US 3194164 A
Description (OCR text may contain errors)
July 13, 1965 A. A. FINK ETAL 3,194,164
FLUID PUMP Filed April 26, 1965 5 Sheets-Sheet 1 HTTENEY f July 13, 1965 A. A. FINK ETAI. 3,194,164
FLUID PUMP Filed April 26, 1963 5 Sheets-Sheet 2 IN V EN TOR5.
BY Jah/7 .fana/meyer July 13, 1965 A. A. FINK ETAL 3,194,154
FLUID PUMP Filed April 26, 1965 3 Sheets-Sheet 3 i .if Y ATTORNEY United States Patent O Madea FLUED PUE/il Abraham Arthur Finir, 132i) Pembroke Lane, Topeka, Kans., and John l. Sandmeyer, Topeka, Kans.; said Sandmeyer assigner to said Finir Filed Apr. Zd, 1963, Ser. No. 275,@33
d Claims. (Qi. MP3-44) This invention relates generally to fluid pumps and, more specifically, to pumping apparatus especially adapted for applications in the medical arts, including the utilization of the apparatus as an artificial heart or as a means for providing the desired fluid ilow in regional perfusion.
By way of background, regional perfusion is `a technique especially utilized in the treatment of neoplastic lesions, especially those that have become malignant. This technique involves the isolation of the tumor-bearing area and the insertion or an extracorporeal circuit to supply the cancerocidal or other agent. The arteries or veins of the patient in the area under treatment are actually utilized to transmit the agent to the point of application while suitable pumping apparatus in the extracorporeal circuit provides the desired flow of the agent. This allows isolation of the remainder of the body from the toxic agent thus greatly minimizing the possibility of systemic toxicity. It is requisite in this technique, as Well as in the utilization of pumping apparatus as an articial heart, that the iluid pumping mechanism be maintained under the highest sanitary conditions and be capable of precise control by the physician.
It is, therefore, the primary object of this invention to provide a iluid pump especially suitable for use in the aforesaid medical applications, or as an artificial heart.
lt is another object of this invention to provide a pump that may easily be maintained sanitary so that the iluid pumped therethrough will not become polluted and thereby render the fluid unfit for injection into the blood supply system of the human body.
It is another object of this invention to provide a pump utilizing an incompressible fluid to collapse and expand a exible bag which forms the pumping structure of the apparatus, the bag and the` conduits leading therefrom being disposable to facilitate the maintenance of the aforesaid sanitary conditions.
It is still another object of this invention to provide apparatus for reciprocating a shaft or stern operably coupled to a pumping mechanism, such apparatus having means for varying the stroke of said shaft or stem.
It is still another object of this invention to provide such variable stroke, reciprocating apparatus having an assembly adapted for reciprocable movement along a rectilinear path of travel and provided with an element having an elongated slot therein, the longitudinal axis of the slot being at an acute angle with respect to said path of travel, the stem or shaft being coupled with the slot by means enabling the portion of the stem coupled with the slot to ride in the slot longitudinally thereof during movement of the element with the assembly, whereby to reciprocate the stem or shaft in directions transversely of the longitudinal axis of the slot.
It is yet another object of this invention to provide means for varying said acute angle to permit the selection of the desired stroke of the stem and further to provide means for maintaining constant the length of said path of travel regardless of the value of said acute angle.
Other objects will become apparent as the detailed description proceeds.
In the drawings:
FIGURE 1 is a perspective view of the present invention with its case in place;
FIG. 2 is a plan View with the case removed, showing the internal structure of the apparatus for driving the Pump;
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 (with the case in place) showing the flexible bag of the pump in its collapsed condition;
FIG. 4 is a detailed view partially in section and partially in elevation of the pump body and its associated components;
FIG. 5 is a fragmentary, sectional view taken along llne 3 3 of FIG. 2 showing the iiexible bag in its expanded condition;
FIG. 6 is an electrical schematic diagram of the control circuit for the prime mover of the drive apparatus;
FIG. 7 `is a schematic diagram showing an alternate form of control circuit; and
FIG. 8 is a schematic diagram showing another alternate control circuit.
Referring to FIG. 1, it may be seen that the instant invention is housed in a case itl. The case itl has an access door l2 which may be opened to enable the operator to adjust the pumping rate of the device in a manner to be hereinafter described. A window i4 in the case it? enables the operator to ascertain whether or not the drive mechanism is operating properly, such window containing pointers i6 and i8 for purposes to be hereinafter' described. A plurality of teeth or plates Z0 project upwardly through the case and form a part of the magnetic circuit of the prime mover of the drive mechanism. A knob 22 enables the control of the voltage supplied to the prime mover. Switch 2dis an On-@ft switch.
Referring now to FIGS. 1 5, it may be seen that the pump comprises a hollow body 2d in the iorm of a rigid, generally hemispherical shell 2S and a iiexible wall or diaphragm 30 extending across the edge of the shell. The shell 28 may be transparent so that the operator may check the functioning of the pump. The body iid may be a one-piece, disposable unit which is discarded after each pumping operation to assure the maintenance of sanitary conditions. Alternatively, the shell 2S and the Wall 3d may be separate pieces integrally sealed at the mating flanges formed at the edge of the shell and the periphery of the Wall as shown in the figures.
Body 25 is lilled with a substantially incompressible liquid 32. Also, a flexible bag 3411 is disposed within the body and surrounded by the liquid32. The liquid cornpletely lills the body exteriorly of the bag, the Volume eof the liquid being equal to the volume of the body when the Wall or diaphragm 3l) is fully flexed against the liquid less the volume of the bag 34 when the latter is collapsed under the pressure of the liquid. An inlet tube or conduit 36 and an outlet tube or conduit 3S communicates with the bag 34. Check valve assemblies itl and 42, respectively, are provided for conduits 36 and 3S and interconnect the conduits with the bag. A pair of tubular projections la integral with bag 3d connectwith corresponding checlr valves by surrounding and engaging the lower extremity of the respective check valve assembly to form a tight seal as shown in FIGS. 3 and 5. Conduits 36 and 3S then are similarly affixed to the uppermost portions of the corresponding checli valve assemblies. lt may be appreciated that the check valves di? and 42 may be composed of a rubber or plastic material enabling the same to be conveniently cleaned after each operation or disposed of and replaced later when the pump is next used.
A stud 46 extends outwardly from the central portion of wall 3%. Stud 46 contains a T-slot d'7 therein enabling the same to be connected to a mating tongue 59 on stem 48. Reciprocation of stem 48 causes wall El) to iiex alternatively against and away from liquid 32 to, in turn, collapse and expand bag 3d. This action in coarea-,ice
operation with the check valves ttl and i2 enable the apparatus to function as a pump. It may be appreciated that since liquid 32 is substantially incompressible, the bag 34 will be forced to collapse under the pressure of the liquid when the wall 3d is flexed inwardly into the cavity formed by shell 28. This action drives any fluid in the bag outwardly through check valve 42 and cond-uit 38. Flexure of the wall outwardly of the shell removes the pressure against the exterior of the bag and enables uid under pressure to flow into the bag along conduit 36 and through check valve Atti. lt may be appreciated that atmospheric pressure may be utilized to force the fluid into the bag during expansion thereof.
A base d is utilized to mount the pu-mp and the drive mechanism to be hereinafter described. A U-shaped frame 52 is mounted on the base and extends upwardly therefrom. As is especially evident from FIG. 2, each upstanding leg of frame 52 is transversely L-shaped. Opposed, peripheral portions of wall Si? overlie respective legs of frame 52 when the pump is assembled for opera-` tion, and a pair of spring-loaded clamps S4 are utilized to maintain such peripheral portions in engagement with the legs of frame 52. As may clearly be seen in FIG. 2, the clamps 54.- are transversely T-shaped, permitting the same to engage the opposed portions of the liange formed at the edge of shell 28 in mating engagement with the periphery of wall Sil. Thus, the pump body is releasably maintained in place on the frame 52. Note that a ledge 56, extending outwardly from the bight of frame 52, forms a rest or seat for the lowermost portion of the pump body.
A block 5S mounted on base Sil, has bearings d@ disposed thereon to receive the stem 43 and permit reciprocal movement thereof along its longitudinal axis. The driving of the stem is accomplished by a prime mover 62 which may be a linear #actuator of the alternating current, induction motor type designed to reciprocate its armature or shaft 64 along the longitudinal axis thereof. Such actuators are conventional and commercially available components employing la stator Wound so as to create a sweeping magnetic lield which traverses the length of the stator when the motor is energized. For a given line connection, the field sweeps in one direction and, therefore, the `direction of movement of shaft 64 may be controlled by reversing the line connections. Suitable control circuitry for an actuator of this type will be described hereinafter.
An assembly 66, including a member 63, an element 7u swingably attached to the member by a pin 72, and a rod 74 is slidably mounted on the base 50. The mounting of the assembly on the base is achieved by bearings 76 in the legs of a U-shaped bracket 7S. The bight of the bracket 7S is rigid with block 58, the bracket being secured to the block by such means as cap screws 80.
Rod '74 is then received by bearing 76, thus permitting reciprocal movement of the rod along its longitudinal axis. A pair of arms 32 connect the opposite ends of rod 74 with the corresponding opposite ends of shaft 64. Each of the arms 82 may be joined with the corresponding ends of rod 74 and shaft 64 by any suitable means. illustrated in FIG. 2 is a tapped hole along the longitudinal axis of shaft 64 for receiving a cap screw 84 to secure the arm thereto. Therefore, it may be appreciated that reciprocation of the shaft 64 by actuator 62 will effect movement of the assembly 66 therewith.
FIGS. 2 and 3 reveal the constructional features of the assembly 66. The member 68 is formed preferably from a sheet of metal bent to provide an apron 86 to increase the structural strength thereof. The arms 82 are integral with member 63 and formed by bending the plate stock of member 68 in the manner illustrated by FIGS. 2 and 3. It may be appreciated that the cuts in the plate stock needed to form the transverse edges of the apron 86 form the portions of arms S2 that connect to the opposed ends of shaft Gd.
Element 70 is also formed from a plate of preferably metallic material. Element "/'ti has an elongated slot 88 therein presenting a guide 99. The plate forming element Ttl is triangular in configuration and pointed at end 92 thereof. A slot 94 in member 68 receives a fastener (such as a bolt, nut and lock Washer assembly) which is manually operable by rotating a knurled knob 96. The fastener extends through the end 92 of element 70. Thus, clement 'lil may be rotated about pin 72 through an angle defined by the ends of slot 94. This allows the angle formed by the rectilinear path'of travel of assembly 66 and the longitudinal axis of slot 88 to be varied by the operator to control the length of the stroke of stem 4S. A scale 9S on member 68 gives lan indication of the pumping rate of the pump for a given setting. Both the knob 96 and the scale 93 are accessible by the operator through the access door 12.
A portion of member 63 is cut away to afford clearance of the slot 8S in element 7b. This is to facilitate the connection of the end of stem 48 to the slot by such means as a roller liti@ on a pin M2. The pin extends through the bifurcations at the end of stem 4S connecting with element 7@ and the roller lil() rides longitudinally along the slot 88 -as the assembly 66 is reciprocated.
in FIG. 2 a rheostat 164 (the rheostat may -be mounted to either base dil or case llll, knob 22 being secured to the shaft of the rheostat when case lt) is in place), a capacitor E96 and a cycle controller 103 are shown along with the On-Olf switch 2li. These electrical components are also shown in the schematic diagrams of FIGS. 6 to 8 inclus1ve.
Referring rst to lFIG. 6, the actuator 62 in the form of a linear motor as above described is shown with circuitry suitable for operating the motor. The On-Otf switch 2d serves as the main switch to close the power circuit from the motor to a single phase, alternating current supply. The rheostat we is series connected between one side of the line and the linear motor and serves to adjust the level of the voltage applied to the motor. The cycle controller w3 comprises a timing motor 1l@ coupled with a reversing switch 112. Switch i12 is a single pole, double throw switch connected in the power circuit so as to alternately place leads M4 and 116 from the motor in electrical connection with lead 118 from the rheostat 10ft. It may be seen from FIG. 6 that the timing motor lllt of the cycle controller is connected in parallel with the linear tmotor but through main switch 24 so that its energiz'ation is controlled thereby.
As above described, the linear motor 62 is of the type wherein the reversal of the leads to the `stator of the motor causes a corresponding reversal of the sweeping magnetic field and hence a reversal in the direction of the actuation of the armature. Therefore, the direction of movement of armature o4 is dependent `on the position of reversing switch M2, current flow in lead H4 producing motion of armature 64 in a direction opposite to that produced by the How of current `in lead 116. A `capacitor 120 is connected across leads 114 and llo to provide a change in capacitive shifting during reversal of the motor.
The timing motor may be a synchronous motor and the reversing switch 1.12 may be a pair of revolving switches coupled with the armature of the synchronous motor. It may be appreciated that such an arrangement will produce a reversal in the magnetic field of the stator of the motor at predetermined time intervals, depending on the speed of revolution or" the rotor of the synchronous motor. Therefore, it is necessary to provide a means of assuring that the stroke of the armature 64 will be maintained constant for all loads placed thereon. Adjustment of rheostat 104 effects this function because the voltage applied to the motor may be increased or decreased corresponding to a heavier or lighter load .so that the length of the stroke of the reciprocating armature 64 will lremain unchanged.
The full operation of the instant invention will now be described. A sanitary bag 34 and pump body 26 are placed on the ledge 56 against frame 52. The T-slot 47 in the end of stud d6 is then fitted in the mating tongue d@ extending from the end of stem 455 and the pumping unit clamped in place by clamps 54. The T-slot and tongue permit rapid and simple connection and disconnection of stud 46 and stem 4S and, in conjunction with springloaded clamps 54, facilitate rapid coupling ofthe pumping unit with the Idrive mechanism. It should oe noted at this juncture that if it is not desired that the pump body 26 be of one-piece construction, and the bag 3d and tiuid 32 be sealed therein, an inlet may be provided in body 26 to facilitate the adding `of the liquid to the body. The inlet and outlet conduits 36 and 36 are then connected to the external fluid circuit and the operation of the pump may commence. By opening the access door 12, the operator may select the desired pumping rate by sliding the pointer 92 along slot 94 until the desired point on scale 98 isreached, at which time knob 96 may be tightened and the element 70 thus secured to member 66. Upon connecting motor 62 to the appropriate source and placing switch 24 in the On position, the stem t6 will then be caused to reciprocate and the wall or diaphragm 3d flexed against and 4away from the liquid 32.
An indicator 122 on member 68 (shown in FIG. 2) then permits the operator to visually monitor' the stroke of assembly 66 through window 14 in t-he case 10. The space between the pointers 16 and 18 in the window represents the length of travel of the assembly 66 during reciprocation thereof. Prior to energization of motor 62, the indicator 122 will be in alignment with pointer 18. By viewing the movement of indicator 122 through window 14, the operator determines whether or not indicator 12.2 is in alignment with pointer 16 at the end of the path of travel 0f assembly 66. If the indicator and pointer 16 do not line up, the knob 22. controlling rheostat 104 is adjusted until proper alignment is effected. The operator is then assured that the pumping rate of the pump will correspond to the setting on the scale 98.
Referring now to FIG. 7, an alternate control diagram is shown that may be utilized to control the motor 62. T he -system of FIG. 7 shows an anticipated control sequence wherein the duration of the stroke of armature 64 is varied, thereby requiring that the power for each direction of stroke be varied accordingly in order to maintain constant the length of the stroke in either direction. To move the armature through the same distance in either direction in a shorter or longer time interval, an increase or decrease in power, respectively, is required. Therefore, a pair of rheostats M and 104]: is employed.
FIG. 8 illustrates another alternate control system. This system shows a simple means of controlling the motor 62 where variations in load are at a minimum. In FIG. 8 a pair of single pole, single throw limit switches 124 are disposed at 4opposed ends `of the path of travel of armature 64 and are mechanically interconnected by coupling means 126. Each of the switches 124 is of the type such that it will remain closed upon closure thereof by physical c-ontact with the armature. Coupling means 126 permit-s only one switch to be closed at a given time.
Therefore, upon being actuated by the armature 6d, the switch 12d so actuated, and the operation of coupling means 126, effects reversal of the motor.
Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:
1. 1n a pump:
a rigid shell and a flexible diaphragm extending across the edge of the shell forming a hollow body adapted to contain a substantially incompressible liquid;
a exible bag in said body provided with an inlet conduit and an outlet conduit extending through the shell to the exterior thereof, there being 4a check valve in each of said conduits, said liquid completely lling the body exteriorly of the bag;
a reciprocable member connected with said diaphragm and extending away from said body; and
means operably coupled with said member for reciprocating the latter to flex the diaphragm against and away from said liquid to collapse and expand the bag, whereby to pump a tluid into and out of the latter.
2. In a pump;
a hollow body adapted to maintain a substantially incompressible fluid therein, said body having -a relatively rigid wall and a flexible wall spaced from and in opposed relation to a portion of the: rigid wall;
a hollow, flexible bag in said body between `said walls within said iiuid and provided with inlet -and outlet conduits extending through the body to the exterior of the latter; and
means for exing said flexible wall toward and away from said portion of the rigid Wall to collapse and expand the bag, whereby to pump material into and out of the bag, the fluid being solely coniined within yand completely filling the body exteriorly at the bag.
3. The invention of claim i2, wherein is provided a support for said body, and means on the support for releasably clamping the rigid wall and the flexible wall together to provide a seal therebetween.
4. The invention of claim 3, wherein said rigid wall comprises a shell having 'a continuous edge defining an opening in the shell, the latter being provided with an outwardly extending flange at said edge, said `clamping means being engageable with said ange to releasably clamp said Hexible wall between the flange and the support.
References Cited by the Examiner UNITED STATES PATENTS 862,867 8/07 Eggleston 230-160 2,346,964 4/ 44 Harper 10S-44 2,361,810 10/44 Bazley 74--110 2,651,997 9/53 Lyt-h 103--44 2,743,619 5/56 Dushkes etal 74-1'10 2,812,716 11/57 Gray 103-44 2,836,121 5/58 Browne 103-44 3,073,246 1/ 63 Saunders et al 103--44 LAURENCE V. EFNER, Primary Examiner.
ROBERT M. WALKER, Examiner.