EP2310685B1

EP2310685B1 - Priming device for electric pumps

Info

Publication number: EP2310685B1
Application number: EP09804570.1A
Authority: EP
Inventors: Francesco Sinico
Original assignee: DAB Pumps SpA
Current assignee: DAB Pumps SpA
Priority date: 2008-08-08
Filing date: 2009-08-05
Publication date: 2016-03-30
Anticipated expiration: 2029-08-05
Also published as: ES2572205T3; IT1391670B1; CN102112749A; EP2310685A1; ITPD20080249A1; WO2010015650A1

Description

Technical Field

The present invention relates to a priming device for electric pumps.

Background Art

Electric pumps, and in particular centrifugal electric pumps, such as for example self-priming electric pumps, are particularly suitable for the supply of water in domestic systems, small-scale farming, gardening and in general where it is necessary to move liquids.
Self-priming is the ability of a pump to draw liquid into the intake duct during the start-up of the pump, if such pump is located under a head.
In order to achieve this, it is generally necessary to first fill the pump body with liquid to be pumped.
All self-priming pumps are capable of generating a partial vacuum that is sufficient to ensure, during the pumping step, correct operation of the pump.
A one-way valve incorporated within the pump body prevents the emptying of the pump body when the pump stops, allowing quick priming when the pump restarts.
The ability to self-prime allows to use these pumps without filling the intake duct.
Such electric centrifugal pumps often have malfunctions due to lack of skill on the part of the user, who fails to fill beforehand, due to forgetfulness or because he is not aware of the correct operation of the electric pump, the pump body with a certain amount of liquid to be pumped.
This negligence entails the dry running of the electric pump, with consequent damage of its seals, which are generally lubricated by the transferred liquid itself.
At the same time, the absence of liquid in the pump body does not allow the occurrence of the turbulence that is needed in order to generate the partial vacuum required to lift the liquid from outside the pump into the inside of the pump body, and substantially the electric pump fails to pump liquid, with dissatisfaction and discontent of the user.
An example of priming device for a pump corresponding to the preamble of claim 1 is available from US 3,558,012 .

Disclosure of the Invention

The aim of the present invention is to provide a priming device for electric pumps that can obviate the drawbacks of known types of electric pump.
Within this aim, an object of the present invention is to provide a priming device that ensures correct starting of the electric pump with which it is associated even if the pump body is not filled initially by the user.
Another object of the present invention is to provide a priming device that does not compromise the performance of the electric pump with which it is associated.
Another object of the invention is to provide a priming device that can be applied with equal advantages to centrifugal pumps and electric pumps and also to pumps of other types.
Another object of the present invention is to provide a priming device for electric pumps that can be manufactured with known systems and technologies.
This aim and these and other objects, which will become better apparent hereireafter, are achieved by a priming device for electric pumps, according to the present invention, that has the features set forth: in claim 1.

Brief Description of the drawings

Further characteristics and advantages of the invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic side view of a self-priming centrifugal electric pump on which a priming device according to the invention is fitted;
Figure 2 is a sectional view of a detail of the device according to the invention;
Figure 3 is a view of the device according to the invention applied to a horizontal centrifugal electric pump;
Figure 4 is a view of the device according to the invention applied to a vertical centrifugal electric pump;
Figure 5 is a view of the device according to the invention, organized in a kit and applied to a delivery duct of a generic pump.

Ways of carrying out the Invention

With reference to the figures, a priming device for electric pumps according to the invention is generally designated by the reference numeral 10.
The priming device 10 is shown, by way of example, in Figure 1 fitted on a centrifugal electric pump 11 of the self-priming type, but it must be understood that it can be also fitted on an electric pump of another type.
The priming device 10 according to the invention comprises means for the automatic filling of a pump body 12 at startup with liquid that originates from a same basin 13 from which the electric pump 11 is designed to aspirate in the steady state.
The device 10 also comprises an electronic controller 14 for the coordinated management of the power-on and power-off of such automatic filling means and of an electric motor 15 of the electric pump 11, and level sensor means, described in greater detail hereinafter, which are associated with the pump body 12 and are interconnected to the electronic controller 14 in order to detect the level of liquid inside the pump body 12.
Such automatic filling means are constituted, in the embodiment of the invention described here by way of non-limiting example of the invention, by a vacuum pump 16, which is adapted to draw air from inside the pump body 12 of the electric pump 11 by means of a suction tube 17 and by way of the interposition of an automatic vent 18 of a per se known type, which is fixed to the upper part of the pump body 12.
The automatic vent 18 has, inside a cup-shaped body 19 with a lower port 20 to be screwed onto a corresponding collar 21 formed on the pump body 12, a float 22.
The float 22 is coupled to a cover 23 for closing the cup-shaped body 19 by means of an arm 24, to which it is pivoted; the arm 24 in turn is pivoted to the cover 23.
The arm 24 supports a needle plug 25, which blocks or opens an intake hole 26 formed in the cover 23 and to which the suction tube 17 is connected, according to the rising or descending motion of the float 22.
The level sensing means are constituted by a magnet 27, which is integrated within the float 22 and faces a position or displacement sensor 28, for example a Reed bulb, which is arranged outside the cup-shaped body 19 of the vent 18.
The movement of the magnet 27 of the float 22 is detected by the displacement sensor 28, which is connected to the controller 14.
The electronic controller 14 and the vacuum pump 16 are enclosed in an enclosure 29 that protects them.
At the inlet of a delivery duct 30 there is a check valve 31, which allows the vacuum pump 16 to generate the partial vacuum that is necessary without the risk of drawing air from the delivery duct 30.
The operation of the priming device 10 according to the invention is as follows.
When first starting the electric pump 11, the electronic controller 14, by means of the position or displacement sensor 28, detects whether the pump body 12 contains liquid to be pumped in a quantity that is sufficient for correct starting.
If the level of the liquid in the pump body 12 is lower than the preset level, the controller 14 switches on the vacuum pump 16, so that it draws air from a rising duct 32 and from the pump body 12 until it entrains liquid from the basin 13 in such an amount as to fill adequately the pump body 12; in the meantime, the impeller of the electric pump 11 is kept stationary.
When the float 22 of the vent 18 rises, pushed by the liquid, the sensor magnet 28 moves upward and the electronic controller 14 detects, by means of the sensor 28, whether the correct level of liquid within the pump body 12 has been reached, while at the same time the movement of the arm 24 blocks the hole 26 with the needle plug 25.
The controller 14 deactivates the vacuum pump 16 and starts the electric motor 15 to turn the impeller and start actual pumping.
In Figure 3, the device 10 according to the invention is shown installed on a horizontal centrifugal electric pump 111.
In Figure 4, the device 10 according to the invention is shown installed at the upper end of the pump body 212 of a vertical centrifugal electric pump 211, for example of the multistage type.
The priming device 10 according to the invention can be applied easily as a kit to pumps and electric pumps of a known type and already in use, as exemplified in Figure 5.
Figure 5 illustrates a generic delivery duct 330, which exits from a pump body and on which, downstream of the check valve, a pipe is coupled for connection to the automatic vent 18, which is connected to the vacuum pump 16 and is interconnected with the electronic controller 14 by interposition of the position or displacement sensor 28.
The kit exemplified in Figure 5 is completed by a containment and protection enclosure 333, which contain the various elements of the device 10 and is crossed by the delivery duct 330, which is conveniently surrounded by hermetic sealing rings 334.
In practice it has been found that the invention thus described achieves the intended aim and objects.
In particular, the present invention provides a priming device for an electric pump that can ensure correct starting of the electric pump with which it is associated, by way of the vacuum pump or other equivalent means, even if the pump body itself is not filled initially by the user.
Moreover, the present invention provides a priming device for an electric pump that does not compromise the performance of the electric pump with which it is associated.
Further, the invention provides a priming device for electric pumps which makes the electric pump with which it is associated safe and free from risks of early wear due to incorrect starting while the pump body has no liquid inside it.
Moreover, the invention provides a priming device which, by obviating any distractions and negligence of a user, does not cause discontent in such user, making the pump with which it is associated always operational.
Further, the invention provides a priming device which can be applied to electric pumps of the centrifugal type, self-priming or not, but also to other electric pumps which are not centrifugal and are similar and equivalent.
Moreover, the present invention provides a priming device for electric pumps that can be manufactured with known systems and technologies.
The invention thus conceived is susceptible of numerous modifications and variations if within the scope of the appended claims.
In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. PD2008A000249 from the basis from which this application claims priority.
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 interpretation of each element identified by way of example by such reference signs.

Claims

A priming device (10) for electric pumps (11), comprising :
- means for the automatic filling of a pump body (12), upon starting, with liquid that originates from a same basin (13) from which the electric pump (11) is designed to draw when it is in the steady-state condition, said automatic filling means being constituted by a vacuum pump (16) that is adapted to draw the air from the inside of the pump body (12) by means of a suction duct (17),

- an electronic controller (14) for the coordinated management of the power-on and power-off of said automatic filling means and of the electric motor (15) of the electric pump (11), and

- level sensor means, to be associated with the pump body (12) and interconnected with said electronic controller (14), in order to detect the level of liquid inside said pump body (12),
characterized in that it further comprises an automatic vent (18) having a float (22), said vacuum pump (16) being adapted to draw air from the inside of the pump body (12) by way of the interposition of said automatic vent (18) fixed to the upper part of the pump body (12), said level sensor means being constituted by a magnet (27) that is integrated in said float (22) and faces a position or displacement sensor (28), for example a Reed bulb, which is arranged outside the cup-shaped body (19) of the automatic vent (18).
The device according to claim 1, characterized in that said electronic controller (14) and said vacuum pump (16) are enclosed in an enclosure (29).
The device according to claims 1 or 2, characterized in that at the inlet of the liquid delivery duct (30) exiting from the pump body (12) there is a check valve (31) that allows the vacuum pump (16) to generate the necessary negative pressure without the risk of drawing air from said delivery duct (30).
A method for operating the priming device (10) as claimed in one or more of the preceding claims that is provided with an automatic vent (18) having a float (22) and being fixed to the upper part of the pump body (12), interposed between the vacuum pump (16) and the pump body (12) and with level sensor means constituted by a magnet (27) that is integrated in said float (22) and faces a position or displacement sensor (28) which is arranged outside the cup-shaped body (19) of the automatic vent (18), wherein said electronic controller (14) performs the following operations:
- at first startup of the electric pump (11), by way of the level sensor means (27,28) of the liquid within the pump body (12), the electronic controller (14) detects whether said pump body (12) contains liquid to be pumped in a quantity that is sufficient for correct startup,

- if the level sensor means (27, 28) indicate that the liquid is at the preset level, then said controller (14) does not activate the automatic filling means constituted by the vacuum pump (16) and activates the electric motor (15) of the impeller,

- if the level of the liquid in the pump body (12) is lower than the preset level, then it- the level sensor means (27, 28) activates said vacuum pump (16), so that it draws air from the pump body (12) until it entrains liquid from the basin (13) in such a quantity as to fill adequately the pump body (12) itself, while the impeller of the electric pump (11) is kept stationary,

- if the level sensor means (27, 28) detect that the correct level of liquid has been reached inside the pump body (12), the controller (14) deactivates the vacuum pump (16) and starts the electric motor (15) to turn the impeller and to start actual pumping.
An electric pump, characterized in that it comprises a priming device (10) for electric pumps (11) as set forth in any of the claims 1-3.