Measuring and testing – Sampler – sample handling – etc. – Capture device
Patent
1994-11-14
2000-06-13
Williams, Hezron
Measuring and testing
Sampler, sample handling, etc.
Capture device
7386434, 7386383, 7386451, G01N 124
Patent
active
060734981
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a fluid sampling system for effecting the transfer of samples of a second fluid from a body of that fluid into a system incorporating an enclosed volume of a first fluid. The first fluid may or may not circulate within the system.
DISCLOSURE OF THE INVENTION
Such fluid sampling systems are commonly employed in analytical instruments e.g. chromatographs and mass spectrometers where it is needed to transfer for analysis a small sample of gas, vapour or liquid of interest.
Such fluid sampling systems may also be employed, for example, in atmospheric monitoring or analysis equipment where a sample or samples of an ambient atmosphere are to be transferred into a closed loop circulatory system within the equipment and examined for the presence of components of interest.
Atmospheric monitoring equipment of this general type is described in UK Patent No. 2052750 in which an external atmosphere is sampled by drawing a flow of the external atmosphere over a membrane through which a sample of the atmosphere permeates into a closed loop circulatory system and is entrained in the closed loop gas flow, and conveyed to means for detecting and/or identifying vapours or gases of interest in the entrained sample.
Membrane inlet systems, such as employed in the equipment described in UK Patent No. 2052750, suffer a number of significant disadvantages. For example the membrane employed in such systems has a slow response to sampling commands, tends to retain sample from one sampling to the next, and often requires local heating to optimise sample permeation through it. Most inconveniently the transmission characteristics of the membrane cannot be varied, for example to permit variation of instrumental sensitivity or dynamic measurement range.
It is an object of the present invention to provide a novel fluid sampling system in which the disadvantages of such prior art sampling systems are largely overcome or at least mitigated.
According to an aspect of the present invention there is provided a fluid sampling system comprising fluid enclosing means arranged to enclose a volume of a first fluid into which a sample of a second fluid is to be introduced, the fluid enclosing means having an orifice via which the second fluid may be drawn into the fluid enclosing means, and pressure pulse means arranged to apply a negative pressure pulse to the first fluid whereby a sample of the second fluid is drawn into the fluid enclosing means through the orifice. To put it in other words, the invention provides a sample inlet system of the type referred to in which the body of the fluid to be sampled is separated from the enclosed fluid volume into which a sample of the body of fluid is to be transferred, by means including an orifice, and in which means are provided for applying a pressure pulse to the enclosed fluid volume whereby a sample of the fluid body is drawn into the enclosed fluid volume through the orifice. Continuous transfer may be effected by applying a repetitive pressure pulsing to the system incorporating the enclosed fluid volume.
Although repetitive pulsing will cause fluid flow through the orifice from the body of the fluid into the enclosed fluid volume and vice versa, sample material incoming to the enclosed fluid volume will be impelled into the enclosed fluid volume or, in the case of there being a circulatory flow within the system incorporating the enclosed fluid volume, will be entrained in the flow and conveyed away from the orifice, resulting in each case in a net flow of sample fluid into the enclosed fluid volume.
The rate at which sample material is transferred through the orifice may be controlled by variation of the amplitude, the repetition rate, or the duration of, the pressure pulses, or by a combination of two or more of those parameters.
The rate of transfer of sample material through the orifice may be controlled automatically by controlling one or more of the parameters of the pressure pulses applied to the system incorporating the enclosed fluid vo
REFERENCES:
patent: 3093001 (1963-06-01), Williams
patent: 3501964 (1970-03-01), Drummond et al.
patent: 4527953 (1985-07-01), Baker et al.
patent: 4531895 (1985-07-01), Zeck
patent: 4745801 (1988-05-01), Luzier
patent: 4834110 (1989-05-01), Richard
patent: 5038623 (1991-08-01), Zeh
patent: 5297432 (1994-03-01), Traina et al.
patent: 5312757 (1994-05-01), Matsuyama et al.
patent: 5475217 (1995-12-01), Bradshaw
patent: 5811059 (1998-09-01), Genovese et al.
Graseby Ionics Pamphlet titled "CAM Chemical Agent Monitor" publication date unknown.
Reactant Ions in Negative Ion Plasma Chromatography by Glenn E. Spangler and Charles I. Collins published at pp. 393 to 402 of Analytical Chemistry, vol. 47, No. 3, Mar. 1975.
Developments in Ion Mobility Spectrometry by G.E. Spangler, D.N. Campbell, K.N. Vora and J.P. Carrico, published by pp. 17 to 28 of ISA Transactions, vol. 23, No. 1, Copyright 1984.
Bradshaw Robert Fagan Donat
Taylor Stephen John
Fayyaz Nashmiya S.
Graseby Dynamics Limited
Williams Hezron
Wong Steve A.
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