GB2302568A

GB2302568A - Electromagnetic/magnetic reciprocating pump

Info

Publication number: GB2302568A
Application number: GB9512872A
Authority: GB
Inventors: John William Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-06-23
Filing date: 1995-06-23
Publication date: 1997-01-22
Also published as: GB9512872D0

Abstract

A magnetic pump consists of a hollow magnetic pumping member (1) arranged for free reciprocation in a non-magnetic or soft magnetic liner tube (3), the reciprocation being produced by magnetic means around the liner. Fluid is pumped from a tapered inlet flange (6) to an outlet flange (7) via a passage in the pumping member controlled by a non-return valve (2). In the preferred embodiment bipolar electromagnetic fields are induced by the energisation of solenoids (4) separated by isolation washers (4). The non-return valve may or may not include mechanical closing and opening enhancements. Variations include a pressurised casing allowing high pressure application; single unipolar operation of a single solenoid with spring or mechanical return; or synchronous/eddy current types in which a permanent magnetic ring is oscillated over the liner by a motor drive.

Description

ELECTROMAGNETIC/MAGNETIC RECIPROCATING AXIAL PUMP This invention relates to an electromagnetic/magnetic reciprocating axial pump.

The pumping of hazardous liquids i.e. toxic, corrosive, flammable is one of the most demanding of applications found in the fluid movement industry. Currently, such liquids are dealt with by the utilisation of an electrically driven glandless pump. This type of design enables a sealess pump housing to be constructed, thus minimising leakage. However, ingress into the pump chamber is still necessary in order to enable connection of the impeller driveshaft. This creates a major source of leakage necessitating elaborate secondary sealing measures i.e. rotor/stator canning.

The Electromagnetic/magnetic reciprocating axial pump eliminates any requirement for drive couplings to penetrate the pumping chamber, and so, creates a genuinely sealess pumping system, ideal for the handling of hazardous liquids.

The electromagnetic/magnetic reciprocating axial pump is by no means restricted to the above application, indeed the significant cost reduction and performance enhancements possible, make the electromagnetic/magnetic reciprocating axial pump suited to many diverse applications i.e. hydrostatic transmission systems, air compressors, medical equipment, water treatment plant, process plant. Both large and small pumping applications are equally catered for by this technology.

The essential components of the electromagnetic/magnetic reciprocating axial pump consist of a magnetic hollow cored shuttle, usually constructed of permanent or soft magnetic segments, but may be a solid component, also may be encapsulated in a thermally conductive and magnetically permeable jacket, although this is not required for operation, the above item is equipped with an integral non-return valve actuated by mechanical and/or magnetic means, and collectively these items constitute the pumping member.A non-magnetic or soft magnetic liner tube, which may or may not include integral welded flange pieces, whereby completely enclosing the magnetic pumping member and constituting the pump casing; a pair of axially mounted and adjacent solenoids, or a single solenoid, either internal or external to the pump casing, which once energised, provides the prime moving force by inducing electromagnetic fields within the pumping chamber. The induced magnetic fields may be bipolar and opposing i.e. repelling and attracting, or unipolar i.e. one ofthe above.

Electromagnetic insulation washers contain the magnetic fields so as to minimise eddy current losses, and prevent performance reducing interaction of opposing magnetic fields. The pump may or may not include external system fittings to facilitate installation.

A mechanical synchronous or eddy current model replaces the solenoids with a magnetic ring which is mounted externally to the pump casing, and is oscillated back and forth via a motor drive, the magnetic shuttle is either attracted or repelled, i.e.

dependent upon the specific design, by the moving magnetic field induced within the pump casing.

A high pressure ratio model incorporates an external pump casing into the design, containing both magnetic shuttle pumping member, liner and solenoid/s. The pumped fluid may not only provide high pressure energy, but also cooling for the pump components, including the solenoids via channels connecting the high pressure chamber to the solenoid chamber. Alternatively, solenoid cooling may be provided by an independent pressurised cooling system. Such a pump is particularly suited to hydro-static drive applications.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings which: Figure 1. shows a cross-section, the primary components of the twin solenoid electromagnetic reciprocating axial pump.

Figure 2. Illustrates the four principal stages of operation Referring to the drawing, Figure 1, the electromagneticlmagnetic reciprocating axial pump comprises a hollow cored magnetic shuttle pumping member 1, a non-return valve 2 integral to the pumping member, enclosed by a non-magnetic or soft magnetic liner tube 3, a pair of axially mounted and adjacent solenoids 4, electromagnetic isolation washers 5, inlet flange piece 6, and outlet flange piece 7.

The pumping cycle commences with the magnetic shuttle 1 stationary with the nonreturn valve 5 closed as illustrated in figure 2.1. The solenoid coils are energised and the magnetic fields are induced within the pump chamber, with the solenoid enveloping the shuttle inducing a repelling magnetic field, and the adjacent solenoid an attracting magnetic field. The subsequent forces exerted upon the shuttle propels it along the liner tube from left to right, with the non-return valve remaining closed as illustrated in figure 2.2. Thus, a charge of fluid is displaced by the advancing shuttle and expelled out through the outlet flange opening. Simultaneously, an equal charge of fluid is drawn into the pump priming chamber through the inlet flange opening due to the suction action of the retreating shuttle.Once the shuttle has completed the prescribed stroke length, the solenoid polarities are reversed and the magnetic field flips modes i.e. repelling becomes attracting and visa versa. The force upon the shuttle therefore changes direction this time propelling the shuttle from right to left. However, the momentum of the pumped fluid remains from left to right, and combined with the pressurising effect produced in the left hand priming chamber by the shuttles returning momentum, the non-return valve is pushed open by fluid pressure, as illustrated in figure 2.3, so allowing the passage of a fresh charge of fluid to pass through the hollow cored shuttle into the right hand delivery chamber. Once the shuttle pumping member has returned to the original starting position, the solenoid polarities are once again reversed, thus flipping the magnetic fields and forces as previously described, the fluid pressure reduces the subsequent loss in the momentum in the shuttle pumping member, and the non-return valve closes, assisted by a spring or other mechanical means, whereby the process may begin again, as illustrated in figure 2.4.

Claims

CLAIMS.

I. An electromagnetic reciprocating axial pump comprising of a magnetic hollow crowned shuttle pumping member, with integral non-return valve, a non-magnetic or soft magnetic liner tube constituting the pump casing, a pair of axially mounted and adjacent solenoids external to the pump casing, electromagnetic isolation washers between the solenoids and at the solenoid ends, and inlet/outlet ports aligned with pump central axis.
2. An electromagnetic reciprocating axial pump as claimed in claim 1 wherin the pair of solenoids are replaced with a single solenoid, and the shuttle pumping member may or may not include a spring or other mechanical returning mechanism.
3. An electromagnetic reciprocating axial pump as claimed in claim 1 wherin the pair of solenoids are deep wound with ferrous cheeks located at the ends of each solenoid in order to concentrate electromagnetic forces and enhance performance.

The cheeks may or may not include spigots to facilitate solenoid winding and further enhance electromagnetic force transfer.
4. A magnetic reciprocating axial pump as claimed in claim 1 wherin the pair of solenoids are replaced by a magnetic ring, traversed axially along the external pump case via an electric or IC motor drive.
5. An electromagnetic reciprocating axial pump as claimed in claim 1 wherin the pair of solenoids are replaced by a ferrous stators, constructed of axially aligned ferrous plates or solid ferrite mouldings, mounted external to the pump casing.
6. An electromagnetic reciprocating axial pump as claimed in claims 1,2,3 and 5 wherin the magnetic hollow crowned pumping member is replaced with a copper wound hollow crowned pumping member with integral non-return valve. The windings may or may not contain a ferrous core constructed of axially aligned plates or solid ferrite mouldings. This design of pumping member may be energised by eddy currents generated by the externally mounted solenoids or stators, or alternatively by independent means via linear bearing contacts mounted external to the pumping member wall which connect to stationary contacts penetrating the liner tube wall.
7. An electromagnetic reciprocating axial pump comprising a magnetic hollow crowned shuttle pumping member, with integral non-return valve, non-magnetic or soft magnetic liner tube, an enclosing pump casing, a pair of axially mounted and adjacent solenoids external to the liner tube, but internal to the pump casing, electromagnetic isolation washers between solenoids, and between solenoid/casing interfaces.
8. An electromagnetic reciprocating axial pump as claimed in claim 7 wherin the pair of solenoids are replaced by ferrous stators constructed of axially aligned plates or solid ferrite mouldings, mounted externally to the liner tube.
9. An electromagnetic reciprocating axial pump as claimed in claims 7 and 8 wherin the magnetic hollow crowned pumping member is replaced with a copper wound hollow crowned pumping member with integral non-return valve. The windings may or may not contain a ferrous core constructed of axially aligned plates or solid ferrite mouldings. This design of pumping member may be energised by eddy currents generated by the externally mounted solenoids or stators, or alternatively by independent means via linear bearing contacts mounted external to the pumping member wall which connect to stationary contacts penetrating the liner tube wall.
10. An electromagnetic reciprocating axial pump as claimed in claims 1, 2, 3, 4, 5, 6, 7, 8 and 9 wherin a pair of sealing rings are mounted fore and aft of the external shuttle wall and internal to the liner tube.
ii.An electromagnetic reciprocating axial pump as claimed in claims 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 wherin stationary valves are mounted in the inlet and outlet creating isolated chambers within the pump casing.
12. An electromagnetic reciprocating axial pump as claimed in claims 1, 2, 3, 4, 5, 7, 8, 9, 10 and 11 wherin mutiple shuttles act in series to create a multistaged pumping device, actuated either syncroniously or asyncroniously.