US3449958A - Control atmosphere for gas sampling apparatus - Google Patents

Description

R L. BAILEY 3,449,958 CONTROL ATMOSPHERE FOR GAS SAMPLING APPARATUS June 17, 1969 Sheet Filed April 25, 1966 I NVENTOR.

MOLECULAR 9051977 A 19/4/15) BY/ M m June 17, 1969 R. L. BAILEY 3,449,958

CONTROL ATMOSPHERE FOR GAS SAMPLING APPARATUS Filed April 25, 1966 Sheet 2 012 INVENTOR. ROBERT L. Ell/LE Y BY 'M Z M MW ATTYS.

United States Patent 3,449,958 CONTROL ATMOSPHERE FOR GAS SAMPLING APPARATUS Robert L. Bailey, Spokane, Wash., assignor to National Distillers and Chemical Corp., New York, N.Y., a corporation of Virginia Filed Apr. 25, 1966, Ser. No. 544,778 Int. Cl. G01n N22 US. Cl. 73-4215 3 Claims ABSTRACT OF 'THE DISCLOSURE This invention relates to an apparatus to provide a control atmosphere to an atmospheric sampling device for purging the device of contaminated air between successive tests. It also provides a reference atmosphere of known controlled quality to insure accuracy in testing procedures.

This invention relates to an improvement in a device for sampling atmosphere within successive containers to detect the presence of organic vapors or other gases indicative of contamination within the containers. An example of such an apparatus is described fully in my prior patent 3,266,292 granted August 16, 1966. Generally, the apparatus comprises an atmosphere sampler having an inlet through which atmosphere is withdrawn from a container, the inlet of the sampler being movable between a first position at which the atmosphere is removed from a container and a second position wherein the inlet of the sampler is clear of atmosphere from within the container. The sampler can include any type of detection cell or device for monitoring the quality or nature of the atmosphere sample. The present invention adds to this basic combination a source of control atmosphere and a device to insure that the control atmosphere is directed to the inlet of the sampler when the sample inlet is in its second position clear of atmosphere within the container. The use of the control atmosphere provides a known atmosphere reference for balancing and otherwise calibrating the detection cell and associated equipment. It also assists in purging the sampler and associated atmosphere testing devices between successive tests, so that the devices can be recycled and used efiectively to test the atmosphere from within successive containers.

It is a first object of this invention to provide a mechanism for directing a control atmosphere to a sampler inlet movable between a testing position and a position clear of the atmosphere being sampled.

Another object of this invention is to provide a device for directing control atmosphere to an atmosphere sampling inlet during intermittent periods in which the inlet is not being used to draw atmosphere samples for testing purposes, the provision of control atmosphere between testing cycles being automatic and requiring no monitoring or operational controls.

Another object of this invention is to provide a curtain of control atmosphere about the inlet of an atmosphere sampler between successive tests to enable the sampler and associated devices to be recycled between tests and to be calibrated or balanced when necessary.

These and further objects will be evident from the following disclosure taken also with the accompanying drawings, the drawings illustrating a preferred form of the invention. It is to be understood that this form of the invention is only presented by way of examples and that various modifications may well present themselves to one skilled in this art without deviating from the concepts basic to this development. For this reason, the two physical forms of this device shown in the drawings are not to limit the scope of the claimed invention.

In the drawings:

FIGURE 1 is a schematic diagram showing the basic components of the combination including the sampler apparatus and the apparatus for providing control atmosphere to the sampler between tests;

FIGURE 2 is an enlarged fragmentary vertical sectional view through the sampler and stationar hood shown in FIGURE 1, further illustrating the relative positions of containers being tested;

FIGURE 3 is a bottom view of the atmosphere handling apparatus as seen along line 3-3 in FIGURE 2;

FIGURE 4 is a vertical sectional view taken through a second form of the device illustrating alternate positions thereof; and

FIGURE 5 is a top view of the control atmosphere delivering element seen along line 5-5 in FIGURE 4.

FIGURE 1 illustrates the basic combination of device used in sampling atmosphere from within successive containers to determine the presence of contaminating organic vapors or gases inside the container. The device is desirable or necessary in testing containers prior to utilization of the containers for sale or storage of food products, such as milk. The testing procedure is preferably carried out immediately prior to filling of the containers. The atmosphere testing device includes a detector 10 of a type adapted to monitor atmosphere directed thereto and to indicate the presence of organic vapors and other undesirable gases in the sample atmosphere. The detector 10, as an example, might include a vacuum pump or be connected to a source of vacuum pressure to draw atmosphere through detector 10 for testing purposes. As shown, detector 10 is connected by means of a tube 11 to a tubular sampler 12. The sampler 12 has a lower inlet 12w through which atmosphere is drawn for removal and delivery to the detector 10 through tubing 11.

The tubular member 12 is selectively movable by conventional mechanical devices (not shown) between a first position wherein the lower inlet of member 12 can receive atmosphere from within a container 13 and a second position wherein the lower inlet 12a of member 12 is clear of atmosphere within container 13. The first position of member 12 is shown in dashed lines in FIGURE 1, the second position being shown in full lines.

Vacuum is constantly applied to the inside tubular member 12. Member 12 is successively inserted within or placed in close proximity to the interior of containers 13. Atmosphere will be drawn from each container 13 for testing by detector 10. After removal of the inlet of sampler 12 from close proximity to the interior of container 13, it is desirable to provide a control or known sample of atmosphere to the inlet of member 12 so as to purge detector 10 of any trace of contamination between successivetests. This is the primary purpose of the apparatus described below.

In the first form of the invention, FIGURES 2 and 3, an air curtain is provided about the inlet of the tubular member 12 when such inlet is in its upper position and clear of atmosphere within the container 13. As shown, this air curtain is provided within a semi-enclosed member 15 having an aperture 16 closely surrounding the exterior of tubular member 12 and permitting member 12 to slide freely therein. The member 15 includes an inverted chamber 17 to which the control atmosphere is directed by means of a port 18.

The desired control atmosphere is provided by a conventional pump 20 having its inlet connected to the exterior atmosphere in the environment within which the sampling device is used or to any other suitable source of air or gas. This connection is effected through a molecular sieve or other filter devices which remove contaminants from the air drawn by pump 20. The discharge from pump 20 is directed to port 18.

The volumetric flow of atmosphere from pump 20 and sieve 21 to the chamber 17 should be greater than the volumetric rate of flow of atmosphere through the inlet 12a of tubular member 12. The excess air directed into the chamber 17 therefore provides positive pressure about inlet 12:: to further prevent other atmosphere from entering the inlet 1201 While inlet 12a is located within chamber 17.

This form of the invention is particularly simple, since it includes no moving parts. The member 15 can be located in a fixed position upon the frame that it slidably supports tubular member 12 for movement relative to the containers 13 as they are being tested. The pump 20 is preferably operated continuously during use of the testing apparatus, so that the control atmosphere will be directed into the inverted chamber at all times and hence the control atmosphere will pass into inlet 12a of the tubular member 12 except during actual testing of a container 13. The use of a constant supply of control atmosphere permits calibration or balancing of detector 10 at any time during a testing procedure and insures greater accuracy in the detection of contaminants. It further insures the complete purging of the sampler and associated detection devices, particularly immediately following the detection of a high degree of contamination within atmosphere drawn from a container.

A second form of apparatus for directed control atmosphere to the inlet 12a of the tubular member 12 is shown in FIGURES 4 and 5. There is provided a tubular member pivotally mounted at 26 to a frame 22 that movably supports member 12. Tubular member 25 in the full line position of FIGURE 4 intersects the path of movement of the tubular sampler member 12. Tubular member 25 is provided with a discharge opening 23 in fluid communication with a flexible connecting hose 24 operatively connected to the pump 20 and molecular sieve 21 or other suitable filter as previously described. The upper surface of member 25 at the end adjacent to the tubular member 12 is recessed slightly at 27 to seat the lower end of member 12 and therefore substantially seal the inlet 12a and discharge opening 23 when the members 12 and 25 are in the positions shown in full lines in FIGURE 4. Member 25 is biased to this sealing position by means of a counterweight 28. Obviously a spring biasing arrangement can be substituted in place of weight 28, or the location of pivot 26 can be shifted to provide the necessary unbalance along the length of member 25.

As seen in FIGURE 4, downward movement of member 12 will simply pivot the member 25 about its pivotal connection 26, permitting the member 12 to pass freely by the adjacent end of member 25. The slight contact pressure between member 25 and tubular member 12 does not in any manner impede the normal movement of the tubular member 12. The member 25 will return to its horizontal position with discharge opening 23 adjacent to the inlet 12a of the sampler apparatus after completion of the testing cycle. Again, excess air should be supplied from pump 2.0 to insure that all air received through the tubular member 12 between successive tests is of the quality known to be available through the molecular sieve 21.

Having thus described my invention, I claim:

1. In combination with an apparatus for withdrawing a sample of atmosphere from a container by means of a sampler having an inlet subjected to a constant vacuum pressure, the inlet of the sampler being movable from a first position at which atmosphere from a container is withdrawn thereby and a second position clear of atmosphere within the container, the improvements comprising; the sampler being movably mounted on a supporting framework; a source of control atmosphere; and delivery means to direct atmosphere from the source to the sampler inlet when the inlet is located at the second position, the delivery means including a member movably mounted on the frameworks in operative contact with the sampler, said member having a discharge opening being adjacent to and directed toward the inlet of the sampler when the sampler is located at said second position.

2. In combination with an apparatus for withdrawing a sample of atmosphere from a container by means of a sampler having an inlet subjected to a constant vacuum pressure, the inlet of the sampler being movable between a first position at which atmosphere from within a container is withdrawn thereby and a second position clear of atmosphere within the container, the improvements comprising the sampler being movably mounted on a sup porting framework; a source of control atmosphere; and delivery means to direct atmosphere from said source to the sampler inlet when the inlet is located at said second position, said delivery means including a surrounding member positioned about the sampler defining a semi-enclosed chamber about the sampler inlet when the sampler is in the second position, said delivery means including a control atmosphere exit directed toward the interior of the chamber found within said member.

3. In combination with an apparatus for withdrawing a sample of atmosphere from a container by means of a sampler having an inlet subjected to a constant vacuum pressure, the inlet of the sampler being movable between a first position at which atmosphere from within a container is withdrawn thereby and a second position clear of atmosphere within the container, the improvements characterized by; the sampler comprising a hollow tubular member mounted on a supporting framework for reciprocal motion parallel to the axis of the tubular member; a source of control atmosphere; and delivery means to direct atmosphere from said source to the sampler inlet when the inlet is located in its said second position, said delivery means including a hollow member open at one end and surrounding the tubular member along a portion of the length thereof, there being a discharge opening for delivery of control atmosphere to the interior of the ho]- low member.

References Cited UNITED STATES PATENTS 3,266,322 8/1966 Negersmith et al. 73-423 FOREIGN PATENTS 954,067 4/ 1964 Great Britain.

S. CLEMENT SWISHER, Primary Examiner.

US. Cl. X.R. 73l

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