US2318381A - Apparatus for treating and packaging sutures and the like - Google Patents

Description

May 4, 1943. w. s. DAVIS .ET AL APPARATUS FOR TREATING AND PACKAGING SUTURES AND THE LIKE Filed Aug. 8, 1941 3 Sheets-Sheet 1 76 Vacuum Pump 7% Vacuum Pu/m a TANK nv'p/an Tag y w. s. DAVIS ETAL 2,318,381

APPARATUS FOR TREATING AND PACKAGING SUTURES AND THE LIKE Filed Aug. 8, 1941 Q 3 Sheets-Sheet 2 )/a Z Zer 5 Dada' May 4, 1943. i w. s. DAVIS ETAL 2,313,381

APPARATUS FOR TREATING AND PACKAGING SUTURES AND THE LIKE Filed Aug. 8, 1.941 3 Sheets-Sheet 5' 162 106 7Z'erm 05 /a {I ca//y C'a/z fra//eo Va/Ve Patterns, 4, 1943 APPARATUS FOR TREATING AND PACKAG- ING SUTURES AND THE LIKE Walter S. Davis, San Bernardino, and Charles T.

' Davis, Los Angeles, Calif.

Application August 8, 1941, Serial No. 405,973

4 Claims.

The present invention relates to apparatus for treating and packaging sutures and the like and is particularly concerned with apparatus of the type adapted to be used in carrying out various methods of producing packaged sutures which are sterilized and conveniently arranged to be used and to be maintained in a sterilized condition for a long period of time.

One of the specific embodiments of a process embodying the invention is the subject of our prior application Serial No. 284,388 filed July 14, 1939, which issued as United States Patent No. 2,253,287 on August 19, 1941 of which this application is a continuation-impart.

The products made according to said process with apparatus constructed according to the invention has been made the subject of another application which is also a continuation-in-part of the parent application just mentioned and which is entitled Suture packages, Serial No.

'388,948, filed April 17, 1941.

The various processes which may be practiced with or without the apparatus that is the subiect of this application have been covered by another application which is also a continuationin-part of the parent application Serial No. 284,388 flied July 14, 1939, and which is entitled Sutures and methods of packaging and sterilizing the same."

One of the objects of the invention is to provide an improved apparatus by means of whichv the improved suture packages of the copending applications may be made in a very economical and efficient manner with a minimum amount of manual labor and with a minimum of possibility of any kind of contamination of the suture or introduction of any spores or bacteria in the package.

Another object of the invention is the provision of an improved apparatus for handling sutures of either the boilable or non-boilable type.-

Another object of the invention is the provision of an improved apparatus for packaging sutures by means of which the suture or other articles may be more adequately sterilized than by any apparatus of the prior art through the application simultaneously of vacuum and heat to the products which are being sterilized.

Another object of the invention is the provision of an improved apparatus adapted to be used for sterilizing sutures and other articles while in suitable containers which may be filled with a preserving fluid under aseptic conditions and which may then be hermetically sealed while in a sterile condition without any possibility of bacterial contamination.

Another object of the invention is the provision of an improved apparatus for handling sutures by means of which a constant record may be kept of the various batches of sutures which have been treated and of the vacuum and temperature conditions to which they have been subjected so that the sutures may be permanently identified with their treatment and samples selected at random may be tested and identified with the complete batch to make sure that all of the sutures of every batch have been subjected to proper treatment and have been found substantially perfect in characteristics after completion.

Another object of the invention is the provision of an improved apparatus for treating sutures and other products by means of which the subject-matter for treatment is handled in a bacteriologically closed system so that the possibility of introduction of contaminating influences or bacteria or their spores is reduced to a minimum.

Another object of the invention is the provision of an improved apparatus of the class described in which provision is made for the sterilization or the passage through bacteriaproof filters of every element such as preserving fluid or air introduced into the system so that the system is closed bacteriologically against the introduction of bacteria or their spores.

Other objects of the invention will be apparent from the following description and the accompanying drawings in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings of which there are three sheets:

Fig. l is an enlarged elevational view of a suture package which has been subjected to treatment by the apparatus constructed according to the invention and which may be regarded as an intermediate product-ready for-immediate use in the hospital.

bending force at the right point.

Fig. 2 is another similar view of a suture package treated according to the invention withthe present apparatus as it appears after the glass tube has been sealed so that the suture and package are in condition to be shipped or stored for a long period of time without possibility of contamination.

Further information as to other products which may be made according to the invention may be had by reference to the copending application Serial No. 388,948, filed April 1'7, 1941, entitled Suture packages, or the copending application on Sutures and methods of packaging and sterilizing the same, Serial No. 284,388, filed July 14, 1939, Patent No. 2,253,287 issued August 19, 1941.

Fig. 3 is a diagrammatic sectional view showing one simple form of apparatus adapted to be used in carrying out the methods of the present invention.

Fig. 4 is a similar diagrammatic sectional view of a modified form of apparatus which is especially suitable for use in sterilizing and packaging the boilable type of sutures although it is not limited to use on such sutures.

Fig. 5 is another similar diagrammatic sectional view of a modified form of apparatus epecially suitable for preparing the non-boilable type of by the numeral ID in Fig. 1 and 11 in Fig. 2. This package comprises a glass tube II which is closed with a rounded end portion [3 and which has arestriction ll formed intermediate the ends and in position to engage the suture reel 15. at its upper end. This restriction consists of an inward bend in the wall of the glass tube extending fully around the periphery of the tube and the outer wall of the tube is preferably ground away at the base of the groove l6 which forms the restriction so that there is a flattened wall portion I! which is thinner all the way around the tube.

The combination of the restriction and the thinner wall at that point so weakens the tube that it can be broken ofl squarely, preferably after being wrapped in a towel. Yet there is no danger of the tube breaking in transit when properly packed because the wall of the glass tube is not cracked or nicked and the tube is relatively strong except against the application of such a The upper end of the glass tube open but after the suture has been placed therein, it is plugged with a sterile plug l8 of fibrous material such as cotton, preferably about fivesuture" as employed in the application and claims is synonymous with the term ligature as the same material may beused both for sewing woimds or tying knots about various types of tissue.

IZinFig-lis The porous plug The suture l9 may consist of any suitable type of' suture and it is preferably coiled helically about the reel I5 in a plurality of coils with the upper end projecting from the reel in such a di- 5 rection that it extends into the upper part of the tube l2.

The reel may consist of one or more pieces of flat indurated fiber so long as it is formed with a central groove and upwardly projecting guide 10 flanges on each side of the coiled suture l9. Various types of reels have been disclosed in the aforesaid prior application on Suture packages,

Serial No. 388,948, and in the aforesaid parent application Serial No. 284,388, any of which maybe employed.

There may be a suitable clearance between the reel and the walls of the tube even at the restriction but the suture is not tightly coiled on the reel but forms an easy bend at each end of the reel so that the suture coils expand in the tube I2 below the restriction I4 to retain the coiled suture in that end of the tube.

The sutures may be of the boilable or nonboilable type and are preferably immersed in a preserving fluid such as ethyl alcohol in the case of the non-boilable suture, or an anhydrous organic liquid such as toluene or xylene in the case of the boilable suture. The preserving fluid is indicated at 9 and preferably extends to a point 3 just above the coiled suture so that the suture is substantially all immersed.

The length of the glass tube 12 is preferably such that there is space between the free surface of the preserving fluid 9 and the plug l8 so that 5 the glass tube may be sealed off hermetically at this upper portion without removing the plug It. We have found that sutures which have been suitably treated and sterilized according to the methods of our invention and with our appara- 40 tus may be preserved fora long period of time without contamination merely by means of the filter plugs I8. Therefore, the embodiment of Fig. 1 may be regarded as a finished product, for some purposes, and in some hospitals where it is not necessary to ship the product, shorter tubes may be used and closed with cotton plugs and kept in this condition as illustrated in Fig. 1 until used.

Whenever the sutures are to be preserved in- 60 definitely or packaged for shipment, the glass tube is preferably sealed off hermetically as shown in Fig. 2 and this is accomplished by application of heat tothe tub between the plug I 8 and liquid 9, the tube being rotated and drawn out until the glass melts and is severed and the end of the tube is thus closed and takes a sub stantially spherical form as shown in Fig. 2. The severed end of the tube and plug may then be thrown away.

The foregoing two embodiments are merely exemplary of two of the forms'which the packaged sutures may take, others of which are disclosed in the copending applications above-mentioned. r

Referring to Fig. 3, this is' a diagrammatic elevational view of one form of apparatus adapted to be used for packaging sutures according to the invention. In this embodiment l0 indicates one of the suture packages of Fig. 1 filled with a reeled suture and plugged with a cotton plug l8 as described with respect to Fig. 1 but not yet supplied with its preserving liquid 9. While only one of these tubes is shown, it should be understood that a multiplicity of tubes and sutures can be treated at th same time and in fact a very The tubes may be placed in wire racks which preferably hold the tubes in vertical position and the racks fit in the sterilizing chamber 20. In other embodiments of the invention, glass, porcelain or earthenware jars have been used for supporting the suture-filled glass tubes in vertical position inside the jar and the jars may be piled in the sterilizing chamber in the same manner as the racks with their upper ends open.

indicates a sterilizing chamber providedwith a cover 2| adapted to be secured by bolts or other fastening means in such manner that the chamber 20 can be hermetically sealed. The sterilizing chamber 20 is housed entirely within a suitable oven 22 which may be heated with electricity or gas, but which is preferably of the electrical heating type. the suture packages III in the sterilizing chamber 20 to the desired sterilizing temperature which may be maintained for such a period of time that all of the bacteria and their spores are killed.

For example, the sterilization with. dry heat may be at a temperature of 300 F. for a period of three hours.

The controls for the heating apparatus are preferably such as to maintain the oven at the predetermined temperature desired automatically.

The sterilizing chamber 20 .is provided with a pipe 23 having a valve 24, the actuating handle of which extends out through the wall of the oven. The further extension 25 of this pipe leads to a suitable vacuum pump preferably adapted to maintain a very high vacuum such as for example 29 or 29 inches of mercury or better.

The sterilizing chamber 20 is also provided with another pipe or conduit 26 controlled by another similar valve 21 and having its xtension 23 leading to a sterilized bacteria-proof air filter 29.

The sterilizing chamber is also provided with a conduit 30 which extends into or to the bottom of the sterilizing chamber and which is provided with a valve'3l and a bacteria-proof filter 32. A pipe 33 leads from the bacteria-proof filter 32 to atank 34 containing the preserving liquid with which the tubes are to be partially filled, such as alcohol, toluene or xylene.

The tank 34 is provided with a conduit 35 controlled by a valve 33 and the conduit 35 also leads The oven 22 is adapted to heat the sterilizing chamber is hermetically sealed. The temperature of the oven 22 may then be raised gradually to the desired sterilizing temperature and simultaneously the air may be pumped out of the hermetically sealed sterilizing chamber 20 to produce a vacuum by means of the pump connected to the conduit 25, the valve to another or the same vacuum pump previously described so that a vacuum may be created in the tank 34. Another conduit 31 provided with a valve 38 extends from the tank 34 to a bacteriaproof air filter "39 which is open to the air at its lower end.

The oven 22 is preferably provided with devices for indicating temperature of the oven while the sterilizing chamber is preferably provided with devices for indicating both the internal temperature in the chamber 20 and the vacuum and for recording continuously the temperature and vacuum throughout'the period of sterilization.

These indicating devices are designated by the member 40 in the sterilizing chamber 20 connected by member 4| to the indicator or dial and recordingmechanism indicated at 42.

The operation of the apparatus of Fig. 3 is as follows: After the sterilizing chamber has been filled with the tubes l2 containing sutures and filter plugs, the valves 3l' and 21 may be closed and the cover 2|. clamped down tightly so that 24 being open.

We have discovered that the simultaneous action of vacuum and sterilizing heat will effect sterilization more efilciently and more quickly and will kill bacteria and their spores that might resist the application of heat alone. The use of the vacuum introduces the element of an insu- After the sterilization has been carried on for a sufllcient length of time, such as for example a temperature of 300 F. for a period of three hours or more, the entire contents of the chamber 20 willbe completely sterile. The temperature attained at the innermost portion "of the chamber 20 is constantly measured and preferably recorded by the recording mechanism 42 and a similar record is preferably kept of the vacuum applied.

After the sterilization has been effected, the valve 24 is closed and the valve 21 is opened slightly in order to break the vacuum gradually. Then sterile air, taken from the interior of the oven 22 through the bacteria-proof filter 29, enters the sterilizing chamber 20. This is'preferably continued until the pressure in the sterilizing chamber, substantially atmospheric pressure and the'valve 21 is then closed.

Thereafter the valve 3| may be opened, thus establishing connection between the tank 34 which contains sterile alcohol or someother suitable preserving liquid and a vacuum is applied. I

to the tank 20 by means of the pump attached to conduit 25 with the valve 24 open.

In other embodiments of the invention, pressure may be applied to theliquid in the tank 34 by means of a pressure pump attached to pipe 35 and the liquid forced into the sterilizing chamber 20 while the valve 21 is open', permitting the air to be forced out of the chamber 20. This is continued until there is a sumcient amount of liquid in the chamber 20 to cover the open ends of all the tubes l2 and to provide enough liquid to fill the tubes to a predetermined level. While the plugged ends of all the tubes are covered with preserving liquid. the liquid does not at this time pass into the tubes on account of the pressure of the air inside the tubes.

In some embodiments ofthe invention where the tubes are packed in porcelain jars or other containers, the cover 2| of the chamber 20 may be removed and the jars filled with the preserving liquid by pouring into the jars until the glass tubes are submerged to a predetermined degree. Thereafter the cover 2| may again be applied and the apparatus is ready for. the rest of the steps of the process which may be carried out in the same way whether the chamber 20 is filled with liquid or the jars are filledwith liquid.

It should be noted, that although the removal of the cover 2| is no desirable as this may permit the introduction bacteria into the chamber 20, the sutures are, nevertheless, protected against contamination by the filter plugs l 8. In the preferred practice of the process and operation of the apparatus, the cover 2| is not removed, thus keeping the sterilizing chamber in a sterile condition at this time.

When a suiiicient amount of liquid has entered the chamber 20, the valve 3| may be closed, shutting oif the connection between the preserving fluid tank 34 and the sterilizing chamber 20, and with the valve 21 closed, valve 24 may be opened and air again exhausted from the chamber 20 to a predetermined degree of vacuum. This causes the air in the tubes l2 to expand and the' air passes out of the-tubes through the filter plugs l8 and bubbles up through the preserving liquid.

It is found that such glass tubes vary slightly in their internal diameter but they are all of substantially the same length. The product is more salable and more desirable if the preserving liquid is brought to substantially the same level in all of the tubes and this can be accomplished with the present apparatus because the diameter of the tube does not affect the amount of liquid which is drawn into the tube in the next step.

when the pressure in the tubes has been reduced to a predetermined degree which may be determined by trial or by calculation, the vacuum pump may be shut off and valve 24 closed. This precise degree of vacuum depends upon the external atmospheric pressure and the efiect secured depends upon the net difference in pressure between the outside and inside of the chamber 20. This, for example, may be inches of mercury in a tube of the type illustrated.

The valve 2'! then may be opened slightly in order to break the vacuum slowly in the chamber 20. If the vacuum is broken too quickly, the increased pressure in thechamber on the liquid may cause all of the cotton plugs to shoot to the bottom from the open end of the tube, that is, down to the suture or restriction.

If the vacuum is broken gradually, the gradually increased pressure on the liquid in the chamber 20 will cause the liquid to filter through the plugs into the tubes gradually so that the plugs will not be displaced.

After the valve 21 .has been partially opened and a short period of time has passed, the preserving liquid will have filtered into all of the tubes I! to substantially the same level.

In some embodiments of the invention a pressure pump may be connected to the bacteriaproof filter 29 and pressure may be applied to the liquid in the chamber 20' at this stage instead of applying a vacuum and breaking the vacuum. The net result is brought about by the difierential of pressure between the air in the tubes and the air in the chamber to fill the tubes to a predetermined level. In either case, after the tubes have bee fllled to a predetermined level, atmospheric pressure is again reestablished in the chamber 20 and the cover may be removed.

The jars containing the tubes and liquid may then be removed from the tank 20 and the excess liquid poured off from the jars or, in case racks are used, the excess liquid may be drawn off from the tank 20 before removing the cover, by opening the valve 3] and applying suction tothe tank 34 through pipe 35 with valve 36 open. The purpose of the valve 38 on tank 34 is to permit the ingress of air through the filter 39 when-liquid is being drawn from the tank 34 into the chamber 20.

The cotton-plugged tubes l0 containing the sterile sutures immersed in preserving liquid may then be permitted to sit in the oven for a predetermined. period of time such as over night until the alcohol in the plugs [8 has evaporated or the alcohol-wet plugs I8 maybe ignited and permitted to burn until all the alcohol burns ofi. Unless this is done when heat is applied to the tube I2 between the preserving liquid and the plug Hi, the vaporization of the alcohol would produce pressure within the tube, blowing out the glass and this would introduce difiiculties in the sealing of the glass tube.

The'glass tubes may then be sealed between the plug and the suture without removing the plug and the end of the tube and the plug may be thrown away.

Referring to Fig. 4, this is a similar diagrammatic sectional view of an improved form of apparatus having additional advantages over those shown in Fig. 3. In the apparatus of Fig. 3 the preserving fluid was preferably ethyl alcohol and the tubing fluid was not heat-sterilized with the sutures. Consequently, other means had to be employed for ensuring the sterility of the fluid. The ethyl alcohol in that case was denatured by means of the addition of mercury which made the fluid bacteriologically safe and sterile.

There are, however, a small percentage of patients who have an allergy to mercury and the use of mercury for this purpose is undesirable. In the apparatus of Fig. 4 its use is avoided by employing apparatus in which the sterility of the v fluid is accomplished without the use of mercury or any other germicidal substance. This is accomplished by including a special tank for the tubing fluid in the same oven so that the tubing fluid is subjected to substantially the same degree of heat as the sutures.

This apparatus is particularly suitable for use when sterilizing the boilable type of sutures. In such case the tubing fluid is preferably waterfree hydrocarbon of comparatively high boiling point. Being without moisture content, the efiect of this tubing fluid on the micro-organisms is the same as dry heat of an oven which is not nearly so effectual as wet heat at equivalent temperatures, and therefore it withstands, and requires, a high degree of heat for sterilization.

Therefore, the fluid. to be rendered sterile must be subjected to as much heat as is used in sterilizing the sutures. Having a high boiling point, this can be done without creating a dangerously high pressure within the fluid sterilizing chamber.

When the non-boilable type of sutures are to be prepared with the same apparatus, the tubing fluid chamber must be constructed in such manner as to withstand the .high pressures which would be created by heating the alcohol or other low boiling fluids to such a temperature as 356 F.

The apparatus of Fig. 4 also preferably includes an oven 22 which may be provided with the same sterilizing chamber 20 having a cover 2 I. The oven may be heated by means of hot air which is heated in an electric heater 45 contained in house ing 46' which has a conduit 41 communicating with the upper part of the interior of the oven 22.,

' The housing 46 of the heater 45 has an outletconduit 48 connected with the inlet 49 of a centrifugal blower 50 the outlet of which is conand blown into the bottom of the oven in large volume so as to heat the oven to a substantially uniform temperature.

The temperature inside the oven is substantially that of the temperature of the air passing out of the upper'conduit 41 and this conduit is preferably provided with a suitable temperature responsive mercury bulb or other thermostatic electric switch 52 connected by a cable 53 having suitable conductors to the conductors of the cable 54 leading to the electric heater 45.

The electric heater may have a plurality of ranges of heat provided by switch contacts for cutting in difierent sections of the heating coils so that the oven may be maintained at substantially constant temperature determined by the setting of the thermostatic switch 52 at a temperature controller 55.

The oven may also be provided with an angle thermometer 56 having its mercury bulb located inside the oven and its indicating portion located on the outside for checking the temperature.

The temperature in the sterilizing chamber 20 may lag considerably below that of the temperature in the oven 22 on account of the insulating v 22 like the filter 29.

the amount which has been drawn from this tank into the vacuum tank 20. r

The tubing fluid tank 34 is also provided with a bacteria-proof filter 64 communicating with the tank through a valve 65, the other end of the filter being open to the air inside the oven All of these filters may consist of compact plugs or bodies .of sterile cotton closely packed in a cylindrical container. They are, of course, maintained in sterilized condition by the sterilizing temperatures in the oven.

The tubing fluid tank 34 has its interior in communication with a pipe 66 which may lead from its upper end to a valve 61 and thence to a T connection 68. The T connection has one opening connected by means of a pipe 69 to a helically coiled pipe located in an insulated chamber 1| and packed with solid carbon dioxide.

The lower end of the helically coiled pipe. 10 is open and the object of the unit II is to connected to the hermetically sealed chamber H by pipe 13.

The vacuum air pump 12 is driven by ,motor 14 through belt 15. The other end of the T coneffect of the vacuum in the chamber surrounding the tubes containing the sutures. For example, there may be a temperature differential of about 54 F. between the temperature inside the oven 22 and that at the center of the sterilizing chamber 20.

There is also a time lagof several hours between the time when the operating temperature is reached in the oven 22 and the desired operating temperature isreached inside the sterilizing chamber 20. Thus, the temperature of the air circulated in and about the oven chamber 22 must be about 54 higher than that inside the chamber 20, the exact amount being determined by means of the readings of a temperature recorder 51 which has a clock-driven dial upon which an inked pen constantly indicates graphically the temperature existing on the inside of the sterilizing chamber 20. This temperature recorder is connected by a suitable capillary tube 58 with a mercury bulb 59 located inside the vacuum chamber and preferably adjacent the center and the lower part since the upper part and outside are apt to be hotter.

The vacuum chamber 20 in this case is preferably formed with a partially spherical bottom wall 60 draining toward a centrally located well 6| in which is located the end of a pipe 62 used for emptying the tubing liquid from the vacuum tank 20 and for filling the tank.

A valve 3| again controls the conduit which.

however, in this case leads to the sterilizing tank a 34 located in the oven 22. duit 30 extends down into the tank with which it has a sealed connection to a point adjacent the bottom of the tank so that practically all of the fluid in the tank 34 can be used.

Vacuum tank 20 is again provided with the valve 21 controlling the conduit 26 leading to a bacteria-proof filter 29. The sterilizing tank 34 for the tubing fluid may be provided with a gauge glass 63 which indicatesthe height of fluid in the tank and may be used as an indication of Here again the connection 68 is connected by a pipe to a valve 16 which connects with another T connection ll to a pipe I8 leading to the interior of the vacuum chamber 20.

The other end of the T connection Tl has a pipe (9 leading to a vacuum recorder 86 which is essentially a pressure gauge provided with a combined indicator and pen and with a clockdriven dialfor indicating pressure or vacuum so that the vacuum in the chamber 20 or other A difierential manometer 8| has one end of its U tube connected to the pipe 19 and is provided with a scale 82 located between the legs of the manometer and adapted to indicate the difierence in the external and internal pressure by means of the difierence between the elevations of the two columns of mercury in the manometer.

-With this arrangement it is not necessary to make a separate reading of the-air pressure at the time the proper vacuum is determined to effect a filling of the tubes with tubing fluid. The manometer gives the difference in pressure with relation to the external air pressure and eliminates the necessity for calculation. For

example, it might show a differential of 15% blower, the heater will be turned oiT and damage to the mechanism prevented.

The tubing fluid tank 34 preferably communicates through a pipe and valve 34 with a bacteria-proof filter 85 preferably of the Berkefeld or similar type. Filter 85 communicates through pipe 85 with the interior of a standard commercial drum 81 of the tubing fluid, the pipe 86 preferably extending to the bottom of the inside A pipe 88 leads from the top of the interior of the drum to a bacteria-proof air fllter' 39 and thence to another pipe 90 which is connected to the air pressure pump 9| driven by ,motor 92 by means of belt 93. In this case the wire racks for supporting the suture tubes I! in the vacuum chamber 20 are indicated by the numeral 94 and they are preferably circular, having amultiplicity of frame members for engaging the tubes which may be arranged in circles, the center of each rack having an opening to accommodate the pipe 62.

The vacuum chamber 20 preferably has its cover provided with a ground metal surface for engaging a similar surface on the tank so as to assure a vacuum-tight joint. While it is true that there is a possibility of leakage through the multiplicity of different valves employed in the apparatus, the continuous operation of the vacuum pump during the sterilization takes care of the leakage which might occur at these valves or at any other joints and assures the maintenance of a relatively high vacuum of 29 or 29 /2 inches of mercury or more.

94' indicates a union joint which facilitates the disconnection of the pipes from the cover 2| before the cover is removed from the vacuum tank.

The method of manipulation of this apparatus is substantially the same as that described in respect to Fig. 3 except that it is necessary to operate the pressure pump 9| to placepressure on the tubing fluid in the drum 8! while the valves 84 and 65 are open so as to force an adequate supply of tubing fluid into the tubing fluid sterilizing tank 34 before the process of sterilization is begun. Then the tubing fluid is sterilized simultaneously with the sterilization of the sutures in the vacuum chamber 20 except that the sutures are subjected to both vacuum and heat while the tubing fluid is merely subjected to heat in the tank 34 with all the valves 3|, 65 and 84 closed.

The present apparatus is adapted to eliminate all possibility of contamination of the sutures which are to be sterilized and packaged. It is not necessary to use any germicide in the tubing fluid and a purer product may be produced since the tubing fluid is adequately sterilized before it is introduced into the tubes.

The simultaneous application of high vacuum of from 29 to nearly 30 inches of mercury to the sutures at the same time the sterilizing temperatures are applied, contributes to the excellency of the product.

'Another difierence in the operation of the apparatus of'Fig. 4 over that of Fig. 3, although intojgelat'in is reduced to a minimum by the initialapplication of vacuum without heat.

The air drying unit ll of the present apparatus also prevents the drawing of any water or other fluid into the vacuum pump which might cause'damage to the vacuum pump.

both may be operated in the same way, is in the the finished sutures are more flexible than if 3 they are case hardened by the application of heat without subjecting the sutures to vacuum Animal sutures, such as gut and tendons, are composed of a colloidal substance, collagen. When heat is appied to collagen before the extraction of most of its moisture; it is converted into gelatin which .hardens it and reduces its tensile strength and the,degree of its conversion The sutures may then be" subjected to the action of combined vacuum and heat, the temperature being graduallyincreased until the recorder indicates about 300 F. inside the vacuum sterilizing chamber 20 and this temperature may be maintained, for example, for a period of three hours at the end of which period the temperature may be gradually decreased and reduced in the oven by shutting off the electric heater 45 while continuing to operate the blower 59 which causes air at room temperature to circulate through the oven 22 while the lid has been removed from the oven.

In other cases the oven may be left to cool over night or for a predetermined period of time before the next step is taken in the manipulatio of the apparatus.

Next the tubing fluid may be introduced into the tubes in the same manner as described in respect to Fig. 3. The chamber 20 is flooded with a fluid well above the tops of the uppermost layer of tubes such as, for example, to a point three inches below the outlet where the vacuum pipe 13 is attached to the vacuum chamber 20.

The degree of vacuum in the chamber 20 which is produced after the chamber is filled with tubing fluid is read at the manometer 8| and the pump is operated continuously until the desired degree of vacuum is reached. It should also be noted that whenever the vacuum pump is turned oil, the valves 61 and 16 are closed first in order that when the pump is standing still, the oil in the pump may not be drawn into the conduits leading to the vacuum chamber 29.

Then the chamber 20 is again restored to atmospheric pressure and the surplus fluid is removed into the tank 34 where the gauge glass 63 will indicate its usual height of liquid when all has been removed from the vacuum chamber 20.

Referring now to apparatus of Fig. 5, this apparatus is particularly adapted to be used for preparing the non-boilable type of sutures. It is distinguished from that of Fig. 4 inthat, the sterilizing-chamber for the tubing fluid of low boiling point such as ethyl alcohol which is used for non-boilable sutures, is sterilized by heating in a separate liquid heating bath or oven.

This bath or oven is heated by a separate heating unit to the degree of temperature which is required and which need only be sufflcient for sterilization of the tubing fluid which is not subjected to as high a temperature as the sutures for sterilization. Here again, although the apparatus is particularly adapted for preparation of non-boilable sutures, it is not limited to that type as the tubing fluid sterilizer may be operated at a higher temperature for sterilizing the higher boiling fluids that are used for boilable sutures. In the embodiment of Fig. 5, the apparatus is provided with two sterilizing tanks and 96 adapted to receive a heating bath 91 or 98 surrounding the suture sterilizing chamber 20 andthe tubing liquid sterilizing chamber 34, respecsterilizing tank 34 may consist of a bath of glycerine or a bath of oil instead of circulating hot air as in Fig, 4. i

99 indicates a thermostatically controlled valve which is operated responsive to the temperature in the bath 9'! by means of a thermal bulb I connected by a capillary tube IM to the member 99 to control the supply of fuel gas to a heater I02.

A pipe I03 leads from the upper part of the bath 91 to the heating coil I04 and is connected at its lower end to the inlet of a liquid circulating pump I05 which has its outlet connected to the interior of the tank 95 by pipe I06. Outlet pipe I06 preferably leads to the bottom center of the tank 95 and discharges upwardly through an elbow or a bifurcated fitting so that the heated liquid flows upward on all sides of the vacuum chamber 20. I

The same arrangement is utilized in maintaining the heat of the bath 98 in the tank 98 for heating the sterilizing chamber 34 for tubing fluid. There the numeral I01 indicates the thermostatically actuated valve, I08 the capillary tube, I89 the thermal bulb, III] the heater, III the bath intake pipe, H2 the heater coil, H3 the coil outlet pipe, H4 the liquid circulating pump, and- I I! has the valves I I9, I28 'on both sides of a me- Conduit H8 has the valves I22, I23 onv ter I2I. both sides of a Berkefeld filter I24;

Thus. the liquid passing into the vacuum chamber may be metered when it is passing into the chamber, but when it passes out of the chamher, it may be passed through the filter I2I to filter out the cotton fibers.

The fluid liquid supply in chamber 34 may thus always be kept in a state of perfect clarity and the chamber may be kept free of any accumulation of such fibers, which are sometimes very fine and even microscopic.

The pipe I25 leading from the conduits H1, H8 also leads into the bottom of the tank 34 through a T connection and conduit I26 and it may be continued on through the valve I2I to a bacteria-proof filter I28 of the same type and through a pipe I29 leading into the standard drum of tubing liquid through a liquid-tight connection with the top of the drum.

The drum is preferably connected to a conduit leading to a bacteria-proof air filter I30 which is connected to conduit I3I leading to the air pres- A temperature recorder I has a capillary tube I36 leading to a mercury bulb I31 located centrally in the chamber 34 to record constantly on the dial in the same way the changes in temperature of the tubing fluid so as to make a recq 0rd of its sterilization.

The dials of all these recording instruments have scales and indications of the time as well as indications of the pressure or temperature. The recorders draw a curve which indicates these values at all times when the apparatus is operating.

The vacuum tank 20 for sterilizing the sutures may also be provided with a pressure pump I38 connected by pipe I38 to the interior of the tank through a valve I39.

The manipulation of this apparatus is substantially the same as that of the apparatus of Fig. 4 except that the tubing fluid is sterilizedat a different temperature which, while suflicient to sterilize the tubing fluid, would not be sufllcient to sterilize the sutures. Due to the presence of water in alcohol, there takes place in the sterilization what may be called moist heat sterilization which is effective at temperatures upward of 212 F.

-The present apparatus constitutes a bacteriaclosed system in which there is no possibility of accidental contamination of the product. The sterilization by heat is carried out in an hermetically closed chamber, the tubes being secure-' duced into sterile tubes through the sterilizing plugs while the tubes are still within the hermetically closed sterilizing chamber.

The tubes are then sealed without removal of the plugs and therefore this apparatus is capable of producing a product which could not be other than sterile. The system is so positive and definitely predetermined that it does not require the services of an operator skilled in a knowledge of bacteriology.

Furthermore, the sutures prepared by this process possess better fiexibility than when they are prepared by the methods of the prior art and the original tensile strength of the sutures is preserved.

At no point in the handling of the product is it necessary" to employ aseptic technic-in handling the sterilized tubes. So long as the plugs are in the tubes, no bacteria can enter.

It should be noted that the valves through which the tubing liquid flows are located within the sterilizing oven and this is also true of the air filters which are adapted to be sterilized by the oven except the piping, filter I24 and meter I2I which have to be' sterilized on their inside by other means.

In addition to the fact that all of the air admitted to the system has to pass through bacteria-proof air filters, this air cannot gain access to the sutures in the tubes until itv passes through still another sterile and bacteria-proof filter comprising the plugs and the tubes- By means of the recording instruments of temperature and vacuum and of the numbering of the sutures by means of numbered slips placed in the tubes I2, a constant check and record may be kept of the treatment to which any suture has been subjected. Samples of the sutures from ,every batch may be tested for sterility after the process is completed and the results may be taken as an indication of the sterility of the complete batch.

Should any trouble occur, or any complaint be made regarding sutures from any batch, all of the rest of the sutures of that batch may immediately be segregated by reason of the fact that they scope of the appended claims.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In an apparatus for sterilizing sutures or the like, the combination of a pair of bath receptacles for supporting a heating bath, each of said bath receptacles having a heating bath of liquid and conduits extending from said receptacle to a heating coil and back to said bath receptacle, a'liquid pump in one of said conduits for circulating the bath liquid, heating means controlled responsive to the temperature of the bath liquid in the bath receptacle for heating the liquid in said coil, a suture sterilizing receptacle in one of said bath receptacles, and a tubing fluid sterilizing receptacle in the other of said bath receptacles, a connecting conduit joining said two sterilizing receptacles and having a control valve and means for applying a differential of pressure to said sterilizing receptacle whereby the tubing fluid may be caused to flow from the tubing receptacle into the'suture sterilizing receptacle to a predetermined level and by further change of pressure caused to flow into the suture tubes through filters on the ends of said tubes.-

2. In an apparatus for sterilizing sutures or the like, the combination of a pair of bath receptacles for supporting a heating bath, each of said bath receptacles having a heating bath of liquid and conduits extending from said receptacle to a heating coil and back to said bath receptacle, a liquid pump in one of said conduits for circulating the bath liquid, heating means controlledresponsive to the temperature of the bath liquid in the bath receptacie for heating the liquid in said coil, a suture sterilizing receptacle in one of said bath receptacles, and a tubing fluid sterilizing receptacle in the other of said bath receptacles, a connecting conduit joining said two sterilizing receptacles and having a control valve and means for applying a. difierenti'al of pressure to said sterilizing receptacle whereby the tubing fluid may be caused to flow from the tubing receptacle into the suture sterilizing re:- ceptacle to a predetermined level and by further change of pressure caused to flow into the suture tubes through filters on the ends of said tubes,

said conduit between said sterilizing receptacles receptacle.

3. In an apparatus for filling suture tubes to a predetermined level with a preserving fluid, the combination of an hermetically closed receptacle with means for supporting a multiplicity oi suture tubesfilled with sutures and having a filter at their open ends, a bath tank surrounding said receptacle, a heater having hot and cold liquid connections with said bath tank and having a heating coil, thermostatically controlled means forcontrolling the supply of gas to said heater to maintain the liquid in said bath tank at a predetermined sterilizing temperature, a vacuum pump connected with said receptacle, and means interposed between the vacuum pump and the receptacle for removing condensate from the air before it reaches the vacuum pump, valve means interposed between the vacuum pump and said receptacle, and pressure indicating means for indicating the degree of vacuum in said receptacle, said receptacle having a conduit connecting with a supply of tubing fluid, whereby tubing fluid may be drawn into the receptacle by difi'erential of pressure and the pressure again increased to expel air from said tubes and again decreased to cause the tubing fluid to filter through the tube filters to a predetermined level.

4. In an apparatus for filling suture tubes to a predetermined level with a preserving fluid,

the combination of an hermetically closed receptacle with means for supporting a multiplicity of suture tubes filled with sutures and having a filter at their open ends, a bath tank surrounding said receptacle, a heater having hot and cold liquid connections with said bath tank and hav ing a heating coil, thermostatically controlled means for controlling the supply of gas to said heater to maintain the liquid in said bath tank at a predetermined sterilizing temperature, a

vacuum pump connected with said receptacle, and means interposed between the vacuum pump and the receptacle for removing condensate from the air before it reaches the vacuum pump, valve means interposed between the vacuum pump and said receptacle, and pressure indicating means for indicating the degree of vacuum in said receptacle, said receptacle having a conduit contween the supply of tubing liquid and the firstmentioned receptacle, a second bath tank surrounding said tubing tank, and a separate heater for maintaining the bath of said latter bath tank at a predetermined lower sterilizing temperature, whereby a low boiling point fluid may be used for the tubing fiuid.

- WALTER S. DAVIS.

CHARLES T. DAVIS.

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