Patent Application
20070084300
The present invention concerns a receptacle, normally in a vacuumized state, for the selective taking of gas or air samples for forensic evaluation.
In the investigation of events, such as explosions or accidents involving a gas, samples taken are helpful in determining cause and/or origin. The use of stored vacuumized receptacles opened at a site for the intake of ambient air or gas samples has been proposed but to be practical requires that sample taking must occur promptly after the event. In the instance of an explosion chemical analysis of a sample can help in the determination of the explosive type and origin. Similarly, the timely collection of any airborne particulate at a site may be helpful.
It would be desirable to have a number of vacuumized containers stored at selected sites to permit rapid delivery to a leak, spill or explosion site. Heretofore, the maintenance of a vacuumized state in stored containers has proved difficult in view of known valve designs permitting some leakage.
U.S. Pat. No. 3,618,393 discloses a vacuum tank with an inlet controlled by a manually operated valve.
U.S. Pat. No. 4,040,299 discloses a vacuum tank provided with a vacuum controlling valve and an inlet controlling second valve, a vacuum gauge and a filter located at the inlet end of a tubular inlet. A gas sample is drawn from a vacuum tank via a self-sealing septum, as is the case with many prior art vacuum receptacles.
U.S. Pat. No. 6,073,648 discloses a ball valve for use in highly corrosive and highly erosive environments. Wetted surfaces 24a of the valve body and wetted surface 28a of the ball component are firstly coated with a noble metal and secondly with a ceramic material, which per Col 3., Lines 58-63, is conceded to be porous and hence the patented valve does not address the problem solved by the present invention, i.e., sealing a vacuumized receptacle against atmospheric pressure over a period of several months and perhaps years.
The present invention is based upon a vacuumized sample receptacle to maintain a vacuumized state over a period of months or longer until needed for sample taking. A valve component of the present receptacle has a coating of a noble metal contributes to a virtually perfect seal. Further, ambient gas or air entering the receptacle results in the deposit of airborne particulate on screen and fabric components of the receptacle.
The present receptacle provides an adequately sized inlet orifice for the insertion of a probe for retrieving any collected matter for analysis.
In the Accompanying Drawings:
With continuing attention to the drawings, and particularly
A valve component 4 of the receptacle includes a valve body 5 with an end plate at 6. A valve handle 7 actuates a shaft 8 which terminates in engagement with a positionable valve member 10 per
Valve member 10 is plated at 11 with a noble metal, preferably gold as at 11, by the process of electroplating or other suitable plating technique. A suitable plating thickness is of 0.00010 inches while thicker or lesser plating may be utilized and is somewhat determined by the anticipated frequency of receptacle use and cost of manufacture. While other noble metals such as silver or platinum may be suitable for plating of member 10, gold is preferred for its resistance to corrosion and ductility. Further, gold is believed less susceptible to flaking. The surface defining a ball member passageway 13 may be plated and is preferably of at least 0.6250 inches in diameter to permit retrieval of collected particles therethrough.
A suitable material for the valve seats 12 is sold under the trademark Teflon (a registered trademark of DuPont). The seats may be of the biased type. The seat material is further identified by a suffix PTFE 7C. A valve body passageway is at 14.
To reduce the chance of accidental opening of valve 4, it is desirable that handle 7 be parallel to main body 1, when the valve is closed with raising of the handle to the broken line position of
Continuing with a general description of the receptacle, a filter assembly is generally at 20 and includes plates 23 and 24 as viewed in
For use of the receptacle without filter assembly 20, clamp 28-29 is released by opening the clamp and removal of upper plate 23 along with filter 21-22.
In
Use of the receptacle is believed apparent from the foregoing description. Prior to storage of the receptacle at an emergency response facility, the same is evacuated to 30 inches Hq., and valve 4 closed. Accordingly, samples of hazardous or explosive agents may be taken for chemical analysis as well as samples of ambient air at illegal drug laboratories and stored for purposes of evidence.
While I have shown but one embodiment of the invention, it will be apparent to those skilled in the art that the invention may be embodied still otherwise without departing from the spirit and scope of the claimed invention.
