 30 and energises a motor 32 to rotate a peristaltic pump 33 and draw liquid additive from a reservoir 34, via an inlet pipe 35, to a flexible pump tube 33a and expel it into the chamber 30 via an outlet pipe 36. Power for the motor 32 is drawn from a battery 37 (e.g. an array of lithium batteries providing a 6 or 12V supply) via a light-sensitive unit 38 which makes the motor insensitive to the microswitch 31 if the device is in an unlit room. The operation of the motor 32 is controlled to dispense a required volume (e.g. 0.125 ml) on each actuation. The device is completed with a back plate 39 and a front cover 40. The front cover is locked to the back plate 39 by a locking mechanism 41 engaging a flap 42 on the back plate. The reservoir 34 can be filled via a retractable tube 43 through the hole 44 in the cover provided for the locking mechanism.
The device of Figure 4 is identical to that of Figure 3 apart from having a larger volume reservoir 34.
The device of Figure 5 does not require an adjacent cistern, control of the flow of flush water to an outlet pipe 45 being by a solenoid valve 46 connected to a water supply pipe passing through a hole 47 in the back plate 39. When water is flowing through the device, the motor 32 is energised from battery 37 to operate the pump 33 the required number of turns to dispense the desired volume of additive from the reservoir 34 into a chamber 50. The chamber 50 shown in Figure 5 differs from that shown at 30 in Figures 3 and 4 in that no float valve is required but still serves to provide a region where mixing of water and additive can occur. The water valve 46 may be triggered by the presence of someone at the adjacent WC basin and this control (and pump timing) can be effected in an electronic unit 51 coupled to a sensor 52 which operates through a hole 53 in the base plate and a cut-out 54 in the cover 40.
Figure 6 is a flush cistern version which has a remote float switch 55 locatable in a cistern (not shown). The outlet pipe 36, can pass to the cistern or its down pipe 12 and a pre-set volume of additive from the reservoir 34 is fed to the flush water each time the float switch 55 is actuated (normally towards the end of a cistern filling operation).
Figure 7 shows the diffusion chamber of the devices of Figures 3 and 4 in greater detail. A frusto-conical valve 56, carried by a tube 57 is raised by a float 58 when water floods into the chamber from the spur pipe 14. The valve 56 engages a seat 59 when the tube 57 is fully lifted, preventing water spilling out of the open top of a float chamber 60. The pipe 36 connects to the top of the tube 57 and the valve 56 is drilled to allow additive to flow down into the chamber 30 when the pump 33 is operating. As an alternative to injecting the additive through the valve 56, the tube 36 can be inserted into a recess 30a shown in the wall of the chamber 30 so that movement of the valve 56 is not impeded by the tube 36.
Figure 8 shows one variant of the pump 33. A pump head 61 comprises a pair of discs 62, 63 rotated by the motor 32 and a gear train 64. Between the discs 62, 63 are three rollers 65 spaced at 120° intervals around the axis of rotation 66 of the discs 62, 63 and at equal distances from the axis 66. The flexible tube 33a (not shown in Figure 8 but shown in Figure 10) is distorted by the pump head 61 as it rotates to peristaltically pump additive from the reservoir. A cam-operated microswitch 67 is used in the Figure 8 embodiment to control pump rotation.
Figure 10 shows a preferred form of pump 33. The discs 62, 63 are replaced by spiders 62a, 63a and the number of rotations of the spiders is counted by an opto switch 68 which counts the passages of the rollers 65 past it. The small insert in Figure 10 shows a "slug" or pocket of liquid 69 trapped in the tube 33a by two adjacent rollers 35, the arrows indicating how these "slugs" progress along the pump tube 33a as the spiders rotate.
Figure 9 shows a modified form of diffusion chamber. A float switch 55 is included in a side chamber 60a of the float chamber 60. The outlet pipe 36 leads into the chamber 60 (located in a wall recess 70). A deflector plate 71 deflects air and water flowing up and down through the valve seat 59. The spur pipe 14 connects into a socket 71 and the impedance to flow from the chamber 60 to the pipe 14 is controlled by an adjustable base cap 72 which can be screwed up into the chamber 30 to effectively reduce te size of a flow opening 73 when the water pressure is increased above a preferred maximum value. The valve 56 can locate in the cap 72 when the float 58 is not lifting it into engagement with the seat 59.
In place of the float switch 55 in Figure 9 a magnet could be located on the float 58 and used to actuate an adjacent reed switch (not shown) in circuit with the motor of the peristaltic pump 33.
The devices illustrated at least in Figures 3 and 4 can include an air-freshening feature of the kind shown in Figure 2. The air for operating this can be taken from the chamber 30.

Claims

1. A dispensing device in which a volume of a first fluent material is dispensed into a greater volume of a second fluent material by means of a motor-driven pump means wherein the pump means is a peristaltic pump.

2. A device as claimed in claim 1, wherein the pump comprises a loop of flexible tubing made to extend substantially chordally between a plurality of tube-supporting members uniformly spaced apart around an centre of rotation within the loop.

3. A device as claimed in claim 1 or claim 2, wherein the peristaltic pump is driven by an electric motor.

4. A device as claimed in claim 2, wherein means is provided to determine the total angular rotation of the tube-supporting members about the centre of rotation within the loop in each dispensing operation.

5. A device as claimed in claim 3, wherein the electric motor is battery powered.

6. A device as claimed in any one preceding claim, wherein means is provided to time the operation of the pump after each actuation.

7. A device as claimed in claim 2, wherein the timing of the operation of the pump after actuation is determined on the basis of counting the passage of the tube-supporting members past a reference point.

8. A device as claimed in any one preceding claim, in which a mixing chamber is provided into which the volume of the first fluent material is dispensed to be diluted by the second fluent material.

9. A device as claimed in any one preceding claim, in which initiation of operation of the pump is by means of one of a float switch actuated by the second fluent material, a pressure switch, a timing device, a proximity sensor and a photoelectric cell.

10. A dispensing device substantially as hereinbefore descried with reference to, and as illustrated in, Figures 3 to 6 or Figures 3 to 6, as modified by Figures 7, 8, 9 or 10, of the accompanying drawings.