CA1116760A - Aerating liquid stored in a machine tool system settling tank - Google Patents
Aerating liquid stored in a machine tool system settling tankInfo
- Publication number
- CA1116760A CA1116760A CA000295889A CA295889A CA1116760A CA 1116760 A CA1116760 A CA 1116760A CA 000295889 A CA000295889 A CA 000295889A CA 295889 A CA295889 A CA 295889A CA 1116760 A CA1116760 A CA 1116760A
- Authority
- CA
- Canada
- Prior art keywords
- liquid
- tank
- region
- spray
- fresh air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
- B23Q11/10—Arrangements for cooling or lubricating tools or work
- B23Q11/1069—Filtration systems specially adapted for cutting liquids
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Nozzles (AREA)
- Separation Of Particles Using Liquids (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Auxiliary Devices For Machine Tools (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A continuous stream of liquid is drawn from a machine tool system settling tank whilst the system is shut down, aerated outside the tank and returned to the tank. The aerator extends upwards from the liquid in the tank and comprises a series of down-wardly sloping surfaces below a pyramid-shaped deflector which is coaxial with and below the inlet of the aerator. The upper end portion of each downwardly sloping surface extends below a space formed at the lower end of the surface immediately above. A fresh air inlet communicates with each such space. The bottom downwardly sloping surface extends below the level of liquid in the tank. The stream of liquid is directed onto the apex of the deflector by which it is converted into a spray which falls onto and cascades down the downwardly sloping surfaces inter-mingling with fresh air as it passes through the spaces so that the liquid is aerated. The aerated liquid is returned to the tank gently by the bottom downwardly sloping surface.
A continuous stream of liquid is drawn from a machine tool system settling tank whilst the system is shut down, aerated outside the tank and returned to the tank. The aerator extends upwards from the liquid in the tank and comprises a series of down-wardly sloping surfaces below a pyramid-shaped deflector which is coaxial with and below the inlet of the aerator. The upper end portion of each downwardly sloping surface extends below a space formed at the lower end of the surface immediately above. A fresh air inlet communicates with each such space. The bottom downwardly sloping surface extends below the level of liquid in the tank. The stream of liquid is directed onto the apex of the deflector by which it is converted into a spray which falls onto and cascades down the downwardly sloping surfaces inter-mingling with fresh air as it passes through the spaces so that the liquid is aerated. The aerated liquid is returned to the tank gently by the bottom downwardly sloping surface.
Description
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~ his i~ventioD relates to a method of, aDd apparatus for aerating liquid stored in a settlin~ tank of a machiDe tool system iD order to iDhibit the growth o~ anaero~ic bacteria in that liquid, the settling tank comprising a source from which such liquid is dr~wD for use as ~
coolant and/or a lubricant iD a machiniDg operatioD at one or more machini~g stations of the s~stem when the system is operatiDg and to which liquid so used is returned after such useO
lo ~iquid stored in a machiDe tool system settling tank can be aexated by injecting compressed air into the liquid within the tan~ and allowing that compressed air to bubble through the liquid, but the amount of compressed air that is required is such that such a techDique for aeratiDg that liquid is costl~. ~n ob~ect o~ this iDveDt-ioD i8 to pro~ide a method of aDd apparatus for aeratiDg liquid contained within a ~ac~ine tool s~stem settliDg tank which does Dot require such a~ eYpensive suppl~ o~ air.
~ccording to o~e aspect Or this inveDtioD we provide a method of aeratin~ liquid stored in a settliDg taDk of a machiDe tool system ~omprisiDg drawing off li~uid from tbe tank whilst tbe machine tool s~stem is shut dowD, aerating the drawn off li~uid outside the mass of liquid stored iD the tank and returDiDg the aerated liquid to the mass of liguid s~ored in the tank.
~ iquid ma~ be drawD coDtiDuously from the settliDg tank as a str2am, 6'76~
aerated outside the mass of liquid stored iD the tan~ and returDed to the mass of liquid stored iD the ta~k continu-ously whenever the s~stem is shut down. Such a CoDtiDuous stream of li~uid drawn from the settliDg ta~ pre~erabl~
is converted into a spray iD a region into which fresh air flows so that tbe ~resh air and spray intermiDgle i~
that region to aerate the liquid. Preferably the stream of liquid is converted into a spray by being directed to-wards the apèY of coaxial tapered deflectiDg meaDs, the lo stream striking the tapered deflectiDg means and being deflected thereby to form a substaDtially circumfereDtially contiDuous radially directed flow. ProvisioD o~ substaD-tially circumferentially conti~uous outwardly directed flaDge meaDS OD the tapered deflecti~g means, spaced ~rom tbe ape~, whicb coact with the de~le~cted li~uid, enhances conversion of the liguid stream into a radiall~ directed spra~. CoDvenieDtly the spray is allowed to fall onto a slopiDg sur~ace down whi~h it cascades to a secoDd regioD iDto which fresh air flows, the cascading liquid preferably being atomised further as it enters the secoDd resioD so that the ~resh air and li~uid dropl~ts i~termingle in the second re~ion to further aerate t~e liquid. ~he sloping surface may be the first of a series of such sloping surfaces, each of the second and any ~67~
subsequent sloping surface of the series extending below the region to which the immediately preceding sloping surface of the series slopes downwardly, so that the spray that falls onto said first sloping surface cascades down that surface to the respective region, is atomised further as it enters that region so that the fresh air and liquid droplets intermingle in that region to further aerate the liquid as it falls through that region onto the second sloping surface of the series down which it cascades to the respective region and so on until the liquid falls onto the lowermost sloping~
surface of the series from which it is returned to the tank, each such surface being arranged so that liquid received on it cascades down it to the next region where it is atomised and aerated further. Part of the stream of liquid drawn from the settling tank may be bled from the main stream of liquid that is aerated outside the mass of liquid stored in the tank, the bled liquid being injected back into liquid contained within the settling tank in order to generate movement of the liquid that is contained within the settling tank. Fresh air flow into the or each region conveniently is induced by the passage of liquid or liquid spray to and through that region.
According to another aspect of this invention ~ 7~ ~
there is provided apparatus for use with a machine tool s~stem ha~ing a settling tank through which liquid coolant/
lubricant is recirculated during normal operatioD, the apparatus being e~fective to aerate the liquid stored iD
said SettliDg taDk aDd comprising control mea~s which are adapted to,sense the operational state of the machine tool ~ystem, liquid flow iDducing meaDs which are adapted to draw li~uid from the ta~k, the control meaDs beiDg operatively associ at~d with the liquid flow induciDg means such as to actuate the liquid flow iDduciDg means to draw liquid from the tan~ wheD the~ ~ense that the machine tool system is shut down, aerating meaDs disposed ou~side the mass o~ liquid sto~ed in the taDk a~d connected i~ a liquid recirculatioD path with the tank and the liQUid flow inducing means, the aeratiDg means being for aerating liquid drawn from the tank b~ ~aid liquid flow iDduciDg means and thereafter returniDg aerat,ed liquid to the tank.
Preferably said coDtrol means and said liquid f~ow inducing means are arranged suc~ that the liquid flow induciDg means are activiated continuously whilst the mach-iDe tool s~stem is shut dowD so that a stream of liquid is drawD continuously from the tank, aerated outside tke mas~
o~ liquid stored iD the taDk and retulned to the mass of liquid stored in the tan~ coDtiDuousl~ whilst the sy~tem is shut dowD~ ~he aerating means ma~ include a region iDto which fresh air ~lows and means for converting liquid draw~
from the'taD~ by said liquid ~low inducing means into a spray iD that region so that fresh air and the spra~ iDter-mingle in that region to aerate the liquid and may be arra-nge such that flow o~ ~resh air into .
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the region is ind~ced b~ liquid flow through the aeratlDg mea-Ds .
~ he aerati~g meaDs may comprise a hollow casing, aD iDlet duct, a deflector which has a tapered surface and which is supported within th~ hollow casiDg so that its tapered surface tapers towards the iDlet duct with wbich it is substaDtially coasial and so that its radially outermost perlphery is spaced from the adjace~t wall of the casing, aDd ap~rture means iD the easing wall through whicb fresh air from outside the casi~g ~low into the region that extends between tbe tapered surface o~ the deflector aDd the adjace~t wall of tbe hollow casing, the arrangemeDt being such that, iD use of the apparatus, a stream of liquid that is to be aerated is directed throu~h the inlet duct o~to the tapered sur~ace Or the deflector b~ which it is deflected to form a substantiall~
circumrerentially contiDuous radially directed flow which forms a liquid spra~ within said region aDd which draws fresh air iDto the interior Or the casiDg through said aperture means, the ~re~h air and tbe spray intermingling within said regioD to aerate the liquid.
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Preferably a radially outwardly directed flange i~ formed at the radially outermost periphery of the deflector in order to assist in the conversion of the liquid stream into a radially outwardly directed flow of spray. Conveni~tly the flange tapers tow~rds the large end of the tapered surface. ~`he deflector may be pyramid shaped and such a flange may be formed along ea~h edge of it~ base.
Preferably the hollow casing is adapted to be mounted for use with the inlet duct formed in its top surface. One or more members may be supported within the hollow casing below the deflector, the upper surface of each such member sloping downwardly from one end which rests against a respective wall of the hollow c~sing to another end which is spaced from the opposite wall of the hollow casing. Pre~erably there are several such member~ and they extend one below the other~ alternate ones of the members resting against alternate ones of the pair of opposed walls of the hollow casing so that the spray that has ~ntermingled with fresh air in the said re~ion falls onto the upper surface of the uppermost one of said members and cascades down that surface to a second reg~on, ~hich is formed between the lower end of that member and the ad~acent wall of the casing, to fall throug~h ., .
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that second re~ion onto the upper surface of the next to uppermost member, cascade down the upper surface of that next to uppermost member to a third region, which is formed between its lower end and the adjacent wall of the casing, and so on until it reaches the bottom of the loA!ermost downwardly sloping member from whence it flows back into the settling tank. Conveniently further apertures are formed in the casing wall ad~acent each of the regions that are formed between the lower end of the downwardly sloping members and the adjacent; wall of the casing 80 that fresh air from outside t;he casing can flow into the respective region to intermingle within that region with liquid spray which passes through ~hat region en route from one to the other of a juxtaposed pair of the downwardl~ sloping members.
Preferably the hollow casing 19 adapted to be mounted above liquid contained within the settling t~nk so that the lower end of the upper surface of the lower-most downwardly sloping member is below the level of liquid within the settling tank during operation of the apparatus to aerate liquid drawn from the settling tank. Conveniently the or each member has an upwardly directed flange at the lower end of its downwardly sloping surface. ~he upper edge of the or each ~L16~76a~
upwardly dlrected flange may be notched. Conveniently further apertures are formed in the casing wall ad~acent each of the regions that are ~ormed between the lower end of the downwardly sloping members and the adjacent wall of the casing so that fresh air from outside the casing can flow into the respective region to intermingle within that region with llquid spray which traverses through that region whilst passing from one to the other of a ~uxtaposed pair of the downwardly sloping members. ~he further apertures may be arranged such that the flow of fresh air into each region is indubed by the passage of spray through tha-t region. Preferably the hollow casing is adapted to be mounted above liquid contained within the settling tank so that the lower end of the upper surface of the lowermost downwardly sloping member i-s below the level of liquid within the settling tank during operation of the apparatus to aerate liquid drawn from the settling tank, the lowermost downwardly sloping member serving as said means for returning ~erated liquid to the tank.
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One embodiment of this invention will be describednow by way of example, with reference to the accompanying drawings, of which:- .
~ igure 1 i8 a schematic illustration of a system for aerating liquid contained within a machine tool system settling tank in accordance with this invention;
~ igure 2 is a side elevation of a practical embodiment o~ the system illustrated in ~igure 1, the settling tank being shown chain dotted and partl~
broken away for convenience;
~ igure 3 is a plan view of ~igure 2;
Figure 4 is an end elevation o~ Figure 3;
Figure 5 is a transverse cross sec-tion in a ~ertical plane of the aerator unit of the system illus-trated in ~igures 2 to 4t the unit being drawn to a larger scale than in Figures 2 to 4; and Flgure 6 i9 a section on the line VI~YI of ~igure 5"
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Referring to ~igures 1 to 4, a settling tank 10 of a . ~
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machine tool system stores liquid, convenientlya mixture of oil and water, which iQ for use as a coolant and/or a lubricant in a machining operation carriedout at each machine station of each machine tool of the system. ~he tank contains rotary drum ~ilter apparatus (not shown) which has its outlet connected to a pump by which li~uid withln the tank is drawn from the tank through the rotary drum filter apparatus for distribution to each machine station of each machine tool of the ~ystem, ~he pump is.located outside the tank. ~he rotary drum filter apparatus is usually located at the cent.re of the tank 10.
~ iquid used as a coolant or a lubricant in a machinin~ operation carried out at eLlch machine station of each machine tool of the system is collected and returned to the tank 10. The returned liquid, together .
with soils, dirt, swarf and other foreign matter collected with it,. is discharged into the tank at one end 11 which is ~loped suitably. Figure 4 shows that the width o~ the tank 10 at the top is approximately three times that at the bottom, the side walls of the tank tapering inwardly between the top and bottom portiQns of the tank. A conveyor runs along the length of the bottom section of the tank and up the slope at the end 11 of the tank, A part 12 of the conveyor is shown in ~igure 1 at the end 13 of the tank opposite .
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the ~loping end 11. Soils, dirt, swarf and other foreign matter discharged into the tank with liquid returned from the machine tools of the machine tool system gravitate to the narrow bottom section of the tank and onto the upper run of the conveyor and are carried by -that conveyor out of the tank when the machine tool system is running.
~ igure 2 shows that a motor 14 is drivingly coupled to a pump 15, the motor 14 and the pump 15 being mounted outside the tank 10 and below one of the sloping side wall portions o~ the tank 10, Operation of the motor 14 is controlled by the control system of the machine tool system B0 that it is energised to drive the pump 15 when the machine tool system is shut down.
~ he inlet of the pump 15 is connected to one end of an inlet pipe 16 which passes in a fluid tight mann;er through an aperture in a wall of the tanX 10 and which i~ open at its other end which is located just above the upper run of the part 12 of the conveyor. Xence the open end of the inlet pipe 16 is located as near to the bottom of the tank 10 as is practicable and alqo as close as is practicable to the end wall 13 that is opposite the sloping end 11 at which liquid is discharged into the tank along with 80ils, dirt, swarf and other foreign mat-ter. The liquid ad~acent the end wall 13 . . , .
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of the tank 10 tends to be the most stagnant liquid s~ored ~ithin the tank.
lhe outlet of the pump 15 i9 connected by a horizontal pipe 17, which run~ outside the tank 10 for substantially ths total length of the tank 10, to a branch pipe coupling 18 which has two outlets of diffexent diameter. ~he larger diameter outlet of the branch coupling 18 is connected by an angled pipe 19 to an i.nlet duct 21 of an aerator unit 22. ~he smaller diameter outlet of the branch coupling 18 iB
connected by a small bore pipe 23 to an injector 24 which is located substantially at the centre of the tank 10, below the normal level of liquid stored therein and adJacent the sloping end 11 of the tank 10. The small bore pipe 23 passes in a fluid tight manner through an aperture in a wall of the tank 10. A valve 25 in the small bore pipe 2~ controls liquid flow through that pipe. ~he arrangement of the pipes 19 and 23 and the ~alve 25 is such that the vast majority of liquid drawn from within the tank 10 by the pump 15 i~ directed to the aerator unit 22 via the angled pipe 19~ approximately 8~ of the total Yolume of liquid drawn from the tank 10 by the pump 15 being directed through the small bore pipe 23 and the in~ector 24 into liquid within the tank, , .. . .. .....
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~ he aerator unit 22 will be described in detail now with reference to ~igures 5 and 6. It comprises a hollow casing of generally rectangular box construc-tion formed basically of an angle iron framework clad with sheet metal panels which form its vertical side walls 26, 27, 28 and 29 and a top cover 31. The angle iron framework includes four vertical legs, one at each corner of the cas~ing and four horizontal lengths of angle iron at the top. The casing is open at the bottom and is supported ~rom the structure of the tank lO by suitable support means so that its longitudinal axis i~ vertical and so that the bottom of each of the four legs o~ the angle iron framework is immersed in :
liquid con~ained within the tank lO. ~he side wall panels 2fi to 29 are shorter than the vertical legs of the angle section framewor~ and their lower edges are above the level of liquid contained within the tank lO. ~he casing is orientated so that -the wider side wall panels 26 and 27 are substantially normal to the ' longitudinal axis of the tank lO.
~ he top cover 31 carries the in.let duct 21 ~hich is a vertical tube which passes through a ciroular hole within which it is spigotted and which i8 formed at the centre of the top plate 31. A pair oi~ angled strips 32 and 33, which comprise portions :~
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of the top panel 31 bent downwardly from the plane of the remainder of the top panel 31, extend paxallel to the wider side wall panels 26 and 27 over substan-tially the total di~tance between the horizontal length.q of the angle section framework to which the narrower side wall panels 28 and 29 are fastened.
Each angled strip 32, 33 is flat and slopes downwardly in direction outwards from the vertical axis of the aerator unit 221. The wider side wall panels 26 and 27 pro~ect above the horizontal lengths of the angle section framework to forn; flanges 34 and 35 which are bent inwardly towards the axis of` the aerator unit 22 so that each of them extends substantially parallel to the ad~acent angled strip 32, 33. Each angled strip 32, 33 co-operates with the adjacent angled flange 34, 35 to form an angled inlet slot through which air can be drawn into the interior of -the hollow casing from outside, air drawn in through each such angled slot being directed towards the adjacent wider l side wall panel 26, 27. . ,~
A sheet metal de~lector 36 comprises a pyramid-shaped structure with a s~uare base and four outwardly directed angled flanges 37, 38, 39 and 41 which extend one along each edge of the base of the pyramid-shaped structure. Each angled flange 37, 38, 39 and 41 and .
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the ad~acent triangular face of the pyramid-shaped structure Or the deflector 36 converge towards the respective edge of the square base. Ths deflector 36 is supported by an angle iron support framework 42 ~o that it is coaxial with the inlet duct 21 and so that its apex is at its end nearer to the "~
inlet duct 21. There is a space between each angled flange 37, 38, 39, 41 and the adjacent wall panel 26 27, 28 and 29 of the hollow casing.
A pair o~ angle iron support members 43 and 44 slope downwardly from the wider side wall panel 27 to the wider side panel 26, each support member 43, 44 lining a respective one of the narro~ver side wall panels 28 and 29. A planar sheet metal member 45 is supported at either edge by the two members 43 and 44 so that it spans the gap between those members 43 and 44 and slopes downwardly. The upper edge of the sheet metal member 45 abu~s the vertical legs of the angle section frame-work to which the wider side wall panel 27 is fastened.
The planar sheet metal member 45 has an upwardly directed flange 46 extending over substantially the full distance between the narrower side wall panels 28 and 29 at its lower end~ ~even notches are formed in the edge of the ~lange 46 at equi~spaced intervals. ~here is a space between the ~lange 46 and the ad~acent wider ` - 16 --- .
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'sheet metal panel 26 which carries an upwardly opening sheet metal shroud 47. The interior of the shroud 47 communicates with the space between the flange 47 and the panel 26 through an aperture which i9 formed in the panel 26 opposite the flange 46.
A second downwardly sloping planar sheet metal member 45A is supported below the planar sheet metal member 45 in a similar manner by angle iron support members 43A and 44A. ~he upper edge of the second member 45A abuts the vertical legs of the angle iron ~ramework to which the wider sheet metal side wall panel 26 i9 attached just belowr the aperture that is formed in that panel 26 ad~acent the lower end o.~ the shroud 47. A notched flange 4.6A is formed at the lower end of the second member 45A and a space is formed between the notched flange 46A and the adjacent wider sheet metal side wall panel 27. An upwardly opening sheet metal shroud 47A carried by the wider sheet metal side wall panel 27 opens at ~ts lower end into the space formed between the notched panel 46A
and that panel 27 through an aperture fo med in that panel 27 opposite the notched flange 46A.
A third downwardly sloping planar sheet metal member 45B is supported below the ~econd member 45A in a .
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similar manner by another pair of angle iron 5upport member 43B and 44B~ the upper edge of the third member 45B being in abutment with the vertical legs of the angle iron framework to which the wider sheet metal .side wall panel 27 is attached just below the ~.
aperture that is formed in that panel 27 opposite the notched flange 46A. A notched flange 46~ is formed at the lower end of the third member 45B and there is a spaee between that notohed flange 46B and the adjacent wider sheet metal side wall panel 26.
The interior of a second upwardly opening sheet metal shxoud 47~, which i.s carried by the panel 26 below the first such shroud 47, communicates with the space ~or~.led between the notched flange 46~ and that pane' 26 throu~h an aperture which i3 formed in that panel 26 opposite the notched flange 46B.
A ~ourth sheet metal member 48 is supported by suitable angle iron members below the third downw~rdly sloping planar sheet metal member 45~. The fourth sheet metal member 48 extends over substantially the full-distance between the narrower sheet metal side ~all panels 28 and 29, like the other three sheet -met&l ~embers 45, 45A and 45~, but does not slope downwardly over its whole length. That partt 48A, of the fourth sheet metal member 48 that extends below . - 18 -6~
the space between the edge of the notched flange 46~ of the third downwardly sloping planar sheet metal member 45B is substantially hori~ontal and extends almost to the centre oi~ the ho]low casing.
~he fourth member 48 slopes downwardly from the inner edge of the horizontal portion 48A to a point which is just short of the wider sheet metal side wall panel 27 and which is below the level of liquid stored within the tank 10, even when the pump 15 is being driven to draw liquid from the tank and circulate liquid through the pipes 16, 17, l9 and the aerator unit 22. ~he lower end of the downwardly sloping portion 48~ of the ~ouxth member 48 is connected by a second short horizontal,portion 48C -to the :Lower ends of the vertical legs of the angle sec-tion framework to which the wider sheet metal side wall panel 27 is attached.
The aerating apparatus described above with 'reference to and as illustrated in the accompanying drawings is inoperative whenever the machine tool system is in operation. However, as soon as the machine tool system is shut down and the conveyor brought to a halt, the motor l~ is energised and the pump 15 is driven to draw liquid from within the tank lO, adjacent the end 13 of the tank, and to feed the majority of that liquid through the pipes 17 and l9 .~ .
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to the aerator unit 22 through its inlet duct 21. ~he minor part of the liquid that is directed ~.
through the small bore pipe 23 is in~ected back into the liquid within the tank 10 through the injector 24 adjacent the end 11 of the tank 10 into which the liquid, together with swarf, ~oils, dirt and other foreign matter is discharged durin~ operation of the machine tool system, such liquid injected into the tank 10 through the in~ector 24 generating movement of liquid within the tank 10 to reduce stagnation of that liquid.
~ he main stream of liquid that is directed into the aerator unit 22 through thi3 inlet 21 impinges the surfaces of the pyramid-shaped structure of the deflector 36 and is deflected by that impingement and by the action of the angled deflector flanges 37, 38, 39 and 41 so that it is broken up into a radially outwardly directed spray of liquid drople~s which extends sub-stantially continuously around the circumference of the deflector 36. ~he spray is directed across the space between the deflector 36 and the side wall panels 26, 27, 28 and 29 and some of that spray impinges those side wall panels 26 to 29 and rebounds ~rom those side wall panels 26 to 29 so that it is .. .
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'broken up into an even flner spray. Spray within the space between the deflector ~6 and the wider side wall panel 27 as well as spray within the spaces between that deflector 36 and the narrower side wall panels 28 and 29 falls onto the third downwardly sloping planar sheet metal member 45 therebelow.
Spray in the space between the deflector 36 and the ;
wider side wall panel 26 falls through the space between -the notched flange 46 and that panel 26 on-to the downwardly sloping surface of the second planar sheet metal member 45A.
The flow of liquid through the inlet duct 21 onto the deflector 36, radiall~y outwardly from that deflector 36 towards the side wall panels 26, 27, 28 and 29 and then downwardly onto the downwardly sloping members 45 and 45A therebelow, induces air to flow into the hollow ca~ing through the inlets formed by the parallel pairs of angled strips and flanges 32 and 34, 33 and 35 and fresh air so induced to flow into the interior of the hollow casing intermingles with the liquid droplets of the spray within the spaces formed between the deflector 36 and the side wall panels 26, 27, 28 and 29 of the hollow casing and purges that spray of bacteria~
~ iquid that falls onto the first downwardly ~676~ `
sloplng planar sheet metal member 45 tends to bounce on that member 45 and cascade~ down that member 45 and over the notched edge of the notched flange 46 into the second space formed between that notched ~lange 46 and the wider ~heet metal side wall panel 26. Hence the liquid is ~urther broken up into an atomis~d spray of liquid droplets which falls throu~h that second space onto the second downwardly sloping planar support member 45A. Air is induced to flow into that second space through the upwardly opening shroud 47 and'the aperture formed in the side wall panel 26 at the foot of that shroud opposite the notched ~lange 46 and that air in-termingles with the liquid spray within that second space and further purges that liquid.
It'will be appreciated that spray that fall~
onto the second downwardly sloping planar shee-t metal member 45A cascades down that slope to the third ~pace where it intermingles with further fresh air drawn into that third space through the upwardly opening shroud 47A and the aperture formed in the w~der sheet metal side wall panel 27 opposite the notched flange 46A and that that liquid is further purged in that ~pace, It will be appreciated al~o that thè process is repeated again in the fourth space ' that is formed be-twee~ the notched flange 46~ and the wlder side wall panel 26.
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~ iquid that falls through the space formed between the notched panel 46B and the wiaer side wall panel 26 fallR onto tne lowermost sheet metal member 48A and flows down the sloping portion 48A of that panel 48 into the liquid in the tank 10 within which the lower edge of that panel portion 48A is immersed. A tendency -~
for foam t~ be formed by the action of pouring liquid into liquid contained in the settling tank 10 is minimised by arranging for the bottom of the downwardly sloping portion 48~ to be always immersed in that liquid so that the liquid output from the aerator unit 22 is returned relatively gently into the main body of the liquid in the settling tank 10.
~ he notches in the edges of the notched flanges 46, 46A and 46~ assist in breaking up and atomising liquid that cascades down the respective downwardly slop~ng planar member and over the notched surfaces into the respective space formed between those notched edges and the adjacent wider side wall panel 26 or 27, :
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~ his i~ventioD relates to a method of, aDd apparatus for aerating liquid stored in a settlin~ tank of a machiDe tool system iD order to iDhibit the growth o~ anaero~ic bacteria in that liquid, the settling tank comprising a source from which such liquid is dr~wD for use as ~
coolant and/or a lubricant iD a machiniDg operatioD at one or more machini~g stations of the s~stem when the system is operatiDg and to which liquid so used is returned after such useO
lo ~iquid stored in a machiDe tool system settling tank can be aexated by injecting compressed air into the liquid within the tan~ and allowing that compressed air to bubble through the liquid, but the amount of compressed air that is required is such that such a techDique for aeratiDg that liquid is costl~. ~n ob~ect o~ this iDveDt-ioD i8 to pro~ide a method of aDd apparatus for aeratiDg liquid contained within a ~ac~ine tool s~stem settliDg tank which does Dot require such a~ eYpensive suppl~ o~ air.
~ccording to o~e aspect Or this inveDtioD we provide a method of aeratin~ liquid stored in a settliDg taDk of a machiDe tool system ~omprisiDg drawing off li~uid from tbe tank whilst tbe machine tool s~stem is shut dowD, aerating the drawn off li~uid outside the mass of liquid stored iD the tank and returDiDg the aerated liquid to the mass of liguid s~ored in the tank.
~ iquid ma~ be drawD coDtiDuously from the settliDg tank as a str2am, 6'76~
aerated outside the mass of liquid stored iD the tan~ and returDed to the mass of liquid stored iD the ta~k continu-ously whenever the s~stem is shut down. Such a CoDtiDuous stream of li~uid drawn from the settliDg ta~ pre~erabl~
is converted into a spray iD a region into which fresh air flows so that tbe ~resh air and spray intermiDgle i~
that region to aerate the liquid. Preferably the stream of liquid is converted into a spray by being directed to-wards the apèY of coaxial tapered deflectiDg meaDs, the lo stream striking the tapered deflectiDg means and being deflected thereby to form a substaDtially circumfereDtially contiDuous radially directed flow. ProvisioD o~ substaD-tially circumferentially conti~uous outwardly directed flaDge meaDS OD the tapered deflecti~g means, spaced ~rom tbe ape~, whicb coact with the de~le~cted li~uid, enhances conversion of the liguid stream into a radiall~ directed spra~. CoDvenieDtly the spray is allowed to fall onto a slopiDg sur~ace down whi~h it cascades to a secoDd regioD iDto which fresh air flows, the cascading liquid preferably being atomised further as it enters the secoDd resioD so that the ~resh air and li~uid dropl~ts i~termingle in the second re~ion to further aerate t~e liquid. ~he sloping surface may be the first of a series of such sloping surfaces, each of the second and any ~67~
subsequent sloping surface of the series extending below the region to which the immediately preceding sloping surface of the series slopes downwardly, so that the spray that falls onto said first sloping surface cascades down that surface to the respective region, is atomised further as it enters that region so that the fresh air and liquid droplets intermingle in that region to further aerate the liquid as it falls through that region onto the second sloping surface of the series down which it cascades to the respective region and so on until the liquid falls onto the lowermost sloping~
surface of the series from which it is returned to the tank, each such surface being arranged so that liquid received on it cascades down it to the next region where it is atomised and aerated further. Part of the stream of liquid drawn from the settling tank may be bled from the main stream of liquid that is aerated outside the mass of liquid stored in the tank, the bled liquid being injected back into liquid contained within the settling tank in order to generate movement of the liquid that is contained within the settling tank. Fresh air flow into the or each region conveniently is induced by the passage of liquid or liquid spray to and through that region.
According to another aspect of this invention ~ 7~ ~
there is provided apparatus for use with a machine tool s~stem ha~ing a settling tank through which liquid coolant/
lubricant is recirculated during normal operatioD, the apparatus being e~fective to aerate the liquid stored iD
said SettliDg taDk aDd comprising control mea~s which are adapted to,sense the operational state of the machine tool ~ystem, liquid flow iDducing meaDs which are adapted to draw li~uid from the ta~k, the control meaDs beiDg operatively associ at~d with the liquid flow induciDg means such as to actuate the liquid flow iDduciDg means to draw liquid from the tan~ wheD the~ ~ense that the machine tool system is shut down, aerating meaDs disposed ou~side the mass o~ liquid sto~ed in the taDk a~d connected i~ a liquid recirculatioD path with the tank and the liQUid flow inducing means, the aeratiDg means being for aerating liquid drawn from the tank b~ ~aid liquid flow iDduciDg means and thereafter returniDg aerat,ed liquid to the tank.
Preferably said coDtrol means and said liquid f~ow inducing means are arranged suc~ that the liquid flow induciDg means are activiated continuously whilst the mach-iDe tool s~stem is shut dowD so that a stream of liquid is drawD continuously from the tank, aerated outside tke mas~
o~ liquid stored iD the taDk and retulned to the mass of liquid stored in the tan~ coDtiDuousl~ whilst the sy~tem is shut dowD~ ~he aerating means ma~ include a region iDto which fresh air ~lows and means for converting liquid draw~
from the'taD~ by said liquid ~low inducing means into a spray iD that region so that fresh air and the spra~ iDter-mingle in that region to aerate the liquid and may be arra-nge such that flow o~ ~resh air into .
~ 76~
the region is ind~ced b~ liquid flow through the aeratlDg mea-Ds .
~ he aerati~g meaDs may comprise a hollow casing, aD iDlet duct, a deflector which has a tapered surface and which is supported within th~ hollow casiDg so that its tapered surface tapers towards the iDlet duct with wbich it is substaDtially coasial and so that its radially outermost perlphery is spaced from the adjace~t wall of the casing, aDd ap~rture means iD the easing wall through whicb fresh air from outside the casi~g ~low into the region that extends between tbe tapered surface o~ the deflector aDd the adjace~t wall of tbe hollow casing, the arrangemeDt being such that, iD use of the apparatus, a stream of liquid that is to be aerated is directed throu~h the inlet duct o~to the tapered sur~ace Or the deflector b~ which it is deflected to form a substantiall~
circumrerentially contiDuous radially directed flow which forms a liquid spra~ within said region aDd which draws fresh air iDto the interior Or the casiDg through said aperture means, the ~re~h air and tbe spray intermingling within said regioD to aerate the liquid.
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Preferably a radially outwardly directed flange i~ formed at the radially outermost periphery of the deflector in order to assist in the conversion of the liquid stream into a radially outwardly directed flow of spray. Conveni~tly the flange tapers tow~rds the large end of the tapered surface. ~`he deflector may be pyramid shaped and such a flange may be formed along ea~h edge of it~ base.
Preferably the hollow casing is adapted to be mounted for use with the inlet duct formed in its top surface. One or more members may be supported within the hollow casing below the deflector, the upper surface of each such member sloping downwardly from one end which rests against a respective wall of the hollow c~sing to another end which is spaced from the opposite wall of the hollow casing. Pre~erably there are several such member~ and they extend one below the other~ alternate ones of the members resting against alternate ones of the pair of opposed walls of the hollow casing so that the spray that has ~ntermingled with fresh air in the said re~ion falls onto the upper surface of the uppermost one of said members and cascades down that surface to a second reg~on, ~hich is formed between the lower end of that member and the ad~acent wall of the casing, to fall throug~h ., .
_ 7 _ .
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that second re~ion onto the upper surface of the next to uppermost member, cascade down the upper surface of that next to uppermost member to a third region, which is formed between its lower end and the adjacent wall of the casing, and so on until it reaches the bottom of the loA!ermost downwardly sloping member from whence it flows back into the settling tank. Conveniently further apertures are formed in the casing wall ad~acent each of the regions that are formed between the lower end of the downwardly sloping members and the adjacent; wall of the casing 80 that fresh air from outside t;he casing can flow into the respective region to intermingle within that region with liquid spray which passes through ~hat region en route from one to the other of a juxtaposed pair of the downwardl~ sloping members.
Preferably the hollow casing 19 adapted to be mounted above liquid contained within the settling t~nk so that the lower end of the upper surface of the lower-most downwardly sloping member is below the level of liquid within the settling tank during operation of the apparatus to aerate liquid drawn from the settling tank. Conveniently the or each member has an upwardly directed flange at the lower end of its downwardly sloping surface. ~he upper edge of the or each ~L16~76a~
upwardly dlrected flange may be notched. Conveniently further apertures are formed in the casing wall ad~acent each of the regions that are ~ormed between the lower end of the downwardly sloping members and the adjacent wall of the casing so that fresh air from outside the casing can flow into the respective region to intermingle within that region with llquid spray which traverses through that region whilst passing from one to the other of a ~uxtaposed pair of the downwardly sloping members. ~he further apertures may be arranged such that the flow of fresh air into each region is indubed by the passage of spray through tha-t region. Preferably the hollow casing is adapted to be mounted above liquid contained within the settling tank so that the lower end of the upper surface of the lowermost downwardly sloping member i-s below the level of liquid within the settling tank during operation of the apparatus to aerate liquid drawn from the settling tank, the lowermost downwardly sloping member serving as said means for returning ~erated liquid to the tank.
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One embodiment of this invention will be describednow by way of example, with reference to the accompanying drawings, of which:- .
~ igure 1 i8 a schematic illustration of a system for aerating liquid contained within a machine tool system settling tank in accordance with this invention;
~ igure 2 is a side elevation of a practical embodiment o~ the system illustrated in ~igure 1, the settling tank being shown chain dotted and partl~
broken away for convenience;
~ igure 3 is a plan view of ~igure 2;
Figure 4 is an end elevation o~ Figure 3;
Figure 5 is a transverse cross sec-tion in a ~ertical plane of the aerator unit of the system illus-trated in ~igures 2 to 4t the unit being drawn to a larger scale than in Figures 2 to 4; and Flgure 6 i9 a section on the line VI~YI of ~igure 5"
.
Referring to ~igures 1 to 4, a settling tank 10 of a . ~
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, ~ .
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machine tool system stores liquid, convenientlya mixture of oil and water, which iQ for use as a coolant and/or a lubricant in a machining operation carriedout at each machine station of each machine tool of the system. ~he tank contains rotary drum ~ilter apparatus (not shown) which has its outlet connected to a pump by which li~uid withln the tank is drawn from the tank through the rotary drum filter apparatus for distribution to each machine station of each machine tool of the ~ystem, ~he pump is.located outside the tank. ~he rotary drum filter apparatus is usually located at the cent.re of the tank 10.
~ iquid used as a coolant or a lubricant in a machinin~ operation carried out at eLlch machine station of each machine tool of the system is collected and returned to the tank 10. The returned liquid, together .
with soils, dirt, swarf and other foreign matter collected with it,. is discharged into the tank at one end 11 which is ~loped suitably. Figure 4 shows that the width o~ the tank 10 at the top is approximately three times that at the bottom, the side walls of the tank tapering inwardly between the top and bottom portiQns of the tank. A conveyor runs along the length of the bottom section of the tank and up the slope at the end 11 of the tank, A part 12 of the conveyor is shown in ~igure 1 at the end 13 of the tank opposite .
7~
the ~loping end 11. Soils, dirt, swarf and other foreign matter discharged into the tank with liquid returned from the machine tools of the machine tool system gravitate to the narrow bottom section of the tank and onto the upper run of the conveyor and are carried by -that conveyor out of the tank when the machine tool system is running.
~ igure 2 shows that a motor 14 is drivingly coupled to a pump 15, the motor 14 and the pump 15 being mounted outside the tank 10 and below one of the sloping side wall portions o~ the tank 10, Operation of the motor 14 is controlled by the control system of the machine tool system B0 that it is energised to drive the pump 15 when the machine tool system is shut down.
~ he inlet of the pump 15 is connected to one end of an inlet pipe 16 which passes in a fluid tight mann;er through an aperture in a wall of the tanX 10 and which i~ open at its other end which is located just above the upper run of the part 12 of the conveyor. Xence the open end of the inlet pipe 16 is located as near to the bottom of the tank 10 as is practicable and alqo as close as is practicable to the end wall 13 that is opposite the sloping end 11 at which liquid is discharged into the tank along with 80ils, dirt, swarf and other foreign mat-ter. The liquid ad~acent the end wall 13 . . , .
:
76 D ~ ~
of the tank 10 tends to be the most stagnant liquid s~ored ~ithin the tank.
lhe outlet of the pump 15 i9 connected by a horizontal pipe 17, which run~ outside the tank 10 for substantially ths total length of the tank 10, to a branch pipe coupling 18 which has two outlets of diffexent diameter. ~he larger diameter outlet of the branch coupling 18 is connected by an angled pipe 19 to an i.nlet duct 21 of an aerator unit 22. ~he smaller diameter outlet of the branch coupling 18 iB
connected by a small bore pipe 23 to an injector 24 which is located substantially at the centre of the tank 10, below the normal level of liquid stored therein and adJacent the sloping end 11 of the tank 10. The small bore pipe 23 passes in a fluid tight manner through an aperture in a wall of the tank 10. A valve 25 in the small bore pipe 2~ controls liquid flow through that pipe. ~he arrangement of the pipes 19 and 23 and the ~alve 25 is such that the vast majority of liquid drawn from within the tank 10 by the pump 15 i~ directed to the aerator unit 22 via the angled pipe 19~ approximately 8~ of the total Yolume of liquid drawn from the tank 10 by the pump 15 being directed through the small bore pipe 23 and the in~ector 24 into liquid within the tank, , .. . .. .....
:
:
1 l l6 7~;~
~ he aerator unit 22 will be described in detail now with reference to ~igures 5 and 6. It comprises a hollow casing of generally rectangular box construc-tion formed basically of an angle iron framework clad with sheet metal panels which form its vertical side walls 26, 27, 28 and 29 and a top cover 31. The angle iron framework includes four vertical legs, one at each corner of the cas~ing and four horizontal lengths of angle iron at the top. The casing is open at the bottom and is supported ~rom the structure of the tank lO by suitable support means so that its longitudinal axis i~ vertical and so that the bottom of each of the four legs o~ the angle iron framework is immersed in :
liquid con~ained within the tank lO. ~he side wall panels 2fi to 29 are shorter than the vertical legs of the angle section framewor~ and their lower edges are above the level of liquid contained within the tank lO. ~he casing is orientated so that -the wider side wall panels 26 and 27 are substantially normal to the ' longitudinal axis of the tank lO.
~ he top cover 31 carries the in.let duct 21 ~hich is a vertical tube which passes through a ciroular hole within which it is spigotted and which i8 formed at the centre of the top plate 31. A pair oi~ angled strips 32 and 33, which comprise portions :~
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. .7 . .. , 676~ "
of the top panel 31 bent downwardly from the plane of the remainder of the top panel 31, extend paxallel to the wider side wall panels 26 and 27 over substan-tially the total di~tance between the horizontal length.q of the angle section framework to which the narrower side wall panels 28 and 29 are fastened.
Each angled strip 32, 33 is flat and slopes downwardly in direction outwards from the vertical axis of the aerator unit 221. The wider side wall panels 26 and 27 pro~ect above the horizontal lengths of the angle section framework to forn; flanges 34 and 35 which are bent inwardly towards the axis of` the aerator unit 22 so that each of them extends substantially parallel to the ad~acent angled strip 32, 33. Each angled strip 32, 33 co-operates with the adjacent angled flange 34, 35 to form an angled inlet slot through which air can be drawn into the interior of -the hollow casing from outside, air drawn in through each such angled slot being directed towards the adjacent wider l side wall panel 26, 27. . ,~
A sheet metal de~lector 36 comprises a pyramid-shaped structure with a s~uare base and four outwardly directed angled flanges 37, 38, 39 and 41 which extend one along each edge of the base of the pyramid-shaped structure. Each angled flange 37, 38, 39 and 41 and .
~6'76`~ :;` ` ` `
the ad~acent triangular face of the pyramid-shaped structure Or the deflector 36 converge towards the respective edge of the square base. Ths deflector 36 is supported by an angle iron support framework 42 ~o that it is coaxial with the inlet duct 21 and so that its apex is at its end nearer to the "~
inlet duct 21. There is a space between each angled flange 37, 38, 39, 41 and the adjacent wall panel 26 27, 28 and 29 of the hollow casing.
A pair o~ angle iron support members 43 and 44 slope downwardly from the wider side wall panel 27 to the wider side panel 26, each support member 43, 44 lining a respective one of the narro~ver side wall panels 28 and 29. A planar sheet metal member 45 is supported at either edge by the two members 43 and 44 so that it spans the gap between those members 43 and 44 and slopes downwardly. The upper edge of the sheet metal member 45 abu~s the vertical legs of the angle section frame-work to which the wider side wall panel 27 is fastened.
The planar sheet metal member 45 has an upwardly directed flange 46 extending over substantially the full distance between the narrower side wall panels 28 and 29 at its lower end~ ~even notches are formed in the edge of the ~lange 46 at equi~spaced intervals. ~here is a space between the ~lange 46 and the ad~acent wider ` - 16 --- .
1~67'16~
'sheet metal panel 26 which carries an upwardly opening sheet metal shroud 47. The interior of the shroud 47 communicates with the space between the flange 47 and the panel 26 through an aperture which i9 formed in the panel 26 opposite the flange 46.
A second downwardly sloping planar sheet metal member 45A is supported below the planar sheet metal member 45 in a similar manner by angle iron support members 43A and 44A. ~he upper edge of the second member 45A abuts the vertical legs of the angle iron ~ramework to which the wider sheet metal side wall panel 26 i9 attached just belowr the aperture that is formed in that panel 26 ad~acent the lower end o.~ the shroud 47. A notched flange 4.6A is formed at the lower end of the second member 45A and a space is formed between the notched flange 46A and the adjacent wider sheet metal side wall panel 27. An upwardly opening sheet metal shroud 47A carried by the wider sheet metal side wall panel 27 opens at ~ts lower end into the space formed between the notched panel 46A
and that panel 27 through an aperture fo med in that panel 27 opposite the notched flange 46A.
A third downwardly sloping planar sheet metal member 45B is supported below the ~econd member 45A in a .
r -~67~
similar manner by another pair of angle iron 5upport member 43B and 44B~ the upper edge of the third member 45B being in abutment with the vertical legs of the angle iron framework to which the wider sheet metal .side wall panel 27 is attached just below the ~.
aperture that is formed in that panel 27 opposite the notched flange 46A. A notched flange 46~ is formed at the lower end of the third member 45B and there is a spaee between that notohed flange 46B and the adjacent wider sheet metal side wall panel 26.
The interior of a second upwardly opening sheet metal shxoud 47~, which i.s carried by the panel 26 below the first such shroud 47, communicates with the space ~or~.led between the notched flange 46~ and that pane' 26 throu~h an aperture which i3 formed in that panel 26 opposite the notched flange 46B.
A ~ourth sheet metal member 48 is supported by suitable angle iron members below the third downw~rdly sloping planar sheet metal member 45~. The fourth sheet metal member 48 extends over substantially the full-distance between the narrower sheet metal side ~all panels 28 and 29, like the other three sheet -met&l ~embers 45, 45A and 45~, but does not slope downwardly over its whole length. That partt 48A, of the fourth sheet metal member 48 that extends below . - 18 -6~
the space between the edge of the notched flange 46~ of the third downwardly sloping planar sheet metal member 45B is substantially hori~ontal and extends almost to the centre oi~ the ho]low casing.
~he fourth member 48 slopes downwardly from the inner edge of the horizontal portion 48A to a point which is just short of the wider sheet metal side wall panel 27 and which is below the level of liquid stored within the tank 10, even when the pump 15 is being driven to draw liquid from the tank and circulate liquid through the pipes 16, 17, l9 and the aerator unit 22. ~he lower end of the downwardly sloping portion 48~ of the ~ouxth member 48 is connected by a second short horizontal,portion 48C -to the :Lower ends of the vertical legs of the angle sec-tion framework to which the wider sheet metal side wall panel 27 is attached.
The aerating apparatus described above with 'reference to and as illustrated in the accompanying drawings is inoperative whenever the machine tool system is in operation. However, as soon as the machine tool system is shut down and the conveyor brought to a halt, the motor l~ is energised and the pump 15 is driven to draw liquid from within the tank lO, adjacent the end 13 of the tank, and to feed the majority of that liquid through the pipes 17 and l9 .~ .
-- 19 - .
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to the aerator unit 22 through its inlet duct 21. ~he minor part of the liquid that is directed ~.
through the small bore pipe 23 is in~ected back into the liquid within the tank 10 through the injector 24 adjacent the end 11 of the tank 10 into which the liquid, together with swarf, ~oils, dirt and other foreign matter is discharged durin~ operation of the machine tool system, such liquid injected into the tank 10 through the in~ector 24 generating movement of liquid within the tank 10 to reduce stagnation of that liquid.
~ he main stream of liquid that is directed into the aerator unit 22 through thi3 inlet 21 impinges the surfaces of the pyramid-shaped structure of the deflector 36 and is deflected by that impingement and by the action of the angled deflector flanges 37, 38, 39 and 41 so that it is broken up into a radially outwardly directed spray of liquid drople~s which extends sub-stantially continuously around the circumference of the deflector 36. ~he spray is directed across the space between the deflector 36 and the side wall panels 26, 27, 28 and 29 and some of that spray impinges those side wall panels 26 to 29 and rebounds ~rom those side wall panels 26 to 29 so that it is .. .
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'broken up into an even flner spray. Spray within the space between the deflector ~6 and the wider side wall panel 27 as well as spray within the spaces between that deflector 36 and the narrower side wall panels 28 and 29 falls onto the third downwardly sloping planar sheet metal member 45 therebelow.
Spray in the space between the deflector 36 and the ;
wider side wall panel 26 falls through the space between -the notched flange 46 and that panel 26 on-to the downwardly sloping surface of the second planar sheet metal member 45A.
The flow of liquid through the inlet duct 21 onto the deflector 36, radiall~y outwardly from that deflector 36 towards the side wall panels 26, 27, 28 and 29 and then downwardly onto the downwardly sloping members 45 and 45A therebelow, induces air to flow into the hollow ca~ing through the inlets formed by the parallel pairs of angled strips and flanges 32 and 34, 33 and 35 and fresh air so induced to flow into the interior of the hollow casing intermingles with the liquid droplets of the spray within the spaces formed between the deflector 36 and the side wall panels 26, 27, 28 and 29 of the hollow casing and purges that spray of bacteria~
~ iquid that falls onto the first downwardly ~676~ `
sloplng planar sheet metal member 45 tends to bounce on that member 45 and cascade~ down that member 45 and over the notched edge of the notched flange 46 into the second space formed between that notched ~lange 46 and the wider ~heet metal side wall panel 26. Hence the liquid is ~urther broken up into an atomis~d spray of liquid droplets which falls throu~h that second space onto the second downwardly sloping planar support member 45A. Air is induced to flow into that second space through the upwardly opening shroud 47 and'the aperture formed in the side wall panel 26 at the foot of that shroud opposite the notched ~lange 46 and that air in-termingles with the liquid spray within that second space and further purges that liquid.
It'will be appreciated that spray that fall~
onto the second downwardly sloping planar shee-t metal member 45A cascades down that slope to the third ~pace where it intermingles with further fresh air drawn into that third space through the upwardly opening shroud 47A and the aperture formed in the w~der sheet metal side wall panel 27 opposite the notched flange 46A and that that liquid is further purged in that ~pace, It will be appreciated al~o that thè process is repeated again in the fourth space ' that is formed be-twee~ the notched flange 46~ and the wlder side wall panel 26.
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~ iquid that falls through the space formed between the notched panel 46B and the wiaer side wall panel 26 fallR onto tne lowermost sheet metal member 48A and flows down the sloping portion 48A of that panel 48 into the liquid in the tank 10 within which the lower edge of that panel portion 48A is immersed. A tendency -~
for foam t~ be formed by the action of pouring liquid into liquid contained in the settling tank 10 is minimised by arranging for the bottom of the downwardly sloping portion 48~ to be always immersed in that liquid so that the liquid output from the aerator unit 22 is returned relatively gently into the main body of the liquid in the settling tank 10.
~ he notches in the edges of the notched flanges 46, 46A and 46~ assist in breaking up and atomising liquid that cascades down the respective downwardly slop~ng planar member and over the notched surfaces into the respective space formed between those notched edges and the adjacent wider side wall panel 26 or 27, :
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Claims (25)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of aerating liquid stored in a settling tank of a machine tool system comprising drawing off liquid from the tank whilst the machine tool system is shut down, aerating the drawn off liquid outside the mass of liquid stored in the tank and returning the aerated liquid to the mass of liquid stored in the tank.
2. A method according to claim 1, wherein liquid is drawn continuously from the settling tank as a stream which is converted into a spray outside the mass of liquid stored in the tank in a region into which fresh air flows so that fresh air and spray intermingle in that region to aerate the liquid, the aerated liquid being returned to the mass of liquid stored in the tank continuously whenever the system is shut down.
3. A method according to claim 2, wherein the stream of liquid is converted into a spray by being directed towards the apex of coaxial tapered deflecting means and being deflected thereby to form a substantially continuous radially directed flow.
4. A method according to claim 3, wherein conversion of the liquid stream into a radially directed spray is enhanced by coacting the deflected liquid with substantially circumferentially continuously outwardly directed flange means which are provided on the tapered deflecting means spaced from the apex.
5. A method according to claim 1, wherein the spray is allowed to fall onto a sloping surface down which it cascades to a second region into which fresh air flows.
6. A method according to Claim 5, wherein the cascading liquid is atomised further as it enters the second region so that fresh air and liquid droplets intermingle in the second region to further aerate the liquid.
7. A method according to Claim 1, wherein the spray is allowed to fall onto a first of a series of sloping surfaces which each slope downwardly to a respective region into which fresh air flows, each of the second and any subsequent sloping surface of the series extending below the region to which the immediately preceding sloping surface of the series slopes downwardly, so that the spray that falls onto said first sloping surface cascades down that surface to the respective region, is atomised further as it enters that region so that the fresh air and liquid droplets intermingle in that region to further aerate the liquid as it falls through that region onto the second sloping surface of the series down which it cascades to the respective region and so on until the liquid falls onto the lowermost sloping surface of the series from which it is returned to the tank, each such surface being arranged so that liquid received on it cascades down it to the next region where it is atomised and aerated further.
8. A method according to claim 2, wherein part of the stream of liquid drawn from the settling tank is bled from the main stream of liquid that is aerated outside the mass of liquid stored in the tank, the bled liquid being injected back into liquid contained within the settling tank in order to generate movement of the liquid that is contained within the settling tank.
9. Apparatus for use with a machine tool system having a settling tank through which liquid coolant/lubricant is recirculated during normal operation, the apparatus being effective to aerate the liquid stored in said settling tank and comprising control means which are adapted to sense the operational state of the machine tool system, liquid flow inducing means which are adapted to draw liquid from the tank, the control means being operatively associated with the liquid flow inducing means such as to activate the liquid flow inducing means to draw liquid from the tank when they sense that the machine tool system is shut down, and aerating means disposed outside the mass of liquid stored in the tank and connected in a liquid recirculation path with the tank and the liquid flow inducing means, the aerating means being for aerating liquid drawn from the tank by said liquid flow inducing means and thereafter returning aerated liquid to the tank.
10. Apparatus according to claim 9, wherein said control means and said liquid flow inducing means are arranged such that the liquid flow inducing means are activated continuously whilst the machine tool system is shut down so that a stream of liquid is drawn continuously from the tank aerated outside the mass of liquid stored in the tank and returned to the mass of liquid stored in the tank continuously whilst the system is shut down.
11. Apparatus according to claim 9, wherein the aerating means include a region into which fresh air flows and means for converting liquid drawn from the tank by said liquid flow inducing means into a spray in that region so that fresh air and the spray intermingle in that region to aerate the liquid.
12. Apparatus according to claim 9, wherein the aerating means comprise a hollow casing, an inlet duct, a deflector which has a tapered surface and which is supported within that hollow casing so that its tapered surface tapers towards the inlet duct with which it is substantially coaxial and so that its radially outermost periphery is spaced from the adjacent wall of the casing, and aperture means in the casing wall through which fresh air from outside the casing can flow into the region that extends between the tapered surface of the deflector and the adjacent wall of the hollow casing, the arrangement being such that, in use of the apparatus, a stream of liquid that is to be aerated is directed through the inlet duct onto the tapered surface of the deflector by which it is deflected to form a substantially circumferentially continuously radially directed flow which forms a liquid spray within said region and which draws fresh air into the interior of the casing through said aperture means, the fresh air and the spray intermingling within said region to aerate the liquid.
13. Apparatus according to Claim 12, wherein a radially outwardly directed flange which tapers towards the large end of the tapered surface is formed at the radially outermost periphery of the deflector in order to assist in the conversion of the liquid stream into a radially outwardly directed flow of spray.
14. Apparatus according to Claim 12, wherein the deflector is pyramid-shaped.
15. Apparatus according to Claim 12, wherein the hollow casing is adapted to be mounted for use with the inlet duct formed in its top surface, and at least one downwardly sloping planar member is supported with the hollow casing below the deflector, the upper surface of each such planar member sloping downwardly from one end which rests against a respective wall of the hollow casing to another end which is spaced from the opposite wall of the hollow casing.
16. Apparatus according to Claim 15, wherein there are several such downwardly sloping planar members and they extend one below the other, alternate ones of said planar members resting against alternate onesof the pair of opposed walls of the hollow casing so that the spray that has intermingled with fresh air in the said region falls onto the upper surface of the uppermost one of said planar members and cascades down that surface to a second region, which is formed between the lower end of that planar member and the adjacent wall of the casing, to fall through that second region onto the upper surface of the next to uppermost planar member, cascade down the upper surface of that next to uppermost planar member to a third region, which is formed between its lower end and the adjacent wall of the casing, and so on until it reaches the bottom of the lowermost downwardly sloping planar member from whence it flows back into the settling tank.
17. Apparatus according to Claim 15, wherein each planar member has an upwardly directed flange at the lower end of its downwardly sloping surface.
18. Apparatus according to Claim 17, wherein the upper edge of each upwardly directed flange is notched.
19. Apparatus according to Claim 16, wherein further apertures are formed in the casing wall adjacent each of the regions that are formed between the lower end of the downwardly sloping planar members and the adjacent wall of the casing so that fresh air from outside the casing can flow into the respective region to intermingle within that region with liquid spray which traverses through that region whilst passing from one to the other of a juxtaposed pair of the downwardly sloping planar members.
20. Apparatus according to Claim 15, wherein the hollow casing is adapted to be mounted above liquid contained within the settling tank so that the lower end of the upper surface of the lowermost downwardly sloping planar member is below the level of liquid within the settling tank during operation of the apparatus to aerate liquid drawn from the settling tank, the lowermost downwardly sloping planar member serving as said means for returning aerated liquid to the tank.
21. In a machine tool system using a liquid coolant/lubri-cant which normally recirculates through a liquid reservoir during operation of the machine tool system, the improve-ment comprising:
pump means for withdrawing said liquid from said reservoir when the system is inoperative; and aerating means connected in fluid communication with said pump means and with said reservoir for mixing air with said withdrawn fluid and for thereafter returning such aerated fluid to said reservoir.
pump means for withdrawing said liquid from said reservoir when the system is inoperative; and aerating means connected in fluid communication with said pump means and with said reservoir for mixing air with said withdrawn fluid and for thereafter returning such aerated fluid to said reservoir.
22. An improvement as in Claim 21 further comprising con-trol means connected to activate said pump means only when said machine tool system is inoperative.
23. An improvement as in Claim 21 further comprising means for returning a predetermined portion of said with drawn liquid directly to said reservoir, without being aerated, so as to promote continuous circulation of the fluid within said reservoir.
24. An improvement as in Claim 21 wherein said aerating means comprises:
an external housing, inlet and deflection means disposed within said hous-ing and connected to receive said withdrawn fluid from said pump means and to break such received fluid into a spray;
a series of downwardly sloping interleaved members disposed beneath said inlet and deflection means such that said received fluid is caused to cascade downwardly thereover; and air vents disposed in said housing to admit air and to facilitate its mixture with said receiving fluids.
an external housing, inlet and deflection means disposed within said hous-ing and connected to receive said withdrawn fluid from said pump means and to break such received fluid into a spray;
a series of downwardly sloping interleaved members disposed beneath said inlet and deflection means such that said received fluid is caused to cascade downwardly thereover; and air vents disposed in said housing to admit air and to facilitate its mixture with said receiving fluids.
25. An improvement as in Claim 24 wherein said aerating means is partially disposed within said reservoir such that at least the lowermost one of said members is at least partially disposed below the fluid level therein thus fac-ilitating a gentle return of said received fluid to said reservoir.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3915/77 | 1977-01-31 | ||
| GB3915/77A GB1576231A (en) | 1977-01-31 | 1977-01-31 | Methods of and apparatus for aerating liquid stored in a machine tool system settling tank |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1116760A true CA1116760A (en) | 1982-01-19 |
Family
ID=9767290
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000295889A Expired CA1116760A (en) | 1977-01-31 | 1978-01-30 | Aerating liquid stored in a machine tool system settling tank |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1116760A (en) |
| DE (1) | DE2804091A1 (en) |
| FR (1) | FR2378604A1 (en) |
| GB (1) | GB1576231A (en) |
| IT (1) | IT1106549B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0021811A1 (en) * | 1979-06-22 | 1981-01-07 | Cera International Limited | Method of and apparatus for treating liquid stored in a machine tool system settling tank |
| US6096198A (en) * | 1998-06-11 | 2000-08-01 | Halliburton Energy Services, Inc. | Apparatus for conditioning metal cutting fluids |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2149169A1 (en) * | 1971-10-01 | 1973-04-05 | Flaischlen Ekkehard Dipl Ing | DEVICE FOR PROCESSING COOLING AND CUTTING LIQUIDS FOR MACHINE TOOLS |
-
1977
- 1977-01-31 GB GB3915/77A patent/GB1576231A/en not_active Expired
-
1978
- 1978-01-30 CA CA000295889A patent/CA1116760A/en not_active Expired
- 1978-01-30 IT IT67174/78A patent/IT1106549B/en active
- 1978-01-31 FR FR7802677A patent/FR2378604A1/en active Granted
- 1978-01-31 DE DE19782804091 patent/DE2804091A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| IT7867174A0 (en) | 1978-01-30 |
| FR2378604B1 (en) | 1983-11-10 |
| DE2804091A1 (en) | 1978-08-03 |
| FR2378604A1 (en) | 1978-08-25 |
| GB1576231A (en) | 1980-10-01 |
| IT1106549B (en) | 1985-11-11 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |