US20030072655A1

US20030072655A1 - Flow regulator for a water pump

Info

Publication number: US20030072655A1
Application number: US09/977,582
Authority: US
Inventors: Der-Fan Shen
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-10-12
Filing date: 2001-10-12
Publication date: 2003-04-17

Abstract

A flow regulator for a water pump, comprising a control valve, mounted on an inlet pipe of a water pump. The control valve further comprises a passageway, a chamber, a conduit, and a control element. The passageway allows water to flow through the inlet pipe. The chamber reaches across the passageway. The conduit connects to an outlet pipe of the water pump and transmits water pressure from there through a top end of the control valve into the chamber. The control element is inserted in the chamber, having two ends, at least one of which has an opening connected with the conduit, so that water pressure is applied inside the control element. The control element is further made of elastic material and thus expanded to a varying degree according to the water pressure, causing an effective width of the passageway and consequently water flow through the water pump to vary. This allows to adjust supply of water, as delivered by the water pump, to demand.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flow regulator for a water pump, particularly to a flow regulator for a water pump operating in conjunction with an underpressure system.

2. Description of Related Art

For maintaining water pressure as well as ensuring sufficient water pressure at all places in modern high-rise buildings and public places, water pumps are often installed at supply pipes. In addition, pressure control systems are employed. Pressure control systems divide into mechanical underpressure systems and frequency-control led systems, having a frequency converter to drive a motor.

The motor in a frequency-controlled system drives a water pump at a speed that varies according to an input frequency. The frequency converter is control led by a pressure sensor and in turn varies the speed of the motor. If water pressure is low, the motor is accelerated to higher speed. When water pressure is close to a maximum value, motor speed is reduced. When the water pressure exceeds the maximum value, the motor is stopped. Thus, when a large flow of water is demanded, such that a large pressure difference along the supply pipe results, the frequency converter causes the motor to speed up, and pumped water flow is increased. On the other hand, when just a small flow of water is demanded, such that a small pressure difference along the supply pipe results, the frequency converter causes the motor to slow down, and pumped water flow is decreased, so that the pressure difference along the supply pipe increases rapidly.

Using a frequency converter to control the motor for maintaining a constant water pressure has the advantage of rapid reaction to changes in demand and of precise control of pressure. Too steep a rise of water pressure after starting the motor and subsequent sudden stopping of the motor is avoided. Rather, smooth running of the motor is ensured, leading to efficient operation and saving of energy.

However, a frequency-control led pump is complicated and expensive to purchase and to maintain. Furthermore, the frequency converter generates heat, so a control box for housing thereof needs to be provided with a radiator, still the frequency converter often gets too hot during use and burns out For these reasons, frequency-regulated pumps are normally only installed in large supply systems.

Another type of flow-regulating system has a motor which is turned on and off by a pressure-sensitive switch. The motor operates at fixed speed. Upper and lower thresholds of water pressure are preset for the pressure-sensitive switch. When water pressure at a supply pipe falls below the lower threshold, the pressure-sensitive switch turns on the motor. When, on the other hand, the water pressure has risen above the upper threshold, the pressure-sensitive switch turns off the motor, until, due to increased demand, water pressure falls below the lower threshold, which causes the motor to be switched on again. Furthermore, to attenuate pressure rises and falls, a container is installed at an outlet of the flow-regulating system, using air or an elastic membrane to store water pressure. The container takes in water when the motor is turned on and releases water by pressure of air or the elastic membrane when the motor is turned off. Thus changes of the water pressure are smoothed out, and start-stop intervals of the motor are lengthened.

This type of flow-regulating system has a comparatively simple structure and is therefore less expensive and easier to maintain. However, the motor thereof runs at a fixed speed. Thus, each time the motor is turned on, a fixed, maximum value water flow is generated, independent of demand for water.

In order to meet peak demand, the generated water flow is required to be sufficiently large. At times of lower demand, the motor, when operating, still runs at full speed, so that excess water flow results and the water pressure rises quickly above the threshold, which in turn stops the motor. This leads to short start-stop cycles of the motor.

At the moment of starting the motor, electric power consumption has a peak value, so that starting and stopping the motor in short cycles results in high power consumption, even if demand for water is low. What is more, water supply in excess of demand leads to high counterpressure at the outlet and higher load as well as to increased power consumption.

SUMMARY OF THE INVENTION

It is the main object of the present invention to provide a flow regulator for a water pump which avoids short start-stop cycles of a motor, reducing power consumption.

Another object of the present invention is to provide a flow regulator for a water pump generating water output according to demand, avoiding excess outflow of water and resulting waste of energy.

A further object of the present invention is to provide a flow regulator for a water pump which works in conjunction with a mechanical underpressure system, achieving the function of a frequency converter.

The present invention can be more fully understood by reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of the flow regulator for a water pump of the present invention. [0016]
FIG. 1A is an exploded sectional side view of the control valve of the present invention. [0017]
FIG. 2 is a schematic illustration of the flow regulator for a water pump of the present invention in conjunction with a water pump. [0018]
FIG. 3 is a schematic illustration of the movement of the present invention.[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIG. 2, the flow regulator for a water pump of the present invention is used in conjunction with a [0020] water pump 1; an inlet pipe 2, leading water from a water source to an inlet of the water pump 1; an outlet pipe 3, connected with an outlet of the water pump 1; a pressure-sensitive switch 4; and a container 5. The container 5 stores water pressure, attenuating any sudden drop of pressure in the outlet pipe 3. The pressure-sensitive switch 4 senses water pressure in the outlet pipe 3, as compared with preset upper and lower pressure thresholds. When water pressure in the outlet pipe 3 drops below the lower threshold, the water pump 1 is started, and when water pressure in the outlet pipe 3 exceeds the upper threshold, the water pump 1 is stopped. Thus water pressure in the outlet pipe 3 is kept within a preset range.
The flow regulator for a water pump of the present invention mainly comprises a [0021] control valve 10, installed at the inlet pipe 2 of the water pump 1, as shown in FIG. 1. The control valve 10 has two ends with two flanges 11, 12, with the flange 12 being connected with the water pump 1. A passageway 13 inside the control valve 10 connects the two ends with the two flanges 11, 12 thereof. Water flows from the flange 11 through the passageway 13 to the flange 12. A cylindrical main body 14 forms a central part of the control valve 10. A chamber 15 is formed inside the main body 14, having two ends and reaching across the passageway 13, so that water on the way to the inlet of the water pump 1 flows through the chamber 15.
A [0022] control element 20 is inserted in the chamber 15, controlling an effective width thereof that is determined by the width of a gap between the control element 20 and an inner wall of the chamber 15. As shown in FIGS. 1-3, the control element 20 is of cylindrical shape, having an interior and upper and lower ends, and is made of elastic material, like rubber or silicon. Pressure from the outlet pipe 3 is applied to the interior of the control element 20, causing the control element 20 to expand. As shown in FIG. 3, expanding of the control element 20 decreases the effective width of the chamber 15, so that water flow through the control valve 10 decreases.
Referring to FIG. 1A, the [0023] main body 14 has two ends with openings 151, 152 that are located close to the ends of the chamber 15 and allow to insert the control element 20 therein. The openings 151, 152 have inner sides with flat shoulders 153, 154. To the upper and lower ends of the control element 20, two flanges 21, 22 are attached, leaning from outside against the shoulders 153, 154, respectively. A bottom plug 16 having a peripheral thread is screwed into the opening 152, with a pressing ring 23 inserted between the bottom plug 16 and the flange 22 of the control element 20. The bottom plug 16 via the pressing ring 23 presses the flange 22 tight on the shoulder 154.
A [0024] top plug 17 is screwed into the opening 151, with a pressing ring 24 inserted between the top plug 17 and the flange 21 of the control element 20, used to press the flange 21 tight on the shoulder 153. The top plug has a central water entrance hole 18, which is by a conduit 30 connected with the outlet pipe 3, so that water pressure at the outlet of the water pump I is transmitted to the interior of the main body 14.
Referring to FIG. 1, the upper end of the [0025] control element 20 is connected with the opening 151. Thus water pressure in the outlet pipe 3 is via the conduit 30 transmitted into the control element 20, expanding the control element 20.
Referring again to FIGS. [0026] 1-3, since the control valve 10 is via the conduit connected with the outlet pipe 3 of the water pump 1, water pressure at the outlet thereof is directly transmitted to the interior of the control element 20. Being deformable and with the upper and lower ends fixed, the control element 20 has a middle section that is expanded with increasing water pressure. Since the chamber 13 reaches through the passageway 13, expanding of the control element 20 narrows gaps in the chamber 15 around the control element 20, decreasing the effective width of the chamber 15. The control element has a certain elasticity. Therefore, any change of water pressure at the outlet of the water pump I results in a changed width of the control element and consequently in a changed cross-section of the passageway 13, achieving controlled water flow through the passageway 13.
In a state shown in FIG. I where the [0027] water pump 1 is turned off or water pressure at the outlet thereof is relatively low, the control element is exposed to no water pressure and maintains a straight shape. At this time, the effective width of the chamber 15 is maximal, and the passageway 13 has a maximum cross-section, resulting in maximum water flow through the passageway 13.
On the other hand, in a state shown in FIG. 3 where water pressure at the outlet of the [0028] water pump 1 has increased, the control element is exposed to increased water pressure and bends outward. At this time, the effective width of the chamber 15 is reduced, and the passageway 13 has a reduced cross-section, resulting in reduced water flow through the passageway 13.
Furthermore, since the upper and lower ends of the [0029] control element 20 are fixed, expansion thereof due to water pressure is maximal in the middle section thereof. For a linear reduction of the effective width of the chamber 15 with increasing water pressure, the chamber has a relatively large central diameter and relatively small diameters at the ends thereof. This ensures smooth and linear reduction of the gap between the control element 20 and the inner wall of the chamber 15 with increasing water pressure inside the control element 20. Furthermore, as shown in FIG. 2, for maintaining a minimum flow of water even when the gap between the control element 20 and the inner wall of the chamber 15 is entirely closed, the inner wall of the chamber 15 has a rough surface. This allows water to continue to flow and prevents the water pump from running dry, creating underpressure.
When the [0030] water pump 1 has just been turned on or demand for water is large, so that output pressure is low, the present invention, by employing the control element 20, provides an enlarged passageway 13 for water, so that a larger flow of water through the inlet pipe 2 enters the water pump 1. Then a maximum amount of water is furthered by the water pump 1, according to maximum capability thereof. When there is low demand for water or water pressure is close to the upper pressure threshold, the control element 20 narrows the passageway 13, so that water flow into the water pump 1 is reduced.
The present invention regulates water flow into the [0031] pump 1 according to demand and water pressure at the outlet of the water pump 1. At times of low demand, water flow delivered by the water pump 1 exceeds demand, water pressure rises, causing the present invention to reduce water flow into the water pump 1 and consequently water flow from there. Thus, water pressure at the outlet of the water pump will not steeply rise, and frequent turning off and on of the water pump 1 is avoided. Therefore wear of the water pump 1 and energy consumption thereof are reduced. On the other hand, when the water pump 1 has just been turned on or at times of peak demand, low water pressure at the outlet of the water pump 1 causes the present invention to increase water flow into the water pump 1 and from there, so that demand for water is met.
While the invention has been described with reference to a preferred embodiment thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention which is defined by the appended claims. [0032]

Claims

1. A flow regulator for a water pump, comprising a control valve, mounted on an inlet pipe of a water pump, said control valve further comprising:

a passageway, allowing water to flow through said inlet pipe;

a chamber, reaching across said passageway;

a conduit, connecting to an outlet pipe of said water pump and transmitting water pressure from said outlet pipe through a top end of said control valve into said chamber; and

a control element, inserted in said chamber, having two ends, at least one of which has an opening connected with said conduit, so that said water pressure is applied inside said control element, said control element further being made of elastic material and thus expanded to a varying degree according to said water pressure, causing an effective width of said passageway and consequently water flow through said water pump to vary, so that supply of water is adjusted to demand.