Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Reexamination Certificate
1999-02-26
2001-07-24
Walker, W. L. (Department: 1725)
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
C422S105000, C422S124000, C034S080000, C034S082000
Reexamination Certificate
active
06264895
ABSTRACT:
BACKGROUND OF THE INVENTION
Various mechanisms exist for evaporating a solvent from a sample solution in order to extract the solute. Generally, a drying gas is directed across the surface of the solution. For example, U.S. Pat. No. 4,465,554 to Glass discloses a device which evaporates a liquid solvent by impinging a high velocity jet of hot, non-reactive gas on the surface of the liquid. In U.S. Pat. No. 4,707,452 (Friswell), the sample solution is placed in a test tube and a drying gas is directed to flow helically down the side of the tube at a relatively shallow angle. After the gas picks up vapor from the sample, it is withdrawn through an outlet located at the center of the helix. This prevents the incoming and outgoing gases from mixing so that differences between the two gases can be measured.
SUMMARY OF THE INVENTION
Both Glass and Friswell require a supply tube to introduce and aim a jet of drying gas into each sample container. If multiple samples are to be dried at once, a tube must be physically placed into position for each sample. In the present invention, on the other hand, angled inlets are drilled into the top of the unit. An air-drawing source such as a vacuum source pulls room air in through the inlets, creating jets of air which are aimed at the liquid sample. Operation is simple because no tubes need to be inserted into or positioned over the containers. Multiple containers are simply placed in the unit under the inlets.
Thus, in accordance with the present invention, an evaporator comprises one or more pans for holding sample liquid. The pans arc positioned or seated within an enclosure which has at least one inlet above each pan. Each inlet is aimed at the sample liquid within the pan. An air-drawing vacuum source, such as a vacuum, is attached directly to the enclosure, and pulls air in through the inlets. The air contacts the sample liquid, and then is withdrawn by the vacuum, creating an air flow across the tops of the pans. Alternatively a fan may be used to draw air through the enclosure.
The pans are preferably tapered outward from bottom to top. Preferably, standard commercially available pans are used which are about 70 mm in diameter and 16 mm high. Of course, other dimensions may be used such as will fit in the chamber while providing sufficient sample surface over which air can effectively flow. Other containers such as beakers may also be used.
In a preferred embodiment, there are two inlets above each pan, at opposite sides of the pan and aimed at the sample liquid in opposite directions. The inlets are aimed downward at about 37° to 42°.
In a preferred embodiment, the evaporator comprises a base with a vacuum connection. A tray, having seating positions in which to seat the pans, is located in the base. A cover is attached to the base with a hinge, and when closed, fits over the tray, forming a tight fit with the base. When the cover is in the closed position, it is preferably ¼″ to ½″ from the pans. Preferably the cover is transparent to allow observation of the evaporation process.
The cover has angled inlets over each pan seating position such that when a vacuum source is connected to the vacuum connection, air from outside the evaporator is drawn in through the inlets and aimed toward the sample liquid in each pan, inducing a swirling motion in the sample liquid and facilitating evaporation of the sample liquid. Preferably, the vacuum is automatically turned off when the cover is opened.
A heating unit is connected to the base below the tray to warm the sample liquid in the pans to a desired temperature.
REFERENCES:
patent: 2017728 (1935-10-01), Oskamp
patent: 3398935 (1968-08-01), Livesey et al.
patent: 3588053 (1971-06-01), Rothermel
patent: 3658047 (1972-04-01), Happel
patent: 4465554 (1984-08-01), Glass
patent: 4600473 (1986-07-01), Friswell
patent: 4707452 (1987-11-01), Friswell
patent: 4826516 (1989-05-01), Matsuoka et al.
patent: 4922626 (1990-05-01), Fiddler
patent: 5215718 (1993-06-01), Katzer et al.
http://earthl.epa.gov/OST/Methods/1664.html—Method 1664: N-Hexane Extractable Material (HEM) and Silica Gel Treated N-Hexane Extractable Material (SGT-HEM) by Extraction and Gravimetry (Oil and Greease and Total Petroleum Hydrocarbons).
Horizon Technology Application Note: Evaporation Rates and Recovery Data Using the Speed-Vap 9000 Solvent Evaporation System, Apr. 27, 1998.
Horizon Technology—Speed-Vap 9000—Solvent Evaporation System, Apr. 27, 1998.
Hamilton Brook Smith & Reynolds P.C.
Ocampo Marianne
Walker W. L.
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