DE1911538B2 - Device for pumping a fluid along a flow path - Google Patents

Description

is held. predetermined pressure difference between the

2. Apparatus according to claim 1, characterized in that the inlet and outlet ends of the flow path indicates that the line section (40, 25 has.

46, ...) with high flow resistance than in automatic analyzers and similar devices

formed helical pipe coil, it is particularly necessary to use continuous,

is. maintain uniform liquid flows.

3. Apparatus according to claim 1, characterized- For this reason, the invention is characterized in the following r that the line section (40, 30 also in connection with the maintenance of a

46, ...) with high flow resistance as a continuous, uniform flow of liquid

Capillary is formed. explained in more detail in an analyzer.

4. Device according to one of claims 1 In automatic analyzers, such as those from the USA.-Pabis 3, characterized in that the institution specification 2 797 149 are known, there will be many

j ·, device (30, 32, 34, 36) from a sub-35 liquid sample in the form of a liquid flow

i Pressurized fluid source at the inlet of the driven one behind the other through a pipeline,

P consists of a flow path and the fluid is pretreated in succession to the analysis by taking

? constant pressure. they are provided with suitable reagents, for example

5. Device according to one of claims 1 mixed or heated, and then after- * to 4, characterized in that the flow 40 analyzes each other colorimetrically or flame photometrically ■ innngsbahn when pumping through a liquid. The successive samples is closed usually upstream _(one with the liquid gp ^f üllter another by inclusions from I container (38), the liquid non-miscible with them medium, eg. B.] j keitsauslaßöffnung to the line (72) connected to a gas or a liquid, and at a distance, and from which the liquid is expelled by means of a 45 and each individual sample can be divided into several thrusts by means of such high-pressure fluids dividing it into batches serves to divide off partial quantities I 6. Device according to claim 4 or 5, da- the samples and with a proporlio-I characterized in that the fluid source has a nal amount of the reagent uniformly to I compressed gas source (30) 50 and on the other hand the inner walls of the I 7. Device according to claim 6, characterized in that the transport tubes are kept clean Pressurized gas of the various media, ie the sample liquid source (30) is connected to a pressure regulator. speed, the air forming the inserts, the reagents I 8. Device according to one of claims 5 and the like, for example one from the USA.-Pajj to 7, characterized in that several hose squeezing known with 55 tentschrift 2 797 149 I Liquids-filled containers (38, 52, 58) can be used for the backing pump. Such a pump is seen, each having a liquid outlet opening a number of one behind the other arranged \ voltage, each via a line, which metal rods, which on a number of perpendicular to I a section (40, 54, 60) with large The elastic pump hoses arranged in a flow direction stand and act in the direction of flow and close these one after the other in their longitudinal direction with a relatively small direction. An improved hose I flow resistance, to the Transquetschpunipc is from the USA patent. Portröhrensystem are connected. 2935 028 known, in which the pump hoses

9. Apparatus according to claim 8, thereby progressively closed by nip rollers

ϊ indicates that 65 are between the transport tubes. U.S. Patent 3,306,229 is

s r system and the pressurized gas source, or finally an even further improved hose

i. several more, one constant, high current squeeze pump are described. This patent is also

1; tion resistance having lines (46,50) pointed out in detail the problems that arise

result in terms of a continuous flow of liquid when using a peristaltic pump in automatic analyzers. The liquid flows that are used in commercial analyzers are between 0.005 and 4.0 cm ³ / min.

For continuous discharge of liquids other devices have also been proposed with a uniform flow rate been. According to one proposal, a gas powered device is used with the one Liquid in the pnem storage container is uniformly ionized and at the same time in the flame a flame photometer is brought. Here, a closed-loop control system is kept under high pressure Gas first through a high resistance and then through a small resistance driven, which contains the reservoir for the liquid and the burner. Fluctuations in The resistance value of the small resistor and the burner only have a low EmNuS on the flow rate of the gas, which essentially depends on the high resistance. Pie flow velocity of the liquid is in this system of viscosity differences, temperature changes, minor blockages of the 1 transport tubes and the like. Sufficiently independent. However, this only applies in the event that a steady state is present, d. H. for the asymptotic case that the liquid flow approaches an equilibrium value as the pressure in the reservoir containing the sample and do the gas flowing into this reservoir. As long as the state of equilibrium is not reached, none of the values is constant. If you use such a device with a container that has a has a small volume, then the period of time until the equilibrium value is reached can be approximately be half a minute to a minute. For a larger system, such as those mentioned above Automatic analyzers, in which the volume of air in the container is about 500 ml, became the equilibrium reached only in about 15 to 30 minutes. Such a device is therefore for compensation Suitable for very slow changes, but not for short-term, sudden changes.

From U.S. Patents 3,488,154 and 3 284 164 automatic analyzers are known in which the fluctuations in the flow velocity of fluid flows are reduced by moving fluids under pressure through Kapillai tubes are pumped. In the device according to U.S. Patent 3,488,154 z. B. passed a liquid under pressure from containers through several capillary tubes, and also at In the device of U.S. Patent 3,284,164, a liquid under pressure is passed through pumped a measuring capillary tube, the pressure being kept constant. However, this is known Devices the constant flow rate are still inadequate. Due to temperature fluctuations the pressure can change via the changing viscosity of the liquid.

The invention is therefore based on the object for a device of the type mentioned to specify an arrangement by which the constancy of the flow velocity is improved.

The object is achieved in that the line section with high flow resistance the device for forming a predetermined pressure difference is directly connected and upstream of the line section with significantly lower flow resistance in the direction of flow and that the line section with high flow resistance is kept at a constant temperature is.

Compared to the known devices, which also have a glue section with high Flow resistance was switched on for pressure control, results from the erfindungsg.emäße additional temperature control of this line section with high flow resistance over the improved constancy of the viscosity of the liquid an improved constancy of the pressure.

The gas, which is at a regulated, high pressure, is preferably first fed into the liquid container and then the liquid zo through a high resistance and finally still driven by a small resistance, the transport tube system necessary for the pretreatment and the analyzer, e.g. B. a Kolorirnetei contains. By feeding the under high, constant Pressurized gas to the liquid container will have a very quick response to transient Changes ensured. The pressure in the liquid container builds up without any time delay on, d. that is, there is no delay in the flow of liquid. The high resistance is preferable a capillary that is kept at a constant temperature to accommodate any changes to avoid in the viscosity of the liquid.

Further developments and developments of the invention are set out in the subclaims.

In the following, exemplary embodiments of the invention are explained in more detail with reference to the drawings.

Fig. 1 shows schematically the principle; F i g. 2 shows the flow diagram of an automatic analyzer which is equipped with an exemplary embodiment of the device according to the invention and which is used to determine the concentration of glucose in a large number of blood samples. According to the schematic representation in FIG. 1, the device contains, in series connection, a source S for a gas which is at a high pressure kept constant by regulation, a resistor /?, With a high resistance value, for example a capillary with a relatively high flow resistance may contain, as well as a resistance R ₂ with a relatively small flow resistance, which is made up of the transport ^{tube system} required for the pretreatment and analysis.

One can differentiate between the following pressures: P ₁ , the driving pressure; P ₂ , the pressure measured downstream of R _1; and P ₃ , the outflow pressure, which here is equal to atmospheric pressure. The current Q through the system is proportional to P ₁ - P ₃ and inversely proportional to R ₁ + R " if one assumes that there is no gravitational gradient. This results in:

The complete, for pretreatment and analysis

The transport tube system required by a commercial automatic analyzer _{develops a pressure of about 20 cm H 2} O. If P ₁ is regulated to an overpressure of one atmosphere, then P ₁ -P _{3 = 1033CmH 2} O and P ₁ -P ₂ = 1013CmH ₂ O. This results in:

* k ²⁰
Ε, ⁼ 1013 '

_{P 1} and R ₁ are therefore mainly decisive for the flow , whereas significant changes in R ₂ , seen in percentages, which result in the transport tube system used for the pretreatment and analysis, do not significantly affect the flow Q. An increase of R ₂ by 100 ⁰ Zo would result in a change of only 2 °, o in the current Q , for example.

It is advisable to keep the resistance tube at a constant temperature in order to avoid changes in the viscosity of the media flowing through and thus the flow velocities.

The F i g. 2 shows the transport tube system of an automatic analyzer used to determine the concentration of glucose in blood samples is suitable.

In a sample supply device 10, which is known, for example, from US Pat. No. 3,230,776, a plurality of sample cups 12 is held, which are gradually guided one after the other to a removal station 14 which has a removal tube 16. The Entnahmernhr wi.d in the respectively located at the Ent "-ihnn_> i2tion sample cup ciiijetaucht damii Sc FlürsigkeHaprebe be sucked k;. Tnn the downstream g-.iegene end of the sampling tube is connected by a transport tube 18 with the F.ingangsendc a pump hose. 20 of a peristaltic squeeze pump 22 shown, for example, in US Pat. No. 3,306,229 In this way, the sample liquid is sucked out of the sample beaker by the sampling clock.

Fine gas bottle 30. for example with nitrogen is filled. which is at a pressure of 1.52-107 Newtons m- (2200 psi) is about a pressure regulator 32 and a further pressure regulator 34 connected to a manifold 36, which on a constant pressure of, for example, 66.8 cm Hg is maintained.

A reservoir 38 that is partially filled with a diluent, such as water is. has a short inlet tube connected to manifold 36 and a long one, in the liquid-submerged outlet tube which connects via a transport tube 42 to the inlet side of a coil 40 connected by high resistance. The distributor pipe is through a transport pipe 44 36 connected to a coil 46 of high resistance. Through another transport tube 48, the manifold 36 is connected to a coil 50 of high resistance. Another, Storage container 52 filled with a diluent such as water also has a short inlet pipe connected to manifold 36 and a long outlet pipe connected to the manifold 36 a transport tube 56 is connected to a coil 5 ^ of high resistance. Finally is another reservoir 58 for a reagent center: like. for example ferricyanide provided, the eir short inlet pipe connected to the manifold 36 and a long outlet pipe connected to the manifold 36 Iron transport tube 62 with the input side one

ίο Coiled pipe 60 connected by high resistance is.

The inside diameters of the high drag coils 40, 46, 50, 54 and 60 are relatively small, e.g. 0.25 mm.

while the length of the pipe coils is relatively large, for example 5.3 m for liquids, so that the desired high resistance and the resulting flow velocity is achieved. In which The sample liquid also flows through the pump tube 20 as described in the exemplary embodiment described a rate of 0.1 ml / min, the water through the coil 40 at a flow rate of 0.5 ml / min, the nitrogen through coil 46 at a flow rate of 0.2 ml'min, the nitrogen through the coil 50 at a flow rate of 0.2 ml / min, water through the coil 54 at a flow rate of 0.6 ml / min and the ferricyanide solution through coil 60 at a flow rate of 0.5 ml min. The coils are placed in a thermostatic bath 64 which is kept at 37.degree so that the media pass through the pipe connections at a constant temperature and viscosity stream. The reservoirs 38, 52 and 58 as well as the connecting transport tubes can preferably also in a constant temperature bath or similar facility be arranged.

The coils with high resistance ensure that the flow speed of the through them flowing media change linearly with the pressure differences on them. A common Change the pressure on all coils

hence a uniform, proportional change in flow velocities to the foke.

A Tr.insportröhre connected to the pipe coil 46 70 opens into a transport roller 72 connected to the pipe coil 40. whereby that Thinner through (nis inclusions in batches is divided. Through a transport tube 74 connected to the pump hose 20, which is behind it in the transport tube 72 opens, the sample liquid is added to the batches of the diluent

leads. The transport tube 72 leads to a horizontal arranged mixing tube coil 76, for example from US Pat. No. 2,933,293 is known. The output end of the mixing tube coil is via a transport tube 78 with the fio input side of the delivery channel 80 of his dialyzer 82 which is known from U.S. Patent 3,333,706. The home page of this Channel 80 leads to the drain.

A transport tube 84 connected to the output side of the pipe coil 50 opens into one transport tube 86 connected to the coil 54, whereby the diluent flowing through this tube in spaced apart by gas inclusions

^; Thrusts being split. The transport tube 86 leads to the receiving channel 88 of the dialyzer 82, in which some of the samples are transferred through the membrane into the diluent pots Syird. A transport tube 90 connected to the pipe coil 60 opens into a transport tube 92 connected to the outlet side of the receiving channel 88 , as a result of which the reagent is supplied to the diluent batches containing the sample. The introduction of the gas inclusions in the correct phase into the streams flowing through the dispensing and receiving channels is preferably controlled by valves, as described, for example, in U.S. Patent 3,306,229. For this purpose, the transport tube 70 contains an elastic piece of hose which is normally closed by a pinch cock 94 a, while the transport tube 84 has an elastic Schlanchstück which is normally closed by a pinch cock 946. The squeeze cocks are periodically opened by the pump 22 so that the gas can flow through the transport tubes . The transport tube 92 leads to a horizontally arranged mixing tube coil 96, the output side of which is connected to a reaction tube coil 98 which is arranged in a heating bath 100. This device is known from USA.-Fa tentschrift 3,057,603. The mixing tube coil can have an inside diameter of 2 mm and can be kept at 90.degree.

The output side of the reaction tube coil is connected via a transport tube 102 to the input side of a flow cell 104 of a colorimeter IG6. A flow cell can be used as the flow cell, as already proposed in German Offenlegungsschrift 1 673 143. Such a flow cell has an upper passage 108 , the input side of which is connected to the transport roller 102 and the output side of which leads to the drain. It also has a measuring chamber 110 underneath. the inlet side of which is connected to a central opening in the passage 108 and the outlet side of which is connected to a pump hose 112. The pinch hose 112 is also located in the peristaltic pump 22. As a result, a stream of the pretreated sample liquid freed of the gas infiltration is sucked through the measuring chamber and then to the drain at a flow rate of, for example, 0.8 ml / min. With another execution

5.0 approximation form can also be apart from the elimination of the gas inclusions upstream of the measuring chamber and the entire liquid flow divided by gas inclusions can be passed through the flow cell. Such a measure has already been proposed in German Offenlegungsschrift No. 1,673,103. The colorimeter 106 includes a conventional light source 114, filters (not shown), and a light detector 116 connected to a recorder 118 . The one for the colorimeter

Ao and recording device belong to the same facilities are known, for example, from U.S. Patent 3,236,148.

The device is in communication in the provident with a special one for the mood of glucose suitable transport tube system described. The device can also on Such transport tube systems are used with other measuring devices such as nut Flame photo eggs work.

Suitable transport tube systems, such as dialyzers, heating baths or colorimeters can contain, for example, in Jer U.S. Patent 3,241,432. Most of the pump hoses described there through the transport tube described here, which is at regulated pressure and the one ·.:! high resistance coils will. In individual cases, the K0I01 meter shown can be used, for example, by a flame photomc: · r to be replaced according to U.S. Patent 3 177758, namely if, for example, a transport tube system suitable for the determination of sodium or potassium described in said U.S. Patent 3,241,432.

1 sheet of drawings

409521/186

Claims (1)

I are provided with the intermittent loading I claims: operable valves (94 α, 94 b) connected in series I am. I 1. Device for pumping a fluid lengthways 10. Device according to one of claims 1 I a flow path which has a line section 5 to 9, characterized in that the line I with high flow resistance, select a line section with high flow resistance I section with much lower flow is a pipe so long that the flow I resisted the flow rate of an automatic analyzer I with its transport tube system, and fluids linearly with the I a device for the formation of a previous io the pressure difference can be changed.
I determined the pressure difference between the inlet I and the outlet end of the flow path. I shows, characterized in that the I Line section with high flow resistance I was (40, 46, 50, 54, 60) with facility 15 I (30, 32, 34, 36) to form a los- The invention relates to a device for I specific pressure difference is directly connected to pumping a fluid along a flow path that I and the line section with significantly low a line section with high flow resistance There is less flow resistance in the direction of flow, a line section with significantly low I device is connected upstream and that the line 20 riseren flow resistance, which is an automatic I section (40, 46, 50, 54, 60) with a high flow analyzer with its transport tube system f includes resistance at constant temperature, and means for forming a