DE102008041503A1 - Sealing arrangement for e.g. micro-fluid piston pump of high pressure liquid chromatography system, has disk-shaped flange section comprising projection that is turned away from sealing section - Google Patents

Abstract

The arrangement (108) has a sealing section (110) with an inner sealing surface (112) for abutting against a piston (102), and an outer sealing surface (114) for abutting against a seal end piece (106). A disk-shaped flange section (116) is attached at an end section of the sealing section for abutting against a piston housing (104). A circular spring (124) presses internal and outside sealing rims (120, 122) against the piston and the end piece, respectively. The flange section has a projection (118) turned away from the sealing section. Independent claims are also included for the following: (1) a measuring instrument for performing measurement of a sample (2) a method for pumping a fluid (3) a piston pump comprising a seal end piece that exhibits central drilling.

Description

TECHNICAL BACKGROUND

The The present invention relates to seals for piston pumps, especially for HPLC.

In HPLC, a liquid (mobile phase) is typically run at a very precisely controlled flow rate (eg in the range of microliters to milliliters per minute) and at a high pressure (typically 20 to 1000 bar and beyond, currently up to 2000 bar), where the compressibility of the liquid is appreciable, is moved through a stationary phase (eg, a chromatographic column) to separate individual components of a sample liquid introduced into the mobile phase. Such an HPLC system is known for. B. from the EP 0,309,596 B1 Applicant, Agilent Technologies, Inc., which has a dual-serial pumping device.

One System for liquid chromatography in particular the IC system of the Agilent 1200 series of the assignee Agilent Technologies, Inc., dar.

In such and other measuring devices, a piston pump for Use come with the fluidic solutions or samples be pumped through the meter. In such a piston pump can Be provided sealing measures.

DE 9110799 discloses a seal assembly of a piston pump in which a piston is movably mounted in a displacement chamber of the pump, with a positive seal sealing flange seal, which is pressed by a Dichtungsendplatte in a corresponding recess of the pump housing, wherein at least the Dichtungsendplatte or the pump housing, a cutting edge have, which engages in the flange portion of the seal.

EPIPHANY

It It is an object of the invention to provide an efficient seal of a piston pump to enable. The task is done by means of the independent Claims solved. Further embodiments are shown in the dependent claims.

According to one exemplary embodiment is a sealing arrangement for a piston pump for pumping a fluid, wherein in the piston pump, a piston in a displacement chamber the piston pump is movably arranged, wherein the sealing arrangement for sealing the displacer space between the piston, a piston housing and a sealing end piece is providable, wherein the sealing arrangement with a sealing portion an inner and an outer sealing surface, wherein the inner sealing surface for abutment against the piston and the outer sealing surface for abutment is provided on the sealing end piece, and a substantially having disc-shaped flange portion which is connected to a End portion of the sealing portion is attached to abut the piston housing is provided and at its the sealing portion opposite side a supernatant (or a bulge, which projects in the direction of the piston housing).

According to one Another exemplary embodiment is a piston pump created for pumping a fluid, wherein the piston pump a Piston movable in a displacement chamber of the piston pump is arranged, a piston housing, a sealing end piece and a sealing arrangement with the features described above, wherein the sealing arrangement for sealing the displacement chamber between the piston, the piston housing and the sealing end piece is provided.

According to Another exemplary embodiment is a Measuring device for performing a measurement on a Sample provided using a fluid, wherein the measuring device a piston pump with the features described above for pumping of the fluid in the meter.

According to one Another exemplary embodiment is a method for pumping a fluid by means of a piston pump, wherein at the method of the piston of the piston pump in a displacement chamber the piston pump is moved to pump the fluid and the displacer between the piston, a piston housing and a sealing end piece is sealed by a sealing arrangement, wherein the sealing arrangement a Sealing section with an inner and an outer Has sealing surface, wherein the inner sealing surface abuts the piston and the outer sealing surface abuts the sealing end piece, and wherein the sealing arrangement a disc-shaped flange portion, the on an end portion of the sealing portion is attached to the piston housing abuts and on its side facing away from the sealing portion a supernatant having.

According to one exemplary embodiment of the invention, a seal is provided for a piston pump of a microfluidic arrangement, in which a sealing section of this seal is integrated substantially in an interior or in a recess of a sealing end piece. Towards the outside, that is pointing in the direction of a piston housing of the pump, protrudes a supernatant. At an inner sealing surface and at an outer sealing surface of Sealing portion of the seal may be applied to a major part of the stress, so that the seal remains tight on the cylinder surface even at high pressures of 600 to 1200 bar and more and a detrimental influence or even destruction of the pump head can be safely avoided. Such a sealing architecture has the particular advantage that a sealing-critical region is well protected against mechanical abrasion. As a result, a life of the seal can be increased. According to the invention can be achieved by means of the outwardly projecting supernatant for the flange, a good sealing effect, which can withstand high pressures. According to the invention, the supernatant faces a fluid chamber in the piston housing and faces away from the sealing end piece, so that a seal which is suitable in particular for high-pressure HPLC applications can be provided. A difference between an inventive and a conventional seal can be seen in the fact that according to the invention, a flange can be provided on a front side of cylindrical sealing surfaces, whereas a flange can be conventionally provided at the other end of cylindrical sealing surfaces.

in the Further, additional embodiments of the sealing arrangement described. These also apply to the piston pump, the Measuring device and the procedure.

Of the disc-shaped flange section, in which the supernatant is integrated, can be applied to the Dichtungsendstück be provided. The sealing end piece may be a hollow cylindrical component designed with outwardly stepped outer radii be, wherein in an inner recess of the sealing end piece the piston can reciprocate. In this float of the This piston is partially along a portion of the sealing end piece with a small radius and partly along the seal, in an inner recess of the sealing end piece can be accommodated with a larger radius. The sealing portion seals on the one hand the piston and on the other the sealing end piece off. In an upper end section the sealing arrangement is a flange-like attachment to the piston housing allowing, for example, with the sawtooth projection the sealing effect is supported even at high pressures can be.

Of the Sealing section can on the inner sealing surface an inner Sealing lip and on the outer sealing surface have an outer sealing lip, wherein between the inner sealing lip and the outer sealing lip a cavity for receiving an annular spring is formed can be so that by means of the annular spring, the inner Sealing lip against the piston is pressed and the outer Sealing lip against the Dichtungsendstück is pressed. With Such a double sealing lip configuration in conjunction with a compression spring, the sealing effect can be further improved.

Of the essentially disc-shaped flange portion can on its side facing the sealing portion have a recess. The indentation may be in terms of geometry geometry the bulge on the side facing away from the sealing portion of the Follow seal. The flange portion of the sealing arrangement can then a have substantially constant thickness.

in the Further embodiments of the piston pump will be described. These also apply to the sealing arrangement, the meter and the procedure.

at the piston pump, the sealing end piece a recess have, which is adapted to receive the sealing portion. Thus, the sealing end piece and sealing arrangement be provided corresponding to each other and in the Essentially without leaving gaps or voids to be assembled.

The Seal end piece may have a central bore, which is adapted to receive the piston. This hole can an inner diameter substantially equal to an outer diameter the piston corresponds, wherein also the sealing portion of the sealing arrangement an inner cylindrical cavity can form, the also essentially the outer diameter of the piston equivalent. Such a configuration can provide a secure sealing effect be enabled and simultaneously a low-friction movement of the Pistons are allowed.

The Piston housing may have a recess, which for Picking up the supernatant of the disc-shaped Flange section set (in particular shaped accordingly and dimensioned). By also the geometry of the piston housing adapted to the geometry of the sealing arrangement can also in the flange portion by means of the supernatant in combination with the indentation in the piston housing at this point an undesirable leakage of a liquid avoided become.

The seal according to the invention can flexibly adapt to the slightly variable geometric conditions during an up and down movement of the piston and thus continuously provide a reliable sealing effect. Such a sealing arrangement may be, for example, a metal part seal, but may alternatively be made of plastic (for example PE, PTFE). Such seals may also optionally include additives such as For example, contain carbon fibers or ceramics to further improve the sealing effect.

The Piston pump can be used to pump a fluid (for example, a fluid and / or a gas, wherein also be a solid component attached can) in a meter with a pressure of at least about 500 bar, in particular of at least about 800 bar, more particularly at least about 1200 be set up bar. At such high pressures, as for example in life science applications such as HPLC can occur is the lifespan increase the piston pump is an important aspect.

The Piston pump can be set up as a micro- or nanofluidic piston pump be. This means that the piston pump may be suitable volumes on the order of nano- or microliters to pump per minute (or more or less).

in the Further embodiments of the measuring device will be described. These also apply to the sealing arrangement, the piston pump and the procedure.

The Measuring device may be, for example, a microfluidic measuring device, a life science device, a liquid chromatography device or HPLC (High Pressure Liquid Chromatography). However, they are Applications in other technical fields possible.

BRIEF DESCRIPTION OF THE FIGURES

Other Objectives and many of the attendant advantages of embodiments The present invention will be readily apparent and be better understood with reference to the following more detailed description of embodiments in Related to the attached drawings. Characteristics, which are essentially or functionally the same or similar are provided with the same reference numerals.

1 shows an HPLC system according to an exemplary embodiment of the invention.

2 shows a cross section through a piston pump according to an exemplary embodiment of the invention.

3 shows an enlarged portion of the piston pump 2 ,

The Representation in the drawing is schematic.

1 shows the basic structure of an HPLC system 10 as used for example for liquid chromatography. A pump 20 drives a mobile phase through a separation device 30 (such as a chromatographic column) containing a stationary phase. A sample application unit 40 is between the pump 20 and the separation device 30 arranged to introduce a sample liquid in the mobile phase. The stationary phase of the separation device 30 is intended to separate components of the sample fluid. A detector 50 Detects separated components of the sample, and a fractionator 60 may be provided to dispense separated components of the sample liquid, for example, in designated containers or a drain.

While a fluid path between the pump 20 and the separation device 30 typically at high pressure, the sample liquid under normal pressure is first in a separate area from the liquid path, a so-called sample loop (English: Sample Loop), the sample unit 40 entered, which then introduces the sample liquid in the high-pressure liquid path. When connecting the initially under normal pressure sample liquid in the sample loop in the high-pressure liquid path, the content of the sample loop abruptly (typically in the range of milliseconds) to the system pressure of the HPLC system 10 brought.

In the configuration according to 1 is in particular the pump 20 adapted according to the invention, as will be described with reference to the other figures.

2 shows the piston pump 20 in an enlarged view.

The piston pump 20 is intended for pumping a fluid, in particular a solvent and / or a fluidic sample. For this purpose, a fluidic channel 100 shown by the fluid according to 2 can flow from left to right. This fluid is through a reciprocating piston 102 the piston pump 20 promoted. This piston is in accordance with 2 from the piston 102 almost completely occupied displacement of the piston pump 20 movably arranged.

Furthermore, the piston pump 20 a piston housing 104 and a sealing end piece 106 on. 2 shows a cross section of the piston pump 20 in which the substantially hollow cylindrical sealing end piece 106 is visible, however, provided on the outside stepped and inside a double gradation for receiving the piston 102 or a sealing arrangement 108 having.

The sealing arrangement 108 is provided for sealing the displacement chamber and between the piston 102 , the piston housing 104 and the sealing end piece 106 arranged. The sealing arrangement 108 contains a sealing section 110 with an inner sealing surface 112 and an outer sealing surface 114 , wherein the inner sealing surface 112 to the butt on the piston 102 (or at the displacement chamber when the piston 102 just not at the sealing arrangement 108 is present) is provided. The outer sealing surface 114 is for concern at the Dichtungsendstück 106 intended. The sealing arrangement 108 further includes a disk-shaped flange portion 116 at an end portion of the sealing portion 110 is attached, to rest on the piston housing 104 is provided and at its the sealing portion 110 facing away from a supernatant 118 having. The disc-shaped flange portion 116 is for concern at the Dichtungsendstück 106 provided, that is shaped and dimensioned.

The sealing section 110 Contains on the inner sealing surface 112 an inner sealing lip 120 and contains on the outer sealing surface 114 an outer sealing lip 122 , being between the inner sealing lip 120 and the outer sealing lip 122 a cavity for receiving an annular spring 124 is formed, so that by means of the annular spring, the inner sealing lip 120 against the piston 102 is pressable and the outer sealing lip 122 against the sealing end piece 106 is pressable.

The disc-shaped flange portion 116 contains at its the sealing section 110 facing away from a recess 126 , The supernatant 118 and the indentation 126 clearly illustrate a cutting edge.

The piston housing 104 contains a recess, which is used to pick up the supernatant 118 the disc-shaped flange portion 116 is set up.

The sealing end piece 106 has a recess for receiving the sealing portion 110 is set up. The sealing end piece 106 also has a central bore for receiving the piston 102 furnished, that is shaped and dimensioned, is.

With this configuration, the piston pump 20 suitable for pumping a fluid in an HPLC with a pressure of 1200 bar and more.

2 thus shows a partial section through the piston pump 20 with the seal arrangement 108 ,

The cylindrical piston 102 is movable in the cylindrical displacement chamber, that of the pump housing 104 is limited and according to 1 extends in the piston axis and upwards. The piston 102 can be offset by a drive device (not shown) in oscillating motion. The sealing of the pump interior against the environment is performed by the lip seal 110 that the piston 102 surrounds annularly. In an annular groove of the sealing arrangement 108 is the annular spring 124 arranged, which the inner sealing lip 120 against the piston 103 and the outer sealing lip 122 against the sealing end piece 106 suppressed. The sealing arrangement 108 is thus through the Dichtungsendplatte 106 attached to the pump housing 104 can be pressed, fixed at the required location. The seal 108 is as a flange seal with the flange area 116 educated.

3 shows again an enlarged portion of a part of the piston pump 20 which shows the conditions when sealing more accurately.

It It should be noted that the term "exhibit" does not excludes other elements and that the "one" does not exclude a plurality. Also, elements, in connection with different embodiments are described combined. It should also be noted the reference numerals in the claims are not considered the scope of protection to be interpreted as limiting the claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 0309596 B1 [0002]
• - DE 9110799 [0005]

Claims (14)

Sealing arrangement for a piston pump for pumping a fluid, wherein in the piston pump, a piston in a displacer of the piston pump movably arranged is, wherein the sealing arrangement for sealing the Verdrängerraums between the piston, a piston housing and a sealing end piece is providable, wherein the sealing arrangement comprises:  a sealing section with an inner and an outer sealing surface, wherein the inner sealing surface for abutment against the piston and the outer sealing surface for abutment is provided on the sealing end piece; and  one disc-shaped flange portion, which at one end portion the sealing portion is attached to abut on the piston housing is provided and on its side facing away from the sealing portion has a supernatant. A sealing arrangement according to the preceding claim, wherein the disc-shaped flange portion for abutment with the Seal end piece is provided. Sealing arrangement according to one of the preceding claims, wherein the sealing portion on the inner sealing surface a inner sealing lip and on the outer sealing surface having an outer sealing lip, wherein between the inner sealing lip and the outer sealing lip a cavity for receiving an annular spring is formed is, so that by means of the annular spring, the inner Sealing lip against the piston is pressed and the outer Sealing lip against the Dichtungsendstück is pressed. Sealing arrangement according to one of the preceding claims, wherein the disc-shaped flange portion at its the Sealing section facing side has a recess. Sealing arrangement according to one of the preceding claims, wherein the supernatant forms a cutting edge. Piston pump for pumping a fluid, wherein the piston pump having:  a piston in a displacement chamber the piston pump is movably arranged;  a piston housing;  one Sealing end piece;  a sealing arrangement according to a of the preceding claims, wherein the sealing arrangement for Sealing the displacement between the piston, the Piston housing and the seal end provided is. Piston pump according to the preceding claim, wherein the sealing end piece has a recess which is for Recording the sealing portion is set up. Piston pump according to one of the preceding claims, the sealing end piece having a central bore, which is adapted to receive the piston. Piston pump according to one of the preceding claims, wherein the piston housing has a recess which for receiving the supernatant of the disc-shaped Flange section is set up. Piston pump according to one of the preceding claims, adapted for pumping a fluid at a pressure of at least 500 bar, in particular of at least 800 bar, more particularly of at least 1200 bar. Piston pump according to one of the preceding claims, set up as a nanofluidic or microfluidic piston pump. Measuring device for performing a Measurement on a sample using a fluid, the Measuring device, a piston pump according to one of the preceding Claims for pumping the fluid in the meter having. Measuring device according to the preceding claim, selected from the group consisting of a nanofluidic Measuring device, a microfluidic measuring device, a Life science device, a liquid chromatography device and an HPLC. Method for pumping a fluid by means of a Piston pump, the method comprising:  Moving the piston the piston pump in a displacement chamber of the piston pump for pumping the fluid;  Sealing the displacement chamber between the piston, a piston housing and a sealing end piece by means of a sealing arrangement, wherein the sealing arrangement has a sealing section with an inner and an outer sealing surface has, wherein the inner sealing surface bears against the piston and the outer sealing surface on the sealing end piece is applied, and wherein the sealing arrangement is a disk-shaped Flange portion which, at an end portion of the sealing portion is attached to the piston housing rests and on his the side facing away from the sealing portion has a supernatant.