EP1775476A1

EP1775476A1 - Control device for motor pumps

Info

Publication number: EP1775476A1
Application number: EP05022404A
Authority: EP
Inventors: Alessio Pescaglini
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-10-13
Filing date: 2005-10-13
Publication date: 2007-04-18

Abstract

An automatic mechanical device, suitable for controlling the operation of an electric pump responsive to the flow and to the pressure within the device, comprising a hollow body (63) comprising an upper shell (40) and a lower shell (41), having an inlet (20) and an outlet (21). On the external surface of the upper shell (40) means responsive to the pressure (60) are connected comprising a first control body (1) pushed towards said hollow body (63) by a return spring (14). Said first control body (1) is operated by a membrane (16) located outside to the hollow body (63) and perceives the pressure of the liquid within the hollow body (63) through an opening engaged by a check valve (52) and a calibrated hole (53) that time a hydraulic delay of the pressure. The first control body (1) has a stepped protrusion (7) that operates a control sphere (8) that in turn operates a lever (9) having at the end a tip (11) capable to operate a tip (10) belonging to a second lever (12) that, rotating, is capable to operate a switch (13) that starts the pump. The device comprises means responsive to the flow, having a second control body (2) with function of check valve, having a magnet (3) that operates a magnet (4) pivotally connected outside, when the magnet (3) is approached to the magnet (4). The magnet (4) operates a lever (5) having an end (62) capable of pushing on the electric switch (13) that starts the pump.

Description

Field of the invention.

The present invention relates to the field of hydraulics and, in particular, it relates to an automatic mechanical device suitable for controlling the operation of an electric pump responsive to the flow and to the pressure within the device, which can be fixed to hydraulic installations.

Description of the prior art.

In case of hydraulic installations, for example for domestic applications, the need is felt of a device suitable for providing pressure to water ducts, in a way suitable to ensure the correct flow of water to the users, when required.
In order to accomplish this need, different devices are used, among which autoclave installations that are capable to control the pressure but are voluminous and require a separate arrangement.
Alternatively, a variety of types is used of devices for controlling pressure and flow in a pump, suitable for turning on/off an electric pump, arranged as a hollow body of small size next to the pump and through which the flow passes; however, it has the drawback of being completely assisted by an electronic circuit, in particular for blocking the operation in case of absence of water and for timing the delays of the system.
Moreover, the electronic circuit has a cost that is significant on the final cost of the device; in addition, it is used in places where the relative humidity can be even 90%, with negative effect on its correct operation, notwithstanding it is protected by a resin layer coating.

Summary of the invention

It is then a feature of the present invention to provide an automatic control device for pressure and flow of a liquid in a duct, capable of working without the aid of electronics for controlling the operation in case of absence of water and for timing the delays of the system.
It is another feature of the invention to provide a control device that is not expensive with respect to the known systems that have an electronic control.
Another feature of the invention is to provide a device capable of working for long also in strongly humid places.
It is still a feature of the invention to provide a mechanical device capable of measuring the lack of water in a duct and of communicating a corresponding signal to a motor pump.
Another object is to provide a device capable of starting a hydraulic pump responsive to the flow and to the pressure of the liquid that crosses the pump.
A further feature of the present invention is to provide a mechanical control device that has a minimum encumbrance.
These and other objects are achieved, according to the present invention, by a control device for an electric pump, comprising:

a hollow body with an inlet and an outlet, said inlet being connected to the delivery of the pump and said outlet being connected to a liquid consumption point;
means responsive to the pressure of said liquid in said hollow body;
means responsive to the flow in said hollow body between said inlet and said outlet;
means for turning on/off the electric supply to said pump;

said means responsive to the pressure comprises a first control body movable between a first position, when in said hollow body there is a maximum pressure, and a second position, when in said hollow body there is a minimum pressure,
said means responsive to the pressure engaging said means for turning on/off in at least one intermediate position between said first and second position and releasing said means for turning on/off both in said first and in said second position;
said means responsive to the flow comprising a second control body movable between a first position, when in said hollow body there is not presence of flow, and a second position, when in said hollow body there is a maximum flow, said means responsive to the flow engaging said means for turning on/off starting from an intermediate position between said first and second position up to said second position and disengaging the means for turning on/off in said first position.

This way, when the installation is to rest in a condition of zero flow and maximum pressure, i.e. in a condition where there is not a demand of liquid, said first control body is in said first position and also said second control body is in said first position, thus disengaging said means for turning on/off and then not operating the pump. When instead there is a demand of water, the pressure decreases and said first control body moves to an intermediate position engaging said means for turning on/off and then operating the pump. If the flow maintains at a minimum flow rate, for example less than 4 1/min, the second body remains in said first position, and the pump continues to operate until the pressure rises back to the maximum values. When the flow rate rises, also the second control body engages the means for turning on/off, since it moves to its intermediate position. The pump continues to work if the flow increases further and reaches a maximum flow rate, where the pressure decreases and said first control body is in said second position. Even said second control body, owing to the high flow, is in said second position and continues to engage the means for turning on/off maintaining the operation of the pump.
Such a device is also capable of turning off the pump in case of lack of water; in fact, in case of lack of water said first control body is in said second position and said second control body is in said first position. This way the motor pump is not supplied, since the means for turning on/off are disengaged.
Advantageously, said first control body comprises a piston sliding between two positions, said piston having an end connected to an element responsive to the pressure suitable for displacing said piston.
In particular, said piston comprises a stepped protrusion suitable for operating a body with circular cross section, in particular a sphere, movable perpendicularly to the sliding direction of the piston, said body with circular cross section acting on said means for turning on/off the electric supply to said pump.
This way, according to the axial position of the above described piston, said sphere assumes different positions along its path.
In a particular exemplary embodiment, said body with circular cross section acts on the end of a lever pivotally connected to said device, said lever acting on said means for turning on/off the electric supply to said pump.
In particular, said means responsive to the pressure comprises a resilient separating membrane arranged between the liquid contained in said hollow body and the outer environment.
In particular, said membrane is arranged near a wall of said hollow body creating a variable gap between said membrane and said wall, said wall having an opening that allows the liquid to pass from said gap to said hollow body and vice-versa.
In particular, said opening comprises:

a check valve that allows the passage from said hollow body to said gap;
a calibrated hole.

This way, as the pressure in the hollow body decreases, an amount of liquid quickly passes from the hollow body to the gap through the check valve activating the pump and, when the pressure, in the hollow body rises again, the same amount of liquid moves back beyond the membrane passing through the calibrated hole, taking a predetermined time and timing an hydraulic pressure delay.
This way, in the presence of a dripping or a flow very low at the consumption point, the risk is avoided that the pump turns quickly on and off, and the liquid achieves eventually the maximum pressure.
In a preferred exemplary embodiment, said first control body comprises pushing means, in particular a spring, suitable for pushing said control body towards said second position.
In particular, said first control body comprises a device for adjusting the forces applied by said spring to said piston.
In a preferred exemplary embodiment, said second control body of said means responsive to the flow comprises a stem integral to said second control body, arranged in said hollow body, suitable for engaging with said inlet of said hollow body and interrupting the flow when said second control body is located in said first position, said stem operating a flow control lever arranged out of said hollow body, and that is suitable for acting on said means for turning on/off, thus operating the pump.
Advantageously, said second control body comprises a first magnet integral to said body and located at an end opposite to said body with respect to said stem, said magnet being suitable for repelling a second magnet with the same polarity of said first magnet and aligned to said first magnet, said second magnet being arranged out of said hollow body and being suitable for operating a flow control lever that acts on said means for turning on/off, thus operating the pump.
Advantageously a resilient membrane is provided in said hollow body having a portion integral to said second control body, said membrane being suitable for dividing the inner volume of said hollow body into a upper chamber, which is in contact with said means responsive to the flow and the pressure, and a lower chamber, which is in contact with said inlet and said outlet of said hollow body.
Advantageously, means are provided for allowing a controlled passage of liquid through said membrane.
Advantageously, said upper chamber and said lower chamber are in communication with each other through said means for allowing a controlled passage of liquid comprising:

a check valve that allows the passage of an amount of liquid from said upper chamber to said lower chamber when said second control body moves from said first position to said second position;
a calibrated hole that allows a back flow of said amount of liquid from said lower chamber to said upper chamber in a predetermined time, when said second control body moves from said second position to said first position.

In particular, said check valve and said calibrated hole are applied to said flow control membrane.
This way, the flow of this amount of liquid through this calibrated hole is carried out in a predetermined time according to the geometry of the calibrated hole, decelerating the motion of the above described second control body and thus timing a hydraulic delay of the flow, so that in case of sudden block of the flow the second control body is not subject to a water hammer.
In an exemplary embodiment, said means for turning on/off the electric supply to said pump comprises an electric button suitable for turning off/on an electric supply circuit.

Brief description of the drawings.

The invention will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings wherein:

Figures from 1 to 5 represent diagrammatically a cross section of a device according to the invention, respectively in five different steps of the operation;
Figures 6 and 7 show respectively a top plan view and a side cross section of an exemplary embodiment of the device according to the invention.

Description of preferred exemplary embodiments.

The present invention relates to a control device for an electric pump, where the control comprises means responsive to the pressure and to the flow and is capable of turning on/off the electric supply to said pump according to the demands of pressure and flow.
Figures from 1 to 5 represent diagrammatically a cross section of a device according to the invention, respectively in five different steps of its operation.
Figure 1 shows diagrammatically the above described control device in a condition at rest and maximum pressure, ready to deliver liquid. This device, according to the invention, has a hollow body 19 with an inlet 20 connected to the delivery of an electric pump not shown in the figure and an outlet 21 connected to a liquid consumption point 35 shown with a blocking element 22, for example a hand-wheel tap. The device comprises means responsive to the pressure having a first control body 1 sliding along a direction and operated by a resilient membrane 16, located outside to said hollow body 19 as separation between a liquid present in hollow body 19 and the atmospheric pressure, said liquid reaching said membrane 16 through an opening 18 and creating a variable gap 30. This way, first control body 1 can move between a first position corresponding to a maximum pressure and a second position corresponding to a minimum pressure. In particular, in figure 1 a situation is shown of maximum pressure with the first body 1 in said first position. First control body 1 is pushed against the membrane 16 by a return spring 14, whose compression and then the force applied by the same to the body 1 is adjustable by a screw 15. This way, it is possible to set from outside and mechanically the value of the pressure below which the pump is active. The control body 1 comprises a stepped protrusion element 7, integral to the body same 1, this element 7 being suitable for operating a sphere 8 movable in a direction perpendicular to the sliding direction of the control body 1, and said sphere 8 operating in turn an elongated element 9 having a protruding tip 10 on a side. This protruding tip 10, according to its position relatively to another protruding tip 11 integral to a lever 12 hinged in a fixed point, can cause lever 12 to rotate up to bringing its free end to operate a switch 13 that blocks the electric supply circuit of the pump. Figure 1 describes the situation of rest at a maximum pressure, when lever 12 does not operate switch 13 and the supply circuit is open so that the pump is not supplied.
The device according to the invention comprises also means responsive to the flow having a second control body 2, sliding along the axis of inlet 20 between a first position of absence of flow, where the control body occlude inlet 20, and a second position, where the control body 2 is operated by a flow passing through said inlet. This second control body 2 comprises a flange 6 having O-rings not shown, creating, thus, a check valve that allows only an inlet flow and not an outlet flow. The control body 2 comprises a magnet 3 integral to the body same and connected to the end oriented towards the inside. The above described means responsive to the flow and to the pressure comprise also a lever 5, external to hollow body 19 and hinged in a fixed point, said lever 5 having a magnet 4 with the same polarity of magnet 3 and aligned to magnet 3, in such a way that when magnet 3 is approached to magnet 4, along with the second control body 2, a repelling magnetic force is created that tends to push magnet 4 away in order to operate lever 5 that acts on lever 12, which in turn blocks switch 13 for starting the pump. The second control body comprises a spring 25 suitable for pushing the control body 2 to the closed position. In the situation described the device is to rest at the maximum pressure, so the flow is missing being the pump not supplied.
The control device can comprise also mechanical means for timing an hydraulic delay of the pressure and of the flow, not shown in figure but described in figures 6 and 7. They have the object of decelerating the motion of the above described first control body 1 and of the second control body 2, to obtain a graduated variation of the motion of the liquid in the device and then a smooth operation.
Figure 2 shows a configuration of the device according to the invention in a point of pressure starter and following pump start in case of low flow rate. In this situation, the blocking element 22 has been just opened and the liquid starts to flow according to arrow 31, while the pump is still off. In this situation the pressure in hollow body 19 starts to decrease causing the control body 1 to approach hollow body 19 and bringing stepped element 7 to an intermediate position. In this configuration the sphere 8 is approached to the control body 1 and moves element 9 in order to cause the tips 10 and 11 to meet, in order to operate the electric pump. In case of low flow rate, for example less than four 1/min, the second control body moves, but not enough to move magnet 4 and the pump is kept turned on only through the pressure.
Figure 3 shows a configuration of the device during an operation at normal flow rate, during which the blocking element 22 is partially open. In this situation the control is effected by the flow, since the pump is activated by the presence of the flow same. In fact, second control body 2 is pushed by the flow towards the inside of hollow body 19, creating a magnetic repelling action on magnet 4 and pushing element 5 up to pushing lever 12, which keeps switch 13 closed and then keeps the pump on. The position of the first control body 1, in this case, is unimportant, since lever 12 is kept pressed against switch 13, whichever position elongated element 9 reaches responsive to the pressure.
Figure 4 shows a configuration of the device during the delivery of a liquid at a maximum flow rate. In this situation blocking element 20 is completely open, obtaining a minimum resistance against the flow. The pressure in the hollow body in case of high flow rate is low and close to atmospheric pressure, and first blocking element 1 is in its second position, corresponding to a minimum pressure. However, since the flow is high, it pushes second control body 2 towards the inside of hollow body 19, pushing magnet 4 and then closing switch 13 to supply the pump.
Figure 5 shows a configuration of the device during a block caused by lack of liquid in the device. In this situation first control body 1 is in its second position, because there is not liquid in hollow body 19 and the pressure is atmospheric. The flow through hollow body 19 is zero and then the second control body is in its first position. This way, neither element 5 nor element 9 do operate switch 13, and then the pump remains turned off or it is forced to block.
In order to bypass the blocked status of the device caused by lack of liquid, it is sufficient to open the electric supply circuit of the pump for a short time and then to close it again. This way, at the starting of the pump the device is pressurized again up to restoring the situation described in figure 1.
Figures 6 and 7 show respectively a top plan view and a side cross section of an exemplary embodiment of the device according to the invention. This device comprises a hollow body 63 consisting of an upper shell 40 and a lower shell 41, having an inlet 20 and an outlet 21. On the external surface of upper shell 40 means responsive to the pressure 60 are arranged comprising a first control body 1, for example a piston with axially symmetric shape and hollow inside to house a return spring 14, which is adapted to push said first control body 1 towards the inside of hollow body 63. Said first control body 1 can slide axially between a first position of maximum pressure and a second position of minimum pressure. The control body 1 is operated by the deformation of a membrane 16 located outside of hollow body 63 and have a first surface in contact with the liquid contained in the hollow body and a second surface at atmospheric pressure. The membrane 16 perceives the pressure of the liquid in the hollow body 63 through at least one opening, owing to the liquid passing through between the hollow body 63 and the membrane 16. In particular, in figure 6 two apertures are shown engaged by a check valve 52 and by a calibrated hole 53. This way, when the pressure increases an amount of liquid quickly passes through check valve 52, towards the surface of the membrane 16 thus deforming it elastically. When the pressure decreases, this amount moves back hollow body through the calibrated hole 53 in a predetermined time, decelerating the moving back of membrane 16 and then of first control body 1. Thus a hydraulic delay of the pressure is obtained.
First control body 1, during its motion between the first and the second position, in a similar way as described for figures 2 and 3, by a stepped protrusion 7 operates a control sphere 8 that in turn operates a lever 9 present on the upper part of first shell 40. Lever 9 has, at its end, a tip 11 capable to operate a tip 10 belonging to a second lever 12 that, by rotating, is capable to operate a switch 13 that starts the pump. The lever 9 has a return spring 46.
Furthermore, the device according to the invention comprises means responsive to the flow, having a second control body 2 with function of check valve, sliding along a direction between a first position of zero flow and a second position of maximum flow. The above described second control body 2, which for example has a substantially cylindrical shape and has an sealing 0-ring 46, may have at the lower end at least one cylindrical enlargement 42 with function of reference. In a similar way as described for figures 3 and 4, it has at the upper end a magnet 3, integral to the body 2 same. Out of upper shell 40 a magnet 4 is present, aligned with magnet 3, magnetized with the same polarity of magnet 3 in order to feel a repelling force when magnet 3 is approached to magnet 4. Magnet 4 is connected to a lever 5 that is operated when the magnetic repelling force of magnet 3 passes a threshold value. This lever has an end 62 capable of pushing on the free end of lever 12, thus operating switch 13. The above described means responsive to the flow comprises a resilient membrane 43, having its boundary connected to the plane of separation between the two shells 40 and 41, in order to divide the inner volume of the hollow body into a upper chamber 44 and a lower chamber 45, and the centre integral to the control body 2. On this membrane 43 a check valve 50 is present that allows the quick passage of an amount of liquid between upper chamber 44 and lower chamber 45 when the control body 2 moves towards the above. Furthermore, membrane 43 has a calibrated hole 51 that allows a back flow of the liquid in a predetermined time, thus creating a deceleration of the back movement of second control body 2 and then a protection from water hammer, in case of quick interruption of the flow.
The device according to the invention has a completely mechanical operation, even if it can comprise a standard electronics suitable for an output of data relative to the pump operation and for protection in case of block. This way, the electronics is enormously simpler, at the same time ensuring functions of protection in case of lack of water, starter of pressure, block in case of lack of flow, protection from water hammer and prevention from quick turning on/off of the pump in case of dripping.
The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

A control device for an electric pump, comprising:
- a hollow body with an inlet and an outlet, said inlet being connected to the delivery of the pump and said outlet being connected to a liquid consumption point;

- means responsive to the pressure of said liquid in said hollow body;

- means responsive to the flow in said hollow body between said inlet and said outlet;

- means for turning on/off the electric supply to said pump,
characterised in that:
said means responsive to the pressure comprises a first control body movable between a first position, when in said hollow body there is a maximum pressure, and a second position, when in said hollow body there is a minimum pressure,

said means responsive to the pressure engaging said means for turning on/off in at least one intermediate position between said first and second position and releasing said means for turning on/off both in said first and in said second position,

said means responsive to the flow comprising a second control body movable between a first position, when in said hollow body there is not presence of flow, and a second position, when in said hollow body there is a maximum flow, said means responsive to the flow engaging said means for turning on/off starting from an intermediate position between said first and second position up to said second position and disengaging the means for turning on/off in said first position.
A control device, according to claim 1, wherein said first control body comprises a piston sliding between two positions, having an end connected to an element responsive to the pressure suitable for displacing said piston.
A control device, according to claim 2, wherein said piston comprises a stepped protrusion suitable for operating a body with circular cross section, in particular a sphere, movable perpendicularly to the sliding direction of the piston, said body with circular cross section acting on said means for turning on/off the electric supply to said pump.
A control device, according to claim 3, wherein said body with circular cross section acts on the end of a lever pivotally connected to said device, said lever acting on said means for turning on/off the electric supply to said pump.
A control device, according to claim 1, wherein said means responsive to the pressure comprises a resilient separating membrane arranged between the liquid contained in said hollow body and the outer environment, wherein said membrane is arranged near a wall of said hollow body creating a variable gap between said membrane and said wall, said wall having an opening that allows the liquid to pass from said gap to said hollow body and vice-versa.
A control device, according to claim 5, wherein said opening comprises:
- a check valve that allows the passage from said hollow body to said gap;

- a calibrated hole.
A control device, according to claim 1, wherein said first control body comprises pushing means, in particular a spring, suitable for pushing said control body towards said second position.
A control device, according to claim 1, wherein said second control body of said means responsive to the flow comprises a stem integral to said second control body, arranged in said hollow body, suitable for engaging with said inlet of said hollow body and interrupting the flow when said second control body is located in said first position, said stem operating a flow control lever arranged out of said hollow body and that is suitable for acting on said means for turning on/off thus operating the pump.
A control device, according to claim 1, wherein said second control body comprises a first magnet integral to said body and located at an end opposite to said body with respect to said stem, said magnet being suitable for repelling a second magnet with the same polarity of said first magnet and aligned to said first magnet, said second magnet being arranged out of said hollow body and being suitable for operating a flow control lever that acts on said means for turning on/off thus operating the pump.
A control device, according to claim 1, wherein a resilient membrane is provided in said hollow body that has a portion integral to said second control body, said membrane being suitable for dividing the inner volume of said hollow body into an upper chamber, which is in contact with said means responsive to the flow and the pressure, and a lower chamber, which is in contact with said inlet and said outlet of said hollow body, means being provided for allowing a controlled passage of liquid through said membrane.
A control device, according to claim 10, wherein said upper chamber and said lower chamber are in communication with each other through said means for allowing a controlled passage of liquid comprising:
- a check valve that allows the passage of an amount of liquid from said upper chamber to said lower chamber when said second control body moves from said first position to said second position;

- a calibrated hole that allows a back flow of said amount of liquid from said lower chamber to said upper chamber in a predetermined time, when said second control body moves from said second position to said first position.