US 3589870 A
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Description (OCR text may contain errors)
June 29, 1971 T. F. RANKIN I 3,589,870
CANISTER HOLDER Filed Aug. 20, 1969 2 Sheets-Sheet 1 FIG. 2
' ATTORNEYS June 29, 1971 "r. F. RANKIN CANISTER HOLDER 2 Sheets-$heet 2 Filed Aug. 20, 1969 INVENTOR T/voM; F. k/m/z/A/ ATTORNEY United States Patent O ABSTRACT OF THE DISCLOSURE An improved canister seal and support for a respiratory gas absorber having upper and lower housings, each housing having a resilient seal afiixed to its outer periphery.
BACKGROUND OF THE INVENTION This invention relates to an improved canister holder for an anesthetic absorber. In particular, it relates to an improved seal for canisters adapted to purify anesthetic gases containing carbon dioxide.
For many years, anesthetic absorbers, containing a supply of an absorbent material, have been employed to remove carbon dioxide from respiratory gases containing anesthetic vapor. An example of such a carbon dioxide absorber is described in US. Pat. No. 3,088,810. These absorbers are employed in the semi-closed and closed techniques for inhalation anesthesia.
In both types of the above conventional techniques, respiratory gases are introduced into at least one carbon dioxide absorption canister. conventionally, the canisters are held in a vertical position by an absorber frame. Each canister contains soda lime or other conventional carbon dioxide absorbing material.
Exhaled respiratory gases enriched with carbon dioxide are conducted through the absorbing canister and are purified.
Early prior art canisters were transparent glass, plastic or brass cylinders which were filled with soda lime or the like and adapted to pass respiratory gases 'therethrough. Recently, the most widely used canister has been the so-called Roswell Park Absorber, also known as the double-reversible stacked canister. In this design, two stacked inverted canisters are supported by the absorber frame. Each canister is cylindrical with a centrally disposed batfie at each end of the cylinder. At the top end of the canister narrow annular bafiles are employd. At the bottom end of the canister wide annular bafiles are employed.
There is a cover provided at the top end of the canister for filling the canister with absorbent. The narrow annular bafiles are spaced concentrically as an integral part of the canister cover.
Recently, disposable canisters, generally fabricated of plastic or the like, have been employed in place of the refillable, permanent canisters for certain uses. The disposable canisters are pre-packed with absorbent and are thrown away after use.
Certain of these disposable canisters are characterized by the design of the canister cover and lower end. Both the upper and lower baffles are depressed below the top plane formed by the ends of the side walls of the canister. An angular shoulder rises from the periphery of each of said bafiles and extends at least to the side walls. In the case of the shoulder design, the cover extends beyond the plane of the side walls and is bent substantially vertically in order to provide a force fit against the side wall.
To assist in maintaining a tight seal between the side wall and canister cover, to provide a firm support for the vertically disposed cylinders and to provide a broad area for introducing and collecting respiratory gases passing into and exiting from the canisters, various housings (adaptors) were provided. In general, these housings exice tended beyond the outer periphery of the canister cover. Usually, an O-ring seal was provided between the overlapping housing and the canister cover. The sealing forces exerted through the O-ring are uni-planar. Under certain circumstances this seal was subject to gas leakage. This defect cannot be tolerated where highly inflammable anesthetic gases are employed. The housings were bulky and difficult to manipulate.
SUMMARY OF THE INVENTION It is, therefore, a primary object of this invention to provide an improved seal for a carbon dioxide absorber, particularly for an absorber employing double-reversible stacked baflled canisters, commonly known as Roswell Park Absorbers. It is another object of this invention to provide an improved seal for a carbon dioxide absorber employing disposable canisters having depressed baffles.
The above and other objects are met in a respiratory gas absorber utilizing baffled canisters, by upper and lower canister housings and each housing having a resilient seal aflixed about the periphery of the housing.
DESCRIPTION OF THE DRAWINGS Carbon dioxide absorbers having improved seals constructed according to the present invention are illustrated in the accompanying drawings wherein;
FIG. 1 is a front elevational view of a carbon dioxide absorber employing double-reversable baflled canisters;
FIG. 2 is a front elevational view of a carbon dioxide absorber employing a single bafiled canister;
FIG. 3 is an enlarged, fragmentary vertical sectional view of the improved seal of the invention employed with double-reversible bafiled canisters; and
FIG. 4 is an enlarged, fragmentary vertical sectional view of the improved seal of the invention as illustrated in conjunction with a zflat canister end.
DESCRIPTION OF ILLUSTRATED EXEMPLARY EMBODIMENT In FIG. 1 a typical carbon dioxide absorber is illustrated employing stacked, double-reversible baffied canisters. The absorber illustrated is a Model 68 series absorber produced by [Anesthesia Associates, Inc. The same absorber frame is illustrated in FIG. 2 in combination with a single bafiled canister.
Absorber frame 10 has gas conduits 12, 14, 16 and T-bar connector 20 adapted to circulate respiratory gases through stacked canisters 22 and 24 and to thereafter discharge purified respiratory gases into a respiratory control system. In operation, impure gases are conducted, for example, through a hose (not shown) into conduit 14, through T-bar 20 and thereafter into canisters 22 and 24. Purified gases are channeled through conduit 16 into interconnecting frame 10 and are thereafter discharged from the absorber through conduit 12, a communicating conduit with frame 10. Of course, many other variants are possible including the reverse of the previously illustrated flow path. In certain cases respiratory gases may be discharged from the absorber through conduit 16 and thereafter recycled through the absorber and exhausted through T-bar conduit 20 into conduit 12.
Referring now to FIGS. 1 and 3, the improved seal of the invention is illustrated in combination with disposable stacked double reversible canisters having depressed bafiles. Upper and lower conical housings 26 and 28 are integrally flared respectively from the base portions 30 and 32 of conduits 20 and 16. The housings extend angularly downwardly from their respective conduits and terminate beyond the bafiled portions of the cansisters. Canisters 22 and 24 have baffled covers 34 and 36, respectively. Centrally depresed bafiles 38 and 40 are adapted to direct gases centrally of canisters 22 and 24. Covers 34 and 36 have annular shoulders 42 and 44 which extend downwardly beyond the side walls of the canisters to effect a force fit seal. Annular resilient seals 46 and 48 are positioned at the periphery of housings 26 and 28, respectively. Each seal has a transverse slot 50 extending about the inner periphery of the seal and adapted to be force fitted into terminal portions 52 and 54 of housings 26 and 28.
The seals employed are O-rings having a round crosssection and of the proper durometer or resiliency to conform to the shape of the canister when closing pressure is applied. The seal may be rubber, plastic or the like conforming to the above requirements as to resiliency. The seals, of course, should be non-reactive to the respiratory gases and anesthesia employed and should be conductive to reduce static electricity build-up.
Conventionally, upper and lower housings 26 and 28 are forced inwardly away from their integral inlet conduits and toward the stacked canisters by conventional spring means or camming means positioned on the frame of the absorber. This compressive force is directed along flared housings 26 and 28, respectively, and directed through end portions 52 and 54 against seals 46 and 48. Two vectors of compressive force are thereby generated between each of said seals and the covers of each of said canisters. Turning to seal 46, one force vector is directed normally to shoulder 42. A second vector is directed normally to baflle 38. Therefore, a seal is effected on both the plane of the shoulder and the plane of the bafile. The same is true for the forces generated between seal 48 and cover 36. This eifect is also generated between seal 60 and canister cover 62, as illustrated for the single canister absorber of FIG. 2.
In order to seal baflles 64 and 66 of stacked canisters 22 and 24, respectively, a second resilient seal 68 is pro- 'vided. As is illustrated in FIG. 3, seal 68 has the same configuration as seals 46 and 48, except for the absence of a transverse slot. Seal 68 is annular. Tab 72 extends normally from seal 68, positioned in the plane passing through the annular axis of the annular seal. The tab is provided to accommodate a chain or wire (not shown) which chain or wire may be attached to the absorber frame in order to permit the seal to be permanently anchored to frame and to permit and electrical conduit for equalizing static potentials. Another anchoring and/ or conducting means may be employed in place of said tab. If desired, the tab may be eliminated entirely with the concurrent loss of anchoring and conducting means. As illustrated in FIG. 2, in the case of a single absorbing canister, the lower housing and seal are adapted to generate a dual-planed seal with narrow end 78 of canister 80.
Although the seal has been illustrated with a disposable canister, it may be employed with permanent fixed canisters. Further, the improved seal may be employed with canisters having horizontal cover ends and lower ends. An example of this seal is seen in FIG. 4.
Although conical housings are illustrated in the accompanying drawings, housings having other geometrical shapes can be employed. If other shaped covers are employed, it is preferred that the end portions for these covers transmit a compressive force radially inward of said seal in use.
1. In a respiratory gas absorber having a frame, a respiratory gas inlet conduit vertically disposed from said frame, a gas collecting conduit spaced below said inlet conduit and communicatingly connected to said frame, means for exerting a compressive force inwardly along a central axis of said inlet conduit and collection conduit, means for circulating gas into said inlet conduit, means for recycling gas from said collecting conduit to a respiratory control system, the space between said inlet and said connecting conduits being suflicient to house at least one absorbing canister, said canister having a cover, a base, an upper 'bafile centrally disposed in the cover and a lower bafl'le centrally disposed in the base, said baflles depressed respectively below the top of the cover and the bottom of the base, an upwardly facing annular shoulder continuously disposed about the periphery of each of said baflles, said cover shoulder being integral with said cover and said base shoulder being integral with said base, said cover extending beyond the plane of the side walls of the canister and bent substantially vertically in order to provide a force fit against the side wall of said canister, the improvement by means of which at least one canister is vertically stabilized within said frame in the space be tween said inlet and collecting conduits comprising: a conically flared annular housing downwardly disposed from said inlet conduit, an annular conically flared housing disposed upwardly from said collecting conduit, the peripheries of each of said housings being substantially in alignment and an annular resilient seal disposed about the periphery of each of said housings, said seal being adapted to generate a dual-planed seal with the canister.
2. The apparatus of claim 1 in which an annular resilient seal is positioned between the abutting ends of a pair of inverted canisters supported within said frame, said seal having a tab integral therewith, said tab extending perpendicularly away from the central axis of said canisters.
References Cited UNITED STATES PATENTS 3,088,810 5/1963 Hay 23252 3,289,878 12/1966 Williams 220-46 3,355,057 11/1967 MacKenzie et a1. 20-46 JAMES H. TAYMAN, JR., Primary Examiner U.S. Cl. X.R.
23284; 55279, 309, 388, 482, 502, 512; l28l9l; 22046