EP0638729A1

EP0638729A1 - Liquid pump and method

Info

Publication number: EP0638729A1
Application number: EP94112406A
Authority: EP
Inventors: Itzhak Bar-Yona
Original assignee: MARZEVIT TAASIYOT BENIYA Ltd
Current assignee: MARZEVIT TAASIYOT BENIYA Ltd
Priority date: 1993-08-13
Filing date: 1994-08-09
Publication date: 1995-02-15
Also published as: JPH07151100A; IL106683A0

Abstract

A method and apparatus for pumping a liquid from a reservoir, by immersing one end of a tube in a reservoir of the liquid to be pumped, which end includes a one-way valve permitting the liquid to flow into the tube from the reservoir but not vice versa, and cyclically reciprocating by an electrical drive the immersed end of the tube parallel to the axis of the immersed end.

Description

The present invention relates to a method of pumping a liquid, and also a pump operating in accordance with such method. The invention is particularly useful as an inexpensive, low flow-rate pump for pumping water from a lower elevation to a higher elevation, for use, e.g., in watering house plants, and the invention is therefore described below with respect to this application.
An object of the present invention is to provide a novel liquid pumping method, and also a novel pump which requires but a few simple parts that can be constructed in volume and at low cost, and which therefore makes the pump particularly suitable for use in watering house plants and the like.
According to one aspect of the present invention, there is provided a method of pumping a liquid, comprising: immersing one end of a tube in a reservoir of the liquid to be pumped, which end includes a one-way valve permitting the liquid to flow into the tube from the reservoir but not vice versa; and cyclically reciprocating by an electrical drive the immersed end of the tube parallel to the axis of the immersed end.
According to another aspect of the invention, there is provided a pump for pumping a liquid from a reservoir, comprising: a tube having one end immersible in the liquid in the reservoir; a one-way valve carried by the immersible end of the tube permitting the liquid to flow into the tube from the reservoir but not vice versa, and an electric drive for cyclically reciprocating the immersible end of the tube parallel to its longitudinal axis.
A pump constructed in accordance with the foregoing features can be produced in volume and at low cost, thereby making the pump particularly useful as an inexpensive, low flow-rate pump for pumping water to household plants and the like.

Figs. 1-7 schematically illustrate seven constructions of a pump in accordance with the present invention;
and Fig. 8 illustrates one application of the pump for use in watering house plants and the like.

The pump illustrated in Fig. 1 comprises a reservoir 2 containing a supply of water 4 to be pumped via a flexible tube 6 to a higher elevation, e.g., for use in watering house plants and the like. For this purpose, the pump includes a rigid tube 8 connected to the flexible tube 6 and constituting its lower end. The lower end of tube 8 carries a one-way valve 10 which is immersed in the water 4 in reservoir 2. Valve 10 is schematically illustrated in Fig. 1 as including a valve member 12 normally urged by a spring 14 to close an inlet opening 16 such that water may flow from the reservoir 2 into tube 8, but not from tube 8 into the reservoir.
It will be appreciated that the illustrated construction of valve 10 is shown schematically and for purposes of example only, and that other one-way valve constructions that permit water to flow from reservoir 2 into tube 8, but not vice versa, may be used for this purpose.
The pump illustrated in Fig. 1 further includes an electric drive, generally designated 20, for reciprocating the rigid tube 8 parallel to the longitudinal axis of the end of the tube immersed in the liquid 4. The electric motor drive 20 illustrated in Fig. 1 comprises an electromagnet 22 mounted in fixed position with respect to the reservoir 2, and an armature in the form of a magnetic sleeve 24 fixed to the upper end of tube 8. Electromagnet 22 is supplied with AC from the household mains (50/60 Hz) as shown at 26, such as to reciprocate sleeve 24, and thereby tube 8, at the frequency of the supply mains.
Tube 8 is mounted for reciprocation by a pair of diaphragms 30, 32, fixed at longitudinally spaced points to the tube. In this case, the two diaphragms 30, 32, are on opposite sides of the magnetic sleeve 24 to thereby close the opposite ends of the electromagnet 22 enclosing the magnetic sleeve.
The operation of the pump illustrated in Fig. 1 will be apparent from the above description. Thus, the magnetic sleeve 24 will be reciprocated by the AC current supplied to the electromagnet 22, thereby also reciprocating the rigid tube 8 carrying the magnetic sleeve 24. One-way valve 10 carried at the lower end of tube 8 and immersed within the water 4 will also be reciprocated such that when the tube and valve move downwardly, water will flow from the reservoir 4 into tube 8, but when the valve moves upwardly, spring 14 will close opening 16 thereby preventing water from moving from the tube 8 back into the reservoir. At the end of the upward stroke of tube 8, the sudden interruption of the upward stroke produces, because of upward momentum, an upward motion of the water column through the upper end of the tube, creating a low-pressure at the bottom of the water column within the tube. This opens valve 10 to start the inflow of water into the tube, which inflow continues during the downward stroke of the tube.
A construction as illustrated in Fig. 1 was found to pump the water to a vertical head of up to four meters.
Fig. 2 illustrates another pump construction, also including a reservoir 102 containing a supply of water 104, and a rigid tube 108 secured to the lower end of a flexible tube 106 and carrying a one-way valve 110 immersed within the water 104. The electric drive, generally designated 120, for reciprocating tube 108 also includes an electromagnet 122 fixed with respect to the reservoir 102, and a movable armature 124 in the form of a magnetic sleeve fixed to tube 108.
In the pump illustrated in Fig. 2, however, the yieldable means supporting the tube 108 is in the form of a leaf spring 130 having one end 132 secured to a fixed surface 134 and the opposite end mounting the magnetic sleeve 124 in cantilever fashion. Electromagnet 122 is located with respect to sleeve 124 such that the energization of electromagnet 122 by the AC supply mains 126 will oscillate leaf spring 130 and its magnetic sleeve 124. This will reciprocate magnetic sleeve 124, and thereby the one-way valve 110 carried at the lower end of the tube and immersed within the water 104, to pump the water from the reservoir 102 into tube 108, and from there into the flexible tube 106, in the same manner as described above with respect to Fig. 1.
One additional change illustrated in the construction of Fig. 2 is the provision of a frequency divider circuit 140 between the supply mains 126 and the electromagnet 122, to reduce the frequency of reciprocations of the tube 108. Thus, reciprocating the one-way valve 110 at the frequency of the supply mains (e.g., 50/60 Hz) would require a relatively light one-way valve and a relatively small amplitude of reciprocation. However, reducing the frequency of the supply mains by the frequency divider circuit 140 (e.g., to 12.5 Hz or 6.25 Hz) permits larger amplitudes of reciprocation, and more sturdy valves to be used.
It will be appreciated that a frequency divider circuit, such as shown at 140 in Fig. 2, could also be used in the construction illustrated in Fig. 1.
Fig. 3 illustrates a pump construction in which the frequency of reciprocation is reduced by mechanical means, rather than by an electronic frequency divider as in Fig. 2. Thus, the pump illustrated in Fig. 3 also includes a reservoir 202 containing the water 204 to be pumped, and a flexible tube 206 fixed at its lower end to a rigid tube 208 carrying a one-way valve 210 immersed in the water 204 of the reservoir. In this case, the electric drive 220 includes an electromagnet 222 and a magnetic armature 224 spaced laterally from tube 208. The tube 208 is connected to the armature 224 by a coil spring 230 attached at one end to armature 224, and at the opposite end to a lug 232 carried by tube 208. In addition, a second spring 234 is interposed between the bottom of the one-way valve 210 and the reservoir 202 so as to springly support the one-way valve, together with the rigid tube 208 secured to the lower end of the flexible tube 206.
Spring 230 is a soft spring, whereas spring 234 is a relatively stiff spring. Spring 234 is selected such that when electromagnet 222 is energized by the AC supply mains (e.g., at 50 Hz), the spring produces a natural frequency which is a sub-harmonic of the 50 Hz driving frequency, e.g., 12.5 or 6.25 Hz. As described in the embodiment of Fig. 2, this reduction in the frequency of reciprocation of the rigid tube 208 and its one-way valve 210 permits larger amplitudes of reciprocation.
Fig. 4 illustrates a further pump construction also including a rigid tube 308 connected to the lower end of a flexible tube 306 and immersed in water 304 contained in a reservoir 302, with the immersed end of tube 308 including a one-way valve 310. However, the electrical drive 320 is slightly different from those illustrated above.
Thus, drive 320 in the pump of Fig. 4 includes two electromagnets 321, 322 disposed on opposite sides of a magnetic armature 324 secured to the upper end of rigid tube 308. In this case, the magnetic armature 324 is of a disc configuration, and the two electromagnets 321, 322 are each supplied alternately with half-cycle alternations of the AC power supply such as to vibrate or reciprocate magnetic armature 324, and thereby rigid tube 308, at the frequency of the half-cycle alternations.
Fig. 5 illustrates a construction similar to that of Fig. 4, except that the electrical drive 420 for vibrating or reciprocating the rigid tube 408, includes one electromagnet 422 on one side of the magnetic armature 424 secured to the rigid tube 408, and a pair of springs 431, 432 on opposite sides of the magnetic armature 424. All the foregoing elements are enclosed within a housing 433.
Thus, when the electromagnet 422 is energized by AC or pulsed DC, the magnetic armature 424 floating between the two springs 431, 432, will be reciprocated in the direction parallel to the axis of tube 408.
Fig. 6 illustrates a still further construction which is similar to that of Fig. 1, except that the rigid tube 508, which is reciproated by the drive 520, is disposed horizontally, rather than vertically, within the water 504 in the reservoir 502. In addition, the opposite ends of tube 508 are each provided with a one- way valve 510, 511, respectively, which permit water to flow from the reservoir into the respective end of the tube, but not vice versa. It will be seen that when the two electromagnets 521, 522 of the electrical drive 520 are energized, they will reciprocate the magnetic armature 524 parallel to the longitudinal axis of the rigid tube 508 (i.e., along the horizontal axis in this case). This will cause water to enter, alternately through both ends of tube 508, via the two one- way valves 510, 511, and thereby to pump the water through the flexible tube section 506.
Fig. 7 illustrates a stil further construction, wherein the electrical drive 620, and the rigid tube 608, are mounted on springs 640, and form a vibratory assembly to resonate at the frequency of the electrical drive 620. Springs 640 are of conical shape, decreasing in diameter from their base resting on reservoir 602 to their tops supporting housing 620. One such spring 640 is provided at each of the four corners of the housing 621.
The electrical drive 620 includes a rigid housing 621 containing an electromagnet 622 having its South (S) and North (N) poles, respectively, in vertical alignment. Housing 621 is formed with an opening 621a in its lower end for receiving the rigid tube 608 immersed at its lower end in the water 604 of the reservoir 602. As in the previously described embodiments, the lower end of tube 608 carries a one-way valve 610 permitting water to flow into the tube from the reservoir, but not vice versa. The upper end of tube 608 carries a magnetic armature 624 which is reciprocated vertically by the energization of electromagnet 622. Magnetic armature 624, together with rigid tube 608 to which it is secured, are both supported in cantilever fashion by a U-shaped leaf spring 630 having a pair of parallel end legs 631, 632 secured to housing 621, and an intermediate cross leg 633 secured to the magnetic armature 624.
It will be seen that when electromagnet 622 is energized, this will vibrate or reciprocate the magnetic armature 624 in the vertical direction, which will thereby pump water via the one-way valve 610 through rigid tube 608 to the flexible tube 606. The U-shaped spring 630, supporting the magnetic armature 624 and rigid tube 608, produces vertical reciprocations of tube 608.
A vibrating assembly is thus produced including the U-shaped leaf spring 630, rigid tube 608, its one-way valve 610, magnetic armature 624, electromagnet 622, housing 620, flexible tube 606, and the water column within tubes 608 and 606. By appropriate design, this vibrating assembly may be tuned to have a self-resonance at the frequency of the current energizing the electromagnet 622 (e.g., 50 or 60 Hz). Thus, when the electromagnetic is energized at the self-resonance frequency of the described assembly, housing 624 will resonate on the springs 640 to produce a strong pumping force pumping the water via tubes 608 and 606.
Fig. 8 illustrates one application of the pumps described above, namely for feeding water to a house plant or the like. Thus, as shown in Fig. 8, the house plant, generally designated 700, is supplied with water via a flexible tube 706 by means of a pump including a rigid tube 708 having a lower end carrying a one-way valve 710 immersed in the water 704 within the reservoir 702, the rigid tube 708 being reciprocated parallel to its longitudinal axis by an electrical drive 720, according to any of the above-described constructions.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

A method of pumping a liquid from a reservoir, comprising: immersing one end of a tube in a reservoir of the liquid to be pumped, which end includes a one-way valve permitting the liquid to flow into the tube from the reservoir but not vice versa; and cyclically reciprocating by an electrical drive the immersed end of the tube parallel to the axis of said immersed end.
The method according to Claim 1, wherein said tube is a short rigid tube and is connected to a longer flexible tube through which the liquid is pumped by the reciprocations of said short rigid tube.
The method according to Claim 1, wherein said tube is cyclically reciprocated at a frequency of at least 5 Hz.
The method according to Claim 1, wherein said immersed end of the tube is reciprocated by an electromagnet.
The method according to Claim 4, wherein said immersed end of the tube is supported by yieldable means permitting the tube to be reciprocated.
The method according to Claim 5, wherein said yieldable means comprises a diaphgram.
The method according to Claim 5, wherein said yieldable means comprises a spring.
The method according to Claim 1, wherein the electrical drive and said tube are mounted on springs and form a vibratory assembly tuned to resonate at the vibratory frequency of said electrical drive.
A liquid pump for pumping a liquid from a reservoir, comprising: a tube having one end immersible in the liquid in the reservoir; a one-way valve carried by said one end of the tube permitting the liquid to flow into the tube from the reservoir, but not vice versa; and an electrical drive for cyclically reciprocating said one end of the tube parallel to the longitudinal axis of the tube.
The pump according to Claim 11, wherein said electrical drive is enclosed within a housing through which said tube passes, and said housing is supported on springs and forms a vibrating assembly tuned to resonate at the frequency of said electrical drive.