DE102019120852A1 - Centrifugal pump and process for temperature control - Google Patents

Abstract

Centrifugal pump (1) for pumping a temperature control medium, in particular for pumping a temperature control medium for extracorporeal temperature control of patients, with a chamber (3), a rotor (5) which is arranged in the chamber (3), the chamber (3) having : an inlet (7), an outlet (9) and a central tap (11), the inlet (7), the central tap (11) and the outlet (9) in this order from radially inside to radially outside with respect to an axis of rotation ( 15) of the rotor (5) are arranged in the chamber (3).

Description

Field of invention

The invention relates to a centrifugal pump for pumping a fluid, in particular for pumping a liquid temperature control medium for the extracorporeal temperature control of patients and a method for temperature control.

State of the art

For extracorporeal temperature control of patients, methods and devices are known which use or include centrifugal pumps for pumping a temperature control medium. In the case of centrifugal pumps, two separate centrifugal pump chambers along a pump shaft or two separate centrifugal pumps are used in many cases to generate an overpressure at one connection of the centrifugal pump and a negative pressure at another connection of the centrifugal pump. In many cases, a water-based liquid is used as a temperature control medium to transport heat or cold.

However, previously known solutions from the prior art require complex sealing of the centrifugal pump, the chambers of the centrifugal pump must be operated in a liquid bath, have restrictions with regard to the structural volume or with regard to the permanent fulfillment of hygiene requirements, or they are just complex to clean. Two separate centrifugal pumps also cause a lot of effort and require twice the installation space.

Disclosure of the invention

The invention is based on the object of specifying an improved centrifugal pump for pumping a fluid, in particular for pumping a liquid temperature control medium for extracorporeal temperature control of patients, and an improved method for temperature control. In particular, the structure should be simplified or the hygiene improved, or the structure should be easier to clean or otherwise facilitate compliance with hygiene standards.

According to one aspect of the invention, a centrifugal pump for pumping a fluid, in particular a liquid temperature control medium, in particular for pumping a liquid temperature control medium for extracorporeal temperature control of patients or for applying technical temperature control applications, with a chamber, a rotor, which is arranged in the chamber wherein the chamber comprises: an inlet, an outlet and a central tap, the inlet, the central tap and the outlet being arranged in this order from radially inward to radially outward with respect to an axis of rotation of the rotor in the chamber. Typical temperature control media or fluids which are used in connection with exemplary embodiments are liquid.

According to a further aspect of the invention, a temperature control circuit is specified which has a centrifugal pump according to one of the embodiments described herein as a pressure / suction pump. The temperature control circuit can, for example, apart from an expansion tank that is open to the environment, be constructed hydraulically closed or hydraulically open.

According to a further aspect of the invention, a method for temperature control, in particular for extracorporeal temperature control of patients or for applying technical temperature control applications, in particular for cardioplegia or hypothermia, using a centrifugal pump, in particular corresponding to a centrifugal pump according to one of the embodiments described herein, with connection of a Circulation of a temperature control medium to an inlet of a chamber of the centrifugal pump and to an outlet of the chamber, connection of an expansion tank to a central tap of the chamber, the inlet, the central tap and the outlet in this order from radially inside to radially outside with respect to an axis of rotation of the centrifugal pump in the chamber, and after connecting, using the centrifugal pump to pump the temperature control medium.

Typical centrifugal pumps are connected to a temperature control circuit in which a liquid temperature control medium can be received. With the temperature control circuit, a body fluid of a patient or an animal is temperature-controlled extracorporeally in typical embodiments. In typical embodiments, the temperature control medium comprises at least 90% by weight or at least 95% by weight of water, in particular water for injection purposes (WFI). In a typical embodiment, the temperature control medium is a physiological or isotonic medium. Typically, the temperature control medium is sterile or largely germ-free and has, for example, fewer than 1000 or a maximum of 100 colony-forming, aerobic germs per liter. Physiological or isotonic media are, for example, a 0.9% solution with table salt (sodium chloride, NaCl) or a Ringer's solution.

In typical embodiments, the centrifugal pump is designed as a pressure / suction pump. The centrifugal pump is typically set up to provide a negative pressure at the inlet, the negative pressure being less than a reference pressure an the center tap, and an overpressure at the outlet, the overpressure being greater than the reference pressure at the center tap. In particular, the center tap can be connected to a compensation vessel in which ambient pressure or atmospheric pressure prevails. For example, the centrifugal pump can be set up in such a way that ambient pressure or atmospheric pressure prevails at the center tap. Typically, the centrifugal pump is set up such that temperature control medium flows into the chamber at the inlet and temperature control medium flows out of the chamber at the outlet during pumping.

In the present application, the terms “axial”, “radial” or “tangential” are typically to be understood in relation to the axis of rotation of the rotor of the centrifugal pump. In particular, “axial” can be understood to mean a direction parallel to or along the axis of rotation of the rotor, and “tangential” a direction perpendicular to a radial direction. In particular, the axis of rotation of the rotor corresponds to the axis of rotation of the centrifugal pump.

In typical embodiments, the inlet, the outlet or the center tap are designed as openings in the chamber. The inlet is typically aligned axially, in particular along the axis of rotation of the rotor. Typically, the center tap is located axially on the same side of the chamber as the inlet. In typical embodiments, the outlet is oriented at least substantially tangentially. The inlet, the outlet or the central tap are typically designed with a detachable connection, in particular for connecting the centrifugal pump to a connecting element or to a further connecting element, for example a hose or a pipe. In particular, the detachable connection can be designed as a bayonet connection.

In typical embodiments, the center tap is arranged at a distance of at least 20%, in particular at least 30% or at least 40%, of the radial distance between the inlet and the outlet from the axis of rotation of the rotor. In other typical embodiments, the center tap is arranged radially in the area of the rotor.

Typically, the center tap is arranged in a different radial direction with respect to the axis of rotation of the rotor than the outlet. In further typical embodiments, the central tap and the outlet, in particular the central tap, the outlet and the inlet, are arranged at least substantially along a single radial direction.

In typical embodiments, the center tap is axially aligned. In further typical embodiments, the center tap is oriented obliquely to an axial direction, in particular in a tangential direction and obliquely to an axial direction.

The center tap typically has an inner diameter of at most 30% of the rotor diameter, in particular of at most 25% or 20%. The “rotor diameter” is to be understood in particular as the diameter of the rotor with respect to the axis of rotation of the rotor. In typical embodiments, the center tap has an inside diameter of at least 1 mm, in particular of at least 3 mm or 5 mm, or of a maximum of 40 mm, in particular of a maximum of 30 mm or 25 mm.

In typical embodiments, a temperature control circuit or the centrifugal pump comprises an equalizing tank, which is in fluid connection with the central tap of the centrifugal pump. There is typically an ambient pressure in the expansion tank. In typical embodiments, the compensation vessel is open to the environment or is in fluid connection with the environment. In other typical embodiments, the compensation vessel is closed to the environment. In particular, the compensation vessel can have a flexible wall. For example, the compensation vessel can be designed as a flexible bag that is closed to the environment. Typically, a flexible wall of an expansion tank, for example a flexible wall of a bag, is set up to equalize a pressure inside the expansion tank and an ambient pressure outside the expansion tank.

In typical embodiments, the rotor is designed with one or more blades. The rotor is typically designed as a radial impeller. In particular, the rotor is designed to accelerate the temperature control medium radially outward during pumping.

Typically the rotor is designed as a magnetic stir bar. The rotor typically has magnetic properties, in particular ferromagnetic properties or permanent magnetic properties.

The rotor is typically magnetically supported or magnetically driven. In typical embodiments, the centrifugal pump includes a magnetic drive for driving the rotor, in particular a rotor, which is designed as a magnetic stir bar or has magnetic properties. Typically there is no direct physical contact between the magnetic drive and the Rotor. Driving a magnetic rotor or driving a rotor with an interposed magnetic coupling can have the advantage that no shaft has to be guided into the chamber and, in particular, a shaft seal is absolutely necessary.

In further typical embodiments, the rotor is driven via a shaft of a drive. Typically, the chamber includes a shaft opening through which the shaft for driving the rotor is guided. The shaft opening is typically arranged on the side of the chamber axially opposite the inlet. The shaft is typically sealed off from the shaft opening, in particular by a radial shaft sealing ring. The shaft is typically supported on one side, in particular on or outside the side of the chamber axially opposite the inlet.

In typical embodiments, the chamber comprises at least two chamber parts. The chamber parts are typically releasably connected to one another, for example by a bayonet connection. Typically, the chamber parts are sealed against one another, in particular by means of a housing seal.

In typical embodiments, at least one chamber part of the chamber or the rotor is designed as a disposable article for single use. In this way, reliable compliance with hygiene standards can be achieved. In particular, the chamber part intended for single use or the rotor intended for single use is not autoclavable. The chamber part or the rotor is typically made sterile or largely sterile. In further embodiments, the chamber part or the rotor is designed for multiple use, in particular constructed to be autoclavable. In this way, the chamber part or the rotor can be used several times, which saves waste.

The chamber is typically made at least essentially from metal, in particular from stainless steel. In further typical embodiments, the chamber is made at least essentially from plastic.

In typical embodiments, the rotor is made from metal or from plastic, for example from PTFE, in particular from metal and plastic.

For example, a rotor, in particular a magnetic stir bar, can be made of magnetic metal and plastic, in particular PTFE.

The centrifugal pump is typically designed in one stage. In particular, the centrifugal pump is designed as a single-stage pressure / suction pump. Typically the centrifugal pump has a single chamber or a single rotor.

In typical embodiments, the centrifugal pump has a delivery rate of at least 0.05 l / min, in particular at least 0.1 l / min or 1 l / min, for example at least 3 l / min or 5 l / min, or a maximum of 100 l / min, in particular from a maximum of 70 l / min or 50 l / min, for example from a maximum of 20 l / min or 15 l / min or 3 l / min. Typical delivery rates correspond to the delivery rates of 3 to 15 l / min required for patient temperature control. Typical delivery rates correspond to the delivery rates of 0.1 to 3 l / min required for cardioplegia application.

In typical embodiments of a temperature control circuit, the centrifugal pump is integrated into the temperature control circuit at the inlet and at the outlet. The centrifugal pump is typically connected at the inlet or at the outlet to further connecting elements of the temperature control circuit, for example a hose or a pipe. During pumping through the centrifugal pump, temperature control medium of the temperature control circuit typically flows into the chamber of the centrifugal pump at the inlet. Typically, temperature control medium flows out of the chamber at the outlet. The temperature control medium can, for example, be passed through a heat exchanger in the temperature control circuit. In typical embodiments, the temperature control circuit comprises at least one heat exchanger, in particular at least two heat exchangers. The centrifugal pump of the temperature control circuit is typically designed in one stage. The centrifugal pump of the temperature control circuit is typically surrounded by air. In particular, the centrifugal pump is not arranged in a liquid bath.

In typical embodiments of the method, using the centrifugal pump comprises providing a negative pressure at the inlet and providing an overpressure at the outlet, the negative pressure at the inlet being smaller than a reference pressure at the center tap, and the positive pressure being greater at the outlet as the reference pressure at the center tap. The reference pressure typically corresponds at least substantially to an ambient pressure.

The use of the centrifugal pump typically includes drawing in the temperature control medium at the inlet of the centrifugal pump. The use typically includes ejecting the temperature control medium at the outlet.

In typical embodiments, while the centrifugal pump is being used for pumping, the centrifugal pump, in particular a rotor of the centrifugal pump, is driven by means of a magnetic drive.

Typically, after the centrifugal pump has been used, the centrifugal pump is separated from the temperature control circuit or from the compensation tank. Typically, when the centrifugal pump is disconnected from the temperature control circuit or from the expansion tank, use of the centrifugal pump, use of a chamber part of the chamber or use of the rotor ends.

Typically, at least a chamber part of the chamber or a rotor of the centrifugal pump is disposed of after a certain number of uses. In typical embodiments, at least one chamber part or the rotor is disposed of after a single use. Disposal after a single use can, for example, at least reduce the formation of germs in a temperature control circuit.

In further typical embodiments, a chamber part of the chamber or a rotor of the centrifugal pump is disposed of after repeated use, in particular after at least 2 times, in particular at least 3 or 5 times, or after a maximum of 10 times, in particular after a maximum of 20 or maximum 30 times, use discarded. Repeated use can, for example, save waste.

Typically, after the centrifugal pump has been used, the centrifugal pump is cleaned or sterilized. In particular, in the case of a chamber with at least two chamber parts, the at least two chamber parts can be separated. The at least two chamber parts, in particular the at least two chamber parts and the rotor, are typically cleaned separately from one another, in particular mechanically cleaned, sterilized or dried. In typical embodiments, at least one of the at least two chamber parts or the rotor is disposed of. Separating the chamber parts can, for example, enable the chamber parts or the rotor to be cleaned or dried more easily or more thoroughly, which in particular improves the hygiene of the centrifugal pump. Typically, after cleaning, the centrifugal pump is used again, in particular when controlling the temperature of another patient.

Typically, the compensation vessel is at least partially filled with temperature control medium during use. Typically, there is ambient pressure in the expansion tank during use. In further embodiments, a pressure which differs from the ambient pressure can be set in the compensation tank, for example in order to influence the suction or pressure performance of the centrifugal pump.

Typically, the centrifugal pump is surrounded by air during use or during operation. In particular, the chamber of the centrifugal pump is surrounded by air on the outside during use. Typically, the centrifugal pump is not placed in a liquid bath during use. The centrifugal pump according to embodiments offers the advantage that, compared to two-stage pumps, there are fewer critical seals, so that a liquid bath does not have to be absolutely necessary for operation.

Typical advantages of embodiments include, for example, that a centrifugal pump can be designed as a single-stage pressure / suction pump. The centrifugal pump can be designed with less structural volume. Another advantage can be that the centrifugal pump can be operated without a liquid bath. For example, the centrifugal pump can be sealed more easily or have a lower risk of contamination of the temperature control medium. In particular, embodiments, for example embodiments with a magnetic drive, can be implemented without a seal on a pump shaft. Another advantage can be that embodiments have a simpler structure. Embodiments may be easier to clean, sterilize, or dry, or include parts that can be made as disposable or disposable. Embodiments can improve the hygiene of centrifugal pumps or temperature control circuits, in particular in cardioplegia, hypothermia, in circuits for blood heat exchangers or for oxygenators.

Figure list

• 1 eine schematische Aufsicht einer typischen Kreiselpumpe;
• 2 eine schematische Seitenansicht einer typischen Kreiselpumpe;
• 3 eine schematische Aufsicht einer weiteren typischen Kreiselpumpe;
• 4 eine schematische Ansicht einer typischen Kreiselpumpe mit Ausgleichsgefäß;
• 5 eine schematische Ansicht eines typischen Temperierkreislaufs;
• 6 ein Verfahren in einer typischen Ausführungsform.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings. Show in it:

• 1 a schematic top view of a typical centrifugal pump;
• 2 a schematic side view of a typical centrifugal pump;
• 3 a schematic plan view of another typical centrifugal pump;
• 4th a schematic view of a typical centrifugal pump with compensation tank;
• 5 a schematic view of a typical temperature control circuit;
• 6 a method in a typical embodiment.

Description of the exemplary embodiments shown in the figures

Typical exemplary embodiments of the invention are described below, with the same reference numerals being used in some cases for the same or similar parts and, under certain circumstances, not being explained again with each figure. The invention is not restricted to the typical embodiments described below. For the sake of clarity, in some cases not all respective features can be provided with a reference symbol.

In the 1 is a schematic plan view of a centrifugal pump 1 which is a typical embodiment of the invention. Under “supervision” here is a view perpendicular to the axis of rotation of a rotor 5 the centrifugal pump 1 to understand. The centrifugal pump 1 includes a chamber 3 with an inlet 7th , an outlet 9 and a center tap 11 . The one in the chamber 3 arranged rotor 5 is indicated with dashed lines. The rotor 5 is freely rotatable in the chamber. Typically the rotor 5 around the axis of rotation of the rotor 5 in one direction of rotation 13 of the rotor 5 driven, for example by a magnetic drive (not shown).

In the 1 runs the axis of rotation of the rotor 5 at least substantially perpendicular to the view of FIG 1 and at least substantially centrally through the inlet 7th the centrifugal pump 1 . The inlet 7th , the center tap 11 and the outlet 9 are in this order with respect to the axis of rotation of the rotor 5 arranged from radially inside to radially outside. The inlet 7th , the center tap 11 and the outlet 9 are as openings in the chamber 3 carried out and include in the exemplary embodiment of 1 each one from the respective opening of the chamber 3 outward connection. The inlet 7th and the center tap 11 are axially aligned, the outlet 9 aligned tangentially.

In the 2 Figure 3 is a schematic side view of a typical centrifugal pump 1 shown. The inlet 7th is along the axis of rotation 15th of the rotor 5 arranged. The center tap 11 is at a radial center tap position 18th at a distance 19th to the axis of rotation 15th arranged. The outlet 9 is at a radial outlet position 17th at a radial distance 20th from the inlet 7th away. In the embodiment of 2 is the distance 19th the center tap 11 from the axis of rotation 15th more than 20% of the radial distance 20th between the inlet 7th and the outlet 9 .

The 3 shows a schematic plan view of a further typical embodiment of a centrifugal pump 1 . The center tap 11 is radial between the inlet 7th and the outlet 9 arranged. The center tap 11 is with respect to the axis of rotation of the rotor 5 arranged in a different radial direction than the outlet 9 . In the 3 the center tap is axially on the same side of the chamber 3 arranged like the inlet 7th . A connection to the center tap 11 is at an angle to the plane of view 3 and aligned at least substantially in a tangential direction. For example, when aligning a connection, the center tap 11 at an angle to the plane of view during pumping, a dynamic pressure or a dynamic pressure or a sum of them at the center tap 11 form.

The 4th Figure 3 shows a schematic view of a typical centrifugal pump 1 with a compensating vessel 25th , which with the center tap 11 via a connecting element 23 , in the 4th a hose in fluid communication. The compensation tank 25th is particularly during use of the centrifugal pump 1 for pumping at least partially with temperature control medium 27 filled. The compensation tank 25th is for coupling 29 the pressure inside the expansion tank 25th to an ambient pressure outside the expansion tank 25th furnished. In the 4th is the compensation tank 25th designed as a flexible bag.

In the 5 Figure 4 is a schematic view of a typical temperature control circuit 31 shown. The temperature control circuit 31 includes a centrifugal pump 1 according to one of the embodiments described herein, for example the centrifugal pump 1 the 4th with a compensating vessel 25th . The temperature control circuit 31 the 5 includes further fasteners 35 , for example hoses, which provide a fluid connection between a heat exchanger 33 and the inlet 7th and a fluid connection between the heat exchanger 33 and the outlet 9 produce. The temperature control circuit 31 comprises a temperature control medium, which is in a hydraulically closed circuit of the temperature control circuit 31 by the centrifugal pump 1 can be pumped.

While pumping with a typical centrifugal pump 1 can be a temperature control medium, which at the inlet 7th into the chamber 3 enters through the rotor 5 are accelerated radially outward and at the outlet 9 out of the chamber 3 step out. This allows between the outlet 9 and the inlet 7th form a pressure gradient. Through the center tap 11 which radially between the inlet 7th and the outlet 9 is arranged, the pressure can be at the center tap 11 for example, can be set at least substantially to an ambient pressure. Due to the pressure differential between the inlet 7th and the outlet 9 can at the inlet 7th a negative pressure with respect to the ambient pressure and at the outlet 9 an overpressure with respect to the ambient pressure can be generated. The centrifugal pump 1 can be used as a pressure / suction pump.

The 6 shows a procedure 100 according to a typical embodiment described herein. At 110 a temperature control circuit of a temperature control medium is connected to an inlet of a chamber of a centrifugal pump and to an outlet of the chamber.

At 120 a compensation tank is connected to a central tap of the chamber, the inlet, the central tap and the outlet being arranged in this order from radially inside to radially outside with respect to an axis of rotation of the centrifugal pump in the chamber. The compensation vessel is at least partially filled with temperature control medium. The pressure inside the expansion tank is coupled to an ambient pressure outside the expansion tank. In further embodiments, the expansion tank is connected before or during the connection of the temperature control circuit to the inlet and the outlet.

After connecting the centrifugal pump will be at 130 used for pumping the temperature control medium. The temperature control medium is pumped through at least one heat exchanger in the temperature control circuit. In the heat exchanger, in particular in a blood heat exchanger, the temperature control medium can, for example, absorb heat from the blood of a patient or an animal or give off heat to the blood. The temperature control medium can be pumped in the temperature control circuit through a further heat exchanger in which a temperature of the temperature control medium is regulated. The centrifugal pump is at 130 surrounded by air. A rotor of the centrifugal pump is driven magnetically.

In the exemplary embodiment of the method of 6 is at 140 the centrifugal pump is separated from the temperature control circuit and, in particular, emptied.

At 150 In a centrifugal pump which comprises at least two chamber parts, the chamber parts and in particular the rotor are separated from one another.

At 160 the centrifugal pump is cleaned. In particular, in the case of a centrifugal pump which comprises at least two chamber parts, the chamber parts and in particular the rotor can be cleaned, sterilized or dried separately. In further typical embodiments, at 160 at least one chamber part or the rotor disposed of.

After 160 can the centrifugal pump or parts of the centrifugal pump can be re-used in a method according to method 100 be used, especially for a certain number of uses.

Claims (16)

Centrifugal pump (1) for pumping a fluid, in particular a liquid temperature control medium, in particular for pumping a liquid temperature control medium for extracorporeal temperature control of patients with - a chamber (3); - A rotor (5) which is arranged in the chamber (3); - wherein the chamber (3) has: o an inlet (7), o an outlet (9) and o a center tap (11), - wherein the inlet (7), the central tap (11) and the outlet (9) are arranged in this order from radially inside to radially outside with respect to an axis of rotation (15) of the rotor (5) in the chamber (3). Centrifugal pump (1) Claim 1 , wherein at least one chamber part of the chamber (3) and / or the rotor (5) is designed as a disposable article for single use. Centrifugal pump (1) according to one of the preceding claims, wherein the center tap (11) from the axis of rotation (15) of the rotor (5) at a distance (19) of at least 20% of the radial distance (20) between the inlet (7) and the outlet (9) is arranged. Centrifugal pump (1) according to one of the preceding claims, wherein the center tap (11) has an inner diameter of at most 25% of the rotor diameter. Centrifugal pump (1) according to one of the preceding claims, wherein the centrifugal pump (1) comprises an equalizing tank (25) which is in fluid connection with the center tap (11). Centrifugal pump (1) Claim 5 , with ambient pressure prevailing in the expansion tank (25). Centrifugal pump (1) according to one of the preceding claims, wherein the rotor (5) is designed as a magnetic stirring bar and / or as a radial impeller. Centrifugal pump (1) according to one of the preceding claims, wherein the rotor (5) is designed with one or more blades and is magnetically supported and / or magnetically driven. Centrifugal pump (1) according to one of the preceding claims, wherein the chamber (3) comprises at least two chamber parts. Centrifugal pump (1) according to one of the preceding claims, wherein the centrifugal pump (1) is designed in one stage. Temperature control circuit, in particular for pumping a liquid temperature control medium for extracorporeal temperature control of patients and / or for the application of technical temperature control applications, which has a centrifugal pump (1) according to one of the preceding claims as pressure / suction pump. Method (100) for temperature control, in particular for extracorporeal temperature control of patients, in particular for cardioplegia and / or hypothermia and / or for the application of technical temperature control applications, using a centrifugal pump, in particular a centrifugal pump (1) according to one of the Claims 1 to 10 , with - connecting (110) a temperature control circuit of a liquid temperature control medium to an inlet of a chamber of the centrifugal pump and to an outlet of the chamber; - connecting (120) a compensation tank to a central tap of the chamber, the inlet, the central tap and the outlet being arranged in this order from radially inside to radially outside with respect to an axis of rotation of the centrifugal pump in the chamber; and - after connecting (110, 120), using (130) the centrifugal pump for pumping the temperature control medium. Method (100) according to Claim 12 wherein using (130) the centrifugal pump comprises providing a negative pressure at the inlet and providing a positive pressure at the outlet; wherein the negative pressure at the inlet is less than a reference pressure at the center tap, and wherein the overpressure at the outlet is greater than the reference pressure at the center tap. Method (100) according to one of the Claims 12 to 13 , at least a chamber part of the chamber and / or a rotor of the centrifugal pump being disposed of after a certain number of uses. Method (100) according to one of the Claims 12 to 14th , wherein the compensation vessel is at least partially filled with temperature control medium during use (130). Method (100) according to one of the Claims 12 to 15th wherein the centrifugal pump is surrounded by air during use (130).

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