CA1061596A - Fluid metering displacement device, method and system - Google Patents
Fluid metering displacement device, method and systemInfo
- Publication number
- CA1061596A CA1061596A CA197,287A CA197287A CA1061596A CA 1061596 A CA1061596 A CA 1061596A CA 197287 A CA197287 A CA 197287A CA 1061596 A CA1061596 A CA 1061596A
- Authority
- CA
- Canada
- Prior art keywords
- diaphragm
- volume
- fluid
- displacement device
- concave surfaces
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F11/00—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it
- G01F11/02—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement
- G01F11/08—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the diaphragm or bellows type
- G01F11/086—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the diaphragm or bellows type using an auxiliary pressure to cooperate with the diaphragm or bellows
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/02—Burettes; Pipettes
- B01L3/021—Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B43/00—Machines, pumps, or pumping installations having flexible working members
- F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
- F04B43/06—Pumps having fluid drive
- F04B43/073—Pumps having fluid drive the actuating fluid being controlled by at least one valve
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Clinical Laboratory Science (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Sampling And Sample Adjustment (AREA)
- Reciprocating Pumps (AREA)
- Optical Measuring Cells (AREA)
- Automatic Analysis And Handling Materials Therefor (AREA)
- Devices For Use In Laboratory Experiments (AREA)
- Measuring Fluid Pressure (AREA)
- Actuator (AREA)
Abstract
ABSTRACT
A fluid displacement device, and method for making and using same in a system for dispensing a measured quantity of fluid. The device comprises two fluid receiving chambers separated by a flexible diaphragm which is movable between the wall surfaces of the chambers upon a suitable change of pressure within either cavity. The device is incorporated into a liquid sampling system including a throttling mechanism and a valve for controlling the flow of pressure or vacuum to the volume displacement device.
The method utilized by the liquid sampling system includes the steps of operating the volume displacement device to draw a first volume of fluid into the system, and then operating the volume displacement device to push out a larger second volume of fluid which includes the first volume and can include a subsequent volume of air for cleaning the system of residue of the first volume of fluid.
A fluid displacement device, and method for making and using same in a system for dispensing a measured quantity of fluid. The device comprises two fluid receiving chambers separated by a flexible diaphragm which is movable between the wall surfaces of the chambers upon a suitable change of pressure within either cavity. The device is incorporated into a liquid sampling system including a throttling mechanism and a valve for controlling the flow of pressure or vacuum to the volume displacement device.
The method utilized by the liquid sampling system includes the steps of operating the volume displacement device to draw a first volume of fluid into the system, and then operating the volume displacement device to push out a larger second volume of fluid which includes the first volume and can include a subsequent volume of air for cleaning the system of residue of the first volume of fluid.
Description
~ 59 ~
The embodied methods, devlce and system relate to precision moveTnent o small vol~nes of fluid, Generally speaking, the movement of small volumes of fluid, for example liquid chemicals and reagents in analysis arrangements, has been accomplished by several forms of devices and systems having as a common goal the precise reproducibility of the vol~ne movement, i.e, displacement. The embodiments : hereinafter disclosed also have the goal of volume displacem~nt reproducibility with the use of a displacement device having a . cavity in which there is a diaphragm which is pressure driven ; between two opposite stable conditions, which enables the vol~me o ~he cavity to deine the desired volume displacement, : l'he pri~ari1y e~bodiPd di~phra~m does not have to be of an e1~s~omeric ma~erial and can be inert ~o a large ran~e of ! 15 chemicals.
-, :
In a fluid displacem2nt systeT.n~ it is desirable that a ~ minimum of cross-contamination between samples be incurred.
Accordingly, a method and system of sampling a liquid utilizin~
the fluid displacement device hereinaf~er to be described in ~ 20 detail, provides for a minimum of cross-contamination between ;. .
liquid samples.
:.
.J ~ccording to t'ne invention there i9 provided a method o making a fluid displacem~nt device which has asubs~antially -' constant voluTne displacemen~, said met:~od comprisin~ the ,.
.~. 25 steps of: employing a hollow ~ody of filced volume with . ` oppositely facing, interlor, sim:ilarly sllaped concave suraces ; ~ 2 ~
~ 6 having substantially eq-~al surface areas, deforming permanently a flexible diaphragm to ca~se it to have subs~antially the same shape and surface area as the shape and surface area of each concave surface; clamping the periphery of the diaphragm between the peripheries of the concave surfaces 9 and thereby mounting the diaphragm for movement between and against the - concave surfaces; diaphragm movement from one surface to th~
other surace defining the fixed volume to be displaced.
According to the invention there further is provided a fluid displacement d~vice made in accordance with the just above set forth method.
According ~o the invention there rurther is pro~ided a method ~or utilizir.g a fluid displa~ement device of the t~p2 described, t~e device being couplQd to a sampllng ele~en~ for ` 15 sampling a precise amount of a sample material from a source thereof, comprising ~he s~eps orO placin~ the diaphragm in a predetermined first position intermediate the two concave surfaces of the hollow body of the device, the diaphra~m and a ~irst of the concave surfaces defining therebetween a prede-~ermined first volume which is significan~ly less than the total displacement volume of the device; the samplin~ element being in fluid connection with the interior of the displacement device ~!, by way of its ~second concave surface, and the sampling cl2m2n~
being in contact with the sample material; moving the diaph~a~m to a second position conforming against the first conca~e surface and thereby drawing into the sampling element a first - 3 ~
~ . . . .
~ S~ 6 vol~me of the sample material equal to said first defined volume; separating the sampling ele~ent from the source of sample and moving the diaphragm to a thlrd position confo~ming against the second of the concave surfaces and thereby dispens-ing ~rom ~he sampling element a total volume equal to the total : displacement volume of the device a~d ~h~s all of said first volume of the sample material and an additional volume of substance, such as air, for cleaning sampling element prior to a next cycle of sampling by this method.
~ .
The preferred embodiments of this lnvention now will be described, by way of example, with reference to the dra~7ings acco~panying this specification in which:
~îgu~e 1 i5 a ront perspecri~e vie~q oE ~ fluid displace~
`; ment device;
Figure 2 is an exploded perspective view oE the de~Jice sho~n in Figure l;
Figure 3 is a sectional view taken ~hrough the device along the line 3-3 of Figure 1 and in the general direction indicated;
Figure ~ is a vertical plan vie~J par~ially schema,ic and with por~ions broken away of one embodiment of a liquid sampling system embodying the device o~ Figure l; and ~~ Figures 5A-5~ ar2 vertical planviews partially schem2tic and wi~h portions broken a~ay o ~nother embodiment of ~he 'j 25 liquid sampling system of Flgure 4 showing different stages of operation thcreof.
~: - 4 -, 5~ ~
Referring to Figure 1, the embodied fluid displacement device 10 has three principal partsO T~o of the parts are a pair of mating half shells 12, 14 which can be injection-molded an~ preferably are substantially identical and possess annular flanges 19, The third part is a flexible diaphragm 16 sand-wiched between the two shell halves 12 and 14 and held in place by fasteners engaged through registering openings in the annular flanges, Each shell has a nipple 22, 24 ~hich is connectable to conduits 26, 28 for connecting the fluid displacement device into a fluid system, such as sho~ in Figure 4.
Referring to Figure 2, the shells 12, 14 have chambers 30 - and 32 each bordered by its flange 19. Each of the flanges 19 includes an annular clamping ring 41, 42 having the diaphragm 16 sandwiched therebetween.
Diaphragm 16 is clamped between the shells in such a . manner that the total area of the diaphra~m within the clzmping - rings 41, ~2 is greater than the central planar area derined by the annular ring by an amo~mt su~ficient for the diaphragm to be able to conform with and alternately lie against the interior sur~ace of the chambers 30, 32. During construction ~; the diaphragm is assembled and pressure is applied to drive ~:~ the diaphragm into engagement and conform with the inner surface of one chamber of one shell, While in this condi~ion, the shells are permanently fastened together, Thereafter, the diaphragm can be moved by fluid pressure dlffer~ntials from one ~06~59~i to the other interior surf~ce of the device in a toggle-like action, with little or no stre~clhing of the diaphragm.
The term "toggle-lilce action" is employed herein to designate the property of the diaphragm and the operation of the device 10, which provides two stable s~ate positions, as shown in Figure 3 as 16 and 16', both conforming wi~h the inner wall of the chambers 30 and 32~ Suitable differential pressure is employed to drive, by pushing or pullingj~the diaphrag~i through its "toggle-like action".
Hence, the diaphragm can be of a material which is not elastomeric~ For example, the dia?hra~m can be made of polytetrafluoroethylene which also is quite inert.
Each of the shells has an antechamber 46, 48 interposed bet~een the nipples 22, 24 and the chambers 30, 32. Tne ante-chambers 46 and 48 enable suficient differential pressure to be applied to either side of the diaphragm 16 to cause the diaphragm to toggle back and forth.
When the diaphragm is being moved into position 16 ', -; fluid will be forced out of the chamber 32 ~ia the entry ori~
ice 46 through the nipple 24, and fluid ~ill be forced into the chamber 30 via the entry orifice 48 through the port 42 ~, from tube 26 coupled thereto.
The fluid volume displaced by the toggLe-like action o the diaphragm 16 will not change ~7ith time, since the ~olume .: .
~ .3~ 25 - is dependant only upon the fixed vol~me of the chambers 30 and i ~
32; hence, an accurately ~eproducible volume displacement of ,- i .: - . .
.~ .. ~ .
LS9~
~luid is achieved by the subject ~evice 10.
A llquid sampling system utilizing the fluid displacement device 10 of ~igures 1 - 3 generally is indicated by the reference numera1 110 in ~igure 4. The system 110 includes a sampling element, ~or example a cuvette 112, the fluid dis-placement device 10, a fluid connection line 116 connecting the device 10 with the upper end 117 of the cuvette 112, and a line 152 between the device 10 and a control valve arrangement 118 for controlling the operatlon o~ the device 10. The arrangement of the ~ntechambers 46, 48 and niy~les 2~, 24 are not sllown in Figure 4, for simplicity of drawing. The valve arrangement 118 includes a control valve 154 and a throttling device 156 ~` in ~he ~orm o a needle valve. A~ sllo~m, a fluid line 15~
le~ding to a source o vacuum and a fluid line 160 leadin~ to a source of pressure are connected to the valve 154, . .
In the illustrated embodiment o~ the liquid sampling system 110 sho~.*n in Figure 4, an air line 162 with a valve 16~ therein - is connected into the ~luid line 116 between the displacement device 10 and the cuvette 112. The valve 164 is operable to .' 20 communic~te pressurized air throu~h the flui~ line 116 to the upper end 117 o~ the cuvette 112, , / T11e method of usinS tlle syste;n 110 is initiated by oper-:;1 ating the valve 154 to connect the pressure line 160 through the throttling device 156 to the volume displacement dev~ce 10 to push ~he diaphragm 16 upward against the inner surLace o the cavity 30, Then, the lower end 122 of the cuvette 112 is - 7 ~
.: : . : . . .. . ~
1~6~591~
placed lnto a body of sample liquid 166 3 as ~n a test tube 168.
Next, the valve 154 is operated to connect the vacuum line 158 to the device 10 to pull the diaphragm downwardly to the position shown in Figure 4. In this way, a precise quan~ity of fluid is drawn up frcm the body of liquid 166 in~o the cuvette 112. The needle valve 156 throttles the suction applied to the device 10 so that the diaphragm 16 can move slowly from the sur~ace of the cavity 30 to the sur~ace o the cavity 32, As a result, the liquid drawn into the cw ette 112 is drawn thereinto slowl~J and smoothly without splashing of the liquid ~; into the upper end 117 of the cuvette 112.
Al~hough the sampling el~ment 112 is no~. a limitation upon the scope o the invention, the cuvette 112 and pho~ometric elemen~s 13~ and 132 are described as a prac.tical exam~le. A
photometric analysis now can be made by passing li~ht throug~
the cuvette from the source L30 to the photosensi~ive device 132. Before or after the photometric analysis, the lower end 122 of the cuvette 112 is removed from the bod~J of liquid 166.
Then, after the photometric analysis has been made, the valve 154 is operated again to connect the pressure line 1~0 to the volume displacement device 10~ to move the diaphra~m 16 against :, ,.
i the inner surface of the cavity 30 and thereby force the liquid out of the cuvette 112. Next, with the lowe~ end of the ~ j .~ cuve,tte 122 open to the ambient air above a waste container :~ 25 (not showm), the valve 154 is opera~ed to connect the vacuu~
I line 158 to device 10 to draw a quantity of air into the :! 8 .
i lOG15~3~
cuvette 112 after which the val~e 154 is connected to the pressure line 160 to operate the devîce lO to force the air out of the cuvette 112 and in so doing to eject from the cuvette any droplets of liquid ~'nich may have clung to the interior side walls o~ the cuvette.
As a modification to the method of operating the liquid sampling system described above, after the liquid sample is ejected from the cuvette 112, the cuvette 112 can be lowered into a source of rinse liquid which is then dra~ up into the cuvette and subsequently purged from the cuvette prior to the drawing o~ air into the cuvette. This is accomplished by operating the valve 154 in the manner described above to oper-- a~e tlhe volume displacement device 10 in the ma~ner ~.escr~bed abcve~
Also, and to save time and to provide for a better blowing out of liquid from the cuvette 112, the step of pushin~ air through the cu~ette 112 can be performed or assisted by operat ing the valve 164 to transmit pressurized air in the line 162 - through the fluid line 116 to the interior of the cuvette 112.
- 20 With this modification, the device 10 need not be operated to pull air into and then force air out of the cuvette 112, Turning no~ to Figures 5A - 5D, another method o~ operating the ~mbodied liquid sampling is shown. With appropriate ..
I pressure differential being applied to the dlaphragm 16, it ; 25 will lie in a neutral position between the shells 12, 14 as shown in Figure 5A.
_ g _ 106~5~6 The valve arrangement 218 is operable to connect the cavity 30 to either a line 244 leading to ambient air, a llne 246 leading to a source of vacuum or to a llne 248 leadin~, to a source of pressure. If desired~ a connecting line 250 of the valve arrangement 218 can include a throttling device similar to the needle valve 156 shown in Figure 4.
In the method of util~zing the liquid sampling system and assuming the neutral diaphra~m position divides the volume defined by the cavities 30 and 32 in half, the valve arrangement 218 is operated to connect the cavity 30 to the ambient air - line 244 so that the diaphragm 16 is in a neutral position with: half of the volume capacity of the device 10 on either side of the diaphragm and with air in the cavity 32~ It is lmclerstood that the diaphragm 16 can have a neutral position which i9 not necessarily at the midpoint of the chamber defined by the ~:
.` cavities 30 and 32. Then the lower en~ 122 of the cuvette is lowered into the body of liquid 166. SU'DSeqUent1Y, the valve ! arrangement 218 is operated to connect the cavity 30 to the vacuum line 246 as sho~ in Figure 5B. This results in a volume displacement o one-half the volume capacity of the .
', device 10 to draw that quantity o the liquid in the container 168 upwardly in~o the cuvet~e 11 After a photometric analysis of the sample in the cuvette 112 is made and after ~;3 the cuvette is removed from the container 168 and placed Gver -, 25 a waste fluid receptacle 260 shown in ~igure 5C, the valve 1' arrang2ement 218 is operated to comm.unicate the cavity 30 with :;
~, - 10 -... .
The embodied methods, devlce and system relate to precision moveTnent o small vol~nes of fluid, Generally speaking, the movement of small volumes of fluid, for example liquid chemicals and reagents in analysis arrangements, has been accomplished by several forms of devices and systems having as a common goal the precise reproducibility of the vol~ne movement, i.e, displacement. The embodiments : hereinafter disclosed also have the goal of volume displacem~nt reproducibility with the use of a displacement device having a . cavity in which there is a diaphragm which is pressure driven ; between two opposite stable conditions, which enables the vol~me o ~he cavity to deine the desired volume displacement, : l'he pri~ari1y e~bodiPd di~phra~m does not have to be of an e1~s~omeric ma~erial and can be inert ~o a large ran~e of ! 15 chemicals.
-, :
In a fluid displacem2nt systeT.n~ it is desirable that a ~ minimum of cross-contamination between samples be incurred.
Accordingly, a method and system of sampling a liquid utilizin~
the fluid displacement device hereinaf~er to be described in ~ 20 detail, provides for a minimum of cross-contamination between ;. .
liquid samples.
:.
.J ~ccording to t'ne invention there i9 provided a method o making a fluid displacem~nt device which has asubs~antially -' constant voluTne displacemen~, said met:~od comprisin~ the ,.
.~. 25 steps of: employing a hollow ~ody of filced volume with . ` oppositely facing, interlor, sim:ilarly sllaped concave suraces ; ~ 2 ~
~ 6 having substantially eq-~al surface areas, deforming permanently a flexible diaphragm to ca~se it to have subs~antially the same shape and surface area as the shape and surface area of each concave surface; clamping the periphery of the diaphragm between the peripheries of the concave surfaces 9 and thereby mounting the diaphragm for movement between and against the - concave surfaces; diaphragm movement from one surface to th~
other surace defining the fixed volume to be displaced.
According to the invention there further is provided a fluid displacement d~vice made in accordance with the just above set forth method.
According ~o the invention there rurther is pro~ided a method ~or utilizir.g a fluid displa~ement device of the t~p2 described, t~e device being couplQd to a sampllng ele~en~ for ` 15 sampling a precise amount of a sample material from a source thereof, comprising ~he s~eps orO placin~ the diaphragm in a predetermined first position intermediate the two concave surfaces of the hollow body of the device, the diaphra~m and a ~irst of the concave surfaces defining therebetween a prede-~ermined first volume which is significan~ly less than the total displacement volume of the device; the samplin~ element being in fluid connection with the interior of the displacement device ~!, by way of its ~second concave surface, and the sampling cl2m2n~
being in contact with the sample material; moving the diaph~a~m to a second position conforming against the first conca~e surface and thereby drawing into the sampling element a first - 3 ~
~ . . . .
~ S~ 6 vol~me of the sample material equal to said first defined volume; separating the sampling ele~ent from the source of sample and moving the diaphragm to a thlrd position confo~ming against the second of the concave surfaces and thereby dispens-ing ~rom ~he sampling element a total volume equal to the total : displacement volume of the device a~d ~h~s all of said first volume of the sample material and an additional volume of substance, such as air, for cleaning sampling element prior to a next cycle of sampling by this method.
~ .
The preferred embodiments of this lnvention now will be described, by way of example, with reference to the dra~7ings acco~panying this specification in which:
~îgu~e 1 i5 a ront perspecri~e vie~q oE ~ fluid displace~
`; ment device;
Figure 2 is an exploded perspective view oE the de~Jice sho~n in Figure l;
Figure 3 is a sectional view taken ~hrough the device along the line 3-3 of Figure 1 and in the general direction indicated;
Figure ~ is a vertical plan vie~J par~ially schema,ic and with por~ions broken away of one embodiment of a liquid sampling system embodying the device o~ Figure l; and ~~ Figures 5A-5~ ar2 vertical planviews partially schem2tic and wi~h portions broken a~ay o ~nother embodiment of ~he 'j 25 liquid sampling system of Flgure 4 showing different stages of operation thcreof.
~: - 4 -, 5~ ~
Referring to Figure 1, the embodied fluid displacement device 10 has three principal partsO T~o of the parts are a pair of mating half shells 12, 14 which can be injection-molded an~ preferably are substantially identical and possess annular flanges 19, The third part is a flexible diaphragm 16 sand-wiched between the two shell halves 12 and 14 and held in place by fasteners engaged through registering openings in the annular flanges, Each shell has a nipple 22, 24 ~hich is connectable to conduits 26, 28 for connecting the fluid displacement device into a fluid system, such as sho~ in Figure 4.
Referring to Figure 2, the shells 12, 14 have chambers 30 - and 32 each bordered by its flange 19. Each of the flanges 19 includes an annular clamping ring 41, 42 having the diaphragm 16 sandwiched therebetween.
Diaphragm 16 is clamped between the shells in such a . manner that the total area of the diaphra~m within the clzmping - rings 41, ~2 is greater than the central planar area derined by the annular ring by an amo~mt su~ficient for the diaphragm to be able to conform with and alternately lie against the interior sur~ace of the chambers 30, 32. During construction ~; the diaphragm is assembled and pressure is applied to drive ~:~ the diaphragm into engagement and conform with the inner surface of one chamber of one shell, While in this condi~ion, the shells are permanently fastened together, Thereafter, the diaphragm can be moved by fluid pressure dlffer~ntials from one ~06~59~i to the other interior surf~ce of the device in a toggle-like action, with little or no stre~clhing of the diaphragm.
The term "toggle-lilce action" is employed herein to designate the property of the diaphragm and the operation of the device 10, which provides two stable s~ate positions, as shown in Figure 3 as 16 and 16', both conforming wi~h the inner wall of the chambers 30 and 32~ Suitable differential pressure is employed to drive, by pushing or pullingj~the diaphrag~i through its "toggle-like action".
Hence, the diaphragm can be of a material which is not elastomeric~ For example, the dia?hra~m can be made of polytetrafluoroethylene which also is quite inert.
Each of the shells has an antechamber 46, 48 interposed bet~een the nipples 22, 24 and the chambers 30, 32. Tne ante-chambers 46 and 48 enable suficient differential pressure to be applied to either side of the diaphragm 16 to cause the diaphragm to toggle back and forth.
When the diaphragm is being moved into position 16 ', -; fluid will be forced out of the chamber 32 ~ia the entry ori~
ice 46 through the nipple 24, and fluid ~ill be forced into the chamber 30 via the entry orifice 48 through the port 42 ~, from tube 26 coupled thereto.
The fluid volume displaced by the toggLe-like action o the diaphragm 16 will not change ~7ith time, since the ~olume .: .
~ .3~ 25 - is dependant only upon the fixed vol~me of the chambers 30 and i ~
32; hence, an accurately ~eproducible volume displacement of ,- i .: - . .
.~ .. ~ .
LS9~
~luid is achieved by the subject ~evice 10.
A llquid sampling system utilizing the fluid displacement device 10 of ~igures 1 - 3 generally is indicated by the reference numera1 110 in ~igure 4. The system 110 includes a sampling element, ~or example a cuvette 112, the fluid dis-placement device 10, a fluid connection line 116 connecting the device 10 with the upper end 117 of the cuvette 112, and a line 152 between the device 10 and a control valve arrangement 118 for controlling the operatlon o~ the device 10. The arrangement of the ~ntechambers 46, 48 and niy~les 2~, 24 are not sllown in Figure 4, for simplicity of drawing. The valve arrangement 118 includes a control valve 154 and a throttling device 156 ~` in ~he ~orm o a needle valve. A~ sllo~m, a fluid line 15~
le~ding to a source o vacuum and a fluid line 160 leadin~ to a source of pressure are connected to the valve 154, . .
In the illustrated embodiment o~ the liquid sampling system 110 sho~.*n in Figure 4, an air line 162 with a valve 16~ therein - is connected into the ~luid line 116 between the displacement device 10 and the cuvette 112. The valve 164 is operable to .' 20 communic~te pressurized air throu~h the flui~ line 116 to the upper end 117 o~ the cuvette 112, , / T11e method of usinS tlle syste;n 110 is initiated by oper-:;1 ating the valve 154 to connect the pressure line 160 through the throttling device 156 to the volume displacement dev~ce 10 to push ~he diaphragm 16 upward against the inner surLace o the cavity 30, Then, the lower end 122 of the cuvette 112 is - 7 ~
.: : . : . . .. . ~
1~6~591~
placed lnto a body of sample liquid 166 3 as ~n a test tube 168.
Next, the valve 154 is operated to connect the vacuum line 158 to the device 10 to pull the diaphragm downwardly to the position shown in Figure 4. In this way, a precise quan~ity of fluid is drawn up frcm the body of liquid 166 in~o the cuvette 112. The needle valve 156 throttles the suction applied to the device 10 so that the diaphragm 16 can move slowly from the sur~ace of the cavity 30 to the sur~ace o the cavity 32, As a result, the liquid drawn into the cw ette 112 is drawn thereinto slowl~J and smoothly without splashing of the liquid ~; into the upper end 117 of the cuvette 112.
Al~hough the sampling el~ment 112 is no~. a limitation upon the scope o the invention, the cuvette 112 and pho~ometric elemen~s 13~ and 132 are described as a prac.tical exam~le. A
photometric analysis now can be made by passing li~ht throug~
the cuvette from the source L30 to the photosensi~ive device 132. Before or after the photometric analysis, the lower end 122 of the cuvette 112 is removed from the bod~J of liquid 166.
Then, after the photometric analysis has been made, the valve 154 is operated again to connect the pressure line 1~0 to the volume displacement device 10~ to move the diaphra~m 16 against :, ,.
i the inner surface of the cavity 30 and thereby force the liquid out of the cuvette 112. Next, with the lowe~ end of the ~ j .~ cuve,tte 122 open to the ambient air above a waste container :~ 25 (not showm), the valve 154 is opera~ed to connect the vacuu~
I line 158 to device 10 to draw a quantity of air into the :! 8 .
i lOG15~3~
cuvette 112 after which the val~e 154 is connected to the pressure line 160 to operate the devîce lO to force the air out of the cuvette 112 and in so doing to eject from the cuvette any droplets of liquid ~'nich may have clung to the interior side walls o~ the cuvette.
As a modification to the method of operating the liquid sampling system described above, after the liquid sample is ejected from the cuvette 112, the cuvette 112 can be lowered into a source of rinse liquid which is then dra~ up into the cuvette and subsequently purged from the cuvette prior to the drawing o~ air into the cuvette. This is accomplished by operating the valve 154 in the manner described above to oper-- a~e tlhe volume displacement device 10 in the ma~ner ~.escr~bed abcve~
Also, and to save time and to provide for a better blowing out of liquid from the cuvette 112, the step of pushin~ air through the cu~ette 112 can be performed or assisted by operat ing the valve 164 to transmit pressurized air in the line 162 - through the fluid line 116 to the interior of the cuvette 112.
- 20 With this modification, the device 10 need not be operated to pull air into and then force air out of the cuvette 112, Turning no~ to Figures 5A - 5D, another method o~ operating the ~mbodied liquid sampling is shown. With appropriate ..
I pressure differential being applied to the dlaphragm 16, it ; 25 will lie in a neutral position between the shells 12, 14 as shown in Figure 5A.
_ g _ 106~5~6 The valve arrangement 218 is operable to connect the cavity 30 to either a line 244 leading to ambient air, a llne 246 leading to a source of vacuum or to a llne 248 leadin~, to a source of pressure. If desired~ a connecting line 250 of the valve arrangement 218 can include a throttling device similar to the needle valve 156 shown in Figure 4.
In the method of util~zing the liquid sampling system and assuming the neutral diaphra~m position divides the volume defined by the cavities 30 and 32 in half, the valve arrangement 218 is operated to connect the cavity 30 to the ambient air - line 244 so that the diaphragm 16 is in a neutral position with: half of the volume capacity of the device 10 on either side of the diaphragm and with air in the cavity 32~ It is lmclerstood that the diaphragm 16 can have a neutral position which i9 not necessarily at the midpoint of the chamber defined by the ~:
.` cavities 30 and 32. Then the lower en~ 122 of the cuvette is lowered into the body of liquid 166. SU'DSeqUent1Y, the valve ! arrangement 218 is operated to connect the cavity 30 to the vacuum line 246 as sho~ in Figure 5B. This results in a volume displacement o one-half the volume capacity of the .
', device 10 to draw that quantity o the liquid in the container 168 upwardly in~o the cuvet~e 11 After a photometric analysis of the sample in the cuvette 112 is made and after ~;3 the cuvette is removed from the container 168 and placed Gver -, 25 a waste fluid receptacle 260 shown in ~igure 5C, the valve 1' arrang2ement 218 is operated to comm.unicate the cavity 30 with :;
~, - 10 -... .
2:
,. , ,, , ', ., ! ',, .' ,,,', , ', , , . . , . . . , " , ,. ' ' . , ~,' ' ., .,' , ' '., . , ~ , ., . : ' ' .
.'.' ."'. '.'.''' " '' ` .' ," ' ~" ,'"' ' . '," "'. .,', ' ' ."" '.~ ,'' .',,' ' , ''" '. " ' '' " " ' ' .
'1~6 ~ 5~ ~
the pressure line 248, The diaphragm 16 thus is moved completely across the devlce 10 Erom tlle lnner surface of the cavity 30 to the inner surface oE the cavity 32. In this way, not only is the fluid in the cuvette 112 forced out of the cuvette 112, but also a quantity of air,which had been stored in the cavity 30 and which is equal to one-half the volume displacement of the device lO,is orced out of the cuvette.
This quantity of air serves to remove droplets of the sample liquid which may have clung to the interior side walls of the cuvette 112. Subsequently, and as shown in Figure 5D, the valve arrangement 218 is operated to connect again the ambient air line 244 to the c~vity 30 so that the diaphra~m 16 is - returned to its neutral position and a quantity of air equal to one-half th~ volume displace~ent of the device 10 is dra~n lnto the cavi~y 32. The system now is ready for the sampling of ancither liquid sample from a next container.
. From the oregoing description, i~ will be apparent ~hat the embodied displacement device, liquid samplin2 system and ~- the methods of liquid sampling described provide ror a very -: ' `
ef~icient and precise sampling of liquid with li~tle or no cross-contamination between samplings of liquid~
~ ..
~, ' ' '. .
.,, ;, ~ lL -~; , .
,, .
., ~ .
:i
,. , ,, , ', ., ! ',, .' ,,,', , ', , , . . , . . . , " , ,. ' ' . , ~,' ' ., .,' , ' '., . , ~ , ., . : ' ' .
.'.' ."'. '.'.''' " '' ` .' ," ' ~" ,'"' ' . '," "'. .,', ' ' ."" '.~ ,'' .',,' ' , ''" '. " ' '' " " ' ' .
'1~6 ~ 5~ ~
the pressure line 248, The diaphragm 16 thus is moved completely across the devlce 10 Erom tlle lnner surface of the cavity 30 to the inner surface oE the cavity 32. In this way, not only is the fluid in the cuvette 112 forced out of the cuvette 112, but also a quantity of air,which had been stored in the cavity 30 and which is equal to one-half the volume displacement of the device lO,is orced out of the cuvette.
This quantity of air serves to remove droplets of the sample liquid which may have clung to the interior side walls of the cuvette 112. Subsequently, and as shown in Figure 5D, the valve arrangement 218 is operated to connect again the ambient air line 244 to the c~vity 30 so that the diaphra~m 16 is - returned to its neutral position and a quantity of air equal to one-half th~ volume displace~ent of the device 10 is dra~n lnto the cavi~y 32. The system now is ready for the sampling of ancither liquid sample from a next container.
. From the oregoing description, i~ will be apparent ~hat the embodied displacement device, liquid samplin2 system and ~- the methods of liquid sampling described provide ror a very -: ' `
ef~icient and precise sampling of liquid with li~tle or no cross-contamination between samplings of liquid~
~ ..
~, ' ' '. .
.,, ;, ~ lL -~; , .
,, .
., ~ .
:i
Claims (17)
1. A method of making a fluid displacement device which has a substantially constant volume displacement, said method comprising the steps of: employing a hollow body of fixed volume with oppositely facing, interior, similarly shaped, concave surfaces having substantially equal surface areas; deforming permanently a substantially inelastic and flexible diaphragm to cause it to have substantially the same shape and surface area as the shape and surface area of each concave surface, wherein the step of deforming comprises the steps of holding the periphery of the diaphragm between the concave surfaces and effecting a pressure differential on opposite sides of the diaphragm such that the diaphragm permanently deforms to conform to one of the concave surfaces; clamping the periphery of the diaphragm between the peripheries of the concave surfaces;
and thereby mounting the diaphragm for movement between and against the concave surfaces; diaphragm movement from one surface to the other surface defining the fixed volume to be displaced.
and thereby mounting the diaphragm for movement between and against the concave surfaces; diaphragm movement from one surface to the other surface defining the fixed volume to be displaced.
2. The method according to claim 1 wherein the pressure differential is obtained by applying fluid pressure to one side and vacuum to the other side of the diaphragm.
3. A fluid displacement device for defining and displacing a substantially constant volume displacement and operating in response to fluid pressure differentials, said device comprising: a hollow body of fixed volume with oppositely facing, interior, similarly shaped, concave, smooth surfaces having substantially equal surface areas; a permanently deformed, inelastic and flexible diaphragm having and retaining substantially the same shape and surface area as the shape and surface area of each concave surface and being of a material other than metal; the periphery of the diaphragm being fixedly clamped between the peripheries of the concave surfaces;
the size, shape, material permanent deformation, inelasticity, and fixed clamping of said diaphragm causing it to be mounted for movement by fluid pressure differential on opposite sides of said diaphragm between and banking against the concave surfaces; diaphragm movement banking from one surface to the other surface defining the fixed volume to be displaced, such fixed volume being consistently attained upon each banking reciprocation movement of said diaphragm.
the size, shape, material permanent deformation, inelasticity, and fixed clamping of said diaphragm causing it to be mounted for movement by fluid pressure differential on opposite sides of said diaphragm between and banking against the concave surfaces; diaphragm movement banking from one surface to the other surface defining the fixed volume to be displaced, such fixed volume being consistently attained upon each banking reciprocation movement of said diaphragm.
4. The fluid displacement device according to claim 3 including: fluid ports opening through the concave surfaces for establishing pressure differential on opposite sides of the diaphragm for effecting diaphragm movement.
5. The fluid displacement device according to claim 4 wherein each of the concave surfaces includes an antechamber interposed between the interior of the device and one of said ports.
6. The fluid displacement device according to claim 5 including an annular ring on the periphery of each of the concave surfaces for holding the periphery of the deformed diaphragm therebetween, said annular rings defining a clamping plane having an area substantially less than the surface area of the diaphragm clamped within said annular rings.
7. The fluid displacement device according to claim 6 wherein said diaphragm and said annular rings have a substantially circular periphery.
8. The fluid displacement device according to claim 4 wherein a sampling element is coupled to one of said ports and pressure differential means are coupled to another of said ports for coupling alternately to said device a source of pressure and vacuum such that said device draws liquid into and pushes liquid out of said sampling element when pressure differentials are created on both sides of said diaphragm.
9, The fluid displacement device according to claim 8 wherein said pressure differential means include throttling means for throttling the magnitude of the differential pressure created on both sides of said diaphragm to cause said diaphragm to move slowly from one surface to the other thereby causing liquid to be drawn into and pushed from said sampling element smoothly and slowly.
10. The fluid displacement device according to claim 3 including an annular ring on the periphery of each of the concave surfaces for holding the periphery of the deformed diaphragm therebetween, said annular rings defining a clamping plane having an area substantially less than the surface area of the diaphragm clamped within said annular rings.
11. The fluid displacement device according to claim 10 wherein said diaphragm and said annular rings have a substantially circular periphery.
12. The fluid displacement device according to any one of claims 3, 5 or 9 wherein said diaphragm is of a chemically inert material.
13. The fluid displacement device according to any one of claims 3, 7 or a wherein said diaphragm is polytetrafluoroethylene.
14. A method for utilizing a fluid displacement device made as set forth in claim 1, the device being coupled to a sampling element for sampling a precise amount of a sample material from a source thereof, comprising the steps of: placing the diaphragm in a predetermined first position intermediate the two concave surfaces of the hollow body of the device, the diaphragm and a first of the concave surfaces defining therebetween a predetermined first volume which is significantly less than the total displacement volume of the device; the sampling element being in fluid connection with the interior of the displacement device by way of its second concave surface, and the sampling element being in contact with the sample material; moving the diaphragm to a second position conforming against the first concave surface and thereby drawing into the sampling element a first volume of the sample material equal to said first defined volume; separating the sampling element from the source of sample and moving the diaphragm to a third position conforming against the second of the concave surfaces and thereby dispensing from the sampling element a total volume equal to the total displacement volume of the device and thus all of the said first volume of the sample material and an additional volume of substance, such as air, for cleaning the sampling element prior to a next cycle of sampling by this method.
15. The method according to claim 14 in which said first diaphragm position is attainable repeatedly in each of a plurality of subsequent cycles according to this method and the said moving to all of the positions is accomplished by applying differential pressures to the diaphragm.
16. The method according to claim 15 including the applying of fluid pressure to the side of the diaphragm facing the first concave surface for obtaining the differential pressures.
17. The method according to any one of claims 14, 15 or 16 including the step of throttling the moving of the diaphragm to draw and dispense smoothly and slowly sample into and from the sampling element.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US35179373A | 1973-04-16 | 1973-04-16 | |
| US35220073A | 1973-04-18 | 1973-04-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1061596A true CA1061596A (en) | 1979-09-04 |
Family
ID=26997260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA197,287A Expired CA1061596A (en) | 1973-04-16 | 1974-04-10 | Fluid metering displacement device, method and system |
Country Status (12)
| Country | Link |
|---|---|
| JP (2) | JPS5013069A (en) |
| BR (1) | BR7402881D0 (en) |
| CA (1) | CA1061596A (en) |
| CH (1) | CH593428A5 (en) |
| DE (1) | DE2417626C2 (en) |
| ES (1) | ES425253A1 (en) |
| FR (1) | FR2225727B1 (en) |
| GB (1) | GB1455664A (en) |
| IL (1) | IL44596A (en) |
| IT (1) | IT1018646B (en) |
| NL (1) | NL7404866A (en) |
| SE (1) | SE405511B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2629154C2 (en) * | 1976-06-29 | 1984-05-17 | Ahrens & Bode GmbH & Co Maschinen- und Apparatebau, 3338 Schöningen | Sampling device for take-over devices for milk |
| IL59942A (en) * | 1980-04-28 | 1986-08-31 | D P Lab Ltd | Method and device for fluid transfer |
| US4461181A (en) * | 1983-01-06 | 1984-07-24 | Becton Dickinson And Company | Control for sample volume metering apparatus |
| JPS6017442U (en) * | 1983-07-14 | 1985-02-06 | 株式会社島津製作所 | Liquid suction nozzle device |
| US4537231A (en) * | 1983-08-29 | 1985-08-27 | Becton, Dickinson And Company | Dispenser apparatus for simultaneously dispensing predetermined equal volumes of liquid including a disposable dispenser module |
| GB9906477D0 (en) | 1999-03-19 | 1999-05-12 | Pyrosequencing Ab | Liquid dispensing apparatus |
| US7942647B2 (en) * | 2004-11-01 | 2011-05-17 | Octec Inc. | Pump for supplying chemical liquids |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2946488A (en) * | 1957-12-26 | 1960-07-26 | August L Kraft | Metering and dispensing systems |
| GB1032119A (en) * | 1962-09-07 | 1966-06-08 | Nat Res Dev | Improvements relating to breath-alcohol analysing apparatus |
-
1974
- 1974-04-10 CA CA197,287A patent/CA1061596A/en not_active Expired
- 1974-04-10 IL IL7444596A patent/IL44596A/en unknown
- 1974-04-10 DE DE2417626A patent/DE2417626C2/en not_active Expired
- 1974-04-10 CH CH505274A patent/CH593428A5/xx not_active IP Right Cessation
- 1974-04-10 IT IT50305/74A patent/IT1018646B/en active
- 1974-04-10 SE SE7404863A patent/SE405511B/en unknown
- 1974-04-10 BR BR2881/74A patent/BR7402881D0/en unknown
- 1974-04-10 FR FR7412637A patent/FR2225727B1/fr not_active Expired
- 1974-04-10 JP JP49040080A patent/JPS5013069A/ja active Pending
- 1974-04-10 NL NL7404866A patent/NL7404866A/xx not_active Application Discontinuation
- 1974-04-10 ES ES74425253A patent/ES425253A1/en not_active Expired
- 1974-04-10 GB GB1600774A patent/GB1455664A/en not_active Expired
-
1982
- 1982-12-01 JP JP1982182408U patent/JPS6015130Y2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IT1018646B (en) | 1977-10-20 |
| JPS5013069A (en) | 1975-02-10 |
| DE2417626C2 (en) | 1986-07-24 |
| FR2225727B1 (en) | 1979-07-06 |
| SE405511B (en) | 1978-12-11 |
| JPS58109024U (en) | 1983-07-25 |
| NL7404866A (en) | 1974-10-18 |
| IL44596A0 (en) | 1974-06-30 |
| BR7402881D0 (en) | 1974-11-19 |
| ES425253A1 (en) | 1976-12-16 |
| DE2417626A1 (en) | 1974-11-07 |
| GB1455664A (en) | 1976-11-17 |
| CH593428A5 (en) | 1977-11-30 |
| JPS6015130Y2 (en) | 1985-05-14 |
| FR2225727A1 (en) | 1974-11-08 |
| IL44596A (en) | 1977-04-29 |
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