Hydraulic pump with integrated flow detection system

Abstract

A hydraulic pump comprising a path for the liquid from a suction entrance for sucking the liquid into the pump to a delivery exit for discharging the liquid from the pump, and along this path, - downstream of the suction entrance, a pressurizing section configured to increase the liquid pressure, - an intermediate portion of the path, - a bypass conduit for bypassing the intermediate portion, connected at its inlet and outlet respectively upstream and downstream of the intermediate portion, - a slider provided within the bypass conduit, movable in the conduit due to the change in the liquid flow in the conduit, the movement of which is adapted to enable flow detection.

Description

HYDRAULIC PUMP WITH INTEGRATED FLOW DETECTION SYSTEMDescriptionTechnical Field

[0001] The present invention relates to the field of hydraulic pumps.

[0002] More specifically, the invention relates to a hydraulic pump with integrated flow detection system.State of the Art

[0003] As is known, automatic hydraulic pumps, i.e., pumps capable of autonomous operation, require a mechanical / electronic system for starting and stopping.

[0004] These pumps are thus equipped with devices such as pressure switches, pressure-flow controls and / or inverters. An example of a device applied externally upstream of a pump, i.e., downstream of the pump delivery, is described in JPS50100101U.

[0005] In general, pressure switches and inverters only operate based on the principle of pressure change; a direct consequence thereof is the tendency of the hydraulic flow to oscillate and the lack of effective protection against dry running.

[0006] To overcome the above-mentioned drawbacks, accessories are generally added to the pump, such as a large expansion vessel (the larger the vessel, the less noticeable the pressure fluctuation) and a float switch for protection against dry running.

[0007] Inverters can replace the float switch with complex "software" whereby, below a certain pressure value (or electrical parameter), they stop the pump assuming that it is dry running (actually, the pump might as well continue pumping water, therefore a float switch is still needed for absolute certainty).

[0008] The pressure-flow controls provide a pressure sensor (simple or advanced), a mechanical flow sensor, and a small accumulator. The combination of these elements ensures a constant flow (albeit along the pump curve) and certain protection against dry running.

[0009] The flow / pressure metering device (sometimes a pressure-flow control, sometimes only a pressure switch, sometimes only a flow switch) is applied to the pump delivery and thus adversely affects the hydraulic flow rate of the pump by increasing pressure drops.

[0010] Positioning the metering device on the outside of the pump, at the pump delivery, advantageously allows the pump to be kept on as long as a water flow is present and the system to be protected in case of dry running.

[0011] However, the limitations of this solution are, for example, the difficulty in maintaining a constant minimum flow that is sufficiently "low" to allow the pump to continuously operate even in case of small but constant drawdown, and the increase in pressure drops, which are greater as the delivery diameter is increased or a constant and "low" minimum flow is sought. Other limitations of this solution include, for example, the difficulty in correctly detecting the flow in case of "turbulence" caused by the suction / delivery, the increase in pump noise due to the water flows around the flow switch, or even the likely blockage of the management device due to solids that may pass through the pump.Summary

[0012] The task of the present invention is to solve the problems associated with the use of automatic hydraulic pumps.

[0013] Within this task, an important object of the present invention is to provide a hydraulic pump that allows the flow of liquid through the pump to be accurately detected, even in case of low flow rates.

[0014] Another important object of the present invention is to provide a hydraulic pump that allows to detect the liquid flow without reducing the liquid flow rate at the pump delivery.

[0015] A further important object of the present invention is to provide a hydraulic pump that allows to detect the liquid flow without reducing the liquid flow rate at the pump delivery.

[0016] A further important object of the present invention is to provide a hydraulic pump that allows to reduce the risk of blockage of the liquid flow management device due to any solids.

[0017] These and other objects, that will become clearer later, are achieved through a hydraulic pump comprising a path for the liquid from a suction entrance for sucking the liquid into the pump to a delivery exit for discharging the liquid from the pump, and along this path,- downstream of the suction entrance, a pressurizing section configured to increase the liquid pressure,- an intermediate portion of the path,- a bypass conduit for bypassing the intermediate portion, connected at its inlet and outlet respectively upstream and downstream of the intermediate portion,- a slider provided within the bypass conduit, movable in the conduit due to the change in the liquid flow in the conduit, the movement of which is adapted to enable flow detection.

[0018] Preferably, the intermediate portion of the path is provided between the pressurizing section and the delivery exit.

[0019] Preferably the intermediate portion of the path is a portion of conduit inside the pump.

[0020] The use of a bypass and a slider in the bypass, which substantially acts as a component of a flow detection device, for example a flow switch, for example positioned near the slider (outside the bypass), makes it possible to solve the aforementioned drawbacks, and moreover ensures a constant minimum flow and allows precisely to set the desired flow, without impacting the pump pressure drops. Indeed, it is possible, for example, to create a minimum resistance on the delivery to allow the flow to pass through the flow switch and to lift it (this allows the solution to be replicated on any diameter / size of the pump delivery and to change the minimum flow simply by acting on the flow switch without intervening on the delivery).

[0021] The flow detection system is not subject to the turbulences generated by the pump because they cross the delivery and only minimally affect the bypass.

[0022] By using a bypass and a slider in the bypass, the noise of the pump due to the water flows is reduced, as the part that generates the flow in the bypass does not have to make the same resistance as a flow switch connected to the pump delivery (i.e., outside the pump).

[0023] The likelihood that solid parts block the bypass is greatly reduced, as these pass through the pump in the section of greater diameter / flow. Furthermore, once the slider has been lifted, it obstructs the bypass, remaining lifted by the pressure generated by the pump. Consequently, by inhibiting the flow within the bypass, it is impossible for solids to pass through it and to block it.

[0024] According to preferred embodiments, a flow obstruction valve is provided in the intermediate portion of the path.

[0025] Preferably, the flow obstruction valve comprises a shutter movable from a position of maximum obstruction to a position of minimum obstruction, and a spring element adapted to be compressed by the shutter due to the flow thrust directed towards the delivery.

[0026] Preferably, the position of maximum obstruction still allows the passage of fluid, or- is such that the passage of fluid is completely closed, therefore the obstruction valve is a check valve, preferably a sealing seat being provided for the shutter corresponding to the position of maximum obstruction.

[0027] Preferably, the movement of the shutter from the position of maximum obstruction occurs when the pressure upstream of the shutter is such as to overcome the resistance of the spring element and the pressure downstream of the shutter.

[0028] According to preferred embodiments, the pump comprises an outer casing containing the suction entrance, the delivery exit, the path and at least part of the bypass conduit.

[0029] Preferably, the bypass conduit is completely realized within the casing.

[0030] Preferably, the casing is composed of multiple pieces structurally fixed together and the bypass conduit is integrated, i.e., made, in the same monolithic piece of the casing in which at least a part of the intermediate portion of the path is provided.

[0031] According to preferred embodiments, the slider is or comprises a magnet, a magnetic element, or an element capable of producing, or interacting with, an electromagnetic field.

[0032] According to preferred embodiments, the slider comprises a floating element.

[0033] According to preferred embodiments, the pump comprises a liquid flow detection device; the liquid flow detection device comprises the slider arranged within the conduit, and a sensor adapted to detect the movement of the slider.

[0034] According to preferred embodiments, a branch section extends from the bypass conduit, the branch section being configured to be connected to a sensor device for detecting one or more liquid parameters, preferably a pressure sensor device.Brief description of the drawing

[0035] The invention will be better understood by following the description below and the attached drawing, showing some non-limiting embodiments of the invention. More particularly, in the drawing:

[0036] Fig. 1 is a schematic front view of a portion of a pump according to the invention, partially cut-away;

[0037] Fig. 2 is a schematic view of a portion of the pump of Fig. 1, cut-away along the plane II-II of Fig. 1;

[0038] Fig. 3 is a schematic front view of a portion of a pump according to the invention, of the submersible type.Detailed description of embodiments

[0039] With reference to the previously cited figures, a pump according to the invention is indicated as a whole with the reference number 10.

[0040] The pump 10 includes an outer casing 11, on which there are defined the suction entrance 12 for sucking the liquid into the pump and the delivery exit 13 for discharging the liquid from the pump.

[0041] Within the casing 11, a path P for the liquid (schematically illustrated by a dashed line) is provided, which extends from the suction entrance 12 to the delivery exit 13.

[0042] A pressurizing section 14 (schematized by a circular ring), configured to increase the liquid pressure, is provided along the path P, within the casing 11, downstream of the suction entrance 12. The pump therefore includes, in succession, a suction section where the entrance 12 is provided, the pressurizing section 14, and the delivery section where the exit 13 is provided.

[0043] Specifically, in this example, the pump is a multi-stage centrifugal pump (in other examples, the pump may be a single-stage pump or a pump other than a centrifugal one) and therefore the pressurizing section 14 provides for a plurality of impellers.

[0044] An intermediate portion Pm of the path P (schematized with a less sparse dashed line compared to the rest of the line indicating the path P, and comprised between two X-marks) is provided, with which a bypass conduit 16 is associated for bypassing the same portion. The bypass conduit is therefore operationally connected at its inlet and outlet respectively upstream and downstream of the intermediate portion.

[0045] In the main configurations of the invention, the intermediate portion Pm is provided between the pressurizing section 14 and the delivery exit 13.

[0046] A slider 17 is provided within the bypass conduit 16, movable in the conduit due to the change in the liquid flow in the conduit, the movement of which is adapted to enable flow detection.

[0047] For example, the slider 17 is a floating body and is, or comprises, a magnet, a magnetic element, or an element capable of producing, or interacting with, an electromagnetic field.

[0048] For example, the slider 17 is floating and comprises a magnet adapted to interact with a sensor 19 A, such as for example a reed switch arranged on an electronic board external to the bypass conduit, which detects the movement of the magnet. For example, the magnet is usually magnetically engaged with the reed switch. When the magnet moves, it magnetically disengages from the reed switch, which opens generating a signal, as better explained below. The slider and the reed switch make up, for example, a liquid flow detection device, such as for example a flow switch.

[0049] For example, a branch section 18 extends from the bypass conduit 16, the branch section being adapted to carry the liquid flowing through the bypass conduit 16 into a sensor device 19B for detecting one or more liquid parameters, such as a pressure sensor device. For example, the pressure sensor device 19B is integrated into a device 19 that also comprises the reed switch 19A. The device 19 is, for example, arranged on the outside of the casing 11. The device 19 can be therefore a pressure-flow control.

[0050] The branch section 18 runs through the casing to the pressure sensor device 19B. If the pressure sensor device 19B is not provided, the branch section can be plugged. In other embodiments, where for example only the flow switch is used, the branch section 18 is not provided (this does not exclude the possibility of having a pressure detector placed elsewhere).

[0051] The bypass conduit 16 has a central portion 16A, in which the slider 17 moves (from which, for example, the branch section 18 extends), delimited by two limit switches against which the slider is adapted to abut, an initial portion 16B for flow inlet that is operationally connected upstream of the conduit forming the intermediate portion Pm, and an end portion 16C for flow outlet that is operationally connected downstream of the conduit forming the intermediate portion Pm. Herein, the terms “inlet” and “outlet” relate to the direction of the flow relative to the driving movement of the slider that detects a flow demand from the pump delivery. Obviously, when, for example, the flow demand ends, the liquid can flow from the end portion 16C towards the initial portion 16B.

[0052] The central portion 16A extends, for example, from the bottom upward. Preferably, also the initial portion 16B extends from the bottom upward, at least in thesection connected to the central portion 16 A. The two portions are, for example, coaxial (e.g., they have circular cross section).

[0053] Conveniently, the initial portion 16B has a cross-sectional dimension smaller than the cross-sectional dimensions of the central portion 16 A, so that a lower limit switch 16D is formed at the joint between the two portions, against which the slider 17 rests when not moving, i.e., the flow passing through the bypass conduit is substantially absent (apart from negligible passages).

[0054] The end portion 16C extends, for example, transversally (e.g., orthogonally) to the central portion 16A (also the end portion 16C may have a circular cross-section).

[0055] An upper limit switch 16E for the slider is thus defined on the wall portion of the end portion 16C that joins to the central portion 16 A. Preferably, also the end portion 16C has cross-sectional dimensions smaller than the cross-sectional dimensions of the central portion 16 A.

[0056] Preferably, the cross-sectional dimensions of the slider 17 are smaller than the cross-sectional dimensions of the central portion 16 A, so that the liquid can pass around the slider (for example, as shown in Figure 2, the slider has a circular crosssection, like the central portion).

[0057] For example, the section Sm of smaller area of the conduit of the intermediate portion Pm has a larger area than the area of the port LI of intersection between the bypass conduit 16 and the path P downstream of the intermediate portion Pm and, preferably, also larger than the area of the port L2 of intersection upstream of Pm. Preferably the section Sm of smaller area of the bypass conduit is at least 1.5 times, and more preferably at least 2 times, greater than the area of the port L1 / L2.

[0058] Preferably, also the area of the cross-section of the central portion 16A where the slider 17 moves is smaller than the area Sm of the conduit Pm, for example the area Sm is at least 1.5 times, and more preferably at least 2 times greater than the area of the cross-section of the central portion 16 A.

[0059] The conduit that defines the intermediate portion Pm of the path P has a housing 20 for a flow obstruction valve 21.

[0060] The flow obstruction valve 21 comprises, for example, a shutter 22 movable from a position of maximum obstruction to a position of minimum obstruction, and an spring element 23 (such as a coil spring) adapted to be compressed by the shutter 22 due to the flow thrust directed toward the delivery exit 13.

[0061] For example, the position of maximum obstruction is such that fluid is still allowed to pass through a controlled passage port. For example, the shutter abuts against a seat 24 that corresponds to the position of maximum obstruction, and the shutter is provided, in the abutment area, with one or more through pockets, not shown in the figures, that allow the passage of the liquid, as shown by the arrow F.

[0062] For example, the seat 24 is defined on a shoulder formed by an enlargement of the transverse dimensions of the cross-section of the conduit of the intermediate portion Pm.

[0063] Along the conduit of the intermediate portion Pm, downstream of the seat 24, a ring 25 is provided that defines an abutment for one end of the spring element 23, while the opposite end of the spring element 23 abuts against the shutter 22.

[0064] Thus, the liquid can flow through the flow obstruction valve 21. When the flow pressure is such that it overcomes the resistance of the spring element, 23, the shutter 22 rises from the seat 24, increasing the area for the passage of the liquid.

[0065] In other embodiments, the shutter 22, when in the seat 24, is shaped to completely close the passage of the liquid, so that the seat 24 is a sealing seat. In practice, in this case, the flow obstruction valve 21 is a check valve, as the flow from the delivery exit toward the suction entrance through this valve is prevented by the shutter, which completely obstructs the port of the conduit Pm.

[0066] Appropriately, the bypass conduit 16 is completely realized within the casing 11.

[0067] For example, the casing 11 is composed of multiple pieces structurally fixed together and the bypass conduit 16 is integrated, i.e., made, in the same monolithic piece of the casing in which at least a part of the intermediate portion of the path is provided. For example, in Fig. 1 the bypass conduit 16 is integrated in two pieces 11’and 11” of the casing 11. It is evident that the bypass conduit 16 can be made entirely within a single piece of the casing.

[0068] Fig. 3 shows a pump according to the invention, of a different type than that of the previous example, of the submersible type. In this case again, the pump is equipped with a bypass conduit 16 for bypassing the intermediate portion Pm of the path P. The management electronics can be provided either inside the pump (thus in water) or outside the well / tank C in which the pump is placed. In the figure, the same numbers indicate the same or equivalent parts to those of the previous embodiment.

[0069] From an operational point of view, when there is flow demand from the users downstream of the pump, for example because a tap is opened in a household network, a pressure drop occurs downstream of the pump, and consequently the flow toward the user begins. For example, in the initial step the slider 17 rests on the lower limit switch 16D of the central portion 16 A.

[0070] When the flow is less than the preset threshold value that allows the slider to be raised, the magnet of the slider interacts with the reed switch (that is closed, in this step) of the flow detection device. When the slider rises, following the flow demand from the users, the magnet magnetically disengages from the reed switch, which opens, thereby generating a consent signal for the start of the pump, which will operate for as long as the slider remains raised.

[0071] If also a pressure switch is associated with the branch section 18, it is the pressure sensor that determines the moment when the pump should start (at the set pressure value) while the flow sensor has the task of keeping the pump on as long as the flow is present.

[0072] The two starting modes mentioned above may be present simultaneously or not in the logic of an automatic pump. It is therefore possible to adopt one mode at a time or both. The choice essentially depends on the final destination of the product. The stop of the pump is instead generally caused by the lack of flow, therefore by the slider of the flow switch that returns to the "rest" position.

[0073] The application of the bypass conduit with a slider associated with a flow switch ensures a constant minimum flow and allows to precisely detect the desiredflow without affecting the pump pressure drop. In fact, it is sufficient to create a minimal resistance on the delivery to allow the flow to pass through the slider and to raise it.

[0074] This allows the solution to be replicated on any diameter (pump delivery dimension) and the minimum flow to be changed simply by acting on the flow switch without the need for intervening on the delivery.

[0075] The system is not subject to the turbulences generated by the pump as they cross the delivery and only minimally affect the bypass.

[0076] The system reduces the noise of the pump caused by the water flows as the part generating the flow in the bypass does not have the same resistance as the flow switch in the delivery.

[0077] The likelihood that the pressure sensor, if any, is blocked is very low because the solid parts pass through the pump in the section of greater diameter / flow.

[0078] In addition, once raised, the slider obstructs the bypass conduit in the part downstream of the branch section toward the pressure sensor, remaining raised by the pressure generated by the pump. Consequently, by inhibiting the flow within the bypass, it is impossible for solids to pass through it and to block it.

[0079] It is understood that what is illustrated purely represents possible non-limiting embodiments of the invention, which may vary in forms and arrangements without departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided for the sole purpose of facilitating the reading thereof in the light of the description above and the accompanying drawings and do not in any way limit the scope of protection.

Claims

Claims1. A hydraulic pump comprising a path for the liquid from a suction entrance for sucking the liquid into the pump to a delivery exit for discharging the liquid from the pump, and along this path,- downstream of the suction entrance, a pressurizing section configured to increase the liquid pressure,- an intermediate portion of the path,- a bypass conduit for bypassing the intermediate portion provided with an inlet and an outlet, the bypass conduit being connected with said inlet upstream of the intermediate portion, and with said outlet downstream of the intermediate portion,- a slider provided within the bypass conduit, movable in the conduit due to the change in the liquid flow in the conduit, wherein the movement of the slider allows the detection of the flow.

2. The hydraulic pump of claim 1, wherein the intermediate portion of the path is comprised between the pressurizing section and the delivery exit.

3. The hydraulic pump of claim 1 or 2, wherein a flow obstruction valve is provided in the intermediate portion of the path.

4. The hydraulic pump of claim 3, wherein the flow obstruction valve comprises a shutter movable from a position of maximum obstruction to a position of minimum obstruction, and a spring element adapted to be compressed by the shutter due to the flow thrust directed towards the delivery.

5. The hydraulic pump of claim 4, wherein the position of maximum obstruction still allows the passage of fluid, or- the position of maximum obstruction is such that the passage of fluid is completely closed, so that the obstruction valve is a check valve, preferably a sealing seat being provided for the shutter corresponding to the position of maximum obstruction;preferably the movement of the shutter from the position of maximum obstruction occurs when the pressure upstream of the shutter is such as to overcome the resistance of the spring element and the pressure downstream of the shutter.

6. The hydraulic pump of one or more of the preceding claims, comprising an outer structural casing containing the suction entrance, the delivery exit, the path, and at least part of the bypass conduit.

7. The hydraulic pump of claim 6, wherein the bypass conduit is completely formed in the casing.

8. The hydraulic pump of claim 6, wherein the casing is composed of multiple pieces structurally fixed together and the bypass conduit is integrated, or made, in the same monolithic piece of the casing in which at least a part of the intermediate portion of the path is provided.

9. The hydraulic pump of one or more of the preceding claims, wherein the slider is or comprises a magnet, a magnetic element, or an element capable of producing, or interacting with, an electromagnetic field.

10. The hydraulic pump of one or more of the preceding claims, wherein the slider comprises a floating element.

11. The hydraulic pump of one or more of the preceding claims, comprising a liquid flow detection device; the liquid flow detection device comprising the slider arranged within the conduit, and a sensor adapted to detect the movement of the slider.

12. A hydraulic pump according to one or more of the preceding claims, wherein a branch section extends from the bypass conduit, the branch section being configured to be connected to a sensor device for detecting one or more liquid parameters, preferably a pressure sensor device.