US2592705A

US2592705A - Sterilizer

Info

Publication number: US2592705A
Authority: US
Inventors: Raymond L Jewell; Charles E Freese
Original assignee: American Sterilizer Co
Current assignee: American Sterilizer Co
Priority date: 1949-12-05
Filing date: 1949-12-05
Publication date: 1952-04-15
Anticipated expiration: 1969-04-15

Description

A ril 15, 1952 R. L. JEWELL ETAL STEP-\ILIZER 9 Sheets-Sheet 1 Filed Dec. 5, 1949 INVEKNTTM BY h nl o 8% A ril 15, 1952 R. L. JEWELL EI'AL 2,592,705

STERILIZER Filed Dec. 5, 1949 v 9 filgee't's-sheet g A ORNEY INVENTOR F 4 A ril 15, 1952 R. L. JEWELL ETAL 2,592,705

- STERILIZER Filed Dec. 5, 1949 9 Sheets-Sheet 3 STEP/U25 F/a/i 2 INVENTOR S 262w BYCM .Jzaw

ATTO N EY April 15, 1952 R. L. JEWELL ETAL 2,592,705

STERILIZER Filed Dec. 5, 1949 9 Sheets-Shet 4 5a 49 4a (ITEMS! FABRIC k SOLUTION (i; MANUAL 0 52 OFF 5 L L ECTOR DRY FAST Ex. 5Low Ex. CHAMBER INVENTOR F/a. I51 m BYCLMEM Q Han-#00 ATT NEY ApriI 15, 1952 R. 1.. JEWELL ETAL STERILIZER- Filed Dec. 5-. 1949 9 Sheets-6mm 6 77 b 77a, h

INVENTOR.

BY g:

April 15, 1952 a: L. JEWELL ETAL 2,592,705

STERILIZER Filed Dec. 5, 1949 9 Sheets-Sheet 7 {up 5623b 75 77ft L7 7/ H 6.236 m; 23d.

I y ENTOR. BY m April 15, 1952 R. L. JEWELL ETAL 5 I a STERILIZER Filed Dec. 5, 1949 TSheets-Sheet a Patented Apr. 15, 1952 STERILIZER Raymond L. Jewell and Charles E. Freese, Erie, Pa., assignors to American Sterilizer Company, Erie, Pa., a corporation of Pennsylvania Application December 5, 1949, Serial No. 131,236

14 Claims.

In hospital sterilizers, operating requirements vary with the character of the material being sterilized. Metallic articles, such as surgical instruments require merely a definite sterilizing time. After sterilizing the instruments the sterilizer need only be exhausted as rapidly as possible so that the operator can remove the sterilized instruments. In the case of bandages or other cloth material, the sterilizing cycle is preferably followed by a fast exhaust to remove the steam and then a subsequent drying operation to remove any residual moisture in the fabric. In the case of solutions,.the sterilizing cycle should be followed by a slow exhaust to prevent evaporation or boiling of the solution. It is also desirable that the sterilizer be subject to the control of the operator at all times so that special requirements may be met. This invention is intended to provide an automatic control meeting the various requirements of the materials to be sterilized. The control actuates a manually operable multiport valve so that the operation of the sterilizer can always be manually controlled. Further objects and advantages appear in the specification and claims.

In the drawings, Fig. 1 is a side elevation, partly broken away, of the sterilizer; Fig. 2 is a sectional elevation on line 2-2 of Fig. 3 of the valve controlling the sterilizing, exhausting and drying operations; Fig. 3 is a front view partly broken away of the valve; Fig. 4 is a plan View of the valve disc in the off position; Fig. 5 is a section on line 5-5 of Fig. 4; Fig. 6 is a plan view of the valve disc in the sterilize position; Fig. 7 is a section on line 1-! of Fig. 6; Fig. 8 is a plan view of the valve disc in the slow exhaust position; Fig. 9 is a section on line 9-9 of Fig. 8; Fig. 10 is a plan view of the valve disc in the fast exhaust position; Fig. 11 is a section on line I ll I of Fig. 10; Fig. 12 is a plan view of the valve disc in the dry position; Fig. 13 is a section on line l3l3 of Fig. 12; Fig. 14 is a top plan view of the control for the sterilizer; Fig. 15 is a front view of the control panel; Fig. 16 is a perspective view of the valve and the associated manual and motor drive therefor; Fig. 1'7 is a perspective of the timer; Fig. 17a is a perspective of the selector switch in the manual position; Fig. 1% is a view of the selector switch in the fabric position; Fig. 170 is a View of the selector switch in the utensil position; Fig. 17d is a view of the selector switch in the solution position; Fig. 18 is a control diagram, Fig. 19 is a perspective of an automatic reset timer for use in the Fig. 18 control diagram; Fig. 20 is a control diagram in which a pressure control responsive to the steam pressure in the sterilizing chamber terminates the sterilizing cycle in either the fast exhaust (utensil) or "slow exhaust (solution) position. Fig. 21 is a perspective of the timer for the Fig. 20 control; Fig. 22 is a perspective of the cam operated contacts on the valve shaft; Figs. 23a, 23b, 23c, and 23d are perspectives of the selector switch for the Fig. 20 control; Fig. 24 is a control diagram for a fully automatic control in other respects similar to the Fig. 20 control; Fig. 25 is a perspective of the timer for the Fig. 24 control; Fig. 26 is a perspective of the cam operated contacts on the valve shaft; Fig. 27 is a control diagram for a sterilizer having a single exhaust position; Fig. 28 is a perspective of the valve and the associated drive therefor, and Fig. 29 is a perspective of a manual reset timer.

Referring to the drawings, l indicates the sterilizer chamber; 2 indicates the door through which the chamber is loaded and unloaded; 3 indicates a steam jacket around the sterilizer chamber, and 4 indicates the steam line through which the jacket is continuously supplied with steam under the control of a shut-off valve 5. In the lower part of the sterilizing chamber is a drain line 6 leading to a steam trap I. In this drain line is a thermostatic bulb 8 which is associated with a bellows 9 controlling a switch l8 which is closed only after the temperature in the drain line reaches the desired sterilizing temperature. The thermostatic bulb 8 is, in effect, used to prevent the starting of the sterilizing cycle until after the temperature has reached the desired value.

The sterilizing chamber is controlled by a valve H conveniently mounted on top of the jacket. The valve has a casing l2 provided at its lower end with a fitting l3 threaded into a complementary fitting l4 on the jacket. As shown more clearly in Fig. 3, the casing is divided into a chamber I5 which is at all times connected to the steam jacket through the fitting l3, a chamber it which is at all times connected to the sterilizing chamber 1 through a fitting ll connected to a line l8, and an exhaust chamber [9 at all times connected to an injector nozzle and a Venturi ejector fitting 2|. A sidewall of the casing [2 has a valve seat 22 provided with a port 23 leading to the chamber IS, a port 24 leading to the chamber IS, a port 25 leading to the exhaust chamber 19, and a port 26 outside the machined surface of the valve seat 22 leading to the ejector nozzle 2|. The valve seat is enclosed by a bonnet 2'! suitably bolted to the casing and having a stufiing box 28 for a shaft 29 for rotating a valve disc 30. The driving connection to the valve disc is eifected through arms 3! fixed to the inner end of the shaft 29 and

pins

32 and 33 fixed to the valve disc. Pin 32 is solid and is diametrically opposite the pin 33 which has a restricted bore '32. The valve disc 30 is biased against the valve seat 22 by a spring 35 diagrammatically indicated around the shaft 29.

As shown more clearly, Figs. 4-13, inclusive, the valve disc 30 has five equally spaced ports corresponding to the number of positions the valve disc occupies. In the on? position of the valve disc shown in Figs. 4 and 5, a port 36 extending through the valve disc registers withthe port 23 in the chamber 16 which leads through the fitting l1 and the line l8 to the sterlizing chamber 5. In this position a port 3? in the valve disc which carries the hollow pin 33 registers with the port 25 connected to the exhaust chamber l9. In the off position the sterlizing chamber i is accordingly vented to the atmosphere. In the off position, the port 24 leading from the jacket chamber I5 is blocked so'that the steam within the jacket is shut off.

In the sterlize position'of the valve disc shown in Figs. 6 and '7, a way 38 in the valve disc connects the"ports 23 and 22. In this position steam from the jacket flows in the direction of arrow 39-into the port 24 through the Way 38 and out'throu gh the port 23 in the direction of the arrow 40.. This admits the sterilizing steam the restricted passageway 34 to the valve bonnet 21. This permits a flow of steam from the sterilizing chamber 1 to the valve 'bon'net 21. The steam in the valve bonnet flows either'through the passageway 26 or through a port 42 which registers with the port 25 leading to the exhaust chamber 19. The passageway 34 is sufficiently restricted so that the exhaust of steam from the sterilizing chamber i takes a sufiicient length of time so that boiling or bubbling of sterilized solutions is prevented.

In the fast exhaust position shown in'Figs. l0 and 11 the port 24 is closed, the port 23 is connected through the port 4| to the valve bonnet 21 and the exhaust chamber port 25 is connected to the valve bonnet through the port 36. The ports 36 and t! are of such size that the steam from the sterilizing chamber is quickly exhausted. The fast exhaust will ordinarily be completed in less than two minutes. The fast exhaust is desirable for solid materials such as bandages and utensils.

. In the dry position of the valve shown in Figs. 12 and 1-3 the port 23 leading from the sterilizing chamber l is connected through the port 42 to the valve bonnet 21. The port 24 leadingfrom the jacket is connected through-the way 38 to the port 25 leading to the injector nozzleZt. Ih'gh pressure steam from the jacket accordingly fiows into the vent port 25 and out throughthenozzle in the direction indicated by thearrows 23. As is more clearly shown in Fig. 2, the discharge of high pressure steam rotation of the valve disc.

the various positions.

the resetting ornon resetting type.

'restting'ti'm'er illustrated in Fig. 17' comprises 4 through the nozzle 20 has a Venturi action which produces a suction in the passageway 26. Since in this position the passageway 26 is connected to the sterilizing chamber, the suction results in a vacuum within the sterlizing chamber which tends to vaporize residual moisture in the sterilized material. This drying action is desirable in the case of fabrics. The degree of vacuum producedwithin the sterilizing "chamber may be limited by a vacuum breaker.

The valve disc may be rotated sequentially "through the position illustrated in Figs. 4-13, in-

clusive, manually by means of a knob 44 fixed to the shaft. An overrunning clutch indicated diagrammatically as a pawl and ratchet 45 allows manual operation and prevents reverse In sterilizing solutions the valve disc will ordinarily be turned first to the "sterilize position, then to the slow exhaust position, and finally to the 01f position. In "sterilizing metallic articles such as instruments, the knob will be turned first to the sterilize 'pos'ition,secondto the fast exhaust position, and finally to the off position. There is no need for a slow exhaustinthe sterilizing of instruments, noris there any-need for ;a final drying operation since the residual heat in the instruments quickly evaporates moisture. In the sterilizing of fabricsthe valve is turned first to the ste'rilize position, second to'the fast exhaust position, third to the dry positio'n, and finally to the oil position. Thef-fast exhaust quickly removes the steam from the sterilizing chamber. The drying cycle'follows thefast exhaust produces a vacuum within the "sterilizing chamber which causes the evaporationofresidual moisture within the fabric.

Figs. 14 through 19 illustrate a control by which the valve is automatically moved through The control has a panel 35a which is conveniently mounted-on top or the sterilizer. On the panel are temperature indicators 46 and 41' respectively indicating the temperaturein the jacket and chamber, red, yellow and green signal lights, 48, 49, and 50-indicating "thevarious stages of the sterilizingcycle, a timer 'setting knob 5| for setting thetiin'e of the-sterilizing," and a selector knob 4 52 for selecting the cycle to be automatically carried out, or-for cutting out the automatic control so that the sterilizer can be manually controlled. Thevalve controlknob 44 is located in front'of' the panel "65a and the panel carries suitable markings around the knob to indicate'the position'of the valve.

Duringthe operation of the autcmaticcontrol the valve shaft-291s driven by a gearmotor 53 having a pinion "Eton its'low speed shaft 55 which drives a sprocket 56 loose on the valve shaft 29 through a-chain5l'. The driving connectionbetween the sprocket 56 and-the valve shaft 29 is eifected through the'pawl and ratchet 45 which prevents reverse rotation of f the valve shaft. The ratchet is fixed to the valve shaft and the pawls are shown fixed to the "sprocket. The gear reduction inthe motor 53 is sufiicient 'tdpreVe'nt reverse rotation of the motor shaft "55.

Whenever the motor '53 is energized 'the valve'shaft 29 is rotated in' a clockwise direction asview'e'd in Fig. 16.

The timer for the control may be "either'of Th'ehonasynchronous motor '59 "driving a shaft 60 on

switches

64, 65; and 6B. The timer setting knob is fixed directly to the shaft 6!]. In Fig. 17 the timer is shown in the off position in which cam followers 54a, 85a, and 66a rest respectively in lowered

sections

61a, 62a, and 63a of the cams. In this

position contacts

64b, 95b, and 66b are closed and

contacts

640 and 660 are open. Upon turning the knob 5| in a counter-clockwise direction as viewed in Fig. 3, the

cam followers

64a, 65a, and 66a are simultaneously moved to the raised portions 6 lb, 822), and 63b of the cams, thereby simultaneously shifting the position of the contacts. When the cam followers are on the raised portions of the cams, the

contacts

64b, 65b, 66b are opened and the

contacts

640 and 660 are closed. The design of the timer motor is such that the cam shaft 68 may be advanced relative to the timer motor 59 by turning the knob 5!. This permits the operator to select any length of timing cycle from the maximum down to the minimum. In the timer control illustrated, the maximum length of timing for operation of the switch 64 from 640 to 64b is forty fiveminutes. The operator may select any portion of this time.

In the automatic reset timer illustrated in Fig. 19, the motor 5.? drives the cam shaft Bil through a timer clutch 5i normally biased to the open position by a coil spring 68 and closed by a solenoid G9. The cam shaft 60 is normally biased toward the maximum time position by a coil spring 18. Whenever the clutch 6? is disengaged the cam shaft 60 is rotated back toward the maximum time position. The cam shaft is stopped in the desired position by a knob 5la which serves solely to select the time. The knob 5m has a pin 12 which cooperates with a pin 13 on the cam shaft to limit the amount of reverse or resetting movement of the cam shaft. In other respects the operation of the resetting timer is the same as in the direct drive timer illustrated in Fig. 17. In the direct drive timer the knob 5! indicates the position of the timer. In the resetting timer the knob 5la does not indicate the position of the cam shaft to but merely indicates the maximum time for which the timer has been set. If it is desired that the position of the cam shaft be indicated, a separate indicator can, of course, be supplied on the cam shaft 68. This will indicate the remaining time of the time controlled operation.

The selector switch shown in Fig. 17a comprises a shaft l4 carrying the knob 52 and on which is fixed a disc t5 carrying switches 76, T1, and E8. In the manual position shown, the switches are all open. In the fabric position of the selector knob 52 the switch 16 is closed on contact 1611, the switch 11 is closed on contact Ila, and switch 18 is closed on contact 18a. In the utensil position of the selector knob 52, the switch It is closed on contact 16a, the switch 11 is open, and the switch 18 is still closed on the contact lac. In the solution position of the selector knob 52, the switch 16 is open, the switch H is closed on contact 11b, and the switch 78 is still closed on the contact 18a.

The valve motor 53 is controlled by cam operated switches '59, cc, 8!, and 82 controlled by a cam 63 on the valve shaft 28. The switches are illustrated in the off position of the valve. In this position a projection 84 on the cam 83 opens the switch It which is otherwise normally closed. As the cam 83 rotates the projection 84 successively cooperates with the switches B0, 8!, and 82 and shifts the switches from the position illustrated. For example, in the position illustrated the switch has contact 80a open, and

contacts

80b and 800 closed. When the projection 84 engages the switch 80 the switch is shifted to the position in which the contact 80a is closed and the contacts 801) and 800 are open. The switches 8| and 82 have contacts Bla and 82a which are normally open and which are closed when the projection 84 on the cam moves under the switches.

When the selector knob 5'2 is in the manual position, the switch 2'8 in series with the power line 84a is opened. This opens the circuit to the entire automatic control for the sterilizer and permits the operator to manually select any operation in the sterilizer cycle by turning the knob 44. Because of the pawl and ratchet 45 the operator can only turn the knob 44 in a clockwise direction as viewed in Figs. 15 and 16.

In the other positions of the selector knob 52, the switch 18, 18a, is closed and the operation of the sterilizer is controlled by the automatic control. Since the sterilizing cycle is somewhat different for each position of the selector knob 52, the complete cycle will be traced for each position of the selector knob.

In the fabric position of the selector knob 52, switch 16 is closed on contact 1611, switch i7 is closed on contact Tia, and switch 18 is closed on contact l8a. After loading the sterilizer chamber i and lockingthe door 2 to the closed position, the operator starts the sterilizing cycle by first turning the timer knob 5] to the desired sterilizing time and then turning the valve knob 44 to the sterilize position. If the valve knob 4 is turned to the sterilize position before the timer knob 51 has been set to the desired sterilizing time, the control automatically prevents the starting of the sterilizing cycle. The movement of the knob 44 to the sterilize position actuates the switch 30 from the position illustrated in which the contacts 89b and 800 are closed, to a position in which the contact 80a is closed and the contacts 802) and 800 are open. Since in the off position of the timer knob 5|, the switch 64 is closed on the contact 64b, the yellow signal light 49 lights and the valve motor is energized through the

contact

86, 80a, causing rotation of the valve past the sterilize position. As soon as the valve moves past the sterilize position the

contacts

80, 800,, open and the contacts 80b and We close. The closing of these contacts energizes a circuit to a buzzer 85 and to the green light 59 through the contacts 66, 661). A failure of the operator to set the timer knob 5! before turning the valve knob 44 to the sterilizing cycle accordingly results in almost simultaneous lighting of the yellow and green signal lights 49 and 58 and the sounding of the buzzer 85 which ordinarily comes in only at the end of the sterilzing cycle.

If the timer is of the automatic resetting type, illustrated in Fig. 19, of course the operator need not reset the timer knob 5Ia unless the length of the sterilizing cycle is to be changed. With the automatic reset timer the timer cam shaft 60 automatically returns to the position selected by the timer knob 55a whenever the timer clutch solenoid 89 is tie-energized, thereby causing the opening of the timer clutch 61. With the automatic reset timer of Fig. 19, the operator starts the sterilizing cycle by turning the knob 44 to the sterilize position.

If the timer has been set to the desired sterilizing time, either manually or automatically,

the yellow signal light 49.

the turning of the valve knob to -st'erilizvcauses the lightingof the'redsignal light 48 because the switch'tfl closed on contact 640. In the "set position ofthe timer, the contact 651) is open, and the switch '66 is closed on the contact 660, closing the circuit to the timer motor. Ihetiiner motor starts when the temperaturein the exhaust line 6 fromthe sterilizing char-nicer l rises to the desired temperature. At this point the bellows 9 expands and closes the switch liL thereby supplying power to the timer motor' throughcontact 660. The thermostatic switch lfi insures the proper sterilizing time. ing period selected, the timer knob 59 points to O and the'timer shaft Gil has turned to the position in which'the'cam follower E ia drops bit .the raised portion-Bib of the cam 6| onto the lowered portion iiia. This moves the switch M from the contact-64c to the contactfi lb andenergizes The closing of the contact fib also completes the circuit through the switch 89 and contact Btla tothe valveimotor 53 causing rotation of the valve motor from the sterilize-position. Upon reaching the slow exhaust position the switch 8| closes on contact Bid and the switch 80 moves away from contact Sta-and closes contacts 8% and Sec. Because the selector switch it in the fabric position is closed on the contact "16a the valve motor continues rotating past the slow exhaust position until it reaches the fast exhaust position in which the switch 8| opens contact Sta and the switch 82 is closed on 'contact82a. In the fast exhaust position the valve occupies the position shown in Figs. 10 and 11 in which the steam within the sterilizing chamber is exhausted through the port ii to the valve bonnet and through the port 35 and passageway 26 to the atmosphere. At the end of the fast exhaust cycle, which is ordinarily timed forthe order of two minutes, the cam'follower GEamoves from the raised portion EZbof the cam 62 onto the lowered portion 52a and effects the closing of switch 65 oncontact 65b. Since the selector switch 71 in the fabric position is closed on the contact Fla and the switch 82 is closed on the contact 320., a circuit is completed to the valve motor through the switch 64, contact 64b, switch til, contact 882),

switch 65, contact 65b, switch Tl, contact Ha,

switch 82,contac't 82a, to the motor 53. This causes the driving of the motor 53 until the valve has turned to the dry position illustrated in Figs. 12 and 13. The valve stops at'this position because at this position the cam switch 82 is moved away iromthe contact 82a. In the dry position steamfrom the jacket is fed to the injector nozzle 26 and the suction produced by'the'discharge of the high pressure steam into the throat of the ejector Venturi nozzle 2! draws a'vacuum in the sterilizing chamber which evaporates residual moisture. The drying cycle continues until the cam followerGSa drops from the raised portiontiib of the cam 63 onto the lowered portion 63a. When this happens, which mayordinarily be from live to eight minutes after the end of the fast exhaust cycle, the switchliS is moved away from theco'ntactttc to'the contact 661).

This closes'a circuit to the buzzer 85 and also'to the green signal light 56 which signals'to the operator the end of the sterilizing cycle. Atthis time the operator manually turns the knob 44 to the off position, thereby cutting-off the steam supply to the injector nozzle 29] and opening the switch 19 to de-energize the buzzer and lights.

Whenthe selector knob 52 is in the"utcnsil" At the end of the tim position-the start of the sterilizing cycle is'the same as in the' fabric position. The turning of the knob M to the I sterilize :position after the timer knob 5| has :"been set :for the desired sterilizing .timecauses the closing of the switch 19, the closingof the switch '64 on'contact .640,

and the closing of switch :oncontact-tfla and the opening of :switch 80 from contacts Bilband 89c. At the end of the .pre-selected time for the-sterilizing-cycle which isindicated when the knob 5! comes opposite zero on the time dial, the=switch 64 moves away fromthe contact 640 and closes-onthe contact 64b,lightingthe yellow signal light '39 and energizing a circuit to the valve'mo'tor 53 through'the contacts-80, 80a. Because in this position of theselector switch, contactlS is closedon contact'lfia, the valve motor continues to drive the valve-shaft 2 9 untilithe switchfiil is opened from the contact 80a, and the switch --8l is opened away fromthe contact Ma, and theswitch 82 is closed onthe contact 82a. In this position the valve is in the fast exhaust positionillustrated in Figs. 10 andll. Atthe end of the time for the fast exhaustjthe cam follower 55a drops off the high-portionezb of the cam 62 onto'the lower portion 62a andcloses the switch 65 against the contact 65b. Since the 'selector'switch Tl is closed on the contact "Ilb, this completes a circuit from one side of the line through switch 6 3, contact 6th, switch 80, contact 8%, switch 65, contact 55b; switch ll, contact iii; to the buzzer 85 and green light 50. This signals to the operator-the endof'the sterilizing, cycle. The operator shuts off the buzzer by manually turning the dial knob 4t tothe off position in which the switch 19 is open, thereby breaking the circuit buzzer and light.

When the selectorknob 52 is in the solution position the sterilizing operation starts in the same manner as in the other positions by the turning of-theknob 44 to the sterilize" position after the timer knob-5l has been set for the desired sterilizing time. At the end of the sterilizing time, when the cam follower 512, drops ofi the raised portion Blb of the-cam 6| onto the lowered portion em and closes the switch t4 onto the contact-64b, the yellow signal light 49 lights and the valve motor 53 isenergized through the switch 89 and contact 80a. In thisposition of the selector switch the switch 16is open. .Accordingly, the-valve motor merely turns the valve from the sterilize position to the slow exhaust position. In the slow exhaustposition illustrated in Figs. 8. and 9, the switch 30 is closed on contacts 86b and'lmc. Because switch 76 is open, no further energizing of the valve motor53 is possible.

At the end of the slow exhaust time which occurs when cam follower 56a dropsfrom the raised portion 63b of cam 63 onto the lowered portion 63a, the switch 56 is moved from contact 560 to contact 65b, thereby breaking the that previously described. With the direct drive timer the solenoid 69 controlling-the closing of the timer clutch 67 obviously willbe omitted.

timer motor is "energized through :the thermos static switch It} and the switch 66 which is closed on contact 660 until the timer reaches the off position. There are only two conditions on which the operation of the automatic reset timer is different from the direct drive timer. The first condition in which the automatic resetting timer has a different operation is upon failure of the steam pressure during the sterilizing cycle. Under these conditions the thermostatic switch l opens and ole-energizes the timer clutch solenoid 69. The timer clutch (i7 is then opened by the coil spring 68 and the timer cam shaft 6!! is rotated back to the beginning of the sterilizing cycle selected by the position of the knob am. Another condition in which the operation of the automatic resetting timer is different from the direct drive timer is upon failure of the power supply. Failure of the power supply de-energizes both the timer motor 59 and the timer clutch solenoid 69 causing the resetting of the timer back to the beginning of the sterilizing cycle. These are safety features. Another advantage of the automatic resetting timer is that upon manually turning the valve knob 44 to the offposition the timer solenoid 69 is de-energized, thereby causing the resetting of the timer cam shaft 60 back to the position selected by the knob la. This means that with the automatic resetting timer the operator need not first pre-select the steriliz ing time before turning the knob 44 to the sterilize position.

The control illustrated in Figs. 20 through 23d, inclusive, makes use of a number of parts which have been previously described and which are indicated by the same reference numerals. The principal differences in the Fig. 20 control are the omission of contacts 88b and 800 in the cam operated switch 80, the omission of the cam 62 and the associated switch 65, 651), the addition of a normally closed contact 82?) to the cam operated switch 82, the extension of the selector switch contact 'llb so that the contact 17, TH) is closed in both the fast exhaust (utensil) and slow exhaust (solution) positions, and the addition of a normally closed pressure switch 35 having a contact 65a normally held in the closed position by a spring 81. Steam pressure from the sterilizing chamber is admitted through a conduit 88 to the underside of the pressure diaphragm 89. Whenever the steam pressure is less than a low value, for example, lb. per square inch, the contact 85a is closed by the spring.

As in the previously described control, in the manual position the switch 18 is open so that none of the parts of the control is operated.

In the fabric position the selector switch contact 18 is closed, the selector switch contact 1! is closed on contact 17a and the selector contact 16 is closed on contact 16a. The operator starts the sterilizing cycle by first turning the timer knob 5| to the desired sterilizing time and then turning the knob 44 from the off to the sterilize position. Setting the timer knob 5| to the sterilizing time moves the contact 64 from the contact 541) to the contact 640 and also moves the contact 55 from the contact 66b to the contact 660. Upon turning the knob 44 from the off position to the sterilize position, steam is admitted to the sterilizing chamber and the switch 19 is closed on contact 19a and the switch 88 is closed on contact 80a. As soon as the temperature in the sterilizing chamber reaches the desired value the switch is closed by the thermostatic bulb 8 and bellows 9 and the timer motor 59 is energized through switch 56 and contact 66c, starting the rotation of the cams 6i and 63 which determine the time of the sterilizing cycle. At the end of the sterilizing time the cam follower 64a drops off the raised portion Bib of the cam BI and moves the switch 64 from the contact 640 to the contact 64b. This energizes the amber light 49, signaling the end of the sterilizing operation and also energizes the valve motor 53 through the closed contact 80, a. When the valve shaft 29 reaches the "slow exhaust position, the switch 80 moves away from the contact 83a and the switch Bl closes on the contact em. Since the selector switch 16 is closed on contact 16a the valve motor 53 continues its rotation and moves the valve shaft 29 through the slow exhaust position to the fast exhaust position where the switch 8i opens and the switch 82 moves from the contact 821) to the contact 82a. In the fast exhaust position, the pressure in the sterilizing chamber is rapidly reduced and on reaching a safe low value the switch 86 is closed on the contact 86a by the spring 81 which overcomes the pressure exerted on the diaphragm 89. The drop in pressure is accompanied by opening of the thermostatic switch [0 de-energizing the timer and stopping the rotation of the cams 6|, 63. The time required for exhaust is controlled by the pressure switch and not by the timer. The closing of the switch 36 completes a circuit to the valve motor 53 extending through contacts 64, Mb,

contacts

86, 86a, contacts Tl, 11a, and

contacts

82, 82a. This causes the rotation of the valve shaft 29 from the fast exhaust position to the dry position where steam is supplied to the injector nozzle 25. In the dry position the switch 82 moves away from contact 82a and is closed on contact 82b which energizes the timer motor 59 through the

pressure switch contacts

86, 86a and the selector switch contacts 11, 71a. Rotation of the timer continues independent of the thermostatic switch l0 until the cam follower 66a drops oil the elevated portion 6313 on the cam 63 and moves the switch 66 from the contact 650 to the contact 66b. The closing of the contact 86b energizes the green light 5!! and the buzzer 85 which signals the end of the sterilizing cycle to the operator.

In the utensil position on the selector switch the operation is the same as in the fabric position up to the point at which the pressure in the sterilizing chamber drops to a point at which the contact 86 closes on the contact 86a. At this time, since the selector switch 11 is closed on contact Til), the signal light 50 and buzzer alarm 85 are energized signaling the end of the sterilizing cycle to the operator.

In the solution position of the selector switch the operation starts the same as in the fabric position. However, since the selector switch contact '16 is not closed on the contact 16a, the Valve shaft 29 cannot move past the slow exhaust position. In the slow exhaust position the steam in the sterilizing chamber is slowly exhausted through the restricted port 34 so that the temperature of solutions drops at the same rate as the temperature in the sterilizing chamber. The timer 59 continues its rotation until the thermostatic switch H3 is opened by the drop in temperature. This occurs before the cam follower 66a drops off the elevated portion 63b of the cam 63, so that the timer does not control the duration of the slow exhaust. The duration of the slow exhaust cycle is controlled by the pressure switch 85 which closes on contact 86a when the pressure reaches the desired low value at which it-is' safe to open the sterilizing door; The closingof'the pressure switch 86 on the-contact 86a energizes the green signal light 50 and the buzzer alarm 85 through the selector switch" contacts Tl, 'l'lb. Having the duration of the exhaust cycle determined by pressure rather than by time permits a more accurate control. In the fast exhaust'position the pressure control-saves time since it is no longer necessary toallowsufiicient time to take care of all loads. In'the. case of solutions, this is particularly advantageous as with large loads the time required for exhausting the sterilizing chamber is much greater'than with small loads.

The control illustrated in Figs. 24-26 makes use of a number of parts which have been previously-'' described and which are designated by the same'referencenumerals. The principal difference in'the Fig. 24 control is the use of an automatic reset timer as illustrated in Fig. 19, the omission of the cam 62- and the associated switch 65, 6512} the change in position of the contact lea and the addition of a contact 7% so the circuit to '-the"-va'lve motor may be closed at the end of the cycle; the addition of a contact 8 lb to prevent resetting of the timer after the end of the sterilizing operation, the extension of the selector switch contact-H so the contact Tl, 'll'b is-closed in both the'-fast and "slow exhaust position, and the addition of the normally closed pressure switch SWhaV-ing a contact etc normally held'in the-closed position'by a spring 8?.

In the Fig. Zelcontrol, the selector switch is that illustrated'in' Figs. 23-a-23d; Before starting any cycle of'operations, theselector switch is in the manual or ofi position. In this position the circuit to-the timer clutch 59 is broken and the spring 70" returns the cam shaft to the start position determined by the knob Ella which selects the sterilizing time.

In the'sterilizing of fabrics, after the sterilizer has been loaded and the door closed, the operator turnsthe selector switch from manual to fabric. This closesthe switch '88- and causes thelig-hting of the red light t8 through the contacts 64-; 640 which are closed due to the resetting by the spring E0. The valve motor 53 is now energized through contacts 19, 19a and rotates the valve shaft 29 from the off to the sterilize position. Upon reachin the sterilize position,

contacts'lBa, 80b, 890 open and contactsttc, rec close. The rise in temperature accompanying the admission of steam causes the closing of the switch IO' and starting'the timer. If at any time during the sterilizing operation the temperature drops below the desired sterilizin temperature, the switch ill opens and the timer is reset to the starting point; This insures continuous sterilizing at' or above the desired sterilizing temperature for-the full interval selected by the knob 5 l a.

At the end'of the sterilizing time, the cam follower-64w dropsoff the raised portion Bib of'the cami'fi I and'amoves the switch 55 from contact Mic to :contact 6 th. This energizes the amber light ie-signaling the endvof the sterilizing operation and: also energizes thevalve motor 53 through the closed contacts st, Silo. When the valve shaft 29 reaches-the slow exhaust'position, the switch 80: moves away from the contact 58a and the switch 8i moves away from contact tit and closeson contact cm. Since the selector switch Ni ls closed on contact lea, the valve motor 53 continues'its rotation and moves. the shaft 29 throughithe slow exhaust position to the fast exhaustposition in which the switch 8! moves timer motor 59.

12 away from the contact 8 l a. and closes on the contact Blb and the switch 32 closes on contact 32a. The closing of the switch at 'on the contact cab establishes a circuit to the timer motor 59 and to the timer clutch solenoid 68 so that upon opening of the thermostatic switch It due to the rapid'reduction in temperature in the sterilizing chamher, the timer is 'notde-energized and reset by the spring 10. Upon reduction in pressure in the sterilizing chamber to the value at which the door 2 may be safely opened, the pressure switch ti closes on contact 8Saand since the selector switch it is closed on contact Ha, the valve motor 53 is energized through

contacts

88, 88b, 85a, 7?, 11a, 82, and 82a causing rotationof= the valve shaft from the fast exhaust position to the dry position. In the dryposition contacts 82 and82a are opened. Rotation of the timer continues until the cam followertt'a drops off the raised portion 632; on the cam 53and moves the switch 56 from the contact 660 to the contact 6622. The closing of the contact 662)" energizesthe green light 5! and the buzzer 85 and also energizes the valve motor 53 through the closed contact 19b. The valve motor turns until the valve is moved from the dry to the off position in which the contact i917 is opened and the contact 79a is closed. The turning of the valve to the off position cutsofi the supply of steam but does not stop the buzzer or de-energize thegreen light 523. The buzzer and green light are de-energized by turning the selector switch to the manual position in which the switch 18 is opened. This deenergizes all of the signal lights and buzzer and also de-energizes the timer clutch solenoid 69 permitting resetting of the timer cam shaft to the position illustrated in Fig. 25 in which the contact 66 is closed on contact 660 and the contactile is closed on contact Me.

In the utensil positionthe operation is the same as in the fabric position up to the point at which the pressure in the sterilizing chamber drops to the value at which the door 2 can be opened resulting in the closing of the contact 86 on the contact 850;. At this time, since the selector switch 1'! is closed on contact llb, the signal light 55, the buzzer alarm 85, and the valve motor 53 are energized. The valve motor rotates the valve to the olf position atwhich time the contact 19b is open and the contact 19a is closed. The operator shuts on" the buzzer by returning the selector switch to the manual position.

In the solution position of the selector switch the operation starts the same as in the fabric L; position. However, since the selector switch contact It is not closed on the contact 16a, the valve shaft 29 cannot move past the slow exhaust positionin which contact BI is closed on contact 8m and is moved away from contact 8Ib. As soon as the temperature in the sterilizing chamber drops below the sterilizing value, the thermostatic switch [9 opens, de-energizing the timer clutch solenoid 69 and also deenergizing the The spring Hi returns the timer cam shaft to the. starting position in which the contacts 66, fitare closed on the contacts Etc-and 65c. Theresetting of the timer. cam shaft has no elfect upon the operation of the sterilizer. Nothing happens until the temperature within the sterilizing chamber drops to the value at which the door 2 can safely be opened. At this time the switch 85 closes on contact 8611 and energizes the green signal light 5%, the buzzer alarm 85, and the valve motor 53 through the contact 5% and switch '19. The valve motor turns until thevalve 13 shaft 29 is moved to the off position at which the contact 19?) is open and the contact 19a is closed. The operator shuts off the buzzer alarm by turning the selector switch to the manual position.

In the control shown in Figs. 27 to 29, inclusive, the steril'mer has two positions, namely sterilize and exhaust. The valve may be the same as that illustrated in Figs. 4 to 13, inclusive, where the

ports

25, 33, 34, 36, and 42 are plugged. With these changes the valve will have only the sterilize position illustrated in Figs. 6 and 7 and the fast exhaust position illustrated in Figs. 10 and 11. With the elimination of the additional sterilizing operations, the number of switches openated by the cam 83 is also decreased. It is only necessary to have a switch 80 closed on contact 80a in the sterilize position and a normally open switch 82 which closes on contact 82a in the fast exhaust position simultaneously with the opening of the switch 86. The timer is also simplified since it is only necessary to have the cam 6| which controls the length of the sterilizing operation to the time selected by the knob 5|. In the case of a manually reset timer the switch 64 is normally closed on the contact 64b. The switch 64 is closed on the contact 640 when the knob 5| is turned to select the timed duration of the sterilizing operation. In the case of the automatic reset timer the switch 64 can be normally closed on the contact 640 since that is the position to which the timer cam shaft would be returned by the resetting spring 10. In other respects the control is similar to the previously described controls, corresponding parts being indicated by the same reference numerals.

Tostart the sterilizing cycle, the operator, if the timer is of the manually reset type, turns the knob 5| to the desired time duration of the sterilizing cycle and then turns the valve knob 44 to the sterilize position. If the timer is of the automatic reset type and the knob 51a is already set at the correct sterilizing time, the operator need only turn the valve knob to the sterilize position. When the valve knob is in the sterilize position the switch 82 is away from the contact 82a and the switch 80 is closed on the contact 80a. The operator starts the sterilizing cycle by closing the switch 90. As soon as the temperature within the sterilizing chamber rises to the sterilizing value, the switch closes energizing both the timer motor 59 and the timer clutch solenoid 69 if the timer is of theautomatic resetting type. This energizes the red signal light 48 indicating that the sterilizing operation is in progress. At the end of the sterilizing time selected by the knob (or the knob 5la if the timer is of the automatic resetting type) the cam follower 64 drops off the elevated portion Bib of the cam 6| and falls onto the depressed portion filo. thereby opening the switch contact 640 and closing the switch contact 64b. This completes a circuit to the valve motor 53 through the

contacts

64, 64b, and 80, 80a. The valve motor rotates until the cam 83 strikes the contact 82 and moves it against the contact 82a. Simultaneously the switch 80 is moved away from the contact 80a thereby tie-energizing the valve motor. The yellow signal light comes on simultaneously with the closing of the switch 64 on the contact 641). If the timer is of the automatic resetting type, the opening of the thermostatic switch caused by the drop in temperature due to the exhaust of steam de-energizes the timer clutch solenoid 69 and causes the resetting of the timer.

The resetting of the timer however, has no effect upon the operation. The opening of the contact 647) does not extinguish the yellow signal light 49 since a circuit to the yellow signal light has been completed through the switch 82 and contact 82a by the rotation of the valve shaft 29 to the exhaust position. When the pressure within the sterilizing chamber reaches a value low enough so that the door 2 can be opened, the switch 88 closes on the contact 86a completing a circuit to the green light 50 and the buzzer alarm 85. This signals to the operator that the sterilizing operation has been completed and that the load can be removed. To de-energize the buzzer, the operator opens the manually controlled switch 90 which cuts off the power supply.

What we claim as new is:

1. In a sterilizer having a rotary multiport valve movable in sequence to sterilize, slow exhaust, fast exhaust and dry positions, a manually operable control shaft for operating the valve, a motor for driving the shaft in the direction to advance the shaft, an overrunning clutch between the motor and shaft permitting manual movement of the shaft relative to the motor only in the direction to advance the control shaft, motor circuits for energizing the motor for rotating the shaft from each of the positions to a succeeding position, limit switches in the respective circuits operated in each position of the shaft to condition a motor circuit for rotation of the shaft to a succeeding position, time controlled contacts in the motor circuits interrupting the circuits until the lapse of the desired time intervals, and a selector switch having contacts for bridging selected limit switches for the positions to be skipped and other contacts for interrupting the motor circuits for the positions to be eliminated.

2. In a sterilizer, a timer having contacts 0perated at the end of the sterilizing operation and other contacts respectively operated sequentially at intervals thereafter, a manually operable control shaft sequentially movable to sterilize and to a number of different succeeding positions, a motor in circuit with the timer contacts for driving the shaft in the direction to advance the control, an overrunning clutch between the shaft and motor allowing manual movement forward and preventing backward movement of the shaft relative to the motor, motor control switches opening a motor circuit at each position and conditioning th motor for rotation to a succeeding position, a selector switch in circuit with the timer and control switches for selectively bridging one or more of the control switches to skip the selected position of the control shaft.

3. In a sterilizer, a control shaft manually movable to sterilize, slow exhaust, fast exhaust, dry, and off positions, a motor for advancing the control shaft through said positions, an overrunning clutch between the shaft and motor allowing manual operation and preventing reverse rotation of the shaft, motor control switches operated in the sterilize, slow exhaust, and fast exhaust positions to condition the motor for rotation to a succeeding position, time controlled contacts operated respectively at the end of the sterilizing time to close the motor circuit to cause rotation from the sterilize position and other time controlled contacts operated at the end of the time required for fast exhaust and dry, a signal indicating the end of the sterilizing operations, and a selector switch having alterthe motor for operation from slow exhaust to fast exhaust and connecting the fast exhaust from contacts in the motor circuit to cause oneration of the motor to dry and the dry time contacts to the signal.

4. In a sterilizer, a rotary valve connected to the sterilizer and'having steam admission and exhaust positions, a shaft for rotating the valve, a motor for advancing the shaft from the steam admission to the exhaust positions, a power circuit to the motor including contacts closed in the admission and open in the exhaust position of the valve shaft and time controlled contacts open during and closed after the selected sterilizing time whereby the shaft is advanced to the exhaust position at the end of the sterilizing time, s .signal device,,and a pressure switch responsive to the steam pressure in the sterilizer actuating the signal upon drop in pressureto a value safe for unloading the sterilizer.

5. Ina sterilizer, an electrical resetting timer having adevice preventing resetting when energized, valve means controlling they supply of steam for sterilizing and the exhaust of steam at the end of sterilizing, contacts actuated by the timer for controlling actuation of the valve means to sterilize and exhaust conditions, a first power circuit to said device closed through a thermostatic switch closed in response to sterilizer temperature above a safe value whereby upon dropping of the sterilizer temperature below said safe value during sterilize the timer is reset, a second power circuit to said device and a switch in said second power circuit closed in exhaust and open in sterilize whereby resetting of the timer is prevented during exhaust;

6. In a sterilizer, an electrical resetting timer having a device for preventing resetting when energized, a rotary multiport valve for the sterilizer having steam admission, exhaust, and dry positions, a manually operable shaft for operating the valve, a motor for driving'the shaft in the direction to advance the shaft, an overrunning clutch between the motor and shaft'permitting manual movement of the shaft relative to the motor only in the direction to advance the control shaft, motor circuits for energizing the motor for rotating the shaft from each ofthe positions to a succeeding position, limit switches in the respective circuits operated in each position of the shaft to condition a motor circuit for rotation of the shaft to a succeeding position, time controlled contacts in the motor circuits interrupting the circuits until the lapse of the desired time intervals, a selector switch having contacts for bridging selected limit switches for 'the positions to be skipped and other contacts positions, a manually movableshaft for operat ing the valve, a motor for advancin the shaft, means controlling the rotation of the motor to the steam admission and exhaust positions and the length of time the valve remains in such positions to carry out the desired operations forming the sterilizing cycle, a signal energized at the completion of the sterilizing cycle, and a circuit to the valve motor-energized from the signal to cause rotation of the valve to the off position through a switch opened when the valve reaches the off position. i

8. In a sterilizer having a rotary multiport valve having steam admission, exhaust, and off positions, a manually movable'shaft for operating the valve, a motor for advancing the shaft, means controlling the rotation of the motor to the steam admission and exhaust positions and the time the valve remain in such positions to carry out the desired operations forming the sterilizing cycle, said means including an electrical resetting timer having a device effective when energized to prevent resetting, a circuit to said device through a thermostatic switch closed at sterilizer temperatures above a desired value whereby the timer resets if the temperature during sterilizing drops below the desired value, an-

and closed after the steam admission position of the valve, a signal energized at the completion of the sterilizing cycle, and a circuit to the valve motor energized from the signal through a switch opened when the valve reaches the off position.

9. In a sterilizer, a control shaft manually movable to sterilize, slow exhaust, fast exhaust, dry, and off positions, a motor for advancing the control shaft throughsaid positions, an overrunning clutch between the shaft and motor preventing reverse rotation of the shaft, motor control switches operated in the sterilize, slow exhaust, and fast exhaust positions to condition the motor for rotation to a succeeding position, time controlled contacts operated at'the end of the sterilizing time to close the motor circuit to cause rotation from the sterilize position, steam pressure controlled contacts operated upon drop in pressure to a value safe to open the sterilizer and other time controlled contacts operated after the pressure contacts, a signal indicating the end of the sterilizing operations, and a selector switch having alternatively operable (1) contacts interrupting the motor circuit at slow exhaust and for interrupting the motor circuits for the posivalve having steam admission, exhaust, and off.

connecting the pressure controlled contacts to the signal (2) contacts conditioning the motor for operation from slow exhaust to fast exhaust and'connecting the pressure controlled contacts to the signal and (3) contacts interrupting the motor at fastexhaust and connecting the pressure controlled contacts to the motor circuit, and connecting the other time controlled contacts to the signal;

10. In a sterilizer, valve means having a control shaft movable to steam admission, exhaust, and off'positions, a motor for advancing the shaft, means controlling the rotation of the motor to the steam admission and exhaust positions and the length of time the valve means remains in such positions to carry out the desired operations forming the sterilizing cycle, a signal energized at the completion of the sterilizing cycle, and a circuit to the motor for advancing the shaft to the off position, said circuit being energized from the signal through a switch opened whenthe. shaft reaches the off position.

. 11. In a sterilizer, a control shaft manually movable to steam admission and exhaust positions, a motor for advancing the shaft from the steam admission to the exhaust positions, a power circuit to the motor including contacts closed in the admission and open in the exhaust position of the shaft and time controlled contacts open during and closed after the selected sterilizing time whereby the shaft is advanced to the exhaust position at the end of the sterilizing time, a signal device, and a pressure switch responsive to the steam pressure in the sterilizer actuating the signal upon drop in pressure to a value safe for unloading the sterilizer.

12. In a sterilizer, a control shaft sequentially movable to sterilize, slow exhaust and fast exhaust positions, a motor for advancing the control shaft through said positions, motor control switches operated in the sterilize and slow exhaust positions to condition the motor for rotation to a succeeding position, time controlled contacts operated at the end of the desired sterilizing time to close the circuit to the motor to cause rotation from the sterilize position, and a selector switch selectively interrupting or closing a circuit to the motor through the motor control switch for the slow exhaust position whereby the motor stops in the slow exhaust position when the selector switch interrupts the motor circuit and whereby the motor continues through slow exhaust to fast exhaust when the selector switch closes the motor circuit.

13. In a sterilizer, a control shaft sequentially movable to sterilize, slow exhaust and fast exhaust positions, a motor for advancing the control shaft through said positions, motor control switches operated in the sterilize and slow exhaust positions to condition the motor for rotation to a succeeding position, time controlled contacts operated at the end of the desired sterilizing time to close the circuit to the motor to cause rotation from the sterilize position, a selector switch selectively interrupting or closing a circuit to the motor through the motor control switch for the slow exhaust position whereby the motor stops in the slow exhaust position when the selector switch interruptsthe motor circuit and whereby the motor continues through slow exhaust to fast exhaust when the selector switch closes the motor circuit, a signal device, and a pressure switch responsive to steam pressure in the sterilizer in the exhaust positions actuating the signal upon a drop in pressure to a value safe for unloading the sterilizer.

14. In a sterilizer, a control having contacts operated at the end of the sterilizing operation and other contacts operated sequentially at a plurality of intervals thereafter, a control shaft movable to sterilize and to a number of different succeeding positions, a motor in circuit with the contacts for rotating the shaft in the direction to advance the control, motor control switches opening a motor circuit at each position and conditioning the motor for rotation to a succeeding position, a selector switch in circuit with the control contacts and motor control switches for bridging the motor circuits for the positions to be skipped and for interrupting the motor circuits for the positions to be eliminated.

RAYMOND L. JEWELL. CHARLES E. FREESE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,820,252 Shippy Aug. 25, 1931 1,828,126 Brown Oct. 20, 1931 1,865,604 Yarnall July 5, 1932 2,003,739 Clark June 4, 1935 2,050,614 Kerr Aug. 11, 1936 2,254,795 Daniels Sept. 2, 1941 2,272,237 Brown et al Feb. 10, 1942 2,290,626 Bosomworth July 21, 1942 2,325,837 Dyer Aug. 3, 1943