US3007478A

US3007478A - Ultrasonic cleaner

Info

Publication number: US3007478A
Application number: US728667A
Authority: US
Inventors: Charles G Leonhardt; Brian E Baldwin
Original assignee: American Hospital Supply Corp
Current assignee: American Hospital Supply Corp
Priority date: 1958-04-15
Filing date: 1958-04-15
Publication date: 1961-11-07
Anticipated expiration: 1978-11-07

Description

New. 7, 1961 c. G. LEONHARDT ET Al. 3,007, 8

ULTRASONIC CLEANER Filed April 15, 1958 5 Sheets-Sheet l INVENTORS. MELEfi C LEON/4,4207 BE/A V E. BALDW/A/ M 47 oeA/fys NW. 1951 c. G. LEONHARDT ETAL 3,807,47

ULTRASONIC CLEANER 5 Sheets--Sh'eet 2 Filed April 15, 1958 w mMw m O W E m N E EL 2 A w w W M M 5 MM m .1.

New, 7, 1961 c. e. LEONHARDT ET AL fl flm ULTRASONIC CLEANER Filed April 15, 1958 5 Sheets-Sheet s SEE \m QQQU QM 1961 c. G. LEONHARDT ET Al. 3,007,47

ULTRASONIC CLEANER 5 Sheets-Sheet 4 Filed April 15, 1958 mu QQ INVENTORS. c/muzs q Mom/14 207 512/4 5. 5AA DW/A/ United States Patent Ofi" 3,007,478 Patented Nov. 7, 1 9,61

3,007,478 I ULTRASONIC CLEANER Charles G. Leonhardt, Huntington, N.Y., and Brian E. Baldwin, Evanston, 111.; said Leonhardt assignor to 'Acoustica Associates, Inc., Mineola, N.Y., and said Baldwin assignor to American Hospital Supply Corporation, Evanston, 111., a corporation of Illinois Filed Apr. 15, 1958, Ser. No. 728,667 17 Claims. (Cl. 134-57) This invention relates to cleaners, and more particularly to a fully-automatic ultrasonic cleaner.

The primary object of the present invention is to generally improve ultrasonic cleaners. A more particular object is to provide an ultrasonic cleaner which is completely automatic, for which purpose it employs a clock timer and level switches to establish a desired program of washing and rinsing. A more specific object isto provide such a cleaner for hospital and surgical use, for the cleaning of medical and surgical instruments. Still another object is to provide such a cleaner which acts additionally as a sterilizer for the medical instruments.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, our invention resides in the ultrasonic cleaner elements, and their relation to one another, as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which;

FIG. 1 is a perspective view of one part of an ultrasonic cleaner embodying features of my invention;

FIG. 2 is a schematic transverse section. through the cleaner;

FIG. 2a schematically represents a basket which may be loaded with instruments and inserted in the tank;

FIG. 3 is an elevation of a combined cover and spray head;

FIG. 4 is a bottom view of the same; I

FIG. 5 shows the relation of a group of, level switches to the tank; 7

FIG. 6 is a fragmentary view corresponding to a part of FIG. 2, but showing -a modification which provides sterilizing as well as cleaning;

FIG. 7 is a plan view of a part of the modified cleaner, showing clamps applied to the cover;

FIG. 8 is a side elevation of one of the clamps, drawn to enlarged scale;

FIG. 9 is a highly schematic diagram explanatory of the flow circuit, for both water and electricity;

FIG. 10 is. a wiring diagram showing the electrical circuitry;

FIG. 11 is a fragmentary diagram explanatory of a part of the timing of the cams in the clock timer; and

'FIG. 12 shows the complete timing to much smaller scale, and compares the timing with and without sterilization.

Referring to the drawings, and more particularly to FIG. 2, the ultrasonic cleaner comprises a tank 12, having a transducer 14 at the bottom of the tank. This is driven at a suitable ultrasonic frequency, for example, twentyfive kilocycles per second, by an ultrasonic generator not shown here. The transducer and generator may be conventional, and require no detailed description.

There is a Water inlet at the top of the tank, shown at 16 in FIGS. 1 and 2, and a drain 18 at the bottom of the tank. For convenience, the articles to be cleaned, in this case medical and surgical instruments, may be loaded in a basket shown at 20 in FIG. 2a, and the said basket is lowered into the tank. The basket preferably has feet 19, and handles 21. It is drawn to reduced scale in FIG. 2a, and in practice may fit the tank. At the end of the cleaning operation, the basket is removed with the instruments.

The circuitry further includes one or more water level switches connected to the tank, and in FIG. 2, there are three

level switches

31, 32 and 33. These may all be connected to a common point on the tank, indicated at 24, and the connection point is preferably well down, say six inches from the bottom. The arrangement of level switches is better shown in FIG..S, which shows how

switches

31, 32 and 33 are connected bypipes to a common connection point 24 on the tank 12. It may be mentioned that the desired operation could be controlled with a single level switch, the others being a refinement, as is explained later, The level switch is also called a pressure switch, because it responds to the pressure of the water on its reaching a predetermined level.

The tank 12 is concealed within a generally flat sided housing structure somewhat resembling an automatic clothes washer or dishwasher or like appliance, and in the present case, the tank is located at the left end of the housing, while the ultrasonic generator occupies the right end of the housing. The housing may be backed against a wall, as indicated at 26 in FIG. 2, and has permanent plumbing connections, in this case, a hot water line 28, a cold water line 30, and a drain 34. Hot and cold water are mixed, in a mixer valve assembly 36 to,

produce water of desired temperature under thermostat control, which then flows through pipe 38 to a vacuum breaker 40, and thence through pipe 42 to a check valve for removal from the top of the tank, as when inserting or removing the basket 20. Most conveniently, the spray ring 46 is secured directly beneath and forms a part of a cover 48 for the tank, and the use of a flexible hosefor the water supply is avoided -by feeding the water si1pply through the hinge. More specifically, referring to FIG. 1, the cover 48 is carried by a bent pipe 50 sup ported between

elbow couplings

52, 54 with packing nuts at 56. The water supply is connected to either the

elbow

52 or 54, as shown at 58 in FIG. 2.. The construction of the spray head is also shown in FIGS. 3 and 4, thespray ring 46 being secured beneath cover 48, and hav ing a ring of spray holes 60. The water connection to ring 46 is indicated at 16. The hinge action and the open position of the cover and spray head, out of the way of the top of the tank, are shown in FIG. 6.

Reverting to FIG. 2, the drain connection 18 could be a gravity drain, but there are important advantages in using a drain pump, and in the present case, drain 18 leads through pipe 62 to a pump 64, which may be of the centrifugal type, and the discharge of which flows upward through pipe 66, and a check valve 68' to a valve check acting as a vacuum breaker 70, and thence -downward through pipe 72, to a trap 74 and drain pipe 34.

or vacuum breaker 40, and the check valve 44, are requirer'nents of the sanitary code in many communities, in order to prevent any possibility of backed up sewage entering the fresh water supply.

One advantage of the drain pump 64 is that the pump itself may be used under electrical control to time the draining of the tank. The pump may be an open pump, with free fiow ther'ethrough, but there is no drainage except when the pump operates because of the piping to the high point 70, which is at a level higher than the liquid level in the tank. Another advantage-of the pump 64 is that the drain piping may be smaller. In the present case, the tank is an eight-gallon tank, about ten inches in diameter and twenty inches high, yet it may be rapidly drained while using one inch piping at 62, 66, 72, and 74, and although leading into a conventional two-inch waste line 34, which latter is the size of pipe that would be required without the pump.

In FIG. 1, attention is directed to push button 76. This is a preliminary start button which is pressed before beginning operation of the machine, and which serves to supply heater current to the cathodes of the main vacuum tubes of the oscillator. It is customary and desirable to warm the vacuum tube cathodes before applying the high plate voltage, and the latter is not applied'until after the machine is actually started. This actual start of the machine is obtained by turning the dial 22 away from its oil position, as previously mentioned. The part 78 is a pilot lamp which lights whenever the button 76 has been pressed to heat the cathodes. This start button 76 is of the type called push on-push off, meaning that when pushed, the circuit stays on, and when pushed again, the circuit remains off. The only indication that the heater circuit is on is the pilot lamp 78. The dial 80 is a temperature selector dial. In the present case, this provides two temperatures. One temperature is that of the hot water supply available in the building, which may be from one hundred forty degrees to one hundred eighty degrees Fahrenheit. This may be used for the cleaning of ordinary articles. The other temperature is a substantially lower temperature, say one hundred five degrees Fahrenheit, and this is used in hospitals for the cleaning of surgical instruments, because the higher temperature tends to set blood, pus, etc.

Referring now to FIG. 2, the cold water line 30 is tapped by a pipe 82 which supplies cooling water to the water jacket of transducer 14. The flow of cooling water is controlled by a solenoid operated valve 84, and leads into the water jacket at 86. The cooling water is discharged at 88, and the existence of an actual flow of cooling water is detected by a flow detecting device indicated at 90, the purpose of which is explained later. The cooling water then flows upward through pipe 92, and possible back pressure in the transducer jacket is avoided by an open spout 93 and funnel 94. The discharged cooling water flows gravitationally through pipe 96 to the trap 74. A check valve 98 is provided in line 96 to counteract any pressure developed by the drain pump 64, and is anyway desirable in the event of backing up of the waste line 34.

Referring now to FIG. 9, the cold water line is indicatedin the upper left corner at 30, the hot water line at 28, their mixing valve at 36, the waste line in the lower right corner at 72, and the transducer cooling water waste line at 92, 96. The tank 12, with its transducer 14, shower inlet 46, and drain pump 64 are also shown schematically. The three level switches are indicated at 31,

32-and 33, and are connected to the tank at the point 24 by pipes 100 and 102. The cooling water for the transducer is, supplied through pipe 82 (top of diagram) and solenoid valve 84 to the jacket at 86, and leaves at 88 through'pipe 92 and flow switch or flow detector 90. The start button for heating the vacuum tubes is shown at 76 (lower left part of the diagram), and supplies current to a filament transformer 104, and also to the flow detector switch 90. However, the oscillator, indicated at 106, does not start until energized by closing of fiow detector switch 90, as indicated here by the connection 108. This is a safety interlock which insures that power will not be supplied to the transducer 14 unless it first is supplied with cooling water, and the continued operation of the oscillator 106 is dependent at all times on the continued flow of cooling water, as detected by the flow switch 90.

The timer or clock motor is shown at 110. It drives a cam shaft 112 carrying a series of cams which operate switches. The dial of the timer is shown at 22, and by turning this slightly away from its off position, a cam T114 closes a switch to supply current through line 116 to the timer motor 110 if relay K2 is energized, or if relay K1 is de-energized. It also supplies current to timer switches T130, T132, and T142, as shown at 115.

In addition there is a supply of current through

line

118 and 122 to the solenoid valve 84 which controls the flow of cooling water through pipe 82 to the transducer jacket. This in turn starts the oscillator 106 because the flow of cooling water closes the fiow switch 90 and supplies current to oscillator 106.

Before describing the operation in detail, it may be well to refer to the wiring diagram shown in FIG. 10. This is an across the line diagram, with the switching performed in the upper line L1, and with a ground return shown by the lower line L 2. The element 124 is simply an interlock controlled by the front panel of the cleaner, in order to de-energize all of the circuitry if the front panel is removed. This is done because of the high voltages used in the oscillator. A fuse is shown at 126, and a start button at 76, which remains closed, it being a push start push stop button. When the button is pressed, the pilot lamp 78 is lighted, and current is supplied to the filament heating circuit of the oscillator, indicated at 104.

To further start the cleaner, the clock dial is turned away from off position thereby causing a cam to close timer switch T114 leading through line 118 to the solenoid of solenoid valve 84, which causes a flow of cooling water to the transducer. That flow closes the flow detector switch 90, thereby starting the ultrasonic generator 106 by putting high voltage on the plates of the previously warmed tubes. Additional timer switches are shown in generally upright position, and are prefixed by the letter T. The three level switches are shown in generally horizontal position at 31, 32, and 33. The temperature selecting dial and its switch are shown at 80. The timer motor is shown at 110, and the drain pump motor at 64.

The mixer valve is indicated at 36, and it may be explained at this point that it comprises two solenoid valves and a thermostat. It is so constructed as to receive? three pipe connections, two coming in with hot and cold water, and one leaving with mixed water. It alsoreceives only two electrical connections, here symboiiziedi as leading to two solenoids 37 and 39, but the internai construction is not simply two separate solenoid valves operating hot and cold lines. When the hot water solenoid is connected, there is an on and off control of hot water alone. When the warm water solenoid is connected, there is an on and off control of warm water, the Warmth of which depends on a thermostat action which admits and mixes cold water with the hot water in appropriate amounts. When the temperature selector switch is moved to hot, the circuit is closed to contact 81, for on and off control of hot water, and when selector 80 is moved to warm, the circuit is closed to contact 83, for on and off control of warm water. In this case, the flow is further controlled by a thermostat, not shown, When there is to be no flow of water, both circuits are de-energized, and this may be done by open: ing of

level switch

31 or 33. However, with the level s i s e he ow f w er is co tro d by t e.

timer, as indicated for example by the timer switches T130 and T132.

There is a relay K1 which has one pair of contacts, which are normally closed, as shown at 136. There is another relay K2 which has normally open contacts K2A controlling the drain pump motor 64, and K213 shunting the contacts 136.

Operation At the beginning, the timer is in o position, and pressure on push button 76 (FIGS. 9 and 10) turns on the pilot light 78, and heats the tube filament circuit indicate-d at 104.

Before or after pressing the start button 76, the basketful of instruments is placed in the tank, a quantity of detergent is added, say three ounces, and the cover is closed. At any time during this preliminary period, before or after loading the tank, the temperature dial 80 is properly set. If the cleaner is being used continuously for surgical instruments, this dial will simply remain in the warm (one hundred and five degree Fahrenheit) position.

The timer dial is then turned from off into the was cycle. Without the sterilization referred to later, the cleaning operation takes less than fifteen minutes, and a fifteen-minute clock may be used, that is, one which turns one full revolution in fifteen minutes. Most of this is available for the wash cycle, but less than all of the available wash cycle may be used by simply turning the dial further into the wash cycle. In the particular case here illustrated the maximum washing time is 10.4 minutes, but this may be cut down to anything less, if desired, by simply turning the dial as far as desired along thewash cycle.

In any case, movement of the timer from off position starts the flow of cooling water to the transducer through the action of cam T114 and conductors .116, 118, and 122, energizing cooling water solenoid valve 84. The resulting flow of cooling water closes detector switch 90, and starts the ultrasonic generator 106, whereupon the transducer is energized. Meanwhile, water of appropriate temperature is sprayed into the tank by opening of one or both solenoid valves of the mixing valve, and for this purpose, clock switch T130 is closed. thereby supplying energy to the mixer valve, it being kept in mind that the level switches 31 and 33 are closed at this time, and remain closed until the tank is full. Also clock switch T144 is closed. In FIG. 9 the circuit is through level switches 31 and 33 and conductors 133 and 135.

Relay K1 has normally closed contacts 136, However, at this time, the level switch 32 is closed to its lower contact, thereby energizing the solenoid of relay K1, and thus opening the contacts 136-, and because contacts 136 are open, the timer motor 110 does not run. In general, the timer motor is de-energized during filling of the tank, and is energized during washing, and during pants of the rinsing cycles. The relay K2 is energized whenever the drain pump motor operates, because it controls the drain pump motor through its contacts-KZA, and therefore the contacts K213 also close whenever the drain pump motor operates. These shunt the contacts K1 even when the latter are open. Relay K1 opens during filling, and the timer motor stops unless the tank is also draining, in which case the timer motor runs because of closing of contacts K2B.

Thus turning the time dial to any position in the approximately ten minute long wash cycle causes ultrasonic energy to be presented to the tank through energizing of the cooling solenoid, and causes water to spray into the tank, since the fill contact T130 closes and level switch 31 is closed in its relaxed condition. The temperature switch 80 selects either the warm or the hot input, causing warm or hot water to flow. Level switch 32 is closed to its lower contact, thus energizing relay s 6 K1, and so opening contacts 136 and thereby opening the line to the timermotor 110.

It will be noted that the transducer is operating during filling of the tank. This is a significant feature of the invention, because it has been found that this provides rapid degassing of the water. The ultrasonic cleaning action is weakened by gas content in the water. If the tankwere first filled before starting vibration, it would take some fifteen or twenty minutes to degas the water. (Without vibration it would take many hours.) However, by providing transducer vibration during the filling of the tank, the water is degassed in a matter of only two minutes, one of which is anyway occupied by filling of the tank, so that for allpractical purposes, the water is degassed in one additional minute. The tank is filled to a height established by level switch 31, which in the present case. is four inches from the top of the tank. Timer motor will not run until level switch 31 has been tripped open, and relay K1 is thereby de-energized. When the tank has been filled to the said first level, the mixer valve and the relay are de-energized, shutting off input water at mixer 36 and beginning operation of timer motor 110. Motor operation will not be interrupted, and the water level remains constant, throughout wash" interval. I

At the end Tlittlopens and the timer drain contact T142 closes. This energizes therelay K2 and so the drain 64, and therefore the tank empties.

The complete rinse action of the present cleaner may be divided into two main parts. The first may' be referred'to-as a fluctuating-level rinse, which is provided bya continuous inlet or spray rinse accompanied by an intermittent drain,with the drain at a faster rate than the. spray inlet. Thus, there is a continuous spray action, but the level in the tank changes from partly empty to full, and this may be done repeatedlyfor a number of fluctuations determined "by the timer clock, as explained later. In the present case there are three fluctuations.

It has been found that the use of a large distributed spray is highly preferable tomere filling through an inlet at the side or top of the bank, because the spray helps remove any clinging residue of skin on the instruments during draining. These tend to cling, but by using a spray filling or rinsing action during actual bulk drainage ofliquid from the'tank, the clinging of skin to the instruments has been reduced by some ninety percent. Moreover, a side watenconneotion to the tank, for example like that shown for steam at 244 in FIG. 6, creates a vortex which reduces the efficiency of ultrasonic cleaning. It would also fail to have the downward and widely distributed spray for the removal of clinging particles, as does the spray head, which sprays downwardly over the entire basket.

Because the pump drainageis much faster than the spray inlet, the tank is largely, say half or more emptied, in about thirty seconds, whereupon the pump stops, and the continued spray fills the tank again. The filling dur-v ing this fluctuating spray is to a point three inches from the top of the tank, as determined by the level switch 32. The level switches 31 and 32 are set an inch apart in height not only for desired liquid level, but also to make certain that there is no interference in their operation. It would not do to have level switch 32 trip,

when only level switch 31 is supposed to, because then there would be drainage of water and detergent during It is found that a one inch difierence overflow in the event of failure of drainage, or failure of either

level switch

31 or 32. Thus, in FIG. 10, it will be seenthat opening of level switch 33 will de-energize the mixer valve circuit, and so prevent further filling.

Level switch 32, unlike the others, is used in a differof the was cycle, the timer fill contact pump motor 7 ential way, that is, it has two contacts as shown in FIG. I0, the upper of which is closed when the pressure exerted thereon indicates a water level three inches from the; top of the tank, and-the lower of which is connected to the relay coil K1. The upper contact leads to the coil of relay K2, and during the fluctuating rinse period, the; motor 64 is started each time the tank is full. It is stopped when the level switch opens at its upper contact, and this is a diflferential or delayed action which does not take place until the water level has dropped a substantial amount, which in the present case is some eight inches.

Afifi i about thirty seconds, the timer rinse contact T132, closes. Drain continues while water sprays into the tank. The timer continues to run though relay K1 the relay K1 is de-energized, causing closing of contacts- 136 which causes the timer motor 110 to run. Level switch32 also energizesrelay- K2 and causes the, drain pump 64 to come on, while water continues to spray into the tank. The draining, action, is considerably faster than thefilling, and the water level will drop through the ditferential distance of the levelswitch 32. At the. lower level, approximately eight inches below the actuating height, the level switch 32 returns to its relaxed position.

Drain pump 64 and timer motor 110. stop until the water level rises to produce the same cycling over again.

It will thus be seen that the medical andsurgical in-- struments are here subjectedto what is here termed'a fluctuating-level rinse, the rinsingaction being continuous, but the level of water in the tank being cyclically variedbetween a height of, say nine inches, and a height of say seventeen inches. One important advantage of the fluctuating-level rinse isthat it avoids what mightbe termed dead spots, that is, spots. where the ultrasonic activity is weak. By moving the liquid level up and down, different loads are put on the transducer, and the regions of maximum and minimum ultrasonic activity v and consequent cavitation are moved around or changed, so that ,at one time or another, there is strong activity in every part of the tank.

It is importantto understand that the transducer is kept operating throughout the washing and rinsing cycles, and indeedLits operation is continuous. Thus, there is cavitation, and cleaning of any residual bits of skin from the instruments by the body of warm water in the tank, apart from the falling spray action. When the tank is partly emptied, the lower region is subjected to ultrasonic cleaning, andthe upper region to spray action. Thus, considerable overall cleaning time is saved by continuously spraying during the filling and draining of the tank, and by continuing the ultra-sonic vibration during the filling and draing of the tank.

The timer motor runs whenever the drain motor runs. Thus, during the fluctuating-level rinse, the timer motor runs during drain, even though draining and stop page of drain is controlled by the level switch 32. The time of drain is known, it being, say one and one-half second per inch, and thus the clock cam may be set to terminate the fluctuating-level rinse after a desired number of fluctuations, say three in the present case.

After three cycles of raising and lowering of the level, the timer drain contacts 142,close, causing the tank to empty while water still sprays in, and keeping the timer motor 110 running. Also at this time the timer switch 144 moves to the hot contact, so that the ensuing final Relay K2 opens and therefore the 8 rinse is with hot water. After thirty seconds, the timer rinse contact 132 opens.

Timer drain contact 142 remains closed for fifteen seconds to insure completely evacuating the liquid in the tank, the latter being only about half full.

Following this final drain period, the timer on-off contact T114 opens, interrupting the power to all of the timer controlled circuits, and shutting off the generator circuit through the cooling water solenoid valve 84. The generator vacuum tube filaments remain heated until the main switch button 76 is pushed, this being a push on push ofi switch. The pilot lamp shows the need for this final shut down, assuming there are no further batches of instruments waiting to be cleaned.

Timer and circuitry FIG. 11 shows a part of the timer cam operation, drawn to enlarged scale. Without sterilization, the timer duration may be say fifteen minutes, which is represented at 270in FIG. 12, while the portion shown in the dotted rectangle 274 corresponds generally to what is shown in enlarged scale in FIG. 11. In general, when the cam is shown down, its switch is closed, and when the cam is shown up, its switch is open. Thus, the timer switch T114 is closed throughout the cycle, as soon as the dial is turned away from the ofF position, and the oif position is indicated at 300 at the end of the cycle. All camsare raised at this point, so that all switches are open, and it corresponds to the rest or off position of the timer dial.

The timer cam T is closed for most of the cycle, but opens and remains open at the point 302. The timer switch T144 provides hot water for the final rinse, and this switchis therefore open most of the time. It closes at the point'304, which marks the beginning of the second or hot water rinse.

The timer drain switch T142 isopen at 306, closed at 308, open at 310, and closed at 312. However, as will be seen by referring to FIG. 10, this does not constitute the only supply of power for relay K2 and the drain pump, and the relay also may be energized through level switch 32 during the period that timer switch T130 and level switch 31 are closed, and also during the period that timer switch T132 is closed. This takes effect dur' ing the fluctuating-level rinse.

Timer switch 132 is for the both rinses. It differs from timer switch 144, which controls the water temperature, whereas timer switch 132 controls the flow operation of the mixing valve. The power supply is indicated to be on at 318, which corresponds to both the fluctuating-level rinse, and the hot rinse.

Referring now to FIG. 9, the timer cams are schematically indicated at the left of the diagram, and the numbers correspond to the numbers previously used in FIGS. 10 and 11. In FIG. 9, an additional cam 262 is shown, which has to do with sterilization, as is explained later.

The timer has been simplified, and omits the switches at most of the cams. For this reason cams T144 and T114 are shown as though made of insulation. It will be seen that the conductor from cam 130 leads to the level switch 31, as it does in FIG. 10; that the earn 132 leads to level switches 32 and 33, and indirectly to the level switch 31, as it does in FIG. 10; and that the cam 142 leads to the level switch 32 and to the coil of relay K2, as it does in FIG. 10. The cam 114 closes a circuit from the push button start switch 76 and runs as though to the other timer switches at 115, and to valve 84 at 116, 118, and 122. The cam 144 closes a switch leading from level switch 33 to water temperature control 80, also as in FIG. 10.

Sterilization The final rinse is with hot water, regardless of the setting of the temperature selector, and this is so because of the action of the clock timer switch T144 located in FIG. 10 ab v t p ture selector 80, f th a er is not arranged for sterilization, the instruments then simply dry in the machine, which for all practical purposes is shut down. The hot final rinse assists rapid dry.

However, by some modification, the machine may be used to provide sterilization. Referring to FIG. 6, a steam line 242 is connected to the tank at 244, and the supply of steam is controlled by a solenoid operated valve 246. An additional solenoid operated valve 248 is inserted in the water line 58 leading to the spray head 46. A third solenoid operated valve 250 is inserted in the drain line 62. The cover 48 is preferably proviedd with a peripheral gasket 49. Y

Referring now to FIG. 7, the cleaner is provided with a suitable cover locking means, here illustrated by a pair of clamps 252 pivoted at 254. The nature of these clamps will be clear from inspection of ,FIG. 8, in which it will be seen that the working end 256 of the clamp preferably slopes on bottom to provide a camming or wedge action.

Referring now to FIG. 9, the steam line is shown at 242. A pressure regulating or reducing valve 258 may be provided if the steam supply is at too high a pressure. The three added solenoid valves are indicated at 246, 248 and 250. The steam valve 246 is normally closed while the valves 2-48 and 250 are normally open. In'such case, all of the solenoids may be connected together to a common line 260 which leads to an additional cam switch T262 on the timer clock. It will be evident that if switch 262 is energized at the end of the washing and rinsing cycles, steam will be admitted to the tank 12 to sterilize the instruments. The steam will be held under pressure by the closing of the

valves

246 and 250, and the clamp ing of the cover. Sterilization is'ordinarily carried out at a temperature of about two hundred fifty degrees Fahrenheit, by using steam pressure of about thirty pounds per square inch. This is carried out for a period of say one half hour, valthough some may prefer less and others more time.

'In FIG. 10, the added timer switch 262 is shown at the right, and controls all three

solenoid valves

246, 248 and 250. I

Referring now to FIG. 12 of the drawing, this com pares the cleaning cycle without sterilization, shown at 270, 'and the cleaning cycle with sterilization, shown at 272. The cycle shown at 270 is about fifteen minutes long, with about ten minutes devoted to washing. The dotted rectangle 274 corresponds substantially to what is shown to much larger scale in FIG. l-l.

In the cycle shown at 272, the same ten minute wash period is provided, followed by the same rinsing cycle shown in dotted lines at 276, which again corresponds to what is shown in detail in FIG. ll. This is followed by a sterilizing period which, as here illustrated, is about one half hour long. The clock timer used in this case is a three-quarter hour clock, thus providing the desired additional one half hour time for sterilization. At the end of this time, the clock switch T262 in FIG. 9 opens; the steam valve 246 is closed, and the sealing valves'248 and 250 are opened, thus restoring the machine to its off condition.

A one hour clock may be used, and the sterilizing time may be pushed ahead for less time, or a separate adjustment of sterilizing time may be provided. Some doctors believe a much shorter sterilizing time is adequate.

Miscellaneous In FIG. 10, the dial .22 is shown connected to contacts 23. It may be explained that the clock timer is so 1 said generator and water level switch, and providing a ventional clock motors, which are already commercially available on the market. In the present case, the clock timer is made by BaysideTimers of Bayside, Long Island,

New York. It comprises steel cams working on microswitches. A similarly usable timer is made by Hayes Manufacturing Company of Wisconsin.

'The level switches here used are Type No. 18355 made by Bendix Corporation of Cincinnati, Ohio. They may also be Type No. 1466318 made by Westinghouse Electric Company at Mansfield, Ohio. The flow switch which interlocks the cooling water of the transducer with the operation of the ultrasonic generator, is that known commerci-ally as Shur Flow made by Hayes Manufacturing Company of Erie, Pennsylvania, but other flow switches are commercially available.

It will be understood that while we have shown three level switches, only one would be essential, in which case a single tank level would be used for both washing and for the fluctuating rinse, instead of the two slightly. different levels here employed. The use of a second level switch simplifies the circuitry. The third level switch is merely for safety.

"It will be understood that the transducer may be conventional, and may be of the magnetostrictive type, or the piezoelectric type using barium titanate ceramic. The ultrasonic generator also may be conventional, and requires no detailed description.

Suit-able transducers and generators may be obtained from Acoustica Associates, Inc. of Mineola, Long Island, New York.

High temperature water would be used throughout the cleaning operation, instead of only for the final rinse when cleaning articles other than bloody medical instruments.

etc. have already been washed away.

It is believed that the construction and operation of our improved ultrasonic cleaner, as Well as the advant-ages thereof, will be apparent from the foregoing detailed description. It will also be apparent that while we have shown and described our invention in preferred forms,

many changes may be made without departing from thescope of the invention, as sought to be defined in the following claims.

We claim:

1.' An ultrasonic cleaner comprising a top-loading tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain'for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of earns controlling electrical circuitry to provide a program of washing and rinsing, and means connecting said circuitry to first cam and circuit portion arranged in circuit with said generator and adapted to energize said generator substantially throughout said program, a second camand circuit portion arranged in circuit with said flow switch to determine the maximum. depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and clock timer provide a program of washing and rinsing accompanied by ultrasonic cleaning and degassing of water in said tank produced by continuous vibration of said transducer throughout said program.

2. An ultrasonic cleaner comprising a tank, a trans:

Even with medical instruments, the last rinse may be and is a hot rinse, because the blood and skin said circuitry to said generator and water level switch, and providing a first cam and circuit portion arranged in circuit with said generator and adapted to energize said generator substantially throughout said program, a second cam and circuit portion arranged in circuit with said flow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and level switch and clock timer provide a program of washing and spraying.

3. An ultrasonic cleaner comprising a tank which opens at' the top for top loading, a transducer afiixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, and means connecting said circuitry to said generator and water level switch, and providing a first cam and circuit portion arranged in circuit with said generator and adapted to energize said generator substantially throughout said program, a second cam and circuit portion arrangedin circuit with said flow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and clock timer provide a program of washing and rinsing accompanied by ultrasonic cleaning and degassing of water in said tank produced by continuous vibration of said transducer throughout said program, the water inlet being a spray head mounted for movement into or out of the tank to facilitate top loading, and the pipe leading to saidspray head being designed to accommodate such movement.

4. An ultrasonic cleaner comprising a tank, a hinged cover for said tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a water inlet at the top of the tank, a drain for said tank, a water level switch for said tank, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, means connecting said circuitry to said generator and water level switch, and providing a first cam and circuit portion arranged in circuit with said generator and adaptedto energize said generator substantially throughout said program, a second cam and circuit portion arranged in circuit with said flow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and level switch and clock timer provide a program of washing and rinsing, the water inlet at the top of the tank being a spray head mounted for movement into or out of the top of the tank, said spray head being carried by the cover of the tank, the pipe leading to said spray head acting as the hinge for such movement of the cover and spray head.

5. An ultrasonic cleaner for medical and surgical instruments, said cleaner comprising a tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a water inlet at the top of the tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, means connecting said circuitry to said generator and water level switch, and providing a first cam and circuit portion arranged in circuit with said generator and adapted to energize said generator substantially throughout said program, a second cam and circuit portion arranged in circuit with said flow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and clock timer provide a program of washing and rinsing, a mixer valve assembly ahead of said inlet and having cold and hot water inlet connections, said assembly comprising solenoid valves and a thermostat to maintain a desired warm water temperature so low as not to set blood, and a manually controllable selector to make either the thermostat operative, or the hot water supply alone operative, whereby the cleaner may be operated with either the aforesaid low temperature warm water or much higher temperature hot water as desired.

6. An ultrasonic cleaner comprising a tank, a transducer afiixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of Washing and rinsing, and means connecting said circuitry to said gen erator and water level switch, and providing a first cam and circuit portion arranged in circuit with said generator and adapted to energize said generator substantially throughout said program, a second cam and circuit portion arranged in circuit with saidtflow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and clock timer provide a program of washing and rinsing accompanied by ultrasonic cleaning and degassing of water in said tank produced by continuous vibration of said transducer throughout said program, said clock timer and associated circuitry being so arranged that the transducer is vibrated during filling of the tank to provide degassing of water in said tank during said filling.

7. An ultrasonic cleaner comprising a tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch for said tank set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, and means connecting said circuitry to said generator and water level switch, and providing a first cam and circuit portion arranged in circuit with saidgenerator and adapted to energize said generator substantially throughout said program, a second cam and circuit portion arranged in circuit with said flow switch to determine the maximum depth to which said tank can be filled, and further means automatically to drain said tank while continuing to introduce water into said tank through said inlet, whereby said circuitry and level switch and clock timer provide a program of washing and rinsing accompanied by ultrasonic cleaning and degassing of water in said tank produced by continuous vibration of said transducer throughout said program, said clock timer, level switch and associated circuitry being so arranged that the transducer is vibrated continuously throughout the cleaning operation, including filling, washing, and rinsing to provide degassing of water in said tank commencing with said filling and continuing during said operat'orr.

8. An ultrasonic cleaner comprising a tank, a transducer afiixed to said tank, a generator for supplying power to drive said transducer, a Water inlet in said tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a motor driven drain pump for rapid drain, a second'water level switch for said tank set at a lower level than said first-named water level switch, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, said clock timer and level switches and associated circuitry being connected-to provide a first cam controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said first-named water level switch to determine the maximum depth to which said tank can be filled, and a third circuit branch including both of said level switches and the motor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse, said fluctuating-level rinse being provided by a continuous inflow accompanied by an intermittent operation of said pump to provide drain at a faster rate than the inflow said transducer being vibrated continuously throughout the filling of said tank to provide degassing of water in said tank during said filling, and throughout said program and said fluctuating level rinse.

9. An ultrasonic cleaner comprising a tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a motor driven drain pump for rapid drain, a second water level switch for said tank set at a lower level than first-named water level switch, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, said clock timer and level switch and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said first-named Water level switch to determine the maximum depth to which said tank can be filled, and a third circuit branch including both of said level switches and the motor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse, said fluctuating-level rinse being provided by a continuous inflow accompanied by an intermittent operation of said pump to provide drain at a faster rate than the inflow, said circuitry being so arranged that the transducer is vibrated throughout the Washing and fluctuating-level rinse to provide continuous degassing of water in said tank and ultrasonic cleaning of articles which may be in said water.

10. An ultrasonic cleaner comprising a tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a spray head in said tank, a drain for said tank, a motor driven drain pump for rapid drain, a water level switch for said tank set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, said clock timer and level switch and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said water level switch to determine the depth to which said tank can be filled, and a third circuit branch including said water level switch and th emotor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse, said fluctuating-level rinse being provided by a continuous spray through said spray head accompanied by an intermittent operation of said pump to provide drainat a faster rate than the inflow through said spray head, said circuitry being so arranged that the transducer is vibrated throughout the washing and fluctuating-level rinse to provide continuous degassing of 14 water in said tank and ultrasonic cleaning of articles which may be in said water.

ll. An ultrasonic cleaner for medical and surgical instruments, said cleaner comprising a tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch set to fill' the tank deeply for complete immersion of the articles to be cleaned, a motor driven drain pump for rapid drain, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, a mixer valve assembly ahead of said inlet, and having cold and hot water inlet connections, said assembly comprising solenoid valves and a thermostat to maintain a desired warm water temperature so low as not to set blood, a manually controllable selector to make-either the thermostat operative or the hot water supply alone operative, whereby the cleaner may be operated with either the aforesaid low temperature warm water or much higher temperature hot water as desired, said clock timer and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said water level switch and said solenoid valves with said selector intervening to determine the maximum depth to which said tank can be filled and the temperature of the water therein, and a third circuit branch inoluding said water level switch and the motor ofsaid-"drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse, said fluctuating-level rinse being-provided by a continuous inflow accompanied by an intermittent drain at a faster rate than the inflow. y

12. An ultrasonic cleaner for medical and surgical instruments, said cleaner comprising a tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a motor driven drain pump for rapid drain, a water level switch for said tank set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, a mixer valve assembly ahead of said inlet and having cold and hot water inlet connections, said assembly comprising solenoid valves and a thermostat to maintain a desired warm water temperatureso low as not to set blood, a manually controllable selectorto make either the thermostat operative or the hot water supply alone operative, whereby the cleaner may be operated with either the aforesaid low temperature warm water or much higher temperature hot water as desired, said clock timer and level switch and associated circuitry being connected toprovide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said water level switch and said solenoid valves with said selector intervening to determine the maximum depth to which said tank can be filled and the temperature of the water therein, and a third circuit branch including said water level switch and the motor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuatingdevel rinse, said fluctuating-level rinse being provided by a continuous inflow accompanied by an intermittent drain at a faster rate than the inflow, said circuitry being so arranged that the transducer is vibrated throughout the washing and fluctuating-level rinse cycle.

13. An ultrasonic cleaner for medical and surgical instruments, said cleaner comprising a tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a motor driven drain pump for rapid drain, a water level switch for said tank set to fil-l the-tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams control ling electrical circuitry to provide a program of Washing and rinsing, a mixer valve assembly ahead of said inlet and having cold and hot water inlet connections, said assembly comprising solenoid valves and a thermostat to maintain a desired warm water temperature so low as not to set blood, a manually controllable selector to make either the thermostat operative or the hot water supply alone operative, whereby the cleaner may be operated with either the aforesaid low temperatuer warm water or much higher temperature hot water as desired, said clock timer and level switch and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam oontrolled circuit branch including said watel level switch and said solenoid valves with said selector intervening to determine the maximum depth to which said tank can be filled and the temperature of the water therein, and a third circuit branch including said water level switch and the motor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse with warm water, said fluctuatinglevel rinse being provided by a continuous inflow of mixed water accompanied by an intermittent drain at a faster rate than the inflow, said fluctuating-level rinse being followed by a final rinse with only the hot water supply made operative, regardless of the position of the aforesaid selector.

14. An ultrasonic cleaner for medical and surgical instruments, said cleaner comprising a tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a motor driven drain pump for rapid drain, a water level switch for said tank set to fill the tank deeply for complete immersion of the articles to be cleaned, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, a mixer valve assembly ahead of said inlet and having cold and hot water inlet connections, said assembly comprising solenoid valves and a thermostat to maintain a desired warm water temperature so low as not to set blood, a manually controllable selector to make either the thermostat operative or the hot water supply alone operative, whereby the cleaner may be operated with either the aforesaid low temperature warm water or much higher temperature hot water as desired, said clock timer and level switch and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-com trolled circuit branch including said water level switch and said solenoid valves with said selector intervening to determine the maximum depth to which said tank can be filled and the temperature of the water therein, and a third circuit branch including said water level switch and the motor of said drain pump to control operation of said drain pump, and through the cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuatinglevel rinse with warm water, said fluctuating-level rinse being provided by a continuous inflow of mixed water accompanied by an intermittent drain at a faster rate than the inflow, said fluctuating-level rinse being followed by a final rinse with only the hot Water supply made operative, regardless of the position of the aforesaid selector, said circuitry being so arranged that the transducer is vibrated throughout the washing and fluctuatinglevel rinse cycle.

15. An ultrasonic cleaner comprising a. top-loading tank, a transducer affixed to said tank, a generator for supplying power to drive said transducer, a cover for said tank, a water inlet in said tank, a drain for said tank, a valve to seal said drain, a valve to seal said inlet, a lock for the cover of the tank, a steam line connected to said tank, a valve controlling said steam supply, a clock timer driving a series of cams controlling electrical circuitry for controlling said valves and generator to provide a program of washing and rinsing, followed by a sterilizing period, and means connecting said generator and valves in respective circuit branches under control of said cams to provide a first circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second circuit branch including said valve to seal said drain to provide a draining portion of said program, and a third circuit branch including all of said valves to provide a sterilizing period whereby said circuitry and clock timer provide a program of washing and rinsing accompanied by ultrasonic cleanr ing and degassing of water in said tank produced by continuous vibration of said transducer throughout said program, and a sterilizing period following said program of washing and rinsing, during which sterilizing period the inlet and drain valves are closed and the steam valve is opened.

16. An ultrasonic cleaner comprising a toploading tank, a transducer afiixed to said tank, a generator for supplying power to drive said transducer, an openable cover for said tank, a spray head at the top of the tank, within the cover and secured to said cover, a drain for said tank, a valve to seal said drain, a valve to seal said inlet, a lock for the cover of the tank, a steamrline connected to said tank, a valve controlling said steam supply, a clock timer driving a series of cams controlling electrical circuitry for controlling said valves and gen,- erator to provide a program of washing and rinsing, followed by a sterilizing period, and means connecting said generator and valves in respective circuit branches under control of said cams to provide a firstrcircuit branch including said generator and adapted to energize said generator substantially throughout said program, a second circuit branch including said valve to seal said drain to provide a draining portion of said program, and a third circuit branch including all of said valves to provide a sterilizing period whereby said circuitry and clock timer provide a program of washing and spraying and rinsing accompanied by ultrasonic cleaning and degassing of water in said tank produced by continuous vibration of said transducer throughout said program, and a sterilizing period following said program of washing and rinsing, during which sterilizing period the inlet and drain valve are closed and the steam valve is opened.

17. An ultrasonic cleaner comprising a tank, a transducer aflixed to said tank, a generator for supplying power to drive said transducer, a water inlet in said tank, a drain for said tank, a water level switch set to fill the tank deeply for complete immersion of the articles to be cleaned, a motor driven drain pump for rapid drain at a rate greater than the maximum fill rate through said inlet, a low-level water level switch for said tank, a clock timer driving a series of cams controlling electrical circuitry to provide a program of washing and rinsing, said clock timer and level switches and associated circuitry being connected to provide a first cam-controlled circuit branch including said generator and adapted to energize said generator substantially throughout said program, a second cam-controlled circuit branch including said first-named water level switch to determine the maximum depth to which said tank can be filled, and a third circuit branch including both of said level switches and control for said drain, and through said cams under control of said clock timer providing a program including a washing period of desired duration followed by a fluctuating-level rinse during which said drain pump is intermittently 17 operated, said timer and circuitry being so arranged that the transducer is vibrated throughout the washing period and the fluctuating-level rim-e to provide continuous degassing of water in said tank and ultrasonic cleaining of articles Which may be in said Water.

2,278,268 Kempton Mar. 31, 1942 Pauly Apr. 25, 1939 10 18 Walter July 14, Breckenridge Sept. 22, Tannenberg Jan. 2, Burt-Wells Oct. 14, Ringer May 31, Allen June 9, Thomas Dec. 21, Low Nov. 27,

FOREIGN PATENTS Great Britain Oct. 30,