DE2144122B2 - Method for reducing the effect of pulsations in an intermittently operating pumping system - Google Patents

Description

In any intermittent pumping system, for example a system with a Peristaltic pump, a pressure change valve or a control fluid pump, necessarily occur

ben will be that the thrusts from the first fluid have practically the same volume and that the separating fluid thrusts also have practically the same volume.

3. The method according to claim 1 or 2, characterized in that when using a Pump, which contains a squeezable pump hose, the volume of the separating

tendency pumping system, especially in an automatically operating device for continuous Feeding, treating and analyzing samples with constant flow, with a pump,

alternating a first fluid and a separating

sucks in fluid via a pump inlet device, io in the flow or in the flow velocity to form a first fluid flow which is made up of pulsations. In automatically operating devices, a series of fluid batches consists of the first for continuous supply, treatment and ana-fluid, each of which is separated from one another by a separating fluid lysing of samples with constant flow, for example in automatic analyzers as they are characterized in U.S. Patent No. 3,241,432 describes the pumping system which is operated such that the pump inlet is sucking in the first fluid in a flow of successive bursts of sample, as the pump-induced pulsations are used as they are supplying, treating and analyzing the manure of intermittent pumping systems arrive inlet device. with regard to the pulsations of no great importance,

2. The method according to claim 1, characterized in that as a result of the relatively long sample thrust, that the pump system has such suction times and as a result of the relatively high

Flow rate and volume of the sample strokes, the effects of the pulsations are extremely small. the Pulsation effects are namely due to the relatively long time periods and as a result of the relatively large sample volumes and can therefore be tolerated. The more developed However, devices for introducing, handling and analyzing samples work with essential

fluid thrusts are chosen so minimally that there are 30 shorter sample suction times and with a smaller load sufficient to cover the cross-section of the pumping flow and smaller sample volume. In hose to be filled out. These devices make the pulsations disturbing

4. The method according to one of the preceding noticeable, namely in such a way that the phase claims, characterized in that the thrust relationship between the sample bursts and the meow the first fluid has a larger volume than 35 schung ratio between the individual samples Have separating fluid surges. and change the treatment liquid.

5. The method according to one of the preceding claims. The invention is thus based on the object Proverbs, characterized in that on the other hand to reduce the effect of the pulsations that occur during partial merging of the first fluid with operation of an intermittently operating pump second fluid occur at a connector, 40 systems.

in which the flow path is one of the two- To solve this problem, pray at the beginning Fluid formed second fluid flow on the described method according to the invention thereby Flow path of the first fluid stream meets, which is characterized in that the pumping system is operated in such a way-flow paths are designed such that the ben is that the pump inlet device just that Pulsations triggered by the pump at the same time- 45 first sucks in fluid when the pumped off with the separating fluid thrusts at the connection, pulsations at the inlet device and application piece arrive. come.

6. The method according to claim 5, characterized in that if the first fluid indicates a second fluid, that the length of the flow path are partially mixed at a connector of the first fluid flow from the outlet side of 50 is intended, in which the flow path is one of the two-pump to the second fluid flow formed in dependencies up to the connecting piece ability of the flow in this flow path meets the flow path of the first fluid flow are is chosen such that the flow paths triggered by the pump according to the invention Pulsations formed simultaneously with the separation, that the pulsed fluid bursts triggered by the pump anions on the connector simultaneously with the bursts of separating fluid on the come. Connector arrive.

The method according to the invention is preferably applied to a peristaltic pump, in which a squeezable pump hose is driven by several evenly spaced pump rollers is progressively compressed to a stream of successive equal sizes Sample batches from a sample fluid supply device to a sample fluid treatment and analysis

7. The method according to any one of the preceding claims, characterized in that the separating fluid Ambient air is.

The invention relates to a method for reducing the effect of pulsations in one

terminating pump system, in particular _, .... - ^ - j

: re to pump in an automatically operating device for the 65 siereinrichtung. The individual samples are fed continuously. Treat and analyze
: ren of samples with constant flow, with

a pump that alternates between a first fluid and

Thrusts are separated from one another by a separating fluid thrust, which is generally at least one Has air thrust. In the Pumne's conveyor belt

. a pulsation always occurs when a pump roller is used as a peristaltic pump 10 ^ f attaches the pump hose to the pump working together frc

-! .-, irVen and if a pump roller from the direction 12th v. «; <: nid -

? SeÄlauch lifts off The sample fluid exercise is Di, sample feed device 12 ^ ^ ¹ JgJ.

α "from the hose squeeze pump; be constructed from sample 5 in such a way as it is rough '

Sjem filtered off with suction, and been described from the inlet end Patent 3,134,263 is De samples Sr sampling device, the supply device 12 contains the function ^ J ^ * accepts ™% £ _ fer pump inlet means. Current- a circular series of P ^^ * ™ ¹ J _n Jg ₁₁ downward from the pump will point each sample fluid surge. A sampling device M "tna_pfn" must be mixed with a precisely specified quantity ratio with a sampling tube 20 and an actuation device "eVeTobenbehandlngslösung". To DIE richtung22 for ^^^^^^ ST purpose, a treatment liquid flow table 14 is a Waschflus ^ ^ "^ _Dre ° _htisch T Probenstrorn the merged. The net WIR. A drive means as 26treDt £ S pulsations when placed a pump 14 and the ^^^^^^^ SLSL Swalze on the pump hose are formed, are ₁₅ »Jer FIG dureh gesmchete ^ e ^ HS ^ ^ £ reduced in that by corresponding When texmbdsxaBXgtste" ^ n ^ _the

Ceruns of the operating cycle of the pump rollers and the turntable 14 sehrittwe se Werterg _t .

the pump inlet means, the unifying of the sample containers ^l6 _t / ^ ™ ^ gibei is the pump inlet means not the L ^ ^ mgebungsluft nahmeeinnchtungW present aD _that

Seseut is. If these pulsations at that entry ₂ o P ™ ^ ⁿ ^^ ⁱⁿ ™ ^ _m f ^ 20 for a sequent steps: _a ^U arrive This ensures that ^ = ^^ f ^ ™ TSSbotenen Probendie aneesaugten air segments always em gle.cnes pros g ^e | ^e . ^ ⁿ ^ ^ \ ^ltp;? °, 'have a given sample volume. Immersing the effect of the pulsation container ^to J ¹ "'^ ß _d aran gene is the of ™ when lifting the pump rollers" the Umdem pump hose arise ^ Γ rTsTnma ^ merohrdurch, characterized * ₅ inlet end of the Entnahmerohn be irnindert ν that the Length of the flow path between the air and the W outflow, ^ _

Ier the pump roller lift-off point and the pivoting,. ^to ^ ^e '^"1 ^ _MGE ambient air volume ammenführpunkt with the treatment fluid in such a period em ^vo ^^ ^b ^ _s ^S _ch fl ™ f _igkei t! volume on-St ^P is that at the assembly point and em ^ Wb ^ s ^ Fl ^ ^^

There is always a separating air thrust when a 30 is sucked in. From what ^ "^ _{hr $} reaches this point through the pu sation. Thereby theE« £ Ben de des Entn ^^^^

provided that the pulsations, the mixing ratio \ ^m ^ ^ ^{bw M} L _m α? τ Sschenzeit swung the place of the samples Sen relapses and the Behandiungs-, the m of Zw "ch ^s _{m £ n has.}

flu d do not disturb. At least changes ^^ SSS ^ SchibfSgt can therefore be a further _m mixing ratio at most at the beginning or 35 dem Waschflu ^^ _ftv . _o f _{Uinen, which} a ^ S ^ * ^^^^ - ^ ^g ^ ASS lms evaluated the next sample to sample in the analysis and thrust up ^sch ^ _f ^SST _{djese manner, a} n approximately equal to us _a voluminous ^ ^ See the exemplary embodiment of the invention. - ^^^ ηϊη ^ / ^ Α ^

^ ΐ 1 ^ 52RSSSC -er after the t ^^^ £ TSS ^ i ^ _{invention, the peristaltic pump} which works in a ^ uteren ^ HsJ ntiert stream

A device for supplying, treating and analyzing smA D ^ rm JJ ^ _{2Q the pump} is installed for supplying fluid samples and which is located in the 45 w rd about

_e c / .eieten representation is currently in a first operating period, _{h Tsch umpe} 10 can for example be state; _{be constructed in} the same way as in the

d ^ Ä ^^ SsUSÄi

ⁱⁿ Is-B ¹ Sf "η ³ SSS ¹ SSSK representation" M Urungsblöcke 32 and 34 for the Pumdie output of the pump in dependence on penschlauche _Barer ^ p _ump nschlauch 36

the time and illustrates the mteress.erenden ^^^^ η. resistant material

^P Ti ⁿ itSi ^ andemer graphic representation ₅₅ ^^ ΑΑ ⁵ »^

the optical density of treated batches of samples tsüiuk _d f ^^^ _blocks . The pump hose

as a function of time and illustrates the -hen the holding g _ngsblöc ken through the

Lessening the effect of those in the F, g. 3 « ⁿ _{c door} shutters and is with

the pulsations produced: ,,,, ■ * hnrcn sleeves 38 and 40 on the outside

Fi'o s shows a flow plan cmc. by de 60 ψ. llbarcn MuIten _{32 and} 34 held,

in the case shown peristaltic pump ends ^ the Hai ^ ™ " _{f in the cinzclncn in the} r

rönienc en ^g Fluidstmms. where the pump is described in an O.esc Afj ^^ \ y _{m {} . The Em-

S device to be operated differently for a ^^ ^altn _d ^ ⁿ V _u ; _amm e " _q uetschbarcn PunjPCJ-

to perform. Treating and analyzing flu.dprobcn kßcnde ^ des. _{; t Aom pinnacle end}

_Fig , Primeval Rocks , Anonjnun ^ dicnt ^^^^^^^^^

a chain guide body 46 runs and is driven by a sprocket 48 in the clockwise direction.

A plurality of pump rollers 50A, 50B, SOC, and 50D are rotatably attached to the endless chain 44 at equal intervals. The pump rollers located at the top run together with the chain links located there in the illustration according to FIG. 1 from left to right. For the sake of simplicity, only a chain and a sprocket are shown. In reality, however, there are at least two endless chains at a distance from one another and aligned with one another, between which the pump rollers extend.

A pump plate 52 can move from an open position (not shown) to the closed position shown Can be pivoted position in which the pump hose 36 rests firmly on the underside of the plate. The pump hose follows the shape of the underside of the pump plate and is supported by the Pump rollers 50 pressed firmly against the platen, as detailed in U.S. Patent 3,227,091 is described.

An electric motor can be used as the pump drive device 56, which drives the chain wheel 58, as indicated by the dashed line. The mode of operation of the drive device 26 for the sample supply device is synchronized with the mode of operation of the pump drive device 56. The synchronization connection is indicated by a line 58. In a departure from this, however, one can also use a single drive device in the form of a suitably selected electric motor which can drive the pump 10 and the sample feed device 12 synchronously via conventional mechanical coupling devices.

When the chain wheel 48 is driven clockwise, in the illustration according to FIG. 1, the pump rollers 50 located at the top move from left to right and progressively squeeze the pump hose 36 together in this direction. In this way, the sample flow is pumped from the sampling tube 20 via the pump hose 36 to a sample flow feed line 62 which is connected at the point 64 to the pump hose. The sample flow supply line 62 leads to the sample treatment and analysis device (not shown). At this point it should be mentioned once again that the individual batches of samples are separated from one another by a batch of air A 1, a batch of washing liquid W and a further batch of air A 2 .

A treatment fluid supply device 66 guides the sample stream flowing through the line 62 a fluid for treating the samples. The samples should be in a given proportion mix with the treatment fluid.

The supply device 66 for the sample treatment fluid may include, for example, a container 68 with air which is under a pressure of 1510 N cm ² (2200 psi). The container 68 is followed by a pressure regulator 72 via glueing 70, which maintains a constant pressure of about 66.8 cm of mercury in a T-piece 74 connected to the pressure regulator. If the samples are, for example, blood serum samples from different patients, the sample treatment fluid is a color-generating reagent liquid which, after being mixed with the sample batches, enables their colorimetric quantitative analysis with regard to a given substance contained in the blood sample, as described in detail in the U.S. Patent 3,241,432.

A conduit 78 extends from the outlet of T-piece 74 through a screw cap 80 of a reagent flask 82 in order to generate a practically constant pressure inside the piston. From the

ίο An outlet line 84 leads inside the piston 82 to the entry end of a coil 86 which has a precisely calibrated high flow resistance. That The exit end of the flow resistance coil 86 is connected to a reagent liquid supply line 88, which leads to the one inlet of a T-piece 90 which is connected to the sample flow supply line 62 is.

The other outlet of the tee 74 is to the inlet end of a coil 94 via a conduit 92

ao connected, which also have a precisely calibrated has high flow resistance. The exit end of the coil 94 leads to via a line 96 a T-piece 98 which is connected to the reagent liquid supply line 88 as shown.

If, as in the present case, it is a question of the continuous examination of blood serum samples in an automatic analyzer, the flow resistance coil 86 is preferably inserted in a temperature control bath 99 in order to keep the temperature of the coil at an approximately constant value, for example at 37 ^° C. If necessary and / or desired, the piston 82 and parts of the lines 84 and 88 can also be inserted into the temperature control bath.

The pressurized air in the container 68 pumps the reagent liquid R from the piston 82 at a practically constant, predetermined flow rate through the cross-flow coil 86 and through the reagent liquid supply line 88 to the sample flow supply line 62 to mix the reagent liquid with the sample bursts. At the same time, compressed air flows from the container 68 also at a practically constant, predetermined flow rate through the flow resistance coil 94 to the air supply line 96 in order to divide the reagent liquid flow in the reagent liquid supply line 88 in the manner shown by air thrusts. This ensures that the sample flow and the reagent liquid flow in the correct proportion.

ratio mixes.

Although proportioning pumps of the type of peristaltic pump 10 have proven themselves for the operation of automatic analyzers with a practically constant flow rate, for example analyzers according to US Pat Analyzers should work together, which get by with a considerably increased sample analysis speed with a smaller sample volume. In this context, reference is made to FIG. 3, in which the curve 100 shows the delivery rate of the pump as a function of the line

or the running time of one of the pump rollers 50 through a hose squeezing cycle. As can be seen, pulsations 102 and 104 occur in the delivery rate, namely when the pump roller

at the beginning of the pump cycle of interest touches the pump hose 36 and compresses it and when the pump roller at the end of the pump cycle by the squeezable pump

hose lifts off. .

The mentioned sample treatment and analysis device however, only works satisfactorily at a constant flow rate. Also must between the merged sample tubes and the reagent liquid a precisely predetermined one Quantity ratio exist. To do this, it is also necessary that an exactly predetermined phase relationship exists. It is therefore important that the effect of that shown in FIG Pulsations 102 and 104 on the flow, the noise ratio and the phase relationship as above kept as small as possible, but preferred is completely cleared.

First, consider the pulsation 102 that occurs when a pump roller begins to compress the squeezable pump hose 36. This operating state of the peristaltic pump 10 is shown in FIG. The pump roller 50B is just touching the squeezable pump hose 36. * 5 With this placement, a pulsation 102 runs from the point of contact between the pump roller and the pump hose in both directions through the sample flow S in the pump hose ^ The pulsation running from left to right in the illustration in FIG. 1 ends at the pump roller ₃ 0 Λ since this compresses the squeezable pump hose 36 completely. The Pulsat.on 102 can therefore not hmau s via the pump roller 50A

In the representation according to the F1 g. 1 of right-to-left pulsation achieved without hindering "the inlet end of the sampling tube 20. Thus, this has no adverse effect, the extraction pipe 20, the turntable 14 and ™ are * ™ * ^ squeezing pump 10 mun by careful Vorherbesüm, and control of the power stroke the, drive device 26 for the sample supply device and the drive device 56 for before Pum *: operated so that the inlet end of the sampling tube does not beh det in the ambient air when the pulsation 102 reaches the inlet end of the Ent receiving tube. It should be mentioned once again that it is extremely important to maintain an exact base relationship between the individual batches of samples in the squeezable pump hose 36. In order to achieve this, air segments A with a given volume are also required. The same applies to the ash liquid surge W, which prevents contamination of the next batch of samples by the previous one. If the inlet of the extraction tube 20 were exposed to the ambient air ^ when the pulsation arrives there, the amount of air drawn in, which forms the air thrust ^ 4, would be considerably smaller at this time. Under certain circumstances, the entire air thrust could even be lost. If the amount of air sucked in is less but is still sufficient to form a front Luftscgmen X A i I. ^ e it is shown in Fig. 1 and was with a minimal volume, which is just right. jijullen the cross section of the pump hose 36 then this air segment A 1 has a smaller volume than the rear air segment A 2. so that there is a disadvantageous phase shift between the sample bursts. However, if the amount of air sucked in is not sufficient to form a separating air segment A with a minimal volume to fill the pump cross-section, i.e. only a small air bubble is present in the sample flow, or if no air is sucked in at all, then there is more than just a phase disruption , but the cleaning and separating effect of the missing air segment A is also lost.

To illustrate this, it is assumed that a total of 12 seconds are available for the suction of each sample thrust and the separating total fluid thrust, which is composed of two air thrusts A and one washing liquid thrust W. Of these 12 seconds, only 1.5 seconds are spent sucking in the air segments and the washing liquid. If now the pulsation 102 has a duration of one second and the arrangement 8 is made such that the aspirated air segments A have just the minimum volume to fill the cross-section of the pump hose 36, it is highly probable, if the pulsation 102 during FIG. 5 second time for sucking in the air and washing liquid bursts occurs at the inlet of the sampling tube 20, too little or no air volume is sucked in, so that the undesirable condition described above occurs.

As shown in FIG. 1, the sampling tube 20 is controlled in such a way that it can be Inlet is just immersed in a sample container 16 when the pulsation 102 at the inlet of the sampling tube 20 arrives. As a result, the pulsation is absorbed, so that its effect in the with constant flow flowing sample stream is not detectable. Preferably that is Sampling tube 20 in the middle of sucking in a batch of sample when the pulsation at the sampling tube inlet occurs.

On the other hand, the arrangement can also be made such that the sampling tube 20 is just immersed in the washing liquid container 24 when the pulsation 102 occurs at the inlet of the sampling tube 20. However, this can be unfavorable if the time to suck in the washing liquid is so short compared to the duration of the pulsation that the suction time for the washing liquid does not sufficiently cover the duration of the pulsation, so that the sucked in washing liquid thrust W can become too small.

Next, consider the effect of pulsation that occurs when a pump roller lifts from the squeezable pump hose 36. This operating state of the peristaltic pump 10 is shown in FIG. 2 shown. The pump roller 50 A just lifts off the pump hose and stops squeezing it together. The pulsation 104 running from right to left in the illustration shown ends at the pump roller 50 B, which firmly compresses the squeezable pump hose 36 at this point in time. The Pukaiion 104 running from left to right reaches the; T-piece 90, in which the sample sirom is brought together with the reagent liquid flow of the reagent liquid supply line. This can result in a wrong when the two streams are merged

309539/488

ίο

Sample batch-reagent fluid batch -mixing ratio- is that they come repeatedly small volume of each sample p nis. When the pulsation at the T-piece sucks in, separated from each other by small air thrusts A || a sample batch and a reagent liquid- are separated before the main batch of the sample to- · '■' ■ batch R coincides, the current min- is sucked. The small sample bursts take over the change of the sample burst flow with the consequence that in connection with the air bursts as a trend, this sample burst instead of the desired one fluid the function of the washing liquid and a significantly larger proportion of reagent liquid on both sides the residues of the previous sample are mixed so that there is an unusually high dilution of this batch of samples in order to contaminate the subsequent sample. To avoid this. In FIG. 5 there is shown a fluid flow, to avoid adverse effect or at least _1O of the decrease as a result of the operation described above, the length of the fluid flow is formed. The turntable 14, the sampling tube, extend from the point at which the pump 20, the peristaltic pump 10 and the T-piece roll from the squeezable pump 90 are lifted off the hose 36 in the manner described above, as is the case for the pump roller arranged and designed to ensure also 50/4 shown in Fig. 2, up to T-piece 15 that the inlet of the sampling tube is submerged in a 90 sample container in accordance with the fluid flow when the pulsation through that distance is so accurate predetermined that 102 of each pump roller 50 arrives at the inlet, the arrival of the pulsation 104 at the T-piece 90 with and that the arrival of the pulsation 104 of each pump arrival of an air segment A 1 or A 2 together at the T-piece 90 with the arrival of an air falls. As a result, the effect of the pulsation 104 20 segments A will coincide.

on the quantitative ratio between the sample and the entire arrangement is preferably such

the reagent liquid is switched off or hit so little that the pump rollers

kept as possible. In any case, there is at most squeezable pump hose 36 within one

at the beginning or at the end of a sample, a sample thrust thrust S 1, S2, S3 squeeze etc.

Disturbance of the mixing ratio takes place, which occurs instead of a separation fluid surge. This will

however does not affect the analysis result. avoided that by squeezing one

The sample treatment and ana air thrust A, not shown, is divided into two air bubbles, the

lysing device contains a colorimeter, which may no longer result in a single air

the treated sample batches, which then combine the sample segment A and then no longer in the

Form stream S , stream successively. The ₃₀ layers are to cover the entire cross-section of the

A strip chart recorder with zero squeezable pump hose 36 is to be filled in for the colorimeter. the

adjustment downstream, which divides the analysis results of an air segment into two separate air

records the sample batches. This is in detail blows that no longer cover the entire hose cross-

in U.S. Patent 3,241,432. Filling out the section would have the disadvantages mentioned above

in FIG. Curve 106 shown in FIG. 3 now results in 35.

the optical density of the treated sample batches Deviating from the arrangement described above

as a function of time, namely for three voltage you can use the peristaltic pump 10 but

successive batches of samples, which are also formed in such a way that a pump hose

Flow through the colorimeter cell. The pinch point should not point to a sample feed, but rather

It should be mentioned that for the colorimetric quantita- 4O there are two or more _{batches of samples.} In

In a tive analysis, only the middle section of each case should be the number of points of contact

traded sample batches are used and mounted on the pump rollers with the pump hose pro

is drawn. Changes in the optical sample should be as small as possible in order to reduce the

Thrust density, which is as low as possible, for example due to not using the Purnpcn hose 7H

Maintain proper sample to reagent ratio at 45.

Occur at the beginning and at the end of a sample batch. Although the invention is based on a sample batch

could, have no effect on the recording arrangement described, the blood serum samples

nings. for mixing with a color-producing reagent

Although in the representations according to FIGS. 1 supplies liquid, the invention also finds

and 2 before drawing in a new batch of sample 50 sample introduction assemblies application, the other

Use an air thrust A, a fluid, from the sample containers 16. Furthermore, the invention is not

Washer fluid thrust W and another air limited to a supply arrangement in which one

Thrust A are sucked in, the sample peristaltic pump can convey the sample flow. the

feed device 12 also modify so that the invention can rather be used in conjunction with all

Washing liquid container 24 is omitted and ₅₅ pumping devices are used, the pulsa-

the sampling device 18 controlled in such a way generate functions of the type described.

1 sheet of drawings

Claims (1)

Patent claims: I. Method of diminishing the effect pulsations in an intermittently working draws a separation fluid via a pump inlet direction to form a first fluid stream which consists of a series of fluid bursts from the first fluid, each through a separating fluid protector are separated from each other.