EP1503078A1

EP1503078A1 - Electromagnetic pump with oscillating core

Info

Publication number: EP1503078A1
Application number: EP04103598A
Authority: EP
Inventors: Jean Claude Buffet
Original assignee: Invensys Controls Italy SRL
Current assignee: Invensys Controls Italy SRL
Priority date: 2003-07-30
Filing date: 2004-07-27
Publication date: 2005-02-02
Also published as: US20050025638A1; ITUD20030162A1

Abstract

Electromagnetic pump with oscillating core, connected to a hydraulic device, in order to transfer a fluid into said hydraulic device. The pump comprises a containing body (34), a tubular element (11) made of amagnetic material, a core (17) made of ferromagnetic material sliding coaxially to the tubular element (11), an electromagnetic unit (12) arranged around the core (17) and coaxial to the tubular element (11), in order to generate an alternating magnetic field and cause the core (17) to slide axially and alternately with respect to the tubular element (11). The tubular element (11) comprises, in one piece, a first part (11a), projecting outside both the containing body (34) and the electromagnetic unit (12) and provided with attachment means configured to be selectively associated, directly or indirectly, with mating attachment elements of the hydraulic device, and a second part (11b) disposed inside both the containing body (34) and the electromagnetic unit (12) and having an axial cavity in which the core (17) slides. The tubular element (11) further comprises, in one piece, a flange (18) intermediate between the first part (11a) and the second part (11b) and configured to allow the direct mounting of the tubular element (11) to the containing body (34) and to the electromagnetic unit (12).

Description

FIELD OF THE INVENTION

The present invention refers to an electromagnetic pump with oscillating core, that is, of the type comprising an electromagnetic circuit with a core that is able to slide axially and alternately inside a cylindrical seating in order to thrust, a fluid, for example water, towards the exit with a desired pressure. The pump according to the present invention is able to be associated with hydraulic devices such as boilers, electro-valves or other, and comprises a tubular element provided, on the side through which the fluid exits, with rapid attachment means by means of which the pump is able to be coupled with the relative hydraulic device and, on the other side, with the cylindrical seating wherein the core of the electromagnetic circuit is able to slide.

BACKGROUND OF THE INVENTION

Electromagnetic pumps with an oscillating core are known (see, e.g., DE 299 19 575 U1 and DE 15 28 566 B); they generally comprise a tubular element, wherein a cylindrical core made of ferromagnetic material is able to slide, and a fluid to be brought under pressure is able to pass. An electric coil is arranged around the tubular element able to be fed with alternating current, in order to generate an alternating, or pulsating, magnetic field with the same frequency as the alternating current fed (for example 50 or 60 Hz).
Such pumps with an oscillating core are normally used in small household appliances, such as for example ironing apparatuses, coffee machines, steam vacuum cleaners or other, which need small pumps in order to transport a fluid, for example from a water tank to a boiler.
The alternate movement of the ferromagnetic core causes a selective opening, or closing, of a pair of spring-type shutters, which create a determinate pressure on the fluid exiting the pump.
Usually the tubular element is connected to an external terminal shaped in order to be coupled, with precision, to a specific and well defined attachment profile of a hydraulic device of the household appliance, arranged downstream of the pump, be it an electro-valve, the terminal of a pipe of a boiler, or other. The above-mentioned external terminal normally has the end threaded or provided with a rubber-bearing profile. One example of such kind of pump is disclosed in EP-A-288.216, on which is based the preamble of the main claim.
In this way, however, each pump with a determinate external coupling terminal can only be coupled to those hydraulic devices that have a mating coupling profile, while in order to be connected to different hydraulic devices it is necessary to resort to the use of suitable adaptors which have to be placed between the pump and the latter, with a consequent rise in the production and storage costs of the spare parts.
Furthermore, in known pumps, sealing and end-of-travel rings are arranged between the tubular element and the external terminal; such rings separate the low-pressure cavity made inside the tubular element and inside which the ferromagnetic core is able to slide, from the high-pressure one, made in the external cavity and where the spring-type shutters are arranged. Such sealing and end-of-travel rings are inserted during the assembly phase of the pump, making this operation complex and costly.
One purpose of the present invention is to achieve an electromagnetic pump with oscillating core which can be installed in a plurality of electric apparatuses, without needing to adapt the hydraulic devices that constitute said apparatuses, according to the profile of the external terminal of the pump itself.
A further purpose of the present invention is to optimize the electromagnetic circuit of the pump, so that there are no exposed metal parts, so that the pump is completely insulated electrically.
Another purpose of the present invention is to achieve an electromagnetic pump where the elements that constitute it are reduced to the minimum and easily coupled to one another, in order to reduce production times.
The Applicant has devised, tested and embodied the present invention in order to overcome the shortcomings of the state of the art, and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention or variations to the main inventive idea.
In accordance with the above purposes, the electromagnetic pump with oscillating core according to the present invention, which is able to be connected to a hydraulic device such as a boiler, an electro-valve or other, in order to transfer a fluid at a determinate pressure into the hydraulic device, essentially comprises a containing body, a tubular element made of amagnetic material placed inside the containing body, a core made of ferromagnetic material able to slide coaxially and internally to the tubular element, and an electromagnetic unit arranged around the core, external and coaxial to the tubular element in order to generate an alternating magnetic field and cause the core to slide axially and alternately with respect to the tubular element.
According to a characteristic feature of the present invention, said tubular element comprises, in one piece, a first part, protruding outside the containing body and the electromagnetic unit, which defines itself fast attachment means, without threading, able to be selectively associated, directly or indirectly, with mating attachment elements of said hydraulic device, and a second part inside the containing body and the electromagnetic unit, in which the aforesaid core is able to slide.
As an option, an adaptor element, consisting for example of a fast tubular connector, which is shaped so as to be coupled to said attachment elements of the hydraulic device, is able to be coupled to the first part of said tubular element.
According to a further feature of the invention, the tubular element comprises in one piece a flange provided in an intermediate position between the first external part and the second internal part. The flange allows to directly mount the tubular element on a wall of the containing body without needing any auxiliary ring or seal.
The tubular element is internally divided into two coaxial cylindrical cavities: a first high-pressure cavity made substantially in correspondence with said first external part, and a second low-pressure cavity, with a diameter larger than the first cavity, made substantially in correspondence with said second internal part and in which the ferromagnetic core is able to slide.
In the step where the pump is pre-assembled, a metal bushing, for example made of brass, is inserted inside the tubular element in order to separate the two coaxial cavities. Furthermore, a sealing ring and a first elastic ring are placed between the bushing and the first cavity, while a second elastic ring, which acts both as an end-of-travel element for the ferromagnetic core, and also as an absorber for the noise produced by the action of the latter, is placed between the bushing and the second cavity.
The core made of ferromagnetic material is connected to at least one spring-type shutter, arranged in the high-pressure cavity.
In this way, all the elements that in the state of the art were assembled individually and closed between the central element and the external terminal are advantageously pre-assembled into a single piece (the tubular element), which is the same for every pump, irrespective of the different hydraulic devices to be arranged downstream.
The electromagnetic unit, in turn, comprises an electric coil, able to be fed with alternating current, in order to generate a pulsating magnetic field, and cause the core to slide axially and alternately inside the tubular element and, consequently, determine the opening, or the closing, of the shutter.
The pump according to the present invention also comprises clamping means, of the removable type, in order to keep the connector associated to the tubular element. Such clamping means can comprise, for example, an elastic clip, a tooth, a bayonet joint, or other.
According to another characteristic feature of the present invention, the electric coil and the other ferromagnetic parts of the pump are completely covered and electrically insulated with parts made of plastic material, in order to optimize the electromagnetic circuit of the pump and hence the functioning thereof.
In accordance with a further characteristic feature of the present invention, said second part of the tubular element is through inside the electromagnetic unit and is coupled, advantageously by screwing, with a terminal element arranged on the opposite side.
The tubular element and the terminal element are provided with flange means, which enclose the electromagnetic unit and define a structure that is very easy to assemble and, possibly, to dis-assemble.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein:

fig. 1 shows an exploded view of an electromagnetic pump with oscillating core according to the present invention;
fig. 2 is a longitudinal section of the pump in fig. 1 in an assembled condition, including the optional connector;
fig. 3 is an enlarged detail of fig. 2.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

With reference to figs. 1 and 2, an electromagnetic pump 10 according to the present invention is of the type with an oscillating core and is able to be connected to any hydraulic device (electro-valve, boiler or suchlike) of a small household appliance, of a known type and not shown in the drawings, such as for example an ironing device, a coffee machine or other similar electric apparatus, where there is the need to transport a fluid under pressure, for example from a tank to a boiler.
The pump 10 according to the present invention comprises:

a containing body 34,
a central element 11 comprising, in one piece and coaxially to each other, a first part 11a protruding outside the containing body 34 and a second part 11b placed inside the containing body 34,
an electromagnetic unit 12 placed inside, or comprising, the containing body 34 and coaxial to the central element 11, and
a rear closing ring-nut 13 which closes the containing body 34 at the opposite side with respect the protruding part 11a of the central element 11.

The central element 11 and the ring-nut 13 are advantageously made, by means of molding, of amagnetic material, for example of plastic material.
According to a feature of the invention, a circular flange 18 is made in one piece between the first part 11a and the second part 11b and allows to directly mount the central element 11 to the containing body 34 without needing any auxiliary ring or seal.
According to a further characteristic feature of the present invention, the first part 11a of the central element 11, which exits from the containing body 34 and from the electromagnetic unit 12, is configured to be coupled directly, or indirectly, to the different hydraulic devices downstream thereof.
To be more exact, such first part 11a comprises a substantially cylindrical, smooth and non-threaded terminal segment and an attachment zone in which a circumferential groove 42 is made, into which an elastic clip 40 is able to be arranged. In this way the pump 10 can be directly connected to those hydraulic devices that have a substantially cylindrical mouthpiece.
In order to connect the pump 10 to hydraulic devices with a different mouthpiece, at least one optional connector 15 is also provided, also made of amagnetic material, which is able to be associated with the first part 11a of the central element 11 and which will be described in detail hereafter.
The central element 11 is shaped so as to have inside it two coaxial through cavities 16a and 16b, in correspondence with the parts 11a and 11b respectively. A core 17, made of ferromagnetic material, whose functioning will be explained hereafter, is arranged in a sliding manner inside the low-pressure cavity 16b, which has a greater diameter than that of cavity 16a. Inside the high-pressure axial cavity 16a, a wall 19 is provided which reduces the section and is able to define an accumulation chamber 20.
The ferromagnetic core 17 is axially connected to a first shutter 30, substantially formed by a rubber block, arranged in the cavity 16a and put in cooperation with the reducing wall 19. To be more exact, between the shutter 30 and the wall 19, a spring 32 is arranged, able to normally push such shutter 30 towards the ferromagnetic core 17, in order to allow the fluid to pass through the reducing wall 19.
A second shutter 31 is arranged in the accumulation chamber 20, held towards the reducing wall 19 by a spring 33 arranged between such shutter 31 and an internal shoulder of the first part 11a of the central element 11. Advantageously, such internal shoulder 41 is made by riveting the extremity of the first part 11a.
A bushing 45 (fig. 2 and 3), made of brass or other metal material, is inserted, for example driven, between the axial cavities 16a and 16b, and acts as a separator between the high-pressure and the low-pressure zones, in order to prevent the pressure generated by the oscillations of the core from being eliminated by a reflow outside the core. Furthermore, a sealing ring 46, for example made of fluoridized plastic material, is arranged between the bushing 45 and the cavity 16a, and associated with an elastic ring 47. An elastic ring 48, for example made of elastomeric material, is instead arranged between the bushing 45 and the cavity 16b, and functions as an end-of-travel element for the core 17 and reduces the noise thereof.
The electromagnetic unit 12, which is advantageously produced separately before being assembled on the second part 11b of the central element 11, comprises a reel 24 made of plastic material arranged concentric to such second part 11b, that is, in correspondence with the segment where the ferromagnetic core 17 slides. An electric coil 21 is arranged around the reel 24, able to be fed with alternating current in order to generate a pulsating magnetic field. The electromagnetic unit 12 also comprises a ferromagnetic structure 28 arranged around the coil 21 and partially interposed between the reel 24 and the central element 11.
At the front, the ferromagnetic structure 28 rests against the circular flange 18 of the central element 11, in this way defining a positioning wall for the electromagnetic unit 12 with respect to the central element 11.
The electromagnetic unit 12 is drowned in the containing body 34 of plastic material. Such containing body 34 has a front wall 34a against which the circular flange 18 abuts, so as to guarantee an excellent electric insulation of the ferromagnetic parts of the pump 10. Furthermore, two electric terminals 22 are fixed to the front wall 34a, to supply the electric feed for the electric coil 21.
The pulsating magnetic field generated by the electric coil 21 induces, in the known manner, the ferromagnetic core 17 to slide alternately and axially inside the axial cavity 16b. By doing this, the ferromagnetic core 17 alternately moves the shutter 30, in order to piston pump the fluid towards the accumulation chamber 20 and, at the same time, increase the pressure thereof.
The rear ring-nut 13 comprises a substantially tubular part 23 and a flange 26.
The tubular part 23 is provided with an external surface 23a connecting it to a pipe, or other external element, in order to allow the entrance of the fluid that has to be taken under pressure into the pump 10. The ring-nut 13, in fact, has a through hole 25 arranged concentric to the axial cavity 16b, and able to connect the latter with the exterior.
Such tubular part 23 also has an internal thread 23b made in a zone close to the flange 26, so that the ring-nut 13 can be screwed to the second part 11b of the central element 11.
The flange 26 of the ring-nut 13 is made in one piece with the tubular part 23 and has the double function of covering and totally insulating the rear part of the ferromagnetic structure 28 of the electromagnetic unit 12, and of maintaining the latter in abutment against the circular flange 18 of the central element 11.
The ring-nut 13 also has a abutment surface 27, facing towards the axial cavity 16b, against which the end of a helical spring 29 rests, with the other end in contact with the core 17, in order to normally maintain the latter in a position distant from the ring-nut 13, with the shutter 30 moved towards the reducing wall 19.
As shown in fig. 2, the external structure of the electromagnetic unit 12 consists completely of elements made of plastic material which, in cooperation with the flanges 18 and 26, also made of plastic material, totally protect the ferromagnetic components present inside such electromagnetic unit 12, thus insulating and optimizing the electromagnetic circuit of the pump 10.
Furthermore, the thread 23b made on the ring-nut 13 allows the different components to be assembled quickly and simply, noticeably reducing the production costs of the pump 10.
The optional connector 15 comprises an internal surface 35 with a profile mating that of the first part 11a of the central element 11, and an external surface 36 shaped so as to be coupled with other corresponding standard mouthpieces of other hydraulic devices present on the market. The connector 15 also comprises an exit pipe 37 coaxial to the accumulation chamber 20, and a circumferential slot 39, which when in use overlaps the groove 42 and inside which the elastic clip 40, which guarantees the coupling of the connector 15 to the central element 11, is able to be arranged.
Such clip 40 can be selectively removed in order to allow the connector 15 to be detached from the central element 11. In this way it is possible to replace the connector 15 with another connector 15, similar to the first but with an external surface 36 with a different profile.
In this way, it is possible to couple the pump 10 according to the invention with different types or models of hydraulic devices simply by replacing the connector 15, according to the attachment profile of such hydraulic devices.
We thus obtain the advantage of having a pump wherein the elements that form it (and particularly the part 11a where the fluid exits) are the same in any type of hydraulic device that has to be coupled downstream thereof, and wherein a simple adaptor element (in this specific case the connector 15) is able to be optionally associated with the part 11a where the fluid exits, in order to allow it to be connected also to those hydraulic devices which are not already provided with a mouthpiece mating that of said part 11a where the fluid exits.
It is clear, however, that modifications and/or additions of parts can be carried out to the pump 10 described heretofore, without departing from the field and scope of the present invention.
For example, the clip 40 and the relative slot 39 and groove 42 can be replaced by any other removable clamping means, such as for example a bayonet joint, an elastic tooth, a screw, or other. Furthermore, sealing packings of a known type can be provided, according to necessity, arranged so as to make the coupling between the various elements water tight.
Furthermore, the terminal segment of the first part 11a of the central element 11 can have an external profile other than cylindrical, and be for example of the type mating with a corresponding attachment profile of a determinate hydraulic device, in order to allow the direct connection of the pump 10 and said hydraulic device.
It is also clear that, although the invention has been described with reference to a specific example, a person of skill in the art shall be able to achieve other forms of electromagnetic pump with oscillating core, all of which shall come within the field and scope of the present invention.

Claims

Electromagnetic pump with oscillating core able to be connected to a hydraulic device, such as a boiler, an electro-valve or other, in order to transfer a fluid at a determinate pressure into said hydraulic device, comprising a containing body (34), a tubular element (11) made of amagnetic material, a core (17) made of ferromagnetic material able to slide coaxially to said tubular element (11), an electromagnetic unit (12) arranged around said core (17) and coaxial to said tubular element (11), in order to generate an alternating magnetic field and cause said core (17) to slide axially and alternately with respect to said tubular element (11), characterized in that said tubular element (11) comprises, in one piece, a first part (11a), protruding outside both said containing body (34) and said electromagnetic unit (12) and provided with attachment means configured to be selectively associated, directly or indirectly, with mating attachment elements of said hydraulic device, and a second part (11b) disposed inside both said containing body (34) and said electromagnetic unit (12) and having an axial cavity in which said core (17) is able to slide, said tubular element (11) further comprising, in one piece, a flange (18) intermediate between the first part (11a) and the second part (11b) and configured to allow the direct mounting of the tubular element (11) to the containing body (34) and to the electromagnetic unit (12).
Electromagnetic pump as in claim 1, characterized in that said attachments means of said first part (11a) comprise a cylindrical, smooth and non-threaded segment on a rear part of which a groove (42) is provided for the fast snap attachment to mating means of the hydraulic devices.
Electromagnetic pump as in claim 2, characterized in that an adaptor element (15), configured so as to be coupled with said attachment elements of said hydraulic device, is able to be coupled with said smooth segment and with the groove (42) of said first part (11a) of said tubular element (11).
Electromagnetic pump as in claim 3, characterized in that said connector (15) comprises an internal profile (35) for its coupling with the external profile of said smooth segment and with the groove (42) of said first part (11a) of said tubular element (11), and an external profile (36) by means of which it is able to be fast coupled with said hydraulic device.
Electromagnetic pump as in claim 3 or 4, characterized in that selectively removable clamping means (40) are provided in order to maintain said connector (15) associated with said first part (11a) of said tubular element (11).
Electromagnetic pump as in claim 5, characterized in that said clamping means comprise an elastic element (40) able to cooperate with said circumferential groove (42).
Electromagnetic pump as in claim 5, characterized in that said clamping means comprise a bayonet joint.
Electromagnetic pump as in any claim hereinbefore, characterized in that said electromagnetic unit (12) comprises an electric coil (21) arranged around said second part (11b) of said tubular element (11), a ferromagnetic structure (28) arranged around said electric coil (21) and an external insulating layer (34).
Electromagnetic pump as in claim 1, characterized in that said electromagnetic unit (12) is constantly held against said first circular flange (18) by a rear closing ring-nut (13), coupled with said second part (11b) of said tubular element (11).
Electromagnetic pump as in claim 9, characterized in that said rear ring-nut (13) comprises a substantially tubular part (23) coaxial to said tubular element (11), and a second circular flange (26) substantially parallel to said first circular flange (18).
Electromagnetic pump as in claim 10, characterized in that said tubular part (23) of said rear ring-nut (13) is provided with a through hole (25) and with an external surface (23a) connecting it with an external element, in order to allow the entrance of said fluid inside said tubular element (11).
Electromagnetic pump as in claim 11, characterized in that said tubular part (23) also has an internal thread (23b) made in a zone close to said second circular flange (26), able to allow said rear ring-nut (13) to be screwed to said second part (11b) of said tubular element (11).
Electromagnetic pump as in claim 12, characterized in that an elastic element (29) is arranged inside said second part (11b) of said tubular element (11) between said ring-nut (13) and said core (17) in order to constantly thrust said core (17) towards said first part (11a) of said tubular element (11).
Electromagnetic pump as in any claim hereinbefore, characterized in that at least a shutter (31) is housed inside said first part (11a) of said tubular element (11), constantly thrust towards said core (17) by a spring (33) arranged between said shutter (31) and an internal shoulder (41) made in one piece on said first part (11a) of said tubular element (11).
Electromagnetic pump as in any claim hereinbefore, characterized in that said tubular element (11) is internally divided into two coaxial cylindrical cavities, respectively a first high-pressure cavity (16a), substantially made in correspondence with said first part (11a), and a second low-pressure cavity (16b), substantially made in correspondence with said second part (11b) and inside which said ferromagnetic core (17) is able to slide.
Electromagnetic pump as in claim 15, characterized in that a bushing (45) is inserted into said tubular element (11) in order to separate said two coaxial cavities (16a, 16b).
Electromagnetic pump as in claim 16, characterized in that a sealing ring (46) and a first elastic ring (47) are interposed between said bushing (45) and said first cavity (16a).
Electromagnetic pump as in claim 16, characterized in that a second elastic ring (48) is interposed between said bushing (45) and said second cavity (16b), with the function of an end-of-travel element for said ferromagnetic core (17) and of absorbing the noise due to the action of said ferromagnetic core (17) itself.