Abstract:
A portable, patient assignable, medical suction apparatus usable especially in the medical evacuation field. The suction apparatus includes self contained battery energy sourcing in addition to capability of operation and battery charging from a variety of alternating and direct current energy sources as are commonly available in transportation vehicles and ground based medical facilities. The disclosed apparatus includes provisions for suction canister usage, electromagnetic interference reduction, mounting on an existing aircraft stanchion and shelf and hand carriage to a patient&#39;s bedside. Military usage and possible civilian usage are also disclosed.

Description:
RIGHTS OF THE GOVERNMENT 
     The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to the field of medical suction apparatus. 
     Continuing improvement in the battle area medical care available to U.S. military personnel has been noted in the lay media and is a matter of considerable pride to the U.S. military. One need only compare the practice of dispatching military wounded by helicopter to near-by field hospital facilities as used in the Southeast Asian and recent Middle East conflicts with the hours of delay that was frequent in World War II and the days of delay that ensued in the World War I and U.S. Civil War era to appreciate the increased chances of survival and quality of life maintenance available to a present day wounded military person. These improvements have also been carried into everyday life in the form of helicopter equipped trauma centers located in most major cities of the United States. 
     This continuing degree of medical care improvement is of course based on increased medical knowledge and immensely improved treatment options such as more effective drug therapy, but in addition is based on an increased availability of basic medical equipment--equipment that operates well under adverse conditions. The present invention is concerned with one example of this improved equipment--a portable and individual patient assignable suction apparatus. Equipment of this type is often needed for removing patient jeopardizing fluid accumulations from a chest cavity wound or a breathing passage-way for example. The present invention apparatus is therefore arranged to be compatible with most environments expected during a military medical treatment and evacuation and most notably is usable during the several phases of transportation that a wounded military person may experience before reaching a permanent or long term care facility where a basic requirement such as suction is available as an &#34;in the wall&#34; utility. 
     The apparatus of the present invention can for example be employed in a battlefield situation by a medical corpsman and the same apparatus used to accompany the wounded person on an air evacuation helicopter to a local field hospital. The apparatus may continue in its assignment to a particular person during transport from the field hospital to a well behind the lines zonal medical facility and continue even further with this assigned patient during transportation from the zonal hospital to a U.S. mainland medical facility in a multi engine large transport aircraft. The C-130 and C-141 aircraft presently used by the U.S. Air Force for such long distance medical transportation are particular candidates for use of apparatus according to the present invention since continuous suction capability is not provided in these aircraft and medical transportation flights of four to twelve hours duration are commonly encountered with such aircraft. 
     The energy sources available for operating medical equipment such as the present invention suction apparatus may of course vary from zero in a battlefield situation to the low voltage DC systems available in ground vehicle and smaller aircraft and older aircraft to the 400 Hertz three phase systems used on more modern aircraft. Ultimately the 115 volt 60 Hertz or 230 volt 50 Hertz energy that is commonly available in U.S. or European hospital facilities is available for operating such equipment. In the present invention apparatus accompaniment of a patient through environments having several or all of these energy sources is desirable. 
     In the initial battlefield use of an assigned suction apparatus, self contained energy sourcing is of course desirable; this self contained energy sourcing is also useful in stretcher and litter transportation situations and in patient staging areas. At the other extreme for such equipment--during the four to twelve hour flight over water, the ability to use available aircraft energy to maintain uninterrupted operation of this same suction equipment is also of significant value. 
     The U.S. Patent Art illustrates several examples of medical apparatus that is of general background interest with respect to the present invention. Included in this patent art is the U.S. Pat. No. 4,976,694 of G. Schreibman which is concerned with an apparatus and method for preventing infection. In the Schreibman invention a battery operated vacuum pump is used for the purpose of removing contaminated tissue and fluids from a localized skin wound immediately after contamination has occurred. The Schreibman apparatus employs a biopsy punch a tourniquet and other implements as may be helpful in the immediate decontamination of a wound. The disclosed apparatus is however not suited for the immediate and long term uses of a patient and for use in a transportation situation. 
     The patent art of general interest also includes U.S. Pat. No. 5,009,641 of L. A. Gorton an apparatus in which a patient is provided with means of self administering analgesia or pain medication in response to his/her request. Since the Groton apparatus is concerned with medication administration and with patient initiated action, a ready distinction from the present invention is apparent. 
     The Patent Art of general background interest, also includes U.S. Pat. No. 5,242,407 of K. R. Struble et al which discloses a medication infusion pump for administering intravenous fluids to a patient. The absence of a vacuum system or multiple energy sourcing and other present invention capabilities are submitted to distinguish the present invention from the Struble et al invention. 
     The U.S. Pat. No. 5,244,463 of E. T. Cordner, Jr. et al also discloses a medication administering infusion pump. 
     SUMMARY OF THE INVENTION 
     The present invention concerns a patient assignable medical suction apparatus usable for short term and long term care of a patient needing collected fluid evacuation--especially during a plurality of transportation related medical situations. The suction apparatus is provided with several conveniences including suction level control and monitoring, internal or a plurality of external energy sources, operating status indications, and expected environment mounting and carrying capabilities. The apparatus also provides for continuous or intermittent operating cycles, the use of suction canister equipment and is especially suited for service use during long military medical evacuation flights. 
     It is an object of the present invention therefore to provide a multiple energy source suction apparatus for medical usage. 
     It is another object of the invention to provide a patient assignable medical suction apparatus. 
     It is another object of the invention to provide a medical suction apparatus having both continuous and predetermined intermittent cycle operating capabilities. 
     It is another object of the invention to provide a medical suction apparatus of controllable suction capability. 
     It is another object of the invention to provide a medical suction apparatus having internal and plural external energy supply capabilities. 
     It is another object of the invention to provide a medical suction apparatus that is limited in radio frequency interference (RFI) generation characteristics. 
     Additional objects and features of the invention will be understood from the following description in claims and the accompanying drawings. 
     These and other objects of the invention are achieved by: Individual patient assignable portable medical suction generating apparatus comprising the combination of: 
     a low voltage direct current electrical energy operable suction pump member received in a hand carriable and patent litter apparatus mountable housing member; 
     a manually adjustable suction pressure controlling member shunt connected to a suction conduit member joining a suction inlet port of said suction pump member and a suction communicating port of said apparatus; 
     a rechargeable electrical battery member physically received within said housing member and having a nominal low voltage terminal potential that is compatible with said suction pump member; 
     first electrical input port means for receiving externally sourced direct current electrical energy into said apparatus; 
     first means for converting direct current electrical energy received at said first electrical input port means to battery charging direct current energy and suction pump operating direct current energy of said battery member nominal low terminal voltage level; 
     second electrical input port means for receiving externally sourced alternating current electrical energy of predetermined differing voltage level and differing alternation frequency characteristics into said apparatus; 
     second means for converting alternating current electrical energy received at said second input port means to battery charging direct current electrical energy and suction pump operating direct current electrical energy of said battery member nominal low terminal voltage level; 
     switching means for selecting between electrical energy input from said electrical battery number, said first input port means and said second input port means in response to manual and predetermined automatic selection criteria for energizing said suction pump member; 
     electronic timing circuit means responsive to a manual election input for operating said suction pump member in either a predetermined cycle of energized and non energized operating events or a continuously energized operating event. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an overall view of a medical suction apparatus according to the invention with the apparatus mounted in an aircraft. 
     FIG. 2 shows an internal component view of the FIG. 1 apparatus. 
     FIG. 3 shows a mechanical schematic of the FIG. 1 and FIG. 2 medical suction apparatus. 
     FIG. 4 shows an electrical schematic of the FIG. 1-FIG. 3 medical suction apparatus. 
     FIG. 5 shows an electrical schematic of a subsystem in the FIG. 4 electrical schematic, an intermittent operation controlling subsystem. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 in the drawing shows a medical suction generating apparatus according to the present invention in one of its intended environments, a medical transportation arranged military cargo aircraft. 
     In the FIG. 1 drawing the medical suction apparatus 100 is shown to be located adjacent an interior wall 102 of a host aircraft and disposed between two window apertures, 104 and 106, of this aircraft. The suction generating apparatus 100 is shown in FIG. 1 to be mounted on a upstanding post 112 which is part of a &#34;Waters shelf&#34; apparatus that is commonly used in military medical aircraft. The shelf portion of this apparatus is visible at 111 below the housing 108. The suction generating apparatus is secured to this shelf by way of a series of tie down straps which are indicated generally at 114 in FIG. 1. The tie down straps 114 are mated with a handle assembly 116 that is also provided with strap receiving apertures. 
     The suction apparatus 100 includes a suction generating pump assembly and related components, located within the housing 108, and a canister receptacle portion 110 which is removably mounted on either side of the housing 108. The housing 108 of the FIG. 1 suction generating apparatus 100 includes a front panel portion 109 which mounts several components used in controlling and monitoring operation of the apparatus. Included in these front panel mounted components is a group of three electrical switches 118, 120, and 122 which respectively select the alternating or direct current input energy capabilities of the apparatus, the ON or OFF operating status of the apparatus and the continuous or intermittent operating cycle of the suction generating apparatus. 
     Also received on the front panel 109 is a suction monitoring gage 124, a suction control knob member 126, and a suction inlet port 128. At the top most and center portion of the panel 109 are located a series of four indicator lamps, which may be of the light emitting diode type for example, as are represented at 130, 132, 134, and 136. These indicator lamps are arranged to indicate power on, battery charging, internal battery operation and low internal battery condition respectively. 
     Although not clearly visible in the FIG. 1 drawing, the power selection switch 118 is provided with two positions, one, the illustrated left-most switch position, for selecting 115/230 volts alternating current energization of the FIG. 1 apparatus and the other for selection of 28 volt DC aircraft power for energizing the FIG. 1 apparatus. The ON and OFF switch 120 is shown in the left most or ON position in the FIG. 1 view and the continuous intermittent/switch 122 is shown to be in the right most or intermittent operation position. The suction monitor gage, 124 is preferably provided with scaled readings between zero and seven hundred sixty millimeters of mercury column or alternately between zero and 30 inches of mercury column, the intended suction range of the FIG. 1 apparatus. 
     FIG. 2 in the drawings shows a top-panel-removed internal view of the FIG. 1 suction generating apparatus, a view wherein the internal tubing and wiring of the apparatus is also removed for clearer identification of the major internal components. Numbers from the FIG. 1 drawing are repeated as appropriate for the FIG. 2 illustrated components. In addition to these FIG. 1 identified components, there appears in FIG. 2 a suction generating pump assembly 200 which includes a 12 volt direct current motor portion 202 and a vacuum generating portion 201. Also appearing in the FIG. 2 drawing is a switching-type DC to DC converter assembly, with its heat sinking elements indicated at 204, a step-down transformer 206, and full a wave bridge rectifier 212--components of an alternating current power supply apparatus. A pair of input current limiting circuit breaker members, 208 and 210 are also shown in FIG. 2; these circuit breakers 208 and 210 are actually mounted on the rear panel 211 of the FIG. 1 and FIG. 2 apparatus and have operating push button controls which extend through this panel. Additionally received on the rear panel 211, but not shown in the FIG. 2 drawing is an input receptacle for a 28 volt DC connecting cord, an input receptacle for an alternating current power cord and a selection switch enabling use of either 115 volts or 230 volts alternating current energy input. The AC and DC circuit breakers 208 and 210 may have a current ratings of 1 and 8 amperes respectively. Also shown on the back panel 211 of the FIG. 2 apparatus is the mechanical connector member 213 by which the apparatus was shown to engage the upstanding post 112 in FIG. 1. 
     Additional components appearing in the FIG. 2 top view drawing are the suction control valve 214, the rechargeable internal battery 216, and its hold-down strap assembly 218. Although not shown in the FIG. 2 drawing, the battery 216 is preferably received in a close fitting rectangular cup member that is mounted on the floor 220 of the housing 108. 
     FIG. 3 in the drawings shows a suction system mechanical schematic for the FIG. 1 and FIG. 2 apparatus. In the FIG. 3 drawing, several of the components are identified with the identification numbers used in FIG. 1 and FIG. 2 and several additional of the components are provided with letter or letter and number identifications which correspond to the identifications appearing in the Table 1 Mechanical Parts listing which appears below. 
     
                       TABLE I______________________________________MECHANICAL PARTSIdentity Value, Identity                Description______________________________________a        L-06451-21  Male pipe adapter, Tee                1/4&#34; NPT; tubing ID 1/8&#34;b        L-06450-40  Male pipe adapter                1/4&#34; NPT; tubing ID 1/4&#34;c        L-06452-40  Male branch, Tee                1/8&#34; NPT Tubing ID; 1/4&#34;d        #2FTP       FTP Female Tee, Brass                1/8&#34; NPTe,f,g    L-06450-12  Male pipe adapter                1/8&#34; NPT; tubing ID 1/8&#34;h                    1/4&#34; Plastic tubingSuction Inlet        Bellows sealed valve, BrassValve                1/8&#34; NPT inlet &amp; outletSuction              Needle valve, BrassAdjust Valve         1/8&#34; NPT femaleVacuum               0-30 in Hg vacuum gaugeGauge                1/8&#34; NPT, 2.5&#34; dia, panel mount______________________________________ 
    
     Additional information concerning the FIG. 3 mechanical schematic diagram of the FIG. 1-2 apparatus is to be found in Table 2 below herein. In this Table, the schematic symbols appearing with each of the parts in the FIG. 3 diagram is related to a part value or identity and a description of the part and its function is provided in concise narrative form. 
     TABLE 2. MECHANICAL SCHEMATIC DESCRIPTION 
     Air is drawn through the suction inlet port by the suction pump. 
     The suction adjust valve utilizes bleed air to reduce the level of vacuum at the suction inlet port. 
     The vacuum gauge is positioned in line and will indicate the suction level present at the suction inlet port. 
     The exhaust from the motor is run through a T connector. 
     One T outlet tube supplies cooling air to the circuit board components and the other outlet tube supplies cooling air to T1 and FWB. 
     Tee exhaust flow creates a positive air pressure inside of the housing forcing warm air out. 
     The side mounted disposable suction canister brackets are utilized by sliding the suction canister holder into a corresponding side bracket. Only one suction canister can be used at a given time, but the availability of two holders prevents having to move the suction apparatus. The medical attendant can simply attach the suction tubing to the nearest canister in relation to the patient. 
     FIG. 4 in the drawing shows an electrical schematic diagram of the FIGS. 1-3 suction apparatus and includes most of the components illustrated in FIGS. 1-3 along with their previously used identification numbers. Additional components appearing in FIG. 4 include the two DC operated multiple poled relays 400 and 402 and the block 404 which is used to identify the intermittent operation circuitry portion of the apparatus which is more fully disclosed in FIG. 5 of the drawings. The step down transformer 206 is shown in the FIG. 4 drawings to be provided with a dual winding primary which is represented to be connected in its highest voltage or 230 volts input configuration. The upper and lower portions of this primary winding may of course be connected in a parallel configuration for 115 volt input energy as is known in the electrical art. Table 3 which appears below provides a listing and identification of the parts appearing in the FIG. 4 electrical schematic. 
     
                       TABLE 3______________________________________ELECTRONIC PARTS LISTSchematicSymbol  Value, Identity                 Description______________________________________U1      SK3564        555 TIMERU2      4027BMJ       DUAL J-K FLIP-FLOPU3      4520BCL       DUAL UP COUNTERSU4      4012UBCL      DUAL 4-INPUT &#34;NAND&#34;                 GATEU5      4068BC        8-INPUT &#34;NAND&#34; GATEU6      4049U         HEX BUFFERSU7      KZ432         12 VOLT DC-DC                 CONVERTERU8      LM317T        VOLTAGE REGULATORU10     LM358         DUAL OP-AMP (8-PIN)L5      150 mH        INDUCTOR RFI 1 IN                 DIAMETERR1      620KΩ   .5 W; RESISTORR2      13KΩ    .5 W; RESISTORR3, R4  3300KΩ  .5 W; RESISTORR5      240Ω    .5 W; RESISTORR6      3KΩ     .5 W; RESISTORR7      1.5Ω    .5 W; RESISTORR8      3Ω      50 W; RESISTORR9      22Ω     .5 W; RESISTORR10, R12   110Ω    .5 W; RESISTORR11     4KΩ     .5 W; RESISTORR13, R17   22Ω     .5 W; RESISTORR14     75Ω     5 W; RESISTORR15, R16   3300Ω   .5 W; RESISTORR18     100KΩ   POT; RESISTORR19     1Ω      1 W; RESISTORC1      .1 μF      15 V PLASTIC;                 CAPACITORC2      2 μF       15 V PLASTIC;                 CAPACITORC3      47 μF      15 V; CAPACITORC4      1 μF       30 V PLASTIC;                 CAPACITORC5      .1 μF      30 V PLASTIC;                 CAPACITORC6, C12,   4700 μF    25 V ELECTROLYTIC;C13                   CAPACITORC7, C8, 1 μF       15 V PLASTIC;C10                   CAPACITORC9      1 μF       15 V PLASTIC;                 CAPACITORC11     1 μF       15 V PLASTIC;                 CAPACITORC13, C14,   .1 pF         100 V PLASTIC;C15                   CAPACITORD1, D2, 1N4002        1 A DIODED4, D5D3      K8226         3 A DIODEDZ1     9.6 V         1 A ZENER DIODEQ1-Q4   2N2222        TRANSISTORCB2-CB1 W23-X1A1G-{1,8}                 1 &amp; 8 AMP CIRCUIT(208, 210)            BREAKERSF1-F2   MDV (1,8) 250 V                 1 AMP, 5 AMP SLOW                 BLOW FUSESB1      PS1270        12 VOLT BATTERYRELAYS  R10-E1-X4-V185                 4PDT, 12 VDC, P &amp; B(400, 402)FWB     SK3988        8 A FULL WAVE BRIDGET1      P-6378        115-230 VAC/50-400 Hz                 TRANSFORMERL1-L4   JKL 330       12 VDC LEDSWA     TIIL51-1C-BL- 4 Pole 2 Throw ROCKER   FW/BLK        SWITCHSWB     TIHK51-1C-BL- 4 Pole 1 Throw ROCKER   FW/BLK        SWITCHSWC     TIHK51-1C-BL- 4 Pole 1 Throw ROCKER   FW/BLK        SWITCHSWD     V-SERIES      230/115 V SLIDE SWITCHVACUUM  MODD107CDC20  12 VDC, 1/10 HP, 8 A,PUMP                  DIAPHRAGM, THOMAS                 INDUSTRIES______________________________________ 
    
     In addition to the part listing and identification of Table 3 above, a description of the operation of the FIG. 4 of the electrical apparatus in outline form is provided in Table 3 herein. In this Table 4 outline description part identities are provided along with a brief recitation of the part function in the FIG. 4 diagram. 
     TABLE 4, OPERATION OF THE FIG. 4 CIRCUIT 
     A. For Switch A, in DC position: 
     In this position the AC components are isolated from DC input power. A DC cord is plugged into the back of the apparatus. 
     Fuse F1 and Circuit Breaker CB1 protect the components from internal shorts or motor seizure. 
     U7, 12 Volt DC to DC converter, converts the 28 VDC input into regulated 12 VDC power which is used to operate the pump. U8, 317T Voltage Regulator, converts 28 DC input into a regulated 16 VDC to charge battery B1 and operate the circuitry. The output is also regulated to limit the charge current. 
     B. The following applies: in either the AC or DC position. 
     Diode D3 isolates the AC or DC circuitry from the internal battery. Inductor L5, capacitors C12, and C13, comprise a low-pass EMI filter. With switch B in the ON position, power will be present at resistor R9, transistor Q1 and resistor RI0. 
     When Q1 is biased it will turn ON and energize Relay A. This will hold the contacts open and 12 VDC will be applied to Relay B. 
     All normally open contacts are connected in parallel in each relay, also all normally closed contacts. 
     In the event the voltage at Q1 falls below 12 VDC and switch B is in the 0N position, Q1 will turn OFF. The contacts of Relay A will close and 12 volt internal battery power will be applied to the suction pump. 
     This allows automatic switch-over from line power to battery power and uninterrupted service to the patient. 
     Diodes D4 and D5 isolate the FIG. 4 circuit from Relay A and Relay B inductive voltage spikes. 
     LED L2, Battery Charge indicator, will illuminate when external power is applied. 
     The following description applies for operation on internal battery. When switch B is in the ON position and switch C is in the intermittent position, the intermittent circuitry 404 is activated. 
     When the output of circuitry 404 is high, resistors R11 and R12 bias transistor Q2 ON and energize Relay B. This holds the contacts open and the output to the pump is zero. 
     When the output of 404 is low, Relay B is turned OFF, the contacts are closed, and the power supplied by Relay A is used to power the pump. Relay A and Relay B operate in this manner to save energy. 
     When line power is present Relay A remains energized and this power is applied to Relay B which is normally closed. 
     The only time pump operating power is required from the battery is in the intermittent mode; 40 seconds of each minute. 
     LED L1, Power indicator, will illuminate when power is supplied to operate the pump. 
     With switch B, in the ON position, power is applied to U10, 747 dual Op-Amp. 
     One Op-Amp is utilized as a comparator using resistor R14 and diode DZ1. It monitors the power to the chip and compares it to the 9.6 volt reference voltage provided by zener diode DZ1. 
     If the line voltage drops below this value, an analog signal will bias transistor Q3, sending power to LED L4 (low battery). Resistor R13 controls the current flowing through Q3 to L4. When the line voltage is above 9.6 volts, Q3 will be turned OFF and L4 will not light. 
     The apparatus will continue to operate without the internal battery in place and the low battery will remain lighted as a reminder that a battery is not available for use. 
     The other Op-Amp is also used as a comparator. Both inputs to the Op-Amp are referencing line power and battery power simultaneously. 
     Resistors R15 and R16 provide an equal reference for both sources. Capacitors C9 and C10 provide railing of the corresponding signal high or low in the event one of the references changes. With both signals present a zero analog output is sent to transistor Q4 and LED L3 will not light. With only the battery signal present an analog signal is sent, Q4 is biased, and L3 lights. 
     Resistor R17 controls the current flowing through Q4 to L3. The L3 (internal battery) indicator informs the operator that the apparatus is operating on internal battery power. 
     C. Switch A, VAC position: 
     In this position the DC components are isolated from the AC power. The AC power cord is connected to an AC socket on the back of the apparatus. Switch D on the back panel, allows the apparatus to be operated in the 115 VAC or 230 VAC position. 
     Fuse F2 and Circuit Breaker CB2 protect the apparatus from internal shorts or motor seizure. 
     Incoming VAC line power is passed through stepdown transformer T1. The voltage power is stepped down from the line power to 12 VAC. 
     The full wave bridge rectifier (FWB), rectifies the AC voltage to DC voltage. Capacitors C14 and C15 decrease RFI noise 
     Resistor R8 limits the charging current of the internal battery. In this unregulated configuration there is no circuitry to keep the voltage and current output at switch A 4, AC, constant. 
     When the unit is not operating, FWB has a voltage output of 16 V at 1 A. The voltage drop across D3, typically 0.7 volts, provides 15 volts to bias the battery. (Gel cell type batteries maintain a deep charge at a high voltage). When the unit is operating, FWB has a voltage output of 13 volts at 6.5 A. The voltage drop across R8 is minimal to allow maximum voltage output to the internal battery. 
     This voltage potential insures the battery charges at all times when the unit is operating on a VAC power source and is limited to a 1 amp current flow. Switch A 3 and switch A 4 are in the AC configuration. The operation at this point is the same as switch A 3 and switch A 4 switched to the DC position. See B above for a full description. 
     D. The intermittent circuitry represented at 404 in FIG. 4 is shown in schematic form in FIG. 5 of the drawings. As indicated in this drawing, this circuitry includes six standard integrated circuit chips which are connected in a time delay generating arrangement. The standard electronic industry identification of the circuit chips used in the FIG. 5 intermittent timing circuit is provided in Table 3 above. The Pin numbering of these circuit chips follows the conventional arrangement wherein Pin 1 is identified with a white circle inside the circuit identifying rectangle and the ensuing pins proceed downward or to the right and upward or to the left for the opposite side disposed pins. The discrete components appearing in the FIG. 5 circuit are also identified in Table 3. The time modulated output of the FIG. 5 circuit appears at 500 and the input at 502; these nodes are identified in the FIG. 4 schematic. An outline description of the function of the components in the FIG. 5 circuit appears in Table 4 below herein. 
     TABLE 4 THE INTERMITTENT TIMING CIRCUIT, 404 
     The intermittent circuitry sends a low analog signal for 10 seconds when switch C is set in the Intermittent position and switch A is in the 0N position. This activates the circuitry to operate the pump. 
     A high analog signal is then applied for 20 seconds which correspondingly stops the pump. 
     This cycle is repeated until either switch C is set in the Continuous position or switch B is set in the Off position. 
     If the unit is turned ON in the intermittent configuration it will start its cycle by operating for the initial 10 seconds. 
     Power is supplied to the intermittent circuitry when switch C is in the intermittent position. 
     Capacitor C11, buffers the power to the board when switch C closes. Once power is applied a 0.5 sec delay ensues as capacitor C3 charges according to a time constant determined by resistor R2. While capacitor C3 charges, it applies a high signal to the Dual Up Counter U3 which resets the chip and insures a zero analog output for initiation of the sequence. U2, a Dual J-K Flip Flop, sends a low signal to the output node 500. Diodes D1 and D2 isolate the delay portion of the circuit after t=0.5 seconds. U1, a 555 timer, is configured to send out a high analog signal at one second intervals. This signal establishes the counting mechanism for the CMOS logic. 
     U3 receives the timer signal and initiates a binary counting sequence. U4, Dual 4-Input &#34;Nand&#34; Gate, monitors U3 and when the conditions are met for the number 10 (binary) it sends a signal to U2 which in turn sends a high analog signal to the output node 500. 
     U5, 8-Input &#34;Nand&#34; Gate, monitors U3 for the count of 30 (binary). When this condition is met it sends a low analog signal to U2 to the output node 500 and correspondingly resets U3. 
     Resistors R3 and R4 reduce the current at the inputs of the U2 and U6, Hex Buffers. U6 inverts signals to the desired levels for the Nand gate logic chips. 
     The white circles at the outputs of the CMOS chips represent an open connection. 
     The preferred embodiment of the present invention may be characterized in terms of the outline information in Table 6 which appears below. 
     TABLE 6 SALIENT FEATURES OF THE FIG. 1-5 APPARATUS 
     Intermittent circuitry 10-seconds ON/20-second OFF cycle. Operates intermittently or continuously on all power sources Operates on 115 VAC/(50-400 Hz), 1 A; 230 VAC/50 Hz, 1 A; 28 VDC, 6.5 A; and 12 V internal gel cell battery. 
     Back Panel mounted 115/230 VAC switch for transition from U.S. to overseas power sources 
     Continuous charging of the internal battery while connected to any line power source 
     Circuit breaker and fuse protection for both VAC and VDC input 
     Automatic change to internal battery power from line power to provide continuous, uninterruptable operation 
     1-hour internal battery operation 
     Cords for VAC and VDC sources 
     Front Panel Switches 
     On/Off 
     Intermittent/Continuous 
     VAC/VDC with protective cover 
     LED indicators: visible from a distance of 30 feet in subdued light; 
     Power 
     Battery Charge 
     Internal Battery 
     Low Battery 
     Physical Data; 
     Height: 8.25 inches 
     Width: 14.25 inches 
     Depth: 10 inches 
     Weight: 30.75 pounds 
     One bracket on each side for-1200 cc collection canister, Suction adjust; 0-570 mmHg Vacuum gauge (mmHg)-vacuum accuracy ±1% from set rate 
     Motor Rubber feet mounts for sound and vibration attenuation 
     Housing Rubber feet mounts to dampen transmitted vibration and prevent &#34;walking&#34; 
     Circuit board hinged to allow easy access for maintenance 
     Fine Screen shielded air vents on the side and bottom of the apparatus for ventilation and reduced EMI 
     Apparatus can aspirate fluid obstruction from patient airway, oropharyngeal or tracheal regions 
     Apparatus can remove blood or secretions from the stomach, or fluid or air from the thoracic cavity through a chest tube. 
     Apparatus can be used with standard chest drainage collection system 
     Uses standard sized suction tubing 
     Does not vent harmful gaseous vapors 
     Apparatus can operate without internal battery in place 
     Apparatus has securing bracket mounted to the back of housing for securing to pole 
     Capable of tie-down when sturdy securing is needed 
     Handle positioned to match the center of gravity of the apparatus 
     Several alternate arrangements of the invention are possible. Included in these changes are the items listed in Table 7 below. 
     TABLE 7, ALTERNATIVE ARRANGEMENTS 
     Plastic case for final product 
     Weight reduction results 
     Regulated Power Supply for AC line power 
     Weight reduction, if transformer omitted 
     Increased power efficiency, reduction of AC ripple 
     Increased efficiency and control of battery charging 
     A definite advantage if 115 VAC/400 Hz power input is not a requirement 
     Externally adjustable intermittent timer to control cycle time 
     12 VDC power input for ground vehicle and civilian vehicle use 
     Diaphragm suction pressure regulator-non flow rate sensitive 
     Automatic sensing and selection of applied electrical energy, DC, AC and voltage 
     Addition of filter between suction canister and vacuum inlet port--to prevent liquid transfer into suction pump. 
     The suction apparatus of the present invention therefore provides a portable source of medical suction that may be used with an individual patient and in fact accompany the patient during a plurality of transportation stages to a permanent medical facility and may be energized from most commonly available energy sources in transportation, temporary and permanent medical facilities. The apparatus has demonstrated an ability to withdraw 1200 millimeters of fluid in a time of ten seconds and performs successfully in the presence of large blood clots of up to 4 centimeters circumference without requiring special attention. The provided intermittent time cycle although fixed in duty cycle is typical of a time setting used in chest drainage or deep wound drainage. Although intended for use in the Military medical evacuation field the apparatus is readily adapted to use in civilian ambulance and air ambulance evacuation situation or use wherever a permanent suction utility is absent. 
     While the apparatus and method herein described constitute a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus or method and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims