US3514228A

US3514228A - Solenoid type electromagnetic pump

Info

Publication number: US3514228A
Application number: US697821A
Authority: US
Inventors: Akira Toyoda
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-01-15
Filing date: 1968-01-15
Publication date: 1970-05-26
Anticipated expiration: 1987-05-26

Description

May 26, 1970 AKIRA TOYODA 3,514,228

SOLENOID TYPE ELECTROMAGNETIC PUMP Filed Jan. 15, 1968 FIG.I.

9 N O 2 0 IO\ p 2 7 II 8 ii!!! A INVENTOR.

United States Patent 3,514,228 SOLENOID TYPE ELECTROMAGNETIC PUMP Akira Toyoda, 13-16 4-chome, Minamimagone, Ohta-ku, Tokyo, Japan Filed Jan. 15, 1968, Ser. No. 697,821

Int. Cl. F041) 17/04 US. Cl. 417-416 1 Claim ABSTRACT OF THE DISCLOSURE A solenoid type electromagnetic pump comprising solenoid type electromagnetic plungers including an electromagnetic lunger and a discharge plunger an upper and lower spring operatively connected to the plungers for causing both of the plungers to be in contact with each other and a semi-wave rectifier to which the solenoid coil is connected in series.

The present invention relates to a solenoid type electromagnetic pump, to be used for various purposes.

In general, the change of voltage current of an A-C power source forms a periodic wave-type sine curve, and in case this A-C is supplied to the magnetic coil, the size of the absorption force generated in the electromagnetic plunger is caused to change corresponding to the wavetype, and the direction of the absorption force is constant notwithstanding the positive or negative current.

The number of interrupting frequencies of the absorption force, in the case of conventional A-C current, is as follows:

Power source frequency Perior of the absorption force 50 00/ second 100 00/ second 6000 00/ minute 60' 00/ second 120 00/ second 7200 00/ minute The frequency of pump operation of an ordinary electromagnetic pump to be operated by a conventional A-C power source is determined by the frequency of the power sources, and the frequency of the pum operation in the frequency of the power source SOw/second, 6000/ second are lOOoo/second and 120oo/S6C0nd, respectively.

In such high speed periods, the switching operations of tthe inlet check valve and the discharge check valve of the pump and the reciprocal operation of the electromagnetic plunger and the discharge plunger are naturally limited by the resistance of the fluid flowing in the pump and the frictional resistance of the sliding portion in the pump. Therefore, the absorption by the inlet check valve and the discharge check valve, and the discharge efliciency become extremely low, and the period of the reciprocating movements of the electromagnetic plunger and discharge plunger are greatly limited to a short time. The stroke thereof becomes short, resembling vibration, and an improvement of the pump efficiency cannot be achieved.

It is an object of the present invention to provide an extremely high performance electromagnetic pump capable of eliminating uneven operation due to frictional resistance caused in the movement of the electromagnetic plunger and the discharge plunger.

With the above and other objects in view which will become apparent in the following detailed description, the resent invention will be clearly understood in connection with the accompanying drawing, in which:

FIG. 1 is an axial cross-sectional view through an embodiment of a solenoid type electromagnetic pump designed in accordance with the invention; and

FIG. 2 is an electrical circuit diagram of the embodi? ment of FIG. 1.

Referring now to the drawing, an electromagnetic pump in accordance with the present invention includes a solenoid coil 1 of a solenoid type electromagnetic pump which 3,514,228 Patented May 26, 1970 is connected in series to a half-wave rectifier F, as shown in FIG. 2, and by utilizing the half-wave of a conventional A-C power source the frequency of movement of the electromagnetic pump per unit time is made equal to half of the frequency of movement thereof per unit time where the commercial A-C power source is not rectified with a half-Wave. As shown in FIG. 1, an electromagnetic plunger 2 is located in the central portion of the solenoid coil 1 and operates reciprocally along the vertical axis of the solenoid coil by means of the magnetic force. A discharge plunger 3 is provided carrying the suctioned fluid. Both plungers are formed as separate units and are arranged in contact. Also both plungers are caused to operate in a condition where they are compressed between a supporting spring 9 disposed in the upper ortion (hereinafter referred to as an upper spring) and a spring 4 for the back stroke of the discharge plunger 3 disposed in the lower portion (hereinafter referred to as a lower spring).

As shown in FIG. 1, the solenoid 1 of the solenoid type electromagnetic pump of the present invention is connected in series to the half-wave rectifier F and the conventional A-C-current is half-wave rectified and supplied to the solenoid coil 1. The reciprocal movements of the electromagnetic plunger 2 and discharge plunger 3 become 5000/ second and 6000 second, whereby the aforementioned drawbacks of the prior art are eliminated, and the absorption discharge efficiency of the inlet check valve 6 and the discharge check valve 8 are improved thereby making the reciprocal stroke of the electromagnetic plunger 2 and discharge plunger 3 longer. Accordingly an improved high performance pump is obtained.

In the solenoid type electromagnetic pump as shown in FIG. 1, when the A-C is supplied from the power source, the half-wave current rectified in the half-wave rectifier F is caused to flow to the solenoid coil 1 of the pump proper P, intermittently. Therefore the magnetic force generated in the solenoid section is also caused to repeat intermittently.

When the magnetic force is generated between the solenoid coil 1 and the electromagnetic plunger 2 which is in contact with the discharge plunger 3 under pressure from the upper spring 9 and the lower spring 4, the electromagnetic plunger 2 is absorbed in the lower direction. Simultaneously the plunger 3 is caused to move downwardly. When the magnetic force ceases, the electromagnetic lunger 2 and the discharge plunger 3 are returned rapidly to the original position by the action of the lower spring 4. Fluid is absorbed into a plunger chamber 7 through a hose H, a tank 5 and an inlet side check valve 6 from a liquid tank T by means of the vertical reciprocal movements of both

plungers

2 and 3. Then the fluid is condensed, and discharged outside through a discharge check valve 8 by maintaining the specific pressure. The pump operation is effected by repeating the foregoing functions.

Therefore, in order to operate the electromagnetic plunger 2 magnetically and efficiently, the cross-section thereof is limited by the input of the solenoid coil 1. Where a plunger serving both as an electromagnetic plunger and a discharge plunger, is used, it is extremely difficult to obtain the optimum discharge plunger crosssectional area for obtaining simultaneously the desired discharge pressure.

On the other hand, according to the present invention, an electromagnetic plunger 2 having the most suitable cross-sectional area for the input of the solenoid coil 1 can be selected. Also it .is possible to select separately and independently, the discharge plunger having a crosssection most suitable for the required discharge pressure and suitably balanced with the magnetic force.

Furthermore, the discharge plunger 3 prevents leakage of the compressed fluid in order to produce the pressure by minimizing the gap between the cylinder wall 11 of the plunger chamber 7 and the discharge plunger. On the other hand, the electromagnetic plunger 2 must avoid friction with the inner wall of a plunger case when the electromagnetic plunger 2 is caused to effect vertical and reciprocal operation. Therefore the gap is desired to be larger than the gap formed between the discharge plunger 3 and a cylinder wall 11, and also the electromagnetic plunger 2 in its vertical and reciprocal movement. It is extremely difiicult to cause the plunger 2 to operate without any eccentricity to the geometrical vertical axis of the center of the solenoid which is theoretically the magnetic center line, and actually the plunger 2 is caused to slidably operate toward one side of the inner wall of the plunger case 10 which side is olf the axis of the center line, and where the electromagnetic plunger and discharge plunger are mechanically coupled or the electromagnetic plunger of is of its integral construction, the discharge plunger is received with high frictional resistance by the side pressure with the cylinder wall 11, and therefore the smooth operation of the plunger cannot be obtained.

With the present invention, the electromagnetic plunger 2 and the discharge plunger 3 are constructed as a separate unit, and with respect to the movements of both plungers, uneven operation due to frictional resistance, that is, the drawback mentioned in the foregoing, is eliminated, whereby a high performance electromagnetic pump is provided.

What should be specifically noted here is the outstanding effect derived from the combination of the features of: an electromagnetic plunger 2 disposed in a plunger casing 10 through the center of the axial core of the solenoid coil 1 and arranged to reciprocate therein, and a discharge plunger 3 adapted to reciprocate slidingly in the cylinder wall .11 such that the elongated portion thereof is in contact with the electromagnetic plunger 2, compressed between two springs with respective repulsive forces acting in the opposite directions to each other, namely upper and lower springs 9 and 4, respectively, in FIG. 1; intermission of the energizing current to the solenoid coil 1 is made /2 of the frequency of variation of the momentary value of the full-wave A-C current by a half-wave rectification system; and the number of the frequency of reciprocating movement of both

plungers

2 and 3 is synchronized with this frequency. Namely, particularly noteworthy are the following four advantages resulting from the above features: (1) performance of the pump is improved; (2) consumption of electric power required for driving the pump is reduced; (3) burnup-loss of the coil 1 is inhibited due to a comparatively limited rise in the temperature of the coil; and (4) service life of the pump is increased due to no generation of sparks and the elimination of contacts. These advantages will be discussed in more detail hereinbelow.

Adoption of a half-wave rectification system for interruption of the energizing current to the coil 1 will, as mentioned above, appreciably improve efficiency of the pump since the stroke length of the discharge plunger 3 is increased compared to that of one using a full-wave A-C system.

In other words, the system using a half-wave rectifying current consumes less electricity than the system using a full-wave alternating current, so that, in the former system, there is caused a smaller rise in the temperature of the coil 1, which results in a small increase in resistance and retardation of a gradual reduction of the pump discharge output which may otherwise be caused by a gradual rise in temperature due to the electric current supplied to the coil 1. Consequently a reduction of pump performance can be prevented. This is attributable to the fact that since the magnetic attraction produced by applying an electric current to the coil 1 is proportional to the square of the amount of the electric current flowing in the coil 1 and to the product of the number of turns of the coil 1, the rise of electric resistance due to the rise of coil temperature results in a reduction of the amount of electric current flowing in the coil 1, thus weakening the magnetic attraction.

Also, the current interruption system utilizing the halfwave rectifying current is advantageous in that no spark is produced and no wear or loss of contact itself takes place, as compared with the contact system.

Further, since both

plungers

2 and 3 are compressed in contact relationship between the upper and lower springs 9 and 4, when no electric current is applied to the solenoid coil 1, both

plungers

2 and 3 remain still at a position where their opposed repusive forces are balanced, while having the respective amounts of flexibility in inverse proportion to the respective spring constants of the upper and lower springs 9 and 4.

The magnetic attractive force produced upon energization of the solenoid coil 1 causes both

plungers

2 and 3 to move from the balanced position toward the magnetic center, that is, toward the lower part in FIG. 1, and this becomes the pump discharge stroke. Then, when the electric current supply to the solenoid coil 1 is interrupted, both plungers 2 and 3 return to their original positions, thus effecting the pump suction stroke. During these suction and discharge strokes, both the upper and lower springs 9 and 4 absorb alternately the mass of both

plungers

2 and 3 and the kinetic energy of inertia due to their velocity. Namely, they provide bulfer action against shock by increasing their flexing, and then immediately thereafter, the absorbed energy is released, which results in adding to the repulsive forces of the springs, the reinforced repulsive forces being synchronized with reciprocating movements of both

plungers

2 and 3 to elongate the stroke length, thus bulfering the discharging and suction actions and enhancing pump performances.

It is required that the greater the reciprocating velocity of the

plungers

2 and 3, the larger the spring constant of the springs 9 and 4 which repeat elongation and contraction in synchronization with the reciprocation of the plungers. This means that the springs used must be strong. To the contrary, the lower the reciprocating velocity of both

plungers

2 and 3, or the longer the interrupted period of the electric current sent to the solenoid coil 1, the smaller may be the strength of both the upper and lower springs.

Thus, according to the half-wave rectification system, the interruption period of the current supplied to the solenoid coil 1 is double that in an A-C full-wave system, and also the frequency per unit time is V2 thereof, so that both the upper and lower springs 9 and 4 may be correspondingly of relatively low strength. This also means that the repulsive force of the lower spring 4 resisting against the magnetic attraction produced upon energization of the solenoid coil 1 during the pump discharging operation, may be small, which consequently enables full and efficient utilization of the magnetic attractive force during the pump operation, as well as, an increase of the pump stroke length, with a resulting enhanced working efficiency and performance of the pump.

Further, since the

plungers

2 and 3 are compressed between the upper and lower springs 9 and 4, an increase of internal pressure, or discharge pressure, of the pump results in a corresponding increase in the flexing of the upper spring 9 and its stress, whereby an increment of the internal pressure is absorbed and the corresponding operating positions of both

plungers

2 and 3 are moved. This elfects a pump discharge operation within the range of the magnetic attractive force acting on the pump, so that even if the discharge side of the pump is closed, it is possible to restrain the internal pressure of the pump within this range, thus perfectly eliminating any possibility of a break in or damage to, the pump.

Further, the present invention employs a free piston type pump arranged such that the stroke length of both

plungers

2 and 3 is automatically elongated, with the discharge amount being correspondingly increased, when the discharge pressure of the pump is low or when the resistance of the fluid passing in the pump is small, so that in case this pump is used, for example, for supplying of fuel oil to a combustion machine or for spraying purposes, when the oil in the fuel oil tank is emptied, a simple operation of feeding oil into the fuel oil tank will immediately suck up and discharge the air in the pipe line connecting the pump and the oil tank, thus allowing the desired supply of fuel oil or spray.

By adjusting the sum of the amounts of flexing of both upper and lower springs by turning clockwise or counterclockwise the screw member 12 located at a topmost posi-- tion in FIG. 1, it is possible to correspondingly adjust the distance between the magnetic plunger 2 and the magnetic center of the coil 1 and to accordingly adjust the effective force of the magnetic attraction exerted on the electromagnetic plunger 2, which capability of the present device adjusts and regulates pump discharge pressure and flow rate.

As described above, according to the present invention, the electromagnetic plunger 2 and the discharge plunger 3 are formed as separate units and arranged to be in contact, and both plungers are compressed between the upper and lower springs 9 and 4 arranged such as to work against each other with their respective repulsive forces, and also a half-wave rectifier is connected in series to the solenoid coil 1. These three structural conditions combined together provide an improved solenoid type plunger pump which has higher performance, wider versatility in adjustment of discharge pressure and flow rate, and longer service life than any conventional ones.

I claim:

1. A solenoid type electromagnetic pump comprising a solenoid coil,

an electromagnetic plunger slidably disposed reciprocatingly within the center of said solenoid coil,

a separate discharge plunger axially disposed in tandem to and joined to said electromagnetic plunger,

an upper spring and a lower spring, between which said electromagnetic plunger and said discharge plunger are operatively compressed, respectively,

a half-wave rectifier operatively connected in series with said solenoid coil,

a plunger casing extending through the center and concentric with said solenoid coil,

said electromagnetic plunger slidably disposed inside said plunger casing,

a cylinder wall disposed beneath said electromagnetic plunger, said discharge plunger slidably disposed for reciprocation in said cylinder wall,

said discharge plunger disposed below said electromagmetic plunger and having an extended top end portion joined to said electromagnetic plunger,

said upper and lower springs operating with respective repulsive forces in opposite directions, and

a screw means abutting the upper end of said upper spring for being turned to adjust said electromagnetic plunger relative to said solenoid coil, said upper spring operatively abutting at its bottom end the top of said electromagnetic plunger.

References Cited UNITED STATES PATENTS 2,382,426 8/1945 Kocher 103--53 3,139,952 7/1964 Jackson 103-53 XR 3,200,591 8/1965 Ray 10353 XR 3,250,219 5/ 1966 McCarty et al. 10353 3,394,657 7/ 1968 Sanders et al 103--53 ROBERT M. WALKER, Primary Examiner U.S. Cl. X.R.