The invention relates to a liquid pump, comprising a barrel enclosing a pump cylinder with an output bore, an electric cylinder coil for periodically generating a magnetic field, a movable from the magnetic field of the solenoid in the longitudinal direction of the pump chamber armature with a dipping into the pump chamber and by the movement of the armature reciprocating piston therein, wherein the piston-armature member has an axial inlet channel, which anchor is located in an armature space enclosing armature housing and wherein a pressure compensation path between the piston side and the inlet side of the armature is provided.
Such electric fluid pumps, which are also referred to as solenoid pumps due to their electromagnetic drive or due to the movement of their piston-armature component as oscillating piston pump, are used when smaller amounts of liquid are to be promoted and / or when built by a pump a certain pressure shall be. Such liquid pumps are used in household appliances, such as coffee machines, irons or the like. When such a liquid pump is used in a coffee machine, it serves to convey water required for beverage preparation from a water tank to a continuous heating device and then to the brewing unit. If such liquid pumps are used in coffee machines which are suitable as a so-called fully automatic machine for brewing espresso, such pumps can provide the pressure required for an espresso preparation of about 10 bar or more with sufficient delivery rate. Another advantage of such liquid pumps is their small size.
Such a fluid pump is for example off EP 1 818 538 B1
or EP 0 288 216 B1
known. Such a liquid pump is constructed from a cylinder enclosing a pump space, into which a piston moves in a longitudinal axial direction. The cylinder has an outlet bore that expels fluid delivered by the piston during pump operation. For longitudinal axial movement of the piston within the cylinder, this is connected to an armature, which in turn is longitudinally movable in an armature housing. The armature has ferromagnetic properties. The armature housing is surrounded by an electrical coil, through which a periodic magnetic field is generated. The armature is supported by means of a return spring formed as a compression spring at a bottom of the armature housing. The return spring acts on the armature and thus on the piston plunging into the cylinder in such a way that the liquid introduced into the pumping space pushes it out of the outlet bore due to the force of the spring. For supplying water to be pumped into the pump chamber, the magnetic field built up by the cylindrical coil serves to move the armature and thus the piston back against the force of the return spring, increasing the current volume of the pump chamber. The cylindrical coil is designed to generate a periodic magnetic field with alternating voltage and typically comprises a diode with which a magnetic field is generated only over the length of a half-wave of a period. By the return spring at each magnetic field interruption of the piston for pushing out of the same by the withdrawal movement of the pump chamber introduced water through the output bore of the cylinder moves. Thus oscillates the piston-armature component in the frequency having the applied AC voltage.
In order to allow water to flow into the pump chamber, the piston-armature component has a central through-channel. This is acted upon by a water supply, which opens into the enclosed by the anchor housing armature space. The liquid pump has an inlet connection, on which, for example, a hose connected to a water tank is seated.
In order to carry out the above-described water promotion, such a liquid pump has an inlet valve and an outlet valve. Both valves are designed as one-way valves. The valve body of the inlet valve is in its closed position at a located on the projecting into the pump chamber of the cylinder end of the piston, annular valve seat. The valve body of the exhaust valve is in its closed position at one of the output bore of the cylinder associated, annular valve seat.
In order to allow a pressure equalization between the piston side of the armature and the piston-side armature space and the inlet, a transverse bore is introduced in an integrally formed on the armature annular cylinder section, through which a Wegsamkeit is provided by the piston-side armature space to the inlet channel. This annular cylinder section has a larger outer diameter than the piston and does not dip into the cylinder. It is necessary for the functionality of the pressure balance to be open in any position of the oscillating piston.
Out DE 20 2005 006 584 U1
a piston for a solenoid pump is described, which is designed as a composite piston. In this piston is the anchor with its cylinder extension and the Transverse bore made of a first material - a ferromagnetic material - made while the piston may be a metal tube of a general kind with or without seam. In this composite piston of the piston is welded to the integrally formed on the armature cylinder section.
The liquid pumps of the aforementioned type are relatively small. Nevertheless, there is a desire to further simplify this, in particular to make more cost-effective and to reduce the size required, if possible.
Based on this discussed prior art, the invention has the object of developing a fluid pump mentioned above in such a way that it can be performed with a smaller longitudinal axial extent.
This object is achieved according to the invention by a generic liquid pump mentioned above in which the pressure equalization path has at least one channel opening in the piston-side section of the armature space, whose longitudinal axis connecting the piston side to the inlet side runs parallel to the oscillating axis of the piston-armature component.
The piston-armature component of this fluid pump has longitudinal axial travel to provide pressure balance capability between the piston side of the armature and the inlet side. In this case, the inlet side may be the inlet channel section of the inlet channel assigned to the anchor. It is also possible that the pressure equalization in the form of one or more, the armature cross-channels is executed parallel to the longitudinal axis of the armature and thus opens at the inlet-side end side in the this side armature space section.
In the claimed concept no transverse bore is needed. Therefore, placing them on a ring cylinder portion as required in the prior art can be eliminated. Consequently, such a piston-armature component can be made shorter in terms of its longitudinal extent, whereby the total longitudinal extension of the liquid pump can be reduced.
An advantage of this concept is not only the possible shorter design of the liquid pump but also that the pressure compensation path has a longitudinal extension which is parallel to the direction of movement of the piston-armature component. Therefore, an overflow of liquid from the one armature side to the other armature side is flow-optimized, with the reduction of turbulence, which in turn results in a reduction of the overflow of liquid from one armature space side to the other required energy. For the operation of such a liquid pump therefore less energy is consumed at the same capacity as in a conventional liquid pump of the type mentioned. Thus, the restoring compression spring needs to be equipped only with a correspondingly lower restoring force, which is why then the cylindrical coil unit can be made smaller.
According to one embodiment, it is provided that the inlet channel within the armature has a diameter which is greater than the outer diameter of the piston and that the pressure compensation is designed as one or more, the piston-side end face of the armature by cross-bore. It is provided that the at least one executed parallel to the longitudinal axis of the piston-armature component bore is arranged in a radial arrangement with respect to the outside of the piston that it opens into the inlet channel section of the armature. In the case of several holes, these are typically arranged at the same angular distance from each other, enclosing the piston.
According to a further embodiment, the pressure balance, for example in the form of multiple channels, passes through the armature in the longitudinal axial direction. Preferably, the channels are arranged at a distance from the outer lateral surface of the armature. It has been shown that then no loss of control of the armature by the magnetic field of the electric solenoid must be accepted.
The above-described concept of provided with respect to their longitudinal axis parallel to the swing axis of the piston-armature component pressure compensation capability allows the formation of piston-armature components, which are designed as composite components in particular extent. In such a design, the armature may be formed by a pipe section, which makes a machining required in conventional piston-armature components at least largely superfluous. It also goes along with this concept that ultimately no or only little material waste arises. Preferably, one will provide the inner wall of the inlet channel section of the armature cylindrical, so that they do not have to be processed an additional processing step to produce certain geometries. The piston as another piece of pipe, typically made of another, especially cheaper material engages with a portion - a connecting portion - in the inner channel of the armature and is fixed therein, for which purpose preferably a clamping member is used. Such a clamping member can be formed as a slotted polygonal tubular body, in the inner channel of the connecting portion of the piston is received and in turn is pressed into the inner channel of the armature and held therein frictionally engaged. The polygonal configuration of the tubular tubular body is not only useful for concentrating the clamping forces between the clamping member and the inner wall of the armature on the edges, but due to the geometry differences between the clamping member and the inner channel of the armature form the non-filled by the clamping member cross-sectional areas of the round cross-section anchor channel at the same time the desired pressure equalization. Likewise, pressure equalization paths are formed between the clamping member and the connecting portion of the piston.
Further advantages and embodiments of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. Show it:
1 FIG. 3: a longitudinal section through a liquid pump designed as an oscillating piston pump, FIG.
2 FIG. 2 shows a longitudinal section through a piston-armature component according to a further embodiment for an oscillating piston pump, FIG.
2a : An end view of the piston-armature component of 2 .
3 a longitudinal section through a piston-armature component in principle corresponding to that of 2 in an alternative embodiment and
3a : A perspective view of the piston-armature component of 3 ,
A liquid pump operating on the oscillating piston principle 1 , also known as a solenoid pump, has a cylinder 2 who has a pump room 3 surrounds. The pump room 3 is the output side through an output hole 4 limited in the ground 5 of the cylinder 2 is introduced. To the ground 5 is from the pump room 3 groundbreaking a connection socket 6 Molded in the initial hole 4 empties. This has an internal thread for connecting a pressure line. From the inlet side reaches into the pump room 3 a piston 7 one. This is formed in the illustrated embodiment to an anchor 8th , The piston 7 and anchor 8th existing component is made of a ferromagnetic material in stainless steel quality. This component passes through an inlet channel 9 , wherein a first inflow channel section 10 the anchor 8th and the adjoining inlet channel section 10.1 the piston 7 assigned. In the illustrated embodiment, the inner diameter of the channel section 10 larger than the outer diameter of the inlet channel section 10.1 of the piston 7 , In the out of pistons 7 and anchor 8th existing component are in the piston-side end face 11 of the anchor 8th three circumferentially distributed and introduced at equal angular distance from each other arranged pressure equalization holes through which the piston side of the armature 8th with its inflow side - with the inflow channel section 10.1 - connected is. Due to the sectional view are in 1 only two of the three pressure equalization holes 12 . 12.1 recognizable.
This in 1 shown piston-armature component shows such according to a first embodiment, a Druckausgangswegsamkeit between the piston side of the armature 8th and its inlet side. The inlet side of the anchor 8th is in this embodiment, the inlet channel section 10.1 , The longitudinal axes of the pressure compensation openings 12 . 12.1 extend parallel to the swing axis of the component. Arranged are the openings 12 . 12.1 radially immediately adjacent to the outer surface of the piston 7 , The diameter of the inlet channel section 10.1 is larger than the outer diameter of the piston 7 , Therefore, the pressure equalization openings open 12 . 12.1 with parallel alignment in the inlet channel section 10.1 ,
The outer surface of the piston 7 is to form a labyrinth seal against the inside of the cylinder 2 sealed. This is realized by a very narrow gap between these two longitudinally axially movable components. This is between the outer wall of the piston 7 and the inner wall of the cylinder 2 no additional seal necessary. This also requires that the piston 7 in its oscillatory motion within the pumping space 3 easy running. The piston-armature component is moved into the cylinder with respect to its oscillating motion 2 led engaging piston section. Due to the above-described seal tumbling movements of the piston-armature component are avoided.
The anchor 8th is located in an anchor housing 13 that in the illustrated embodiment of the cylinder 2 is formed. In the of the anchor housing 3 enclosed space - the armature space - is located on the inlet side a compression spring 14 as a return spring, with its one end attached to the anchor 8th and with its other end at a bottom ledge 15 a pump housing 16 supported. The ground projection 15 goes on inlet side into a connecting piece 17 over, on which a supply hose (not shown) comes to sit. The inlet hose is connected to a water supply. Due to the above-described leadership between piston-armature component and the cylinder 2 . by which a tumbling motion is avoided or at least as good as avoided, the necessary movement gap between the outer surface of the armature 8th and the inside of the anchor housing 13 be very tight.
In the piston-side part of the armature space is a damper spring 18 accommodated. This is between an outside of the cylinder 2 molded flange 19 and the face 11 held.
On the anchor housing 13 an electric cylinder coil unit is pushed. The cylindrical coil unit is designed and designed so that a periodic magnetic field can be generated by this. If a magnetic field is generated, this becomes the anchor 8th against the force of the compression spring 14 moved and thus the piston 7 increasing the volume of the pumping chamber from the cylinder 2 pulled out. If the magnetic field is interrupted, presses in the compression spring 14 stored energy the anchor 8th and with it the piston 7 back in her in 1 shown position. To generate the periodic magnetic field of the coil unit is associated with a diode and connected so that the magnetic field is generated only at one of the two AC voltage polarities. In this way, the piston-armature component oscillates in the longitudinal axial direction with respect to the longitudinal axis of the cylinder 2 and the armature space in the frequency of the AC voltage.
So as a result of the oscillating movement of the piston 7 Liquid is conveyed, from the inlet side of the pump 1 to the outlet side, is the piston 7 at his in the pump room 3 protruding end with a springless one-way valve as an inlet valve 21 fitted. This opens when the piston 7 is moved in the direction of the inlet side. In the reverse direction of movement towards the ground 5 of the cylinder 2 The valve closes 21 , In the starting hole 4 is a second spring-less one-way valve as an outlet valve 22 used. Both valves 21 . 22 are identical in the illustrated embodiment.
2 shows a further embodiment of a piston-armature component 23 , which is designed as a composite component. In this embodiment, the anchor 24 a piece of pipe made of a ferromagnetic material in stainless steel quality. The anchor 24 is cylindrical, as seen from the view of the component 23 in the 2a recognizable. Thus, the anchor can 24 be made as a pipe section. The piston 25 is also a metal pipe section. The piston 25 is shown without the one-valve inlet valve associated therewith. Visible is inside the piston 25 the introduced in his dipping into the cylinder end portion in the inner wall groove 26 , in which the inlet valve is held clamped. The piston 25 is with the interposition of a clamping member 27 with the anchor 24 connected, wherein the clamping member 27 and the piston 25 in the inner channel 28 pushed the anchor and are clamped therein. At the clamping member 27 it is in the illustrated embodiment is a slotted square tube piece (see 2a ). This distinguishes the cross-sectional geometry of the clamping member 27 from the circular cross-sectional geometry of the piston 25 and the inner channel 28 of the anchor 24 , The clamping member 27 is slotted to apply the desired clamping force. The piston 25 is in the clamping member with a connecting portion 29 held frictionally. The polygonal design of the clamping member 27 , wherein in the illustrated embodiment, a quadrangular (square) cross-sectional shape has been selected, serves the purpose that by the clamping member 27 not the entire inner channel cross-sectional area is filled. In this way, four transfer channels remain 30 between the inner wall of the anchor 24 and the outside of the clamping member 27 , Because the clamping member 27 the illustrated embodiment in total by the anchor 24 extends underneath, also extend the transfer channels 30 through the anchor 24 therethrough. It is understood that to hold the piston 25 the clamping member 27 even shorter could have been designed. In the illustrated embodiment, the clamping member occurs 27 on both ends of the anchor 24 above this. These protruding portions serve to hold a return spring on the one hand and a damping spring on the other hand.
Likewise, also remain between the outside of the piston 25 and the inside of the clamping member 27 as well as within the slot pathways that serve the same purpose as the overflow channels 30 ,
During the oscillating movement of the piston-armature component 23 during operation of the liquid pump in which this component 23 is installed, liquid from the one anchor side unhindered on the above Durchströmungswegsamkeiten, in particular provided by the overflow 30 from one side of the anchor space to the other. The orientation of these pathways to the longitudinal axis of the axis of movement of the piston-armature component 23 allows pressure equalization by overflow of liquid only in the axis of movement. The same also applies to the piston-armature component of the liquid pump 1 , This explains why less energy has to be expended for forcing fluid through this overflow pathway with comparatively equal cross-sectional area.
3 shows a piston-armature component 23.1 , which is basically constructed like the piston-armature component 23 , The piston-armature component 23.1 differs from the component 23 only in that the clamping member 27.1 further away from the anchor on the piston side 24.1 protrudes. The connecting section 29.1 of the piston 25.1 ultimately does not penetrate into the interior of the anchor 24.1 one. The front view of the piston-armature component 23.1 corresponds to the in 2a to the component 23 shown. 3a shows the piston-armature component 23.1 in a perspective view.
The invention has been described with reference to embodiments. Without departing from the scope of the applicable claims, numerous other embodiments for a person skilled in the art will be able to realize the invention without this having to be explicitly explained in the context of these embodiments.
LIST OF REFERENCE NUMBERS
- liquid pump
- pump chamber
- exit bore
- inlet channel
- 10, 10.1
- Inlet channel section
- 12, 12.1
- Pressure equalization port
- armature housing
- compression spring
- bottom projection
- pump housing
- damping spring
- Solenoid assembly
- 21, 21.1
- intake valve
- outlet valve
- 23, 23.1
- Piston-anchor component
- 24, 24.1
- 25, 25.1
- 27, 27.1
- clamping member
- internal channel
- 29, 29.1
- connecting portion
QUOTES INCLUDE IN THE DESCRIPTION
This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
Cited patent literature
- EP 1818538 B1 
- EP 0288216 B1 
- DE 202005006584 U1