Liquid purification or separation – With heater or heat exchanger – Flow line connected in series with distinct separator
Reexamination Certificate
2002-12-09
2003-11-25
Prince, Fred G. (Department: 1724)
Liquid purification or separation
With heater or heat exchanger
Flow line connected in series with distinct separator
C210S184000, C210S188000, C210S258000, C159SDIG001
Reexamination Certificate
active
06652744
ABSTRACT:
This application is a United States national phase filing under 35 U.S.C. §371 of international (PCT) application No. PCT/EP/01/01854, filed Feb. 19, 2001, which claims priority to German Application No. 100 08 023.5, filed Feb. 22, 2000.
TECHNICAL FIELD
The invention relates to apparatus and a process for automatically filtering and eliminating liquids and liquid residues in a vacuum chamber.
BACKGROUND OF THE INVENTION
In numerous technical fields, particularly chemistry, biology and environmental sciences, it is necessary to analyse liquids, break them down into their components or react them with other substances. For this purpose liquids are filtered, dried, washed, pipetted and subjected to other treatment, the term liquid basically meaning any substance which occurs in liquid form or which is found in a liquid. The treatments often consist of a long series of treatment procedures, which means that it is necessary to automate these procedures using robots.
Thus, for example the “BioRobot 9600” produced by the present Applicant has been on the market for some years, for automatically carrying out molecular biological processes such as, for example, the filtering, washing and eluting of nucleic acids or the isolation of RNA and/or DNA. Support members known as filter modules are used for these processes, comprising a plurality of containers arranged in a matrix form. These containers have an inlet aperture at the top and an outlet aperture at the bottom. The containers also contain filter bodies in the form of suitable membranes or filters which are suitable for binding the substances which are to be analysed in the liquid samples.
Thus, for example, in order to produce highly purified DNA plasmids using an individual pipetting device, first of all cell cultures are put into suspension, lysed and then placed in the containers on the support plate by means of a pipetting device. Then the carrier plates holding the filled containers are placed on a vacuum chamber so that the outlet apertures of the containers project into the vacuum chamber. By applying negative pressure in the negative pressure chamber the liquids in the containers are sucked through the filter bodies into the negative pressure chamber. The constituents to be analysed together with other components of the liquid samples remain suspended in the filter bodies. In order to recover the desired components of the liquid samples, the unwanted substances first have to be washed out of the filter bodies. To do this, washing solutions of different concentrations are pipetted into the containers. Using these washing solutions, some of the unwanted components of the liquid samples are detached from the filter bodies. Then the ingredients of interest are released from the filter bodies using an eluant solution and collected.
The solutions used in the individual steps may, however, contaminate the solution used in the next step. Thus, for example, after a washing step, drops of liquid wash solution may form on the outlet apertures of the containers and have to be removed before the following elution step. Previously, the carrier members or microtitre plates were dropped manually onto a substrate of absorbent material to shake off these drops. As described in WO 98/53912, the removal of the residual liquid was automated by the application of a vacuum.
In this apparatus the liquids sucked through the filters usually flowed to a separator, under the effect of gravity. There. the liquid was collected so that it could be re-used and/or examined as necessary. However, liquid residues particularly in the region of the filter body or on the outlet apertures of the containers could not be eliminated by this method, or only very slowly. The drying process of the filter bodies and outlet apertures of the containers therefore takes a long time or is not completed. However, it has been found that liquid residues have to be removed as completely as possible as they affect the purity of the filter residues in the containers which are to be analysed, which are usually only present in small amounts, and alter their chemical characteristics.
DESCRIPTION OF THE INVENTION
The problem of the invention was therefore to provide an apparatus which makes it possible on the one hand to filter liquids with negative pressure and to collect the filtered liquids but on the other hand also to eliminate liquids, particularly liquid residues in the region of the filter body or on the outlet openings of the containers as completely as possible within a short time, so as to solve the known problems of the prior art.
To solve this problem, an apparatus is proposed for treating liquids in a negative pressure chamber with a vacuum pump and a separator, the negative pressure chamber being connected to the separator by a first line and a first closure device being arranged between the negative pressure chamber and separator, while the negative pressure chamber is connected to the vacuum pump via a second line, so that the negative pressure chamber can be evacuated while avoiding the separator.
Is It has been found that, for example, the filter body stores a relatively large amount of liquid by its capillary action, which is not eliminated by means of the vacuum applied. These liquids may also be eliminated by evacuating the negative pressure chamber while avoiding the separator.
By liquids is meant basically any substance which is present in liquid form or which is found in a liquid. This means, in particular, chemical and/or biological samples or chemical and/or biological samples contained in liquids and the substances needed for treating chemical and/or biological samples.
By the treatment of liquids in a negative pressure chamber are meant various activities relating to liquids and/or liquid residues in a negative pressure chamber, such as for example drawing a liquid through a filter, eliminating liquid residues by pumping out or evaporation, which may preferably be referred to as the drying of the negative pressure chamber, as well as collecting liquids in a container or releasing liquids to flow into a separator.
By the separator is meant in particular an apparatus which is able to catch liquids and collect them in a separating vessel. The separating vessel may preferably be large enough to hold some 100 ml of liquid. This collection is achieved, for example, by placing the separator underneath the liquid which is to be collected, so that the liquid flows or falls by gravity into a separation vessel; alternatively, the liquid may also be caught by material structures which oppose the flow of liquid produced by a vacuum pump, for example, so that the liquid is deposited on the material structure and flows or falls into the separation vessel. In a preferred embodiment the separator consists of a sealed separation vessel which has two tubes coming from above which project openly into the separation vessel. One of the tubes is a feed tube through which the liquid is transported by gravity and/or suction by a vacuum pump into the separation vessel and collected therein; the other tube is the outlet pipe to which a vacuum pump is connected. The outlet pipe ends above the level of the liquid, so that the liquids collected in the separation vessel cannot reach the vacuum pump. Preferably, the opening of the outlet pipe is above the opening of the inlet pipes. However, other methods of separating liquids may preferably be used. It is also possible to mount a plurality of separators in various arrangements on the negative pressure chamber or on the pipes.
The evacuation of the negative pressure chamber without a separator is carried out using one (or more) vacuum pumps which are connected to the negative pressure chamber, the separator being separated from the negative pressure chamber or the vacuum pump. The separation is expediently achieved by means of a closure device. By a closure device is meant, for example, a device with an input and output, which can be switched between the throughflow and blocking positions. Preferably, the closure device is a vacuum-t
Collasius Michael
Friederichs Ulf
Lutze Konstantin
Prince Fred G.
Qiagen GmbH
Wesolowski Michael R.
Yankwich Leon R.
LandOfFree
Device for filtering and removing fluids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for filtering and removing fluids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for filtering and removing fluids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3178663