Abstract:
A magnetic pump system includes a ring shaped electric magnet that when pulsed with high voltage and high current, causes a magnetically deflectable elastic member to collapse over a mandrill with an arcuate outer surface. The volume between the arcuate outer surface and the inside of the elastic member is reduced causing compression and expulsion of the fluid therein through a discharge of a one-way passage system. When the magnetic field subsides, the elastic member regains its shape drawing fluid in through an inlet to the one-way passage system.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a flexible tube pump, and more particularly to a pump with a magnetically collapsible elastomeric member which collapses over a mandrel.  
         [0002]     Reciprocating pumps are highly desirable for use in numerous applications, particularly in environments where liquid flow rate is relatively low and the required liquid pressure rise is relatively high. For applications requiring less pressure rise and greater flow rate, single stage centrifugal pumps are favored because of their simplicity, low cost, and low maintenance requirements.  
         [0003]     Another pump type is a flexible tube pump. Such pumps are often used for the transportation and pressurization of sensitive media or for applications in the vacuum field where the achievement of a “Clean” vacuum is relatively important. Common forms of pumps with a flexible member are bellows and diaphragm pumps. The diaphragm is typically an elastomer forming part of the volume being pumped. By reciprocating the flexible member within the pump head space in which are usually located inlet and outlet one-way valves, the media being pumped enters and is then forced out of the pump head. The mechanism for actuating the flexible member may be by linkage to a motor or by valved compressed air.  
         [0004]     Other actuators include a magnetically responsive elastic tube stretched onto, thereby sealing to, a shaft with inlet and outlet ports at or adjacent tube ends. Local to the inlet port a magnetic field is generated within the enclosing body. This field is substantially concentric to the tube, which responds by expanding circumferentially towards the magnetic field. This creates a volume between the tube and shaft, the length of the tube outside the influence of the magnetic field remains sealed upon the shaft. Subsequent movement of the magnetic field along the axis of the pump gives transport to the volume and any media enclosed within from the inlet port to the outlet port, whereupon reduction of the magnetic field results in exhaustion of the volume. This cycle results in a pumping action.  
         [0005]     Disadvantageously, known flexible tube pumps are complicated, relatively costly to manufacture and provide minimal pumping pressure.  
         [0006]     Accordingly, it is desirable to provide an inexpensive flexible tube pump which provides increased pressures.  
       SUMMARY OF THE INVENTION  
       [0007]     The magnetic pump system according to the present invention includes a ring shaped electric magnet that when pulsed with high voltage and high current, causes an magnetically deflectable elastic member to collapse over a mandrill with an arcuate outer surface. The volume between the arcuate outer surface and the inside of the elastic member is reduced causing compression and expulsion of the fluid therein through a one-way passage system. When the magnetic field subsides, the tube regains its shape drawing fluid in through the one-way passage system.  
         [0008]     When the magnet is energized, an intense magnetic field is created. If the elastic member is conductive, eddy currents are generated on the elastic member. This creates a magnetic field that is opposite to the ring magnet field. The two fields repel each other and since the elastic member is elastic it moves towards the mandrill. If the elastic member is magnetic, the fields of the magnet and the ring magnet repel each other and the same action occurs.  
         [0009]     The present invention therefore provides an inexpensive flexible tube pump which provides increased pressures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0011]      FIG. 1  is a side view of a pump system according to the present invention;  
         [0012]      FIG. 2  is a sectional side view of a pump system with the elastic member in an uncompressed state;  
         [0013]      FIG. 3  is a top view of a pump system;  
         [0014]      FIG. 4  is an expanded sectional side view of a manifold for a pump system according to the present invention;  
         [0015]      FIG. 5  is a schematic view of a magnetic field for use with the present invention;  
         [0016]      FIG. 6   a  is a schematic top view of a single bitter disc in which a multiple thereof forms a magnet for use with the present invention;  
         [0017]      FIG. 6   b  is a schematic top view of a magnetic bitter disc showing contact which allows a multiple of stacked bitter discs to form a helical magnetic coil;  
         [0018]      FIG. 6   c  is a schematic top view of a bitter disc showing contact areas which allows a multiple of stacked bitter discs to form a helical magnetic coil;  
         [0019]      FIG. 6   d  is a schematic bottom view of a bitter disc showing a contact area which allow a multiple of stacked bitter discs to form a helical magnetic coil;  
         [0020]      FIG. 7  is a side view of a bitter disc stack between a pair of cooling fins;  
         [0021]      FIG. 8  is a schematic of a control circuit for the pump system according to the present invention; and  
         [0022]      FIG. 9  is a sectional side view of a pump system with the elastic member in a compressed state. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]      FIG. 1  illustrates a general perspective view of a pump assembly  10 . The pump assembly  10  generally includes a mandrill  12 , a magnetically deflectable elastic member  14  mounted about said mandrill  12  and a ring magnet  16  about said deflectable elastic member  14 . It should be understood that although the pump assembly  10  is described as a compressor for a gas, other uses such as that of a fluid pump will likewise benefit from the present invention.  
         [0024]     The mandrill  12  defines a longitudinal axis A. The mandrill  12  is a generally tubular member with an arcuate outer surface  17  defined about the axis A to form a generally hour-glass shape. More preferably, the outer surface  17  is parabolic. A passage system  18  ( FIG. 2 ) having an inlet port  20  and a discharge port  22  are defined within opposed manifolds  24 ,  26  attached adjacent to each longitudinal end of the mandrill  12 . The manifolds  24 ,  26  may be integral to the mandrill  12  or may be separate components, which are attached to the mandrill  12  with fasteners F ( FIG. 3 ) or the like.  
         [0025]     Referring to  FIG. 2 , the passage system  18  communicates with a pumping volume V between the arcuate outer surface  17  defined between the arcuate outer surface  17  and the deflectable elastic member  14 . The passage system  18  includes a multiple of longitudinal passage  18   a ,  18   b  (two shown) which are radially located about the axis A. It should be understood that a multiple of passages are radially disposed about axis A even though only passages  18   a ,  18   b  are illustrated in the cross-section of  FIG. 2 . A single central passage  18   c  located on axis A with passage branches  18   d  which extend off of axis A and communicate with the arcuate outer surface  17  are additionally provided to further increase fluid throughput. It should be understood that various passage paths may be used with the present invention.  
         [0026]     Each passage  18   a - 18   c  of the passage system  18  includes a one-way check valve  28  such that fluid will only flow from inlet port  20  to the discharge port  22 . Each passage is essentially segmented into an input portion, which feeds into volume V, and a discharge portion which feeds from the volume V. The input and discharge portions need not be linearly aligned. Each check valve  28  is preferably threaded into the inner diameter of the passages  18   a - 18   c , however, other mounting arrangements may also be utilized.  
         [0027]     The magnetically deflectable elastic member  14  is preferably a tubular rubber material impregnated with conductor or magnetic materials. Alternately, flexible electrically conductive strips such as copper plated spring steel strips or wires are mounted around the tube.  
         [0028]     The deflectable elastic member  14  is mounted to the mandrill  12  adjacent each manifold  24 ,  26  through an annular clamp ring  30 . The clamp ring  30  includes a wedge shape  32  which corresponds to a mandrill wedge shape section  34  along each rim  36  thereof. The clamp ring  30  is attached to the mandrill  12  though fasteners F (also illustrated in  FIG. 4 ) such as bolts. As the fasteners F are threaded into the clamp ring  30  the clamp ring  30  clamps the deflectable elastic member  14  to the mandrill wedge shape section  34 .  
         [0029]     The ring magnet  16  is preferably a ring magnet which generates a field that is parabolic in shape ( FIG. 5 ) to correspond to the arcuate outer surface  17  of the mandrill  12 . The magnet may be manufactures as a winding of wire around a spool, however, magnets made of discs commonly known as bitter discs  38 , are preferred.  
         [0030]     Referring to  FIGS. 5, 6   a - 6   d , the bitter discs  38  are stamped out of copper or aluminum of a thickness which depends on the current carrying capability and rigidity required. An insulator is stamped out of a thin sheet of insulation, typically fiberglass. Several of these disc and insulator sections are interleaved to form a helix or coil by contact with the adjacent discs ( FIG. 7 ). A contact area C on one side of each bitter disc  38  provides contact with an interference area C 2  on the opposite side of the next bitter disc  38  ( FIG. 6B ) therebetween while the insulator prevents the discs  38  from touching except at the interface I.  
         [0031]     Each bitter disc  38  is rotated relative to the adjacent disc so that each contact area C on one side of a bitter disc  38  contacts the contact area C 2  on an opposite side of the adjacent bitter disc  38 . That is, the contact areas C 1 , C 2  on a single bitter disc are radially displaced and on opposite sides of each bitter disc  38 . By radially displacing each adjacent bitter disc  38  in a stack ( FIG. 7 ), a continuous helical coil of bitter discs is formed. After the discs are stacked, they are clamped together with a multiple of tie bolts  40  or the like ( FIG. 7 ). A cooling fin  42  may also be located at each end of the bitter disc stack.  
         [0032]     Referring to  FIG. 8 , a power supply and control circuit  44  to drive the ring magnet  16  is schematically illustrated. The AC power source is stepped up to a higher voltage by a transformer. The AC switch connects the incoming power to a bridge rectifier. The DC switch connects the capacitor to the ring magnet  16 . The switches may be SCR&#39;s, IGBT transistors and/or other semiconductor devices. Control logic controls the charging of the capacitor and the discharge of the capacitor into the ring magnet  16 .  
         [0033]     This control circuit  44  is preferably a single phase supply, however, a poly-phase supply may be used by replacing the transformer and bridge with a poly-phase transformer and bridge. Depending on the incoming voltage and desired DC voltage the transformer may not be required. For example, if the incoming power is 480V AC the DC voltage will be about 700V. If the switches are designed to handle these voltages no transformer would be required.  
         [0034]     The control sequence of operation is generally as follows: 1) initially AC and DC switches are open; 2) the AC switch is closed and the capacitor charged for time T 1 ; 3) the AC switch is opened; 4) the DC switch is closed discharging the capacitor into the ring magnet; and 5) the DC switch is opened for time T 2 .  
         [0035]     Each time this sequence is executed the ring magnet  16  fires and collapses the deflectable elastic member  14  ( FIG. 9 ). Time T 1  determines the capacitor charge. By varying this time the pressure that the pump  10  develops is controlled. T 2  determines the frequency of cycles. T 2  is preferably a time which allows the deflectable elastic member  14  to regain shape. Higher frequency of operation may be obtained by pressurizing the inlet port  20  with a first stage pump or compressor. This will allow the deflectable elastic member  14  to regain shape faster after being collapsed. Alternatively, or in addition the magnet may be reversed to essentially pull the deflectable elastic member  14  back to the uncollapsed shape ( FIG. 2 ). The first stage pump or compressor may be of a much lower pressure than the pump system  10 .  
         [0036]     One magnet has been illustrated for simplicity of explanation, however, multiple magnets are preferably utilized to produce a greater flow velocity. The magnets are fired in sequence from inlet port to discharge port. The advantage is that as one magnet is firing the firing circuit of the others can be charging. Notably, the deflectable elastic member may extend beyond the inlet and discharge such that if the deflectable elastic member is extended from the inlet to the source and from the discharge to the destination a totally lead free system is achieved.  
         [0037]     It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.  
         [0038]     Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.  
         [0039]     The foregoing description is exemplary rather than defined by the limitations within. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.