Liquid purification or separation – With means to add treating material – Chromatography
Patent
1995-06-11
1997-08-05
Therkorn, Ernest G.
Liquid purification or separation
With means to add treating material
Chromatography
210101, 210656, 417 20, 417 442, 417254, 417503, 417532, B01D 1508
Patent
active
056538766
DESCRIPTION:
BRIEF SUMMARY
The technical scope of the invention(s) is the fine metering of liquids, also at high, pressure (especially the HPLC analysis technique). In this field pumps are needed which deliver free from or with a minimum of flow pulsation and employ two (principally) different design concepts. These are represented on the one side--as most frequent representative--by a reciprocating or high pressure pump set up with two cylinders or pumping units respectively, working together in parallel. On the other hand by a serial arrangement of the pumping units.
In fact, with the pumping units arranged in parallel, usually a low pulsation is achievable--i.e. a very uniform and constant mass flow. At the same time such an arrangement of the pumping units requires larger space. Both cylinders are arranged side by side, and pertinent liquid channels at the high and low pressure side connect the parallel pumping units with alternately working pistons. Examples of the parallel high pressure pump set-up are described in source DE 27 37 062 (Zumtobel) and U.S. Pat. No. 3,917,531 (Magnussen). Besides the parallel high pressure set-up there are also the--mentioned--serial-type high pressure pumps with both pumping units serially arranged in flow direction. Principally there to, both pumping units are configured side by side--as with the mentioned parallel arrangement--however, the channels are embodied in flow direction in such way, that the liquid which is delivered under pressure from the first displacement chamber, is discharged via the second chamber (acting as storage vessel). Such an arrangement is object of source DE 32 03 722 C2 (Gynkotek) with regard to a special configuration of the pistons being linearly driven in a to each other co-ordinated mode with the aim of a reduction of flow pulsation in conjunction with a serial-type pump set-up. Concerning the technical background of the need for a continuous mass flow, here is expressly referred to column 6 in the mentioned documentation (patent). Aim and purpose of said pump set-up is to increase the accuracy of substance determination behind the separation column by minimizing residual pulsation. With the given application no interference signal must occur due to the (low) specific compressibility of the liquid being pumped (eluent) by the high pressure pump set-up.
This is also a task of the invention(s), i.e., to further increase the constancy of the mass flow. This, however, not by a complicated mutual tuning of the reciprocating motions of the pistons (compare latest cited source) but by means of a principal redesign of the pump set-up. This especially, through pumping efficiency by means of minimizing the detrimental dead volume in the liquid displacement system.
This task is solved by a serial-type dual piston pump set-up in a (sub)miniaturized design for constant and continuous mass flow with two pumping units arranged serially--with reference to the flow direction--to each other, each of them having a liquid displacement piston and with two check valves at the feeding side and at the high pressure side, in which a series block/disk-shaped constructional elements with their control surfaces adjacently positioned to each other to form a stack/sandwich-type build-up, with two of the constructional elements having each a liquid displacement chamber, perpendicularly orientated to the axis of the stack/sandwich-type build-up, receiving the respective pistons, and being fitted with liquid ducts for feeding and discharge in a parallel direction of this axis (claim 1).
The same task finds its--independent-solution in an assembly concept for the mentioned high pressure pump set-up in which in the stack/sandwich build-up space a variety of functional units are arranged; the functional units--which perform different functions, such as directing the feeding flow, forming a gradient at the low pressure side, deviating the displacement flow and measuring the working pressure on the discharge side, liquid displacement by the main piston, liquid displacement by the storage piston--are c
REFERENCES:
patent: 2550392 (1951-04-01), Venning
patent: 3792939 (1974-02-01), Zalis
patent: 3917531 (1975-11-01), Magnussen
patent: 4359312 (1982-11-01), Funke et al.
patent: 4456440 (1984-06-01), Korner
patent: 4600365 (1986-07-01), Riggenmann
patent: 4775481 (1988-10-01), Allington
patent: 4808092 (1989-02-01), Funke
patent: 4883409 (1989-11-01), Strohmeier
patent: 4915591 (1990-04-01), Funke
patent: 5089124 (1992-02-01), Mahar
patent: 5158675 (1992-10-01), Allington
patent: 5466128 (1995-11-01), Brown
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