EP3339648B1

EP3339648B1 - Liquid pump with a priming air pump and, between the two pumps, a float actuated valve

Info

Publication number: EP3339648B1
Application number: EP17208932.8A
Authority: EP
Inventors: Sam SPEIJERS
Original assignee: Altop Patents Ii BV
Current assignee: Altop Patents Ii BV
Priority date: 2016-12-21
Filing date: 2017-12-20
Publication date: 2019-07-24
Anticipated expiration: 2037-12-20
Also published as: PT3339648T; ES2752231T3; DK3339648T3; EP3339648A1; NL2018034B1; PL3339648T3

Description

The present invention relates to a pump system according to the preamble of claim 1.
Pump systems comprising a non-self-starting type of pump, such as centrifugal pumps, have a so-termed eye which should be below the level of the liquid medium in a respective pump housing in order to be able to pump the medium. If the eye becomes uncovered by liquid medium, such a pump cannot autonomously draw in new medium and consequently the pump stops operating. To preclude this, the pump system is provided with an air-suction pump or vacuum pump which drains air from the surroundings of the eye and draws in medium. Such an air-suction pump, however, is not water resistant.
US-4 029 438 A discloses a pump system in accordance with the preamble of claim 1. It further describes the member being a flexible valve member one side of which is movable, either by being pushed against the air holes to close them or by being pulled from the air holes, which are provided in a flat valve plate positioned in between the hollow -vacuum- body and the float -housing- chamber.
It is an object of the present invention to provide a level regulator and air separator which not only enables a non-self-starting pump to draw in medium in sufficient quantity, in a low maintenance and reliable manner, but which also ensures that water cannot reach the air-suction pump.
To achieve this, the pump system according to the invention is characterized in that the hollow body is a box-shaped body comprising a plurality of flat walls having the air holes, and in that the member is designed such that the air holes of at least two of said flat walls can be closed or opened simultaneously.
An advantage of the pump system according to the invention resides in that the float moving up and down with the level of the liquid medium provides a reliable indication of the instantaneous level of the medium in the float chamber. Dependent upon the level, which may change rapidly under certain conditions, air holes in the hollow body, allowing air from the pump housing in which the eye is present to enter the air-suction pump, are closed or opened. This results in an instantaneous control mechanism which ensures that when the air holes close, the eye is covered by water, but the water does not reach the air-suction pump, and that when the air holes open, air is drawn from the pump head so that the eye can see sufficient medium to enable the pump to start pumping.
In the pump system according to the invention the member can be moved over the air holes in two or more of the walls in order to open or close them simultaneously, thereby advantageously combining sufficient speed and a low air resistance.
An embodiment of the pump system according to the invention is characterized in that the movable member is an at least partially elastic member, in particular a curtain, which can move or roll over the air holes.
An advantage of the use of an elastic member or curtain resides in that it can be readily pulled over the air holes to close or open air holes in the two or more walls. By means of a rolling curtain, said closing or opening operation can be performed by rolling, which requires little effort, and which enhances the accuracy and reproducibility.
Another embodiment of the pump system according to the invention is characterized in that the movable member is substantially in one of two positions, in which all air holes are closed or open, when the pump system is in operation.
This has the advantage that a regulation is obtained which is characterized by a rapid on/off regulation of the vacuum of the air-suction pump.
A special embodiment of the pump system according to the invention is characterized in that the diameters of the air holes are related to the position of the movable member along the at least one wall of the body, in particular in such a manner that the movement of the movable member extends over first and second air holes, and in that the diameters of at least part of the first air holes are smaller than those of the second air holes.
This embodiment has the advantage that, if the movable member starts to move, i.e., when the movable hollow body is under considerable reduced pressure, the air holes open in such a manner that the small air holes open first. Advantageously this requires comparatively little opening force; briefly put: the movable body does not adhere to the air holes. Subsequently, the opening of the remaining, larger air holes during further movement of the member, at a gradually decreasing underpressure in the hollow body, advantageously requires less effort and little time.
Yet another embodiment of the pump system according to the invention is characterized in that the level regulator is provided with a mass and/or spring and/or damper arranged between the float and the movable, possibly elastic, member.
By means of this, it is advantageously possible to limit the movements of the float caused by the passing water. By virtue thereof, a flexible regulation and water flow, without cavitation, in the respective pump is achieved, even if the medium contains gases.
Further detailed, possible embodiments, which are set forth in the remaining claims, are mentioned together with the associated advantages in the following description.
The pump system according to the present invention will now be explained in greater detail with reference to the figures mentioned below, in which corresponding parts are indicated by means of the same reference numerals.
In the figures:

Figure 1 is a diagrammatic sectional view of a pump system according to the invention;
Figure 2 shows the level regulator applicable in the system shown in figure 1; and
Figure 3 shows a detail of a rolling curtain applicable in the level regulator shown in figure 2.

Figure 1 shows a pump system 1 comprising an inlet 2 for a liquid medium to be pumped, such as water containing or not containing air or gas, and an outlet 3. Such a pump system 1 can be used, for example but not exclusively, as a drainage pump or as a pump for, inter alia, well point dewatering. Between the inlet 2 and the outlet 3 there is a pump head 4 which accommodates a rotor blade 5 of a pump 6 of the non-self-starting type, such as a centrifugal pump. The rotor blade 5 has an eye 7 which should be below the level of the liquid, so that the pump 6 itself starts to pump the liquid, by means of the rotating rotor blade 5, to the delivery side which is provided with a non-return valve 8 and which opens into the outlet 3.
A level regulator 9 having a top connection for an air-suction pump 10 is connected to the pump head 4. In the manner described hereinafter, the level regulator 9 makes sure that any water available at the inlet 2 is drawn into the pump head 4 being under reduced pressure by the air suction pump 10 while the non-return valve 8 is usually automatically in a closed state then. By virtue thereof, the liquid level at the eye 7 is sufficient to enable the pump 6 to self start.
The level regulator 9 is provided with a float chamber 11 for collecting, in said float chamber, air and/or medium from the pump head 4, and with a float 12 which floats on the medium and which contains a measure of the level of the medium in the float chamber 11.
Furthermore, the level regulator 9 shown in figure 2 comprises a hollow body 13 which is connected to the air suction pump 10 and which has two or, if necessary, more walls 14 which are each provided with air holes 15 for passing air which is drawn from the space above the level of the medium in the float chamber 11 and which is drained via holes 15 in the hollow body 13 by the suction pump 10. In practice, holes 15 of certain dimensions in more than two of the walls 14 will be used in particular when required due to the relation between the air passage through the holes 15, the power of the vacuum pump and the volume of medium to be passed through the pipes. Briefly put: larger air holes 15 in a plurality of walls 14 at larger powers and a larger water displacement.
The level regulator 9 also comprises a member 16 which is adequately coupled to the float 12 and which can be moved over the air holes 15 along the outside of the two or more walls 14, said member being capable of closing or opening the passage of air through the holes 15. As a result, via the float 12 to which it is connected, said member 16 moves up and down, in principle without any additional means being required, with the comparatively non-turbulent medium level in the float chamber 11. If necessary, the level regulator 9 may be provided with a mass and/or spring and/or damper - diagrammatically indicated by means of the letter D- arranged between the float 12 and the movable member 16. By virtue thereof, the manner in which the member 16 dynamically moves up and down with the level of the medium can be set, for example dependent upon the viscosity of the medium, the flow behaviour in situ and/or the sand grain content or the presence of gases or air bubbles in the medium.
The operation of the pump system 1 is such that if there is hardly any water at the inlet 2, the float 12 is located at the bottom of the float chamber 11 and the member 16 leaves all air holes open, as a result of which the air-suction pump 10 draws air from the inlet 2 through all air holes. If the air entrains medium from the inlet 2, the pump head 4 and subsequently the float chamber 11 are filled, causing the float 12 and hence the movable member 16 to move upwards and the air holes 15 to be closed. As a result, air is no longer drawn from the float chamber 11, but the pump 6 starts by itself and pumps medium to the outlet 3 through the non-return valve 8. This continues until the supply of medium through the inlet 2 is insufficient, as a result of which the level in the float chamber 11 falls and the air-suction pump 10 again causes an underpressure of air in the pump head 4 for the purpose of drawing in new medium.
The movable member 16 preferably can be at least partly moved elastically over the air holes 15 to be opened and/or closed. Such a member 16, which is made from a suitable lightweight synthetic resin or, for example, rubber, has been found to be fast, reliable and durable, but also, in particular, it has proved to be low-maintenance in comparison with the member according to the state of the art, which has a favourable effect on the cost price. The movable member 16 may be a simple curtain, such as a rolling curtain, roller blind, pleated curtain, or it may be provided with movable blinds.
Figure 3 shows a detailed view of a movable member 13, being a roller blind 16. Such a roller blind is favourable if it rolls along the outside of one or more flat walls 14 of the hollow body 13 and over the air holes 15, in which case the body 13 is preferably box or cube-shaped, because then the curtain 16 can roll well along one or more walls 14 to open or close the holes 15. As shown in figure 3, the curtain 16 may be movable between longitudinal guides 16-1, which are provided with flexible curtain material on either side. Between said longitudinal guides, the curtain material moves up and down with the float 12.
In practice, if the pump system 1 is in operation, the movement of the member 16 will be such that it is mainly in one of two positions. In one position all air holes 15 are open and in the other position all air holes are closed.
Calculations reveal that in dependence on the cross-section and number of the air holes 15, at an underpressure of 1 atmosphere generated by the air pump 10, considerable forces may occur which could hamper the opening of comparatively larger air holes 15. This can be overcome by arranging the air holes 15 according to a certain pattern in the walls 14 of the hollow body 13, so that, for example, when they are gradually opened, an increasing number of air holes 15 are being opened. It is also possible that the diameters of the air holes 15 are related to the position of the movable member 16 along the wall or walls 14 along which the member moves. Based on the insights gained, in figure 3 an embodiment is shown comprising a rolling curtain 16 whose movement extends over first holes 15-1 and second holes 15-2, and wherein the diameters of at least part of the first air holes 15-1 are smaller than those of the second air holes 15-2. By having the descending member 16 open the said part of the first air holes 15-1 having smaller diameters first when the air holes 15 are opening, the occurrence of too large adhesive forces between the usually elastic member 16 and the holes 15 behind which there is an underpressure is precluded. By virtue thereof, a small force is needed initially to rapidly open the curtain 16. If, when the curtain 16 descends further, a number of holes are open already, the underpressure in the float chamber 11 decreases, as a result of which also the larger holes can be opened more easily, leading to a rapid reduction of the pressure in the float chamber 11. As shown in figure 3, in this embodiment, the first small holes 15-1 are located higher in the wall 14 than the second air holes 15-2.
In practice, it has been found that, when opening initially the small air holes 15-1, it is important to make use of two or more walls 14 provided with air holes, along which the member 16 moves downwards initially as shown in figures 2 and 3. By virtue thereof, the controllability of the member 16 used for opening the air holes 15-1 is improved. As use is made of a box-shaped body 13 having a plurality of flat walls 14, such as a cube, a type of bracket mechanism can be selected to enable the member 16 to move simultaneously along a plurality of parallel walls 14 of said body. Preferably, use is then made of a loose coupling between the float 12 and the member 16, enabling the movable member 16, particularly when the float 12 moves downwards, to move downwards at a lower rate, i.e., under the effect of its own weight, independently of the movement of the float. This leads to a still further improved controllability with respect to the opening of the air holes. When said movement is in the upward direction, a more fixed coupling D having the mass and/or spring and/or damper explained hereinabove can be used to close the air holes 15-2, 15-1. In that case the float 12 presses with an upward force against the curtain or member 16 as the case may be, possibly through the coupling D, which force equals the volume of the displaced medium times the specific mass.
The abovementioned opening process is a low=force and low-mass operation because the usually rubber member 16 is pulled downwards only by its own weight without accessories such as roll up systems. By virtue of the low self-weight, the floating power of the float 12 can be kept low. The embodiment then enables a plurality of air holes to be controlled simultaneously by means of a relatively low self-weight of bracket and movable member 16, leading to little influence on the interplay of forces resulting from the mass of water flowing through. The float 12 is less subject to friction when moving up and down with the liquid level, because a slide bearing on the upper side near the control member 16 can be dispensed with. Such a slide bearing causes variable friction, under the influence of forces exerted on the respective axle, which leads to changing friction resulting in variable reaction times and control errors. In this design, such an axle has been omitted as well as a fixed mechanical connection, in both opposite directions, between control member 16 and float 12. In this embodiment, the float 12 closes the control member 16, but the control member 16 opens on gravity force. As a result, the concomitant lateral forces on the bracket, that is exerted on the transverse guide and curtain axis of the member 16, shown in fig. 2, are minimal. The small holes 15-1 open first and if for example four holes having a diameter of 4 mm are being applied at an underpressure of max. 900 mBar than the closing force amounts approximately 450 gram. If thereafter the remaining holes open the underpressure decreases, as a result of which the remaining larger holes 15-2 open much more easily.
In controlling air flows (underpressure) to be withdrawn from the water, it has been found to be of primary importance that the air flow, which is created by the vacuum pump 10, is not hampered by the air separator explained hereinabove. This is because said air flow requires an air passage which is at least equal to that of the pump 10. An air pump having a 2-inch-diameter suction connection thus requires a surface area which is equal to or larger than the passage of the air separator. By virtue of the present solution, a very small increase in weight and a small bracket to move the air separator are sufficient to enable an increase in surface area of 300% to be easily achieved, resulting in a substantial increase of the control range of the air separator. In a way illustrated the total opening is always larger than the diameter of the connection of the air separator, and consequently the air separator does never constitute a barrier.

Claims

A pump system (1) comprising:
- a pump (6) which, to operate, requires a minimum level of liquid medium to be pumped in its pump head (4), and which comprises a non-return valve (8) on its delivery side (3), and

- a level regulator (9) which is connected to the pump head (4) and which has a connection for an air-suction pump (10), said level regulator (9) being provided with:
- a float chamber (11) in which air and/or medium from the pump head (4) is collected,

- a float (12) which moves up and down with the level of the medium in the float chamber (11),

- a hollow body (13) which, in operation, is connected to the air-suction pump (10), said hollow body (13) comprising at least one wall (14) which is flat and has air holes (15; 15-1, 15-2) between said hollow body (13) and the float chamber (11), and

- a member (16) which is coupled to the float (12) and which can be moved over the air holes (15; 15-1, 15-2) along the outside of the at least one wall (14), said member (16) being used to close or open the air holes (15; 15-1, 15-2),

characterized in that the hollow body is a box-shaped body (13) comprising a plurality of flat walls (14) having the air holes (15; 15-1, 15-2), and in that the member (16) is designed such that the air holes (15; 15-1, 15-2) of at least two of said flat walls (14) can be closed or opened simultaneously.
The pump system (1) according to claim 1, characterized in that the movable member (16) is an at least partially elastic member which can move over the air holes (15; 15-1, 15-2).
The pump system (1) according to claim 1 or 2, characterized in that the movable member (16) is a curtain, such as a rolling curtain, roller blind, pleated curtain, or it is provided with movable blinds.
The pump system (1) according to any one of claims 1 to 3, characterized in that the box-shaped body (13) is a cube, four walls (14) of which, forming oppositely located pairs, are provided with said air holes (15; 15-1, 15-2), and the member (16) is designed to simultaneously close or open the air holes (15; 15-1, 15-2) of the four flat walls (14).
The pump system (1) according to any one of claims 1 to 4, characterized in that the air holes (15; 15-1, 15-2) are arranged according to a pattern in the at least one wall (14) of the hollow body (13).
The pump system (1) according to any one of claims 1 to 5, characterized in that the movable member (16) is substantially in one of two positions, in which all air holes (15; 15-1, 15-2) are closed or open, when the pump system (1) is in operation.
The pump system (1) according to any one of claims 1 to 6, characterized in that the diameters of the air holes (15; 15-1, 15-2) are related to the position of the movable member (16) along the at least one wall (14) of the body (13) .
The pump system (1) according to any one of claims 1 to 7, characterized in that the movement of the movable member (16) extends over first (15-1) and second air holes (15-2), and in that the diameters of at least part of the first air holes (15-1) are smaller than those of the second air holes (15-2).
The pump system (1) according to claim 8, characterized in that when the air holes (15; 15-1, 15-2) open, the movable member (16) is in a position in which initially the abovementioned part of the first air holes (15-1) having a smaller diameter is exposed by the movable member (16).
The pump system (1) according to claim 8 or 9, characterized in that the first holes (15-1) in the wall (14) of the hollow body (13) situated in the upper part of the float chamber (11) are in a higher position than the second air holes (15-2).
The pump system (1) according to any one of claims 1 to 10, characterized in that the level regulator (9) is provided with a mass and/or spring and/or damper (D) arranged between the float (12) and the movable, possibly elastic, member (16).
The pump system (1) according to any one of claims 1 to 11, characterized in that the level regulator (9) is provided with a coupling (D) between the float (12) and the movable, possibly elastic, member (16), enabling said movable member (16), at least when the float (12) moves downwards, to move downwards independent of the movement of the float (12) and under the effect of its own weight.
The pump system (1) according to any one of claims 1 to 12, characterized in that the movable member (16) comprises rubber.