GB1574278A

GB1574278A - Additive pumping unit for liquids

Info

Publication number: GB1574278A
Application number: GB18379/78A
Authority: GB
Original assignee: BERELSON R
Current assignee: BERELSON R
Priority date: 1978-05-09
Filing date: 1978-05-09
Publication date: 1980-09-03
Also published as: IT1096485B; SE7806227L; FR2425563A1; NL7805441A; IT7824692A0

Description

(54) ADDITIVE PUMPING UNIT FOR LIQUIDS (71) I, RUDOLPH BERELSON, a British subject, of 'Treelawns', 34 Fallowfield, Stanmore Hill, Stanmore, Middlesex, 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 a pumping unit for dispensing liquid additive, particularly for adding a detergent to water, There are several applications where it is desired to dispense a liquid additive in metered quantities to a main liquid at frequent but not necessarily regular intervals. For example, in the case of dishwashing machines, particularly so-called dump or total loss machines in which all the water is led to waste after the wash cycle, it is desired to add a detergent to each fresh batch of washing water. For relatively inexpensive small commercial dishwashing machines with, say, a two gallow wash tank capacity, it is not viable to install sophisticated metering equipment for automatically injecting the detergent into the washing water. The user must therefore add the detergent by hand, which is a cumbersome and inaccurate procedure to be repeated many times during the day but liable to be forgotten. It would be possible to provide a cheap hand pump but, again, the user must remember to operate the pump and only for as long as it is prescribed to inject the proper amount of detergent. What is more, the required amount of detergent differs according to the type of dishes being washed - a small quantity for, say, glasses as compared with soiled dishes.

The invention aims to provide an inexpensive liquid additive pumping unit permitting automatic dispensing of the liquid additive and, in the preferred form of the invention, also permitting the amount of additive to be varied.

According to the invention, a pumping unit for dispensing liquid additive for a main liquid flowing under pressure comprises a casing, axially expansible and contractible first and second bellows coaxially disposed in said casing, said first bellows having a closed movable end, being sealed at their opposite end to a first wall of said casing and defining an additive chamber in their in exterior, an additive supply passage and an additive delivery passage both in said first wall and both opening into said additive chamber directly, a non-return valve connected to each said passage so that additive is permitted to flow into said additive chamber only from said supply passage upon expansion of said first bellows and be discharged from said additive chamber only through said delivery passage upon contraction of said first bellows, said second bellows having a closed movable end, being sealed at their opposite end to a second wall of said casing and defining in their interior a main liquid chamber which is completely isolated from the interior and exterior of the first bellows, and a main liquid inlet in said second wall opening solely and directly into said isolated main liquid chamber, wherein said first and second bellows are disposed with said closed movable ends in abutment and said first bellows are biassed to an axially expanded condition and are stronger than said second bellows.

By means of the invention the additive is dispensed automatically as soon as there is a flow of main liquid, the pressure of the main liquid flow being instrumental in collapsing the first bellows. Of course the amount of additive dispensed is limited by the capacity of the first bellows and depends on the extent to which the bellows are collapsed by the second bellows. Preferably, this amount is selectively variable by means of an adjustable stop which limits the extent to which the first bellows are expanded in the first place and thus limits the amount of additive entering the first bellows. The entire construction is uncomplicated and cheap and does not involve the use of electricity.

The main liquid inlet leading solely to the isolated main liquid chamber defined by the second bellows is connected to a point at which the main liquid is under pressure flow, say the water supply conduit of a dishwasher downstream of its conventional programmed solenoid control valve or to the output or pressure side of a wash pump provided in a dishwashing machine. Thus, when the control valve for the supply of main liquid is opened or the wash pump is started, a surge of main liquid will enter the second bellows, which expand and cause the first bellows to collapse and discharge their contents of additive. When the control valve is closed again or the wash pump is stopped, the biased first bellows expand to collapse the second bellows and to take in additive in preparation for the next occasion when additive is to be dispsensed.

The bias on the first bellows is preferably achieved by the inherent resilience of the bellows material, the second bellows being of the same but thinner material so that they are weaker. In addition, a compression spring may be contained in the first bellows to assist expansion. Since, in the case of a dishwasher, the second bellows communicate with the main liquid or water downstream of the solenoid valve or on the pressure side of the wash pump, very little resistance is offered to their collapse after the control valve or wash pump is shut off because the main liquid contained in the second bellows will flow to the same destination as does the remainder of main liquid, namely the wash tank.

The invention also extends to a dishwashing machine when fitted with the novel pumping unit.

An example of the invention as applied to a dishwashing machine will now be described with reference to the accompanying diagrammatic drawing in which the single figure is a composite view showing a pumping unit in fragmentary partial cross-section and its relationship to a washing machine and detergent drum.

A dump-type washing machine comprises a tank 1 for washing water 2 which is led to waste when an outlet cock 3 is automatically opened after each wash cycle. Before the dishes are removed after a wash cycle of about 60 sec, hot rinsing water is directed onto them for about 10 sec from jets in a rinse pipe 4 when a solenoid control valve 6 in a supply conduit 7 connected to the pipe 4 is automatically opened, governed by the programme of the machine. The outlet cock 3 is closed before the valve 6 opens so that, after the rinse cycle. the rinsing water collects in the tank 1 and is ready for use to serve as washing water for the next batch of dirty dishes. A so-called wash pump diagrammatically indicated at 8 and having an air bleed hole in the casing normally closed by a screw 9 serves to swill the washing water 2 about and direct it onto the dishes during the wash cycle by circulating the water in the tank under pressure. If the machine is not already provided with a detergent inlet opening, such an opening is provided in the tank 1 so as to connect a delivery conduit such as a pipe or hose 10 leading from an additive pumping unit 11 according to the invention.

The pumping unit 11 is provided to dispense a predetermined quantity of detergent into the wash tank 1 for adding to the water supplied through the conduit 7, the additive reaching the tank either before, during or after the entry of washing water.

The unit comprises an initially two-part pump casing of which a first part 12 consists of a wall 13 at one end of a hollow cylinder 14 which is open at the other end. The end wall 13 contains a supply passage 16 leading from within the cylinder to a tapped socket 17 and a delivery passage 18 leading from within the cylinder to a further tapped socket 19. The second part 21 of the pump casing comprises a wall 22 at one end of a hollow cylinder 23 which is open at the other end. The end wall 22 contains a tapped hole 24 for receiving a water inlet connector 26.

The open ends of the cylinders 14 and 23 are telescoped and eventually interconnected by heat sealing, cementing or in any other secure manner. Before the casing parts are secured together, bellows 27 are heat-sealed or otherwise hermetically sealed by an open flanged end wall 13, the other end of the bellows being closed. The interior of the bellows defines a detergent chamber 28 in direct communication with the passages 16 and 18. Similarly, bellows 29 which are carried with the bellows 27 are hermetically sealed by an open flanged end to the wall 22, the other end of the bellows 29 being closed and abutting the closed end of bellows 27. The interior of the bellows 29 defines a water chamber 31 in communication directly and only with the inlet connector 26. The bellows 27 are made of thicker material than the bellows 29. It will be noted that the chamber 31 is completely isolated from the interior and exterior of the bellows 27.

Prior to the casing parts being intercon necked, both bellows are in the expanded condition but. bv reason of being thicker, the bellows 27 are more biassed to the expanded condition than are the bellows 29.

In other words, the bellows 27 are stronger and, as the casing parts 12 and 21 are telescoped with the bellows in end-to-end contact, the bellows 27 remain expanded and cause the bellows 29 to collapse almost completely. This effect is enhanced by the action of a stainless steel compression spring 35 but the latter is not essential.

A non-return valve housing 32 is in screw-threaded engagement with the tapped socket 17. At the bottom of a recess 30, the housing 32 is formed with a valve seat 33 for a valve ball 34. The recess is closed by an apertured plug 36. The supply passage 16 communicates with the recess 30 through the aperture in the plug 36. Outside the socket 17, the valve housing 32 is formed with an externally screw-threaded nipple 37 for connecting a conduit 38 terminating in a foot valve 39 and immersed in a detergent drum 41. The valve housing 32 contains a bore 42 extending in a detergent drum 41.

The valve housing 32 contains a bore 42 extending from the valve seat 33 to the tip of the nipple.

The tapped socket 19 contains a further non-return valve housing 43 which is of a similar construction to the housing 32 except that in this case a valve seat for a valve ball 44 is formed in a plug 46 closing the recess 47 which communicates with a bore 48. The valve housing 43 is connected to the aforementioned delivery conduit 10.

One end of a water conduit 49 is connected to the inlet connector 26 and, in the illustrated embodiment, the other end is connected to the supply conduit 7 for hot rinsing water, namely downstream of the solenoid control valve 6.

The pumping unit 11 functions automatically as follows. After dishes (not shown) in the tank 1 have undergone a 60 sec washing cycle and the washing water 2 has been led to waste, the dishwashing programme provides for closure of the outlet cock 3 and a hot rinse cycle of about 10 sec by actuating the solenoid valve 6 to allow rinsing water to flow under pressure to the rinse pipe 4. A surge of water is also caused to flow through the conduit 49 and enter the isolated water chamber 31 directly to expand the bellows 29. The latter therefore collapse the bellows 27 and eject detergent from the chamber 28, through the delivery passage 18, past the associated non-return valve and through the delivery conduit 10 into the tank 1. All this occurs very rapidly and certainly before the rinse cycle of the machine has finished.

Upon subsequent closure of the solenoid valve 6. the water pressure in the expanded chamber 31 drops to atmospheric pressure and the bias on the collapsed bellows 27 causes them to expand again, thereby collapsing the bellows 29 and expelling water from the chamber 31 through the conduit 49 and pipe 4 into the tank 1. The rinsing water 2 collected in the tank now contains an amount of detergent additive adequate for the next wash cycle which is initiated after the clean dishes have been removed and a batch of dirty dishes has been loaded.

Whilst detergent was being shot into the tank 1 by way of the delivery passage 18, the valve ball 34 remained pressed onto its seat 33. However, during expansion of the bellows 27, the ball 34 was lifted by a supply of detergent sucked from the drum 41 to enter the chamber 28 through the supply passage 16. The pumping unit 11 is therefore now ready to dispense a further amount of detergent to the tank 1 whenever the solenoid valve 6 is opened again. The actual quantity of detergent dispensed on collapse of the bellows 27 depends on the volume of the detergent chamber 28, which can be designed to hold, say, 50 cc of detergent for a wash tank capacity of 2 gallons, i.e. to provide a detergent concentration of 0.5% in the washing water. However, it is undesirable to have to make and stock various sizes of pumping units for a variety of wash tank capacities and it is also preferable to permit the user to adjust the amount of dispensed detergent to suit the kind of dishes being washed and the hardness of the water supply. Further, one and the same design of pumping unit 11 should preferably be suitable for use other than with dishwashing machines. The invention therefore makes provision for the following very simple manner of adjustment.

In a trough 51 defined between two peaks of the corrugations in the bellows 27, preferably in the trough nearest the closed free end of the bellows, the said bellows 27 support a ring 52 having a cylindrical guide flange 53 which can slide along the inner surface of the casing part 21. A stop member 54 is forcibly displaceable in an axial slot 56 provided in the cylinder 23.

Preferably, the stop member 54 clicks into a selected one of a plurality of lateral detents 57 of the slot. It is also preferred to provide a further such stop member 58 displaceable in an axial slot 59 disposed diametrally opposite the slot 56.

In the drawing, the stop members 54 and 58 are positioned to permit substantially full expansion of the bellows 27. If the stop members were to be disposed near the end wall 13, it will be evident that they would prevent the bellows 27 from expanding fully because the ring 52 would abut against them. Accordingly, with such a setting of the stop members, less detergent is sucked into the chamber 28 and therefore less is dispensed into the tank 1 on subsequent comression of the bellows 27 under the action of the bellows 29. A graduated scale (not shown) may be marked on the cylinder 23 adjacent each slot 56, 59.

To avoid the need for plumbing the conduit 49 into the supply 7, it is possible to connect it instead to the casing of the wash pump 8 after removing the screw 9 from the air bleed hole. The operation of the pumping unit 11 is in that case the same as previously described, except that a shot of detergent is added whenever the wash pump is started.

The pump casing, both valve housings and the two bellows are desirably of plastics material, the casing parts preferably being moulded.

As already mentioned, the pumping unit of the invention is useful for other applications. For example, the unit may be used for dishwashers which are not dump machines but only discharge a fraction of the washing water after each washing cycle. In that case the pumping unit should be set to dispense a small amount of detergent required to maintain the concentration after the tank has been topped up. Further, in many small commercial establishments, dishes are still washed in sinks where it is nowadays usual to install a so-called tap dispenser, which is an attachment for the tap having a hose connection to the detergent drum so that detergent is mixed with the water during the time the water is flowing. The use of tap dispensers is discouraged and even prohibited in some countries because of the danger of water pollution if, under unusual conditions in the water mains, detergent happens to be sucked into the mains. The pumping unit according to the present invention is ideal for sinks because the conduit 49 can readily be attached downstream of the tap without impeding the flow of water, whilst the conduit 10 can simply be immersed in the sink. There is no possiblity of contamination because the detergent and water circuits are entirely separate both within and outside the pumping unit. Should the tap be required for fresh water, a simple manually operated slide valve 61 or the like incorporated in the water conduit 49 may be moved to the off position and the pumping unit will then remain inoperative without the need for disconnecting it from the tap.

To facilitate mounting of the pumping unit at any desired location, e.g. on the dishwashing machine or a wall, the casing part 12 is preferably provided with a pressure-sensitive adhesive pad 62.

WHAT I CLAIM IS: 1. A pumping unit for dispensing liquid additive for a main liquid flowing under pressure, comprising a casing, axially expansible and contractible first and second bellows coaxially disposed in said casing, said first bellows having a closed movable end, being sealed at their opposite end to a first wall of said casing and defining an additive chamber in their interior, an additive supply passage and an additive delivery passage both in said first wall and both opening into said additive chamber directly, a non-return valve connected to each said passage so that additive is permitted to flow into said additive chamber only from said supply passage upon expansion of said first bellows and be discharged from said additive chamber only through said delivery passage upon contraction of said first bellows, and second bellows having a closed movable end, being sealed at their opposite end to a second wall of said casing and defining in their interior a main liquid chamber which is completely isolated from the interior and exterior of the first bellows, and a main liquid inlet in said second wall opening solely and directly into said isolated main liquid chamber, wherein said first and second bellows are disposed with said closed movable ends in abutment and said first bellows are biassed to an axially expanded condition and are stronger than said second bellows.

2. A pumping unit according to claim 1, wherein the extent to which said first bellows are axially expansible is limited by an adjustable stop.

3. A pumping unit according to claim 1 or claim 2, wherein the bias on said first bellows is obtained by the inherent resilience of the bellows material, the second bellows being of the same but thinner material so that they are weaker.

4. A pumping unit according to any preceding claim, wherein said first bellows contain a compression spring biassing them to the expanded condition.

5. A dishwashing machine comprising a solenoid control valve for a supply of rinsing water and a pumping unit according to any preceding claim for dispensing liquid detergent additive and having the main liquid inlet connected to the rinsing water supply downstream of the solenoid valve.

6. A dishwashing machine comprising a wash pump for water and a pumping unit according to any one of claims 1 to 4 for dispensing liquid detergent additive and having the main liquid inlet connected to the pressure side of the wash pump.

7. A pumping unit substantially as hereinbefore described with reference to the accompanying drawing.

8. A dishwashing machine substantially as hereinbefore described with reference to the accompanying drawing.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. connect it instead to the casing of the wash pump 8 after removing the screw 9 from the air bleed hole. The operation of the pumping unit 11 is in that case the same as previously described, except that a shot of detergent is added whenever the wash pump is started. The pump casing, both valve housings and the two bellows are desirably of plastics material, the casing parts preferably being moulded. As already mentioned, the pumping unit of the invention is useful for other applications. For example, the unit may be used for dishwashers which are not dump machines but only discharge a fraction of the washing water after each washing cycle. In that case the pumping unit should be set to dispense a small amount of detergent required to maintain the concentration after the tank has been topped up. Further, in many small commercial establishments, dishes are still washed in sinks where it is nowadays usual to install a so-called tap dispenser, which is an attachment for the tap having a hose connection to the detergent drum so that detergent is mixed with the water during the time the water is flowing. The use of tap dispensers is discouraged and even prohibited in some countries because of the danger of water pollution if, under unusual conditions in the water mains, detergent happens to be sucked into the mains. The pumping unit according to the present invention is ideal for sinks because the conduit 49 can readily be attached downstream of the tap without impeding the flow of water, whilst the conduit 10 can simply be immersed in the sink. There is no possiblity of contamination because the detergent and water circuits are entirely separate both within and outside the pumping unit. Should the tap be required for fresh water, a simple manually operated slide valve 61 or the like incorporated in the water conduit 49 may be moved to the off position and the pumping unit will then remain inoperative without the need for disconnecting it from the tap. To facilitate mounting of the pumping unit at any desired location, e.g. on the dishwashing machine or a wall, the casing part 12 is preferably provided with a pressure-sensitive adhesive pad 62. WHAT I CLAIM IS:

1. A pumping unit for dispensing liquid additive for a main liquid flowing under pressure, comprising a casing, axially expansible and contractible first and second bellows coaxially disposed in said casing, said first bellows having a closed movable end, being sealed at their opposite end to a first wall of said casing and defining an additive chamber in their interior, an additive supply passage and an additive delivery passage both in said first wall and both opening into said additive chamber directly, a non-return valve connected to each said passage so that additive is permitted to flow into said additive chamber only from said supply passage upon expansion of said first bellows and be discharged from said additive chamber only through said delivery passage upon contraction of said first bellows, and second bellows having a closed movable end, being sealed at their opposite end to a second wall of said casing and defining in their interior a main liquid chamber which is completely isolated from the interior and exterior of the first bellows, and a main liquid inlet in said second wall opening solely and directly into said isolated main liquid chamber, wherein said first and second bellows are disposed with said closed movable ends in abutment and said first bellows are biassed to an axially expanded condition and are stronger than said second bellows.