CA1138255A - Additive pumping unit - Google Patents

Abstract

ABSTRACT

A pumping unit primarily for dispensing liquid detergent into the tank of a dishwashing machine comprises a bellows pump of which the bellows define a detergent-receiving chamber communicating with a detergent supply passage and a detergent delivery passage. Each said passage is associated with a non-return value. The bellows are biased to an expanded condition and draw detergent into the additive-receiving chamber on the expansion stroke. Upon collapse of the bellows by means of pressure-responsive and weaker second bellows, detergent is ejected through said delivery passage. The second bellows are in communication with a source of main liquid flow under pressure.

Description

` 1~3825~

The inY~ntion rolates to a pumping unlt for dispensing a 11quid additiYe, pa~ticularly for adding a detergant to wator.
There are several appllcatlonu whore it 1~ deslred to di~pen~e a llquid additive in metsrPd quantitie~ to a mc~in liquid at frequent but not neoe6sarily re~ular inter~als. ~br ex~nple, in the caae of diahwc~ing me~hln2u, varticularly so-called dump or total 10B8 s~c~nee ln uhich all the water is led to wa3te after the wa~h cyole, it is desirod to add ~ doterB~nt to each fra~h batch of wa~hing water.
~br relatlYely inespensive small commercial dishwaahin~ machines with, say, a two gallon wash tan~ capAoity, it i~ not viable to install ~ophistic~ted metering equipment for automatically injecting~he deter-gent lnto the washing water. The user ~u~t therefvre add th~ deterg~t b~ har^d, which i~ a cumber~o~ ~nd li~aco~rate procedure to be repe~tad mflny times durlng tho day but liable to be forgotten. It would be possible to provlde a cheap hand pump but, again, the user _UBt remember to operate the pump and only for ag long as i~ prescribed to ln~eot the proper s~ount of detergent. What i8 more, the required amount of dete~-gent differ~ according to the type of dishes being wa~hcd - a sm~ll quantity fo~ ~ay, glasses as compared with soiled dishes.
ffl 8 lnYention aims to proYide an ~ne~pe~slYe liquid additiYe pumplng unit permittin~ automatlc disp~nsing of the liquid additive and, in the preferred form of the in~-eution, al~o permitting the a~ount of add~tive to be varied.
~ccording to the invention, a pumping unit for di~pe~ing liquid additi~e to a maln liquid under pres~ure comprises a bellows pump of which the ~sll~ws define ~n additi~e-recelYing chamber, And non-retur~
valYe~ oonnected ao that, during collap~e of the bellows, ad~itive w1thiu 11;~82S~
the bellowa i~ aischarged through a delivery pass3ge of the unit connectiblo to Q point where the additive is to be di~pensed and, durin~
oxpr~nsion of the bellows, r~dditive enters the bellows throu~h a ~upply passa~e of the unit con~ectlble to a source of additiv~, wherein the bellows are biassed to the expanded condition and are collapsible by a servo device which is co~tectible to the main liquid ~td which i~
responsivs to the pressure of mR1n liquid flow to operate the bellows.
By means of the invention, therefore, the additive ia dispsn~ed automatically a~ soon a8 ther0 io rb flow of main liquid, the pres~ure of the main liquid flow belng ~tstrumental in collapsing the bellow3. Of course the amount of additive dispensed is limited by the capa~ity of the bello~rs and depends on the estent to which the bellows are collapsed by the ser~o device. Preferably, this amou~tt ls selectively variable by mer~ns of an rdjustable stop ~rhich llmits the ertent to which the bellows are expanded in the flr~t place rmd thus limits the amount of r~dditive ontering the bellowa from the additiva source.
For the purpose of providing a really u~complicated and cheap conutruction which doe~ not involve the use of electricity, the pres~ure re~ponsive servo device is preferably formed by second bellows which are weaker than the biassed additive-receiYing fir~t ballows and are placed end-to-end therewith so that, when the fir~t bellows are substantially fully expanded, the seoond bellowa are substantially completely colla~ed.
~he interior of the second bellows is co~nected to a point at which the maln llquid iB under pressure flow, sa~ the water supply conduit of the dishwasher downstre~m of its conventional progra~med solEnoid control v~lve or to tho output or pressure side of a wash pump provided in the m~chine. Thu8~ when the control valvc for the supply of maln liquld i8 ~3~

opened or ~he waRh pump is started, a ~urge of ma~n liquid will enter tha second bellows, whlch exp~d and c~u8e the fir~t bellows to collapae nnd dischar~a their contents of additive. When the control valve is closed ~aln or the wa~h ~ ~p is stopped, the bias~cd first bellows expand to collap3e the a~cona bellows and to taXe in additive in prepara_ tion for the next occaaion when additive i8 to bs dispensed.
The bias on the first bellows is preferably achiev~d by the inherent resilience of the bellows material, the second bellow3 being of the same but thinner material 80 that they are weaker. In sddition, a compression spring may be contalned in ~he first bellows to assist expansion. Since the second bellows communicate with the main liquid downatream of the solenoid ~alve or on the pres~ure side of the waah pump, very little reslstance is offersd to their collapse after the oontxol Yulve or wash pump iB ahut off because the mcin liquld oontained in thc second bellows will flow to the same deatination ~ does the rem~lnder of main liquid, namely the wash tank in the case of a dishwa~her.
In the prefexred construction, the inYention pro~ides a li~uid detexgent pumping unit for a aishwashing machine comprising a~ially expansible and collapsible first bellows closed at one end, which is mo~able, and sealed at the other end to a stationary firat.wall contain-~ng a suoply passaga and a delivery passa4e for a liquid washin~
detergent, sA~d first bellows defining an interior detergant ch&mber in oommunicatlon with said passages, a non-return valve connected to each said passage 80 that deterBent is permitted to flow into said detergent chamber only from ~aid suoply pa~sage and dischargod from said detergent chambær only through sald deliYery passaga, and sxially e~p~l~ible and collapsible ~econd bellow~ closed at one end~ which i~ ~o~able, and sealed at the other end to a ststionary second wall contain~ng a watar inlet, said 1~13~ZS~

~econd bellows de~inln~ a~ interior water chamber in communication with ~ald inlet, wherein said first and second bellows are disposed wit.h thelr cloaed enda in abutment a~d said firat bellow~ are biaa~ed to an ~xially e~.panded conditlon and aJOstronger than said aecond bellows.
The invention alao extends to a dishwashing machine when fitt*d ~ith the novel pumpin~ unit.
An example of the inv~ntion aa applied to a di3hwashing machine will now be deacri~ed wlth reference to ~e accompanying diagrzmmatio drawin6 in which the singl~ ~igure i8 a compoaite ~i3W ahowing a pumping unit i~ fraementary partial cross-aection and it3 relat~onahip to a washlng machine and detergent drum.
A du~p-type washing machine COmpriEes a tank 1 for ~ashlng ~ater 2 which is led to waste when an outlet cock 3 ia automatically o~ened a~tor eAch wa~h cyole. ~efore the dishea are xemo~ed after a wash oyole Or about 60 se¢, hot rinaing water is direoted onto the~ for about 10 aec from ~ets in a r~nae pipe 4 when a aolRnoia control ~alve 6 ~n a euppl~ conduit 7 connected to the pipe 4 ia automatically opened, governed by the programme of the ~achine. ~he outlet cec~ 3 ia cloaed before the valve 6 opena 80 ~hat, after the rinse cycle, the rin~ing watcr collects in the tank 1 and iB ready for u3e to ~erve a~ wash1n~
water for the noxt batch of dirty dishes. B uo called wash pump diaBrammatic ~ly indicated at 8 and haYing ~1 alr bleed hole in tho cas1ng normally closed by a screw 9 ser~e~ to swill the wa~hing water 2 about and direct it onto the dishe~ *~ring the waah cycle by circulating the water in t~e tank under pressure. If the machine i8 not already provided with a deter~ent inlet openlng, auch an opening ~3 provided in the t~ik 1 ~o as to connect a del1very conduit BUCh as a pipe or ho3e 10 leading - ~38~S~

from an additive pumping unit 11 according to the inventiol~.
~he pumplng unit 11 is providsd to di~pen~e a predetermined quantlty of detorgPnt lnto the wash tan~ 1 for add~ g to the water supplled throu~h the conduit 7, the additive reaohing the tank either before, during or after the entry of wa6hing water. ~he unit comprisee an Lnltially two-part pump casing of which a first part 12 consists of a w~ll 13 at one end of a hollow cylinder 14 which is open at the other er.d.
The end wall 13 contains a supply passage 16 lea~in~ from ~rithin ~he cylinder to a tapped ~ooket 17 and a dalivery passage 18 leadlng fro~
- 10 within the c71inder to a ~urther tapped sock0t 19. The second part 21 Or ths pump oasing compri~es a wall 22 at one end of a hollow cylinder 23 which i8 open at the other end. me end wall 22 contains a tapped hole 24 for receiving a wat0r inlet connector 26. The open endR of the cyli~der~
14 and 23 are telescoped and e~e~tually interconnected by heat sealln~, cementln~ ox in any other ~ecure manner. ~efore tha casin~ part~ are se¢ured to~ether, bellow~ 27 are heat sealed or otherwi~e hermetically sealed by rm open flanged end to the wall 13, the other end of the bollow~
bein~ closed. The interior of the bellows define~ a detergent chamber 28 in communication with the passages 16 and le. Similarly, bellows 29 are hermetically sealed by a~ open flan~ed end to the wall 22, the other end of the bellowa 29 being closed. The interior of the bellows 29 defines a water ch~mb~r ~1 ln communication with the inlct connector 26. The bellows 27 and 29 are of substantiall~ the same length and diameter but tho bellows 27 are made of thicker material than thc bellows 290 Prlor to the ca~ng parts belng lrterconnected, both bellows are i~ the exp~nded condition but, by reason of bein~ thicker, the bellow~
27 are more b~a~ed to the expanded condition th n are thc bellows 29. In ~.~3~

other wordE, tho bellows 27 are strong~r ~nd, aa the caain~ parts 12 ~nd 21 are teleacoped with the bellows in end-to-end contact, the bellows 27 remain exp3nded and cause the bellow~ 29 to collapse almost completaly.
~hls effect is enhanced by the action of a stainl~D steel compres~lon ~prin~ 35 but the latter is not essential.
~ non-return valve houslng 32 is in screu-thre~ded enga8~ment wlth the tapped socket 17. At the bottom of a reces3 30, the housir4~ 32 i~ formed wlth a valve seat 33 fo7 a valve ball 34. The recess is closed by an apertur~d plu~ 36. ~he aupply passa6e 16 com~unlca+es with the recess 30 through the aperture in the plug 36. Outside the 80c~et 17, the valve housing 32 i8 formed with an extornally screw-threaded nipple 37 for connecting a conduit 38 terminating in a foot val~e 39 and immersed in a detergent drum 41. ~he valve hou~ing 32 contains a bore 42 extending from the valve ~eat 33 to the tip Or thc nipple.
The tapped socket 19 contalnc a further non-retur~ valve housing 43 which 1B of a ~imilar con~truction to the housing 32 e~cept that in thi8 ca~e a valve seat for a ~alve ball 44 is for~ed in a plug 46 closing the reces~ 47 which communicates with a ~ore 48. lhe val~e housing a3 is connected to the aforementioned delivery conduit 10.
One ~nd of a water conduit 49 i8 connected to the inlet conneotor 26 and, in the illu~trated e~bodiment, the other end is connectea to the ~upply cond~i~ 7 for hot rinsing water, namely downst~eam of the solenoid control ~alYe ~.
1he pump~ng unlt 11 ~not on3 awtomat,ically a~, follow6. After dl~hes (not ~hown) in the tank 1 hA-~e u~dereGne a 60 ~oo wr3hing cycle and the w~shing water 2 has been led to waste, the dlshwa~hing programme prov1des ~or olosure of the outlet coc~ 3 and a hot rin~e cycle of about 10 seo by actuating the solenoid val~e 6 to allow rln.sir.~ water to flow ~ 7 -under pressura to the rinse pipo 4. A sux~e of water is also c~used to flow through the conduit 49 and enter the watex chambex 31 to expand the bellows 29. The latter therefore collapse the bollows 27 and eject ~etorB~nt from the chamber 28, throu~h the delivery passage 18, past tho assoclatea non-return valve and throu~h the delivery condu~t 10 into the tank 1. All this occurR very rapidly and certainl,y before the rinse c~ycle of th~ ~achlne has finished. ~pou sub6equent closure of the solenoia valve 6, the water pre3sure $n the e~panded chamber 31 drops to at~ospher$c pressure and the bias on the collapsed bellows 27 causes them to expand &~ain, thereby collapsi~g the bellows 29 and expelling water from the chamber 31 throu~h the conduit 49 and pipe 4 into the tank 1.
The rinsing water 2 collected in the tank now contains an ~mount of detsrgent additi~e adaquate for the next wash cycle which is initiated after the clean dishes have been rémoved and a batch of' dirty dishe~ has been loaded.
~ lst d~tergent was beinB shot into the tan~ 1 by way of tho delivery passage 18, the ~al~e ball 34 remained pres~ed onto lt8 seat 33.
~owa~er~ dur$ng expansion of the bellows 27, the ball 34 was lifted by a supply of detereent sucked from the drum 41 to enter the cham~er 28 through the supply passage 16. The pumplng unit 11 i~ therefore now ready to dispenRe a further amount of detergent to the tank 1 whenever the solenoid Y~lYe 6 ~3 opened again. ~he actual quantity of deter~ent dispensed on collapse of the bellows 27 depends on the volume of the detorBent cl~mber 28, which can be designed to hold, Bay~ 50 cc of detergent for a wa~h tank capaclty of 2 gallons, i.e. to provide a deter-gent concentration of 0.5 % ln the wa~hine water. ~owever, it i2 unde~irable to have to make and stoc~ v~rlou~ BiZ~2 of pumping un1ts for a variet~ of - - ~13~

wash tank capacities and it is also pr~ferable to penmit the user to ad~ust the a~ount of dispensad deterg~nt to suit the kind of dishes be~g washed and the hardne~ of the water supply. ~urther, one and the same de~i~n of pumping unit 11 should preferably be suitable for use other than with dlshwashing machines. 'rhe invention therefor~ mak~s provision for the following very simple manner of ad~ustment.
In a trough 51 defined between two peaks of the corru~ations in the bellow~ 27, preferably in the trough nearsst the closed free snd of the bellows, the said bellows 27 support a ring 52 ha~ing a cylindrical guidQ flange 53 which ca~ ~lide along the inner surface of the casi~g part 21. A stop member 54 i8 forcibly displaceable in an axlal slot 56 pro~ided in the cylinder 23. Preferably, the stop member 54 clicks into a aelected one of a plurallty of lateral detents 57 of the slot. It is also preferred to provide a further su¢h stop member 58 displaceable in an axial 310t 59 di~posed diametrally opposite the slot 56.
In the dra~ing, the stop members 54 and 5a are positioned to per~it substantially full e~pansion of the bellows 27. If the stop members were to be disposed near the and wall 13, it will be ~vident that they would prevent the bellows 27 from e~panding fully because the ring 52 would abut against them. ~ccordingly, with such a settins of the stop m~mbers, less detergent is s~cked into the chamber 28 and therefore les~
le dispensed into the ta~k 1 on subsequent compre~sion of the bellows 27 under the ~ction of the bellows 29. ~ graduated scale (not shown) may be m~rked on the cylinder 23 ad~acent ear~h slot 56, 59.
To avoid the need for plumbing the condlit 49 into the supply 7, it i~ possible to con~ect it instead to the ca~ing of the wa~h pump 8 after removing the screw 9 from the air bleed hole. The operation of the _ g _ ~ll31~

pumping ur.it 11 is in that case the same as previously doscribed, except that a shot of detergent i9 added whenever the wash pump i~ started.
The pump casing, both valve housings and the two bellows ara desirably of pla~tic3 material, the casin~ partu preferably being moulded.
AE already mentioned, the pumpin~ unit of the invention i8 useIul fox other applications. ~br example, the ~nit may be used for dishwa3hers which are not dump machines but only discharge a fract~on of the washing water after each wa~hin~ oycle. In that case the pumpinæ u~it should ba set to aispense a small amount of detergellt required to maintain the conosntration after the tank has been topped up. ~urther, in many sm~ll com~ercial establishment~, dishes are still washed in sinks where it i8 nowadays usual to install a so-called tap disp~nser~ which iB an attachment for the tap having a hose connection to the detergent drum 80 that detergent is mixed with the water during the time the water iB flowin~.
The use of tap di~pensers iB di~couraged ~nd even prohibited in some countries bec~use of the dan~er of water pollution if, ~nder unusu21 ¢ondition3 in the water mains, detergent happens to be sucked ~nto the malns. lhe pumpin~ unit a¢cording to the present invention iB iaeal for 8in~9 becau3e the conduit 49 can rea~ily be attached downstream of the t~p without impeding the flow of water, whilst the conduit 10 can simply be lmmersed in the sink. mere is no possibility of contamination beoause the detereent and water clrcult~ are entirely separata both ~ithin and outside the pumpin~ unit. Should the tap be required for fresh ~ater, a simpls manu~lly opexated slide valve 61 or the like incorporated in the water conduit 49 ma~ be moved to the off position and the pumping unit will then remain inoperative without the need for di~connacting lt from the tap.
Io f~cilitate mounting of the ~umping unit at ~ny desired location, ~.g. o~ the di~hwashi~g machina or a wall, the casing part 12 18 preferably provided with a pre~sure-6ensiti~e adhesive pad ~2.
~lthough the unit acoording to the lnvention i~ desi~ned for automati.c operatio~, it ~111 also be appxeciated that, by sim~l~ omlt~i~
the oaai~g part 21, the manufacturer can without fur~her modificat1on supply the unit a~ a hand pump where thi~ might be preferred5 the deter~
gent then being di~penaed by exerting manual prassure o~ the c'o~ed end of the bellows 27.

Claims (4)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pumping unit including a casing comprising first and second casing parts only, each said casing part defining an oppositely arranged end portion of the casing, first and second bellows arranged within the casing, each said bellows having a respective open end and a respective closed end, the open end of the first bellows being hermetically sealed to said end portion of the first casing part to define a first chamber and the open end of the second bellows being hermetically sealed to said end portion of the second casing part to define a second chamber, a fluid supply passage and a fluid delivery passage, each passage being separately connected via the end portion of the first casing part to the first chamber, and a connector in the end portion of the second casing part for conducting fluid into and out of the second chamber, wherein, prior to the assem-bly together of the casing parts to form the casing, each of the bellows is in the expanded condition, the first and second casing parts being so dimensioned lengthwise and the relative strengths and lengthwise dimensions of the bellows being such that, upon the assembly of the casing parts to form the casing, the respective closed ends of the first and second bellows are brought into direct contact without being connected together and the first bellows remain expanded and cause the second bellows to collapse almost completely.

2. A pumping unit as defined in claim 1 having telesco-pically engaged first and second casing parts, a portion of the first casing part extending within the second casing part and a shoulder on the first casing part being engaged by the second casinq part when the casing is formed.

3. A pumping unit as defined in claim 1 and further including a ring extending around the first bellows in a trough of the first bellows, means defining a lengthwise slot in the second casing part, and a stop member arranged in said slot for engagement by said ring upon a selected extension of the first bellows.

4. A pumping unit as defined in claim 1 and further including a compression spring arranged within the first bellows to expand the first bellows.