RU2836509C2 - Fluid pressure reduction valve - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to a valve device for reducing fluid pressure. Spring-loaded valve has an inlet connected by a water main with pressurized water, and an outlet from the chamber is connected to a network of pipelines for local distribution of water. Pressure reduction valve device has a flow pressure regulating plate located opposite the inlet hole. Compression spring acts by its lower end on the upper part of the plate. Upper end of the spring rests against the drive element of the spring at the end of the drive tube of the servo device. Actuating element of the spring can be extended by the motor for further compression of the spring or retracted to release the compression. Local distribution network pipeline extends downstream of the outlet. There is a flow meter and a pressure sensor in it next to the outlet hole. They are electronically connected to the controller. Pressure on the regulator is set based on the measured flow rate.

EFFECT: improving control reliability of the valve device to reduce pressure in accordance with the flow passing through it.

26 cl, 11 dwg

Description

The present invention relates to a valve for reducing fluid pressure, particularly, although not exclusively, intended for water mains.

State of the art

Water supply networks usually contain a local high-pressure main network connected to many local networks. The water pressure in the high-pressure main is usually too high for consumers in the local networks, and therefore pressure reducing valves are located at the junction between the high-pressure main and the local network to reduce the pressure.

A typical pressure reducing valve (PRV) contains a chamber having an inlet connected to the high pressure main and an outlet connected to the local network. Typically, the valve has two chambers, an upper and lower chamber, separated by a diaphragm. Water passes through the PRV through the lower chamber. Downstream pressure reduction is achieved by providing a hydraulic connection between the upstream pressure and the upper chamber of the PRV. In this hydraulic system, water from the upstream side passes through a pilot valve with a spring-loaded regulator to ensure that water is released from the upper chamber if the pressure in the upper chamber exceeds a predetermined level. More complex conventional PRVs incorporate additional hydraulic circuits to provide more precise control of the downstream pressure using various differential control valve designs. A spring may be included in the upper chamber to provide a better seal while allowing the upstream pressure to flow unimpeded into the upper chamber to fully close the valve.

Water loss from a main is a problem that occurs due to the age of the main lines, as well as damage to the main and associated equipment. Many mains are old and have many leaks. Even a new main can leak. Unsurprisingly, the leak is most intense at the highest water pressure.

The problem with installing the spring of such a conventional PRV in a pressure reducing valve at the inlet of a local network with essentially constant water pressure entering the network is that during most of the time, when demand is lower, the local network will be overpressured. This in turn will exacerbate the leakage problem.

Various proposals have been made for pressure reducing valves in which the biasing force applied (e.g. by a spring) to a control plate or valve element can be automatically varied to accommodate changing levels of demand in the local network and thus eliminate or mitigate the overpressure problem.

For example, GB 2176316 (NRDC) discloses a device that is described in the abstract as follows:

A device for controlling the flow of water through a pipeline (26), including a valve (29) and a plate (37) with an opening, and supplying water to a distribution system, containing a regulator (1) that actuates a control valve (14) in a servo system that controls the valve (29). The regulator (1) has two diaphragms (5) and (6), connected by an extension spring (7), the extension of which is determined by the flow through the plate (37) with the hole. The first diaphragm (5) actuates the shut-off element (13) of the control valve (14) and is subjected to the pressure difference created by the flow through the plate with the orifice (37). The second diaphragm (6) is loaded by a compression spring (8), and its displacement depends on the control pressure at the branch (38) of the pipeline (26). The displacement of the shut-off element (14) is a combination of the displacements of the two diaphragms (5 and 6) and increases the control pressure at the branch (38) when the demand for water increases.

GB 2165372 (TLV Co. Ltd) discloses a pressure reducing valve with a pressure adjusting spring associated with an actuator that can change the spring force setting in response to the difference between the pressure on the side downstream of the pressure reducing valve and a desired target pressure exceeding a certain value.

EP 1762922 (R. Nussbaum AG) discloses a pressure reducing valve having a spring-loaded valve element that controls the flow of fluid through a supply opening leading into a chamber having an outlet opening for the fluid. The valve has an electromechanical actuator that can change the spring force setting in response to changes in water pressure downstream of the pressure reducing valve.

WO 03/057998 (Optimus Water Technologies Ltd) discloses a hydraulically controlled PRV, the operation of which is controlled by a complex hydraulic structure comprising a filter unit, a flow restriction orifice, a control valve, a differential control valve (DCV), and a pressure reducing valve (PRV). A bypass pipe diverts a small portion of the water entering the PRV through a control loop linking the control valve and the DCV. A pipe upstream of the control valve is connected to the pressure reducing valve, but enters a pressure chamber containing a spring on the opposite side of the diaphragm from the control valve. Thus, in the PRV of WO 03/057998 there are "wet chambers" on both sides of the diaphragm. The PRV of WO 03/057998 is not provided with an actuator for adjusting the spring pressure. Instead, the DCV is equipped with an actuator that responds to pressure signals received from the controller, and it is the DCV that improves the performance of the PRV. The water pressure control design described in WO 03/057998 appears to have a number of potential drawbacks. Firstly, the hydraulic control system is too complex and there are many components that can fail. Secondly, it is believed that the narrow bore bypass pipes may be more susceptible to clogging and/or freezing, causing the control system to malfunction or stop working. Thirdly, in a PRV, both sides of the diaphragm are exposed to water, meaning that the spring will be constantly surrounded by water, causing limescale to form on the spring itself, which may affect the valve's ability to close completely when required.

Disclosure of the essence of the invention

The object of the present invention is to provide an improved fluid pressure reducing valve that overcomes or at least alleviates the problems in known pressure reducing valves described above.

The inventor has noted a simple relationship between the pressure required downstream of a pressure reducing valve to maintain a specified minimum pressure at a remote point in a local network, with the pressure reducing valve located between a local high pressure source and the local network, on the one hand, and the flow rate in the local network, on the other hand. The required controlled pressure and flow rate downstream of the pressure reducing valve are generally linearly related. Despite this, the inventor is not aware of any pressure reducing valves controlled in accordance with the flow passing through them, with the exception of the somewhat complex design disclosed in GB 2 176 316.

According to one aspect of the invention, a valve device for reducing the pressure of a fluid is provided, comprising:

- a spring-loaded pressure-reducing valve having:

- a housing containing a chamber for the flow of a fluid medium,

- an opening for feeding fluid into the chamber and an opening for removing fluid from the chamber,

- a control plate located opposite the opening and exposed during use to the action of the supplied fluid acting on it,

- a spring, under the action of which the possibility of shifting the plate towards the hole is ensured, and

- a diaphragm between the control plate and the housing for closing the chamber between them, which is subjected to the controlled pressure in the chamber during use,

- a controlled drive with a motor acting between the housing and the end of the spring farthest from the control plate,

- a flow meter located downstream of the outlet, and

- a controller configured to receive flow data from the flow meter and control a servomotor to retract the far end of the spring in accordance with the flow rate measured by the flow meter;

wherein the said design is made in such a way that when used to increase the flow rate on the consumption side, the regulating plate is partially retracted during such an increase to maintain the pressure further downstream, and vice versa

The housing may have an internal cavity divided by a diaphragm into a fluid flow chamber on one side of the diaphragm and a dry chamber on the other side of the diaphragm, wherein the fluid flow chamber is provided with an opening for feeding fluid into the chamber and an opening for removing liquid. By dry chamber is meant that the interior of the chamber does not come into contact with the fluid. This is in contrast to the pressure reducing valve described in WO 03/057998, in which both chambers on either side of the diaphragm in the PRV are "wet" chambers, i.e. exposed to the fluid (in this case water).

The valve device for reducing the pressure of the fluid may also comprise an electronic data store located within the controller or associated with it, wherein the data store comprises data determining the relationship between the flow rate of the fluid and the pressure of the fluid in the pipeline network downstream to which the pressure reducing valve is connected.

Thus, the controller may be configured to receive flow data from the flow meter and control the motorized actuator to retract or advance the distal end of the spring in accordance with the flow rate measured by the flow meter and the relationship between the fluid flow and the fluid pressure, thereby changing the position of the control plate and the fluid flow through the fluid supply orifice to maintain a desired downstream fluid pressure.

In a second aspect of the invention, a valve device for reducing the pressure of a fluid medium is proposed, comprising:

- a spring-loaded pressure-reducing valve having:

- a housing having an internal cavity divided by a diaphragm into a chamber for the flow of fluid on one side of the diaphragm and a dry chamber on the other side of the diaphragm,

- an opening for feeding a fluid into a fluid flow chamber and an opening for removing a fluid from a fluid flow chamber,

- a control plate located opposite the opening and exposed in use to the action of the supplied fluid acting on it, wherein the control plate is connected directly or through a connecting element to the said one side of the diaphragm, and the diaphragm used is exposed in use to the action of the controlled pressure in the chamber for the flow of the fluid,

- a compression spring located in the dry chamber on said other side of the diaphragm, the compression spring being positioned so as to apply pressure through the diaphragm and push the plate towards the opening, and

- a controlled drive with a motor acting between the housing and the end of the compression spring farthest from the control plate,

- a flow meter located downstream from the outlet;

- a controller and an electronic data storage located within or associated with the controller, wherein the data storage contains data defining the relationship between the flow rate of the fluid and the pressure of the fluid in a downstream pipeline network to which the pressure reducing valve is connected;

wherein the controller is configured to receive flow data from the flow meter and control the actuator with the motor to retract or advance the distal end of the spring in accordance with the flow measured by the flow meter and the relationship between the flow of the fluid and the pressure of the fluid, thereby changing the position of the control plate and the flow of the fluid through the opening for supplying the fluid to maintain the desired pressure of the fluid downstream.

Preferably, the controlled motor drive is a servo motor drive.

The fluid can be a liquid or a gas.

In one general embodiment, the fluid is a liquid.

In another general embodiment, the fluid is a gas, such as a hydrocarbon gas.

When the fluid is a liquid, it may be, for example, water or a liquid hydrocarbon.

In one particular embodiment, the fluid is water.

In another specific embodiment, the fluid is a liquid hydrocarbon.

The invention is particularly applicable to water mains. It is expected that the invention will also be applicable to hydrocarbon fluids in both liquid and gaseous states.

The controller may be configured to calculate the action of the servomotor in positioning the spring in accordance with a substantially linear relationship of pressure and flow rate downstream. The calculation may be based on the pressure to be achieved in terms of servo positioning of the spring, or only on servo positioning of the spring. Alternatively, the controller may be configured to ensure that the servomotor operates in accordance with a reference table of pressure and flow rate downstream. Again, the reference table may include pressure values to be achieved, but preferably includes spring positions in terms of servo drive revolutions.

When the fluid is water and the pressure reducing valve is connected to a local water supply network, the controller may be programmed or receive a command from a remote control center to vary the flow rate so that the minimum water pressure provided to a remote user in the network (i.e. the user who experiences the highest pressure drop) is in the range of 0.5 bar to 2 bar. Most often, the controller is programmed or receives a command from a remote control center to vary the flow rate so that the minimum water pressure provided to a remote user in the network is in the range of 0.6 bar to 1.5 bar, most often from 0.7 bar to 1.2 bar. In one embodiment, the minimum water pressure provided to a remote user in the network is approximately 1 bar.

The pressure reducing valve device according to the present invention can be connected to a remote control equipment (which for convenience may be referred to herein as a remote control, even though it may not be a remote control as such). Either of the flow meter and the controller or both can be connected to the remote control equipment (remote control), for example, via wireless communication.

In one embodiment, only the controller is connected to the remote control equipment.

In another preferred embodiment, both the flow meter and the controller are connected to remote control equipment.

The connection of the pressure reducing valve device according to the present invention to a remote control makes it possible to remotely disable local control of the device (for example, manually) for various operational reasons, such as detection of abnormally high flow rates of a fluid (for example, a liquid such as water) in a network, which indicate a major leak, such as a pipe rupture.

The controller can be programmed to send alarm signals to a remote control if fluid flows exceed a certain threshold level.

Accordingly, in another embodiment, the invention provides a fluid pressure reducing valve device comprising a spring-loaded pressure reducing valve, a controlled actuator with a motor, a flow meter and a controller as defined herein, wherein the fluid pressure reducing valve device is connected (e.g. wirelessly) to remote control equipment that enables remote control of the device operation.

The local network typically forms part of a larger network in which each of the plurality of low pressure local networks is connected to a high pressure main by means of a pressure reducing valve device according to the present invention.

Accordingly, in another embodiment of the present invention, a water supply system is provided, wherein the water supply system comprises a plurality of local networks, wherein each of the local networks is provided with a pressure reducing valve device according to the present invention, as defined herein.

The water supply system typically includes remote control equipment (e.g. a main control panel) as defined above, to which the controllers of each of the local network pressure reducing valve devices are connected.

Additionally or alternatively, flow meters of each of the valve devices can be connected to the remote control equipment to reduce the pressure of local networks.

In another embodiment, the invention relates to a method for controlling water pressure in a local water supply network having a pressure reducing valve connecting the local water supply network to a high pressure main, wherein the method comprises:

(i) providing the pressure reducing valve with an actuator with a motor that is designed to change the flow of water into the network after receiving control signals from the controller;

(ii) providing the network with a flow meter and a pressure sensor downstream (e.g. immediately downstream) of the pressure reducing valve, the flow meter and sensor being connected to a controller;

(iii) measuring flows and pressures to establish a relationship between the flow and pressure of water entering the network and storing the data establishing the relationship in the controller and/or at the remote control location;

(iv) using the specified relationship to establish a pressure reducing valve setting at a given time that maintains the required minimum pressure at a given remote location in the network; and

(v) monitoring changes in flow rate in the network detected by the flow meter and actuating the motorized actuator to change the setting of the pressure reducing valve in response to changes in flow rate to maintain the required minimum pressure at a specified remote location in the network.

The pressure reducing valve used in the above method is preferably a pressure reducing valve according to the invention, as defined and described herein.

Brief description of the drawings

Fig. 1 is Fig. 2 of the prior art GB 2176316.

Fig. 2 is a graphical representation of a pressure reducing valve device in cross-section from the side according to one embodiment of the present invention.

Fig. 3 is a schematic view showing the device c of Fig. 2 (but with a slightly differently shaped upper housing) connected to a controller which is also connected to a remote pressure sensor.

Fig. 4 is a typical graph of the pressure required for application in a network to create constant pressure at remote points with variable flow on the consumption side.

Fig. 5 is a schematic view of a water supply network showing a water main having a pressure reducing valve device according to the present invention and a local network containing a plurality of branches for supplying water to consumers (and leaks) downstream of the pressure reducing valve device. The pressure reducing valve device is connected to a main control panel.

Fig. 6 shows an algorithm used to control the operation of the pressure reducing valve device according to the invention. In Fig. 6 F^Drepresents the peak load flow rate on the consumption side, P^Rrepresents the pressure required by the remote user at flow rate F^Dat peak load on the consumption side, P^Drepresents the set pressure at F^Dto obtain pressure P^R, F^NAnd F^N+1represent instantaneous costs, P^Mand P^M+1represent the instantaneous pressure values for the remote user, and P^Nand P^N+1represent instantaneous values of pressure downstream.

Fig. 7 shows graphs of pressure and flow rate over a period of twenty-four hours in a water supply network comprising a pressure reducing valve device according to the present invention. The pressures and flow rates shown in the graphs are required to maintain a water pressure of 1 bar at a remote location in the network. The graph of Fig. 7A shows the network pressure (in bars) on the side upstream of the pressure reducing valve. The graph of Fig. 7B shows the flow rate in liters per second measured by a flow meter immediately downstream of the pressure reducing valve. The graph of Fig. 7C shows the water pressure measured by a pressure sensor immediately downstream of the pressure reducing valve and the flow meter. The graph of Fig. 7D shows superimposed graphs of flow rate and pressure from the graphs of Figs. 7B and 7C.

Fig. 8 shows a comparison of water pressures and water flow rates downstream of a pressure reducing valve over an eleven hour period for a conventional pressure reducing valve (dashed lines) and a pressure reducing valve device according to the present invention (solid lines). The pressures shown in the uppermost graph are the pressures (expressed as water head in meters) required to maintain a water pressure of 1 bar at a remote location in the network.

Implementation of the invention

To facilitate understanding of the invention, specific embodiments of the invention will now be described by way of example and with reference to the accompanying figures from Fig. 1 to 8.

With reference to the figures of the drawings, the spring-loaded pressure-reducing valve 1 has a housing 2 containing a water flow chamber 3. The inlet 4 opens into the water flow chamber through the inlet 5. The inlet is connected to the high-pressure water main 6. The outlet 7 from the water flow chamber is connected to the network of pipelines 8 for local distribution of water to individual consumers. The valve has a flow pressure-regulating plate 9 located opposite the inlet 5. A diaphragm 10 is attached to the plate 9, which diverges from it toward the housing, forming a seal with the upper and lower parts 11, 12 of the housing 2. Thus, the water flow chamber 3 is sealed between the upper and lower parts. The space above the membrane is a dry chamber, i.e. water does not enter this space.

The control plate has a guide rod 14 extending from it downwards into a guide 16 located in the inlet opening 5. The rod passes through both the control plate and the diaphragm. At its upper end, inside the dry chamber, it has a nut 17 resting on a centering spring washer 18, as well as a sealing pressure plate 19 of the diaphragm. In this design, the control plate is held centrally above the inlet opening 5.

In the embodiment, a separate control plate 109 is provided on the lower rod 14 opposite the opening. The diaphragm holds the plate 9/109 in the center above the opening 5.

The compression spring 21, located in the dry chamber, acts with its lower end 22 on the upper part of the pressure plate 19. The spring remains more or less compressed, as explained below. Thus, it remains located around the centering washer 18. Its upper end 23 rests against the drive element 24 of the spring at the end of the drive tube 25 of the servo device 26. The drive tube is placed in a fixed tube 27 of the servo device, attached to the upper part 11 of the valve body 2. The lead screw 28, remote from the spring, is used to align the axis of the drive tube inside the fixed tube. A motor 29 and a reducer 30 are provided to drive the lead screw. A nut 31, preferably a ball nut, is fixed to the remote end of the drive tube 25, wherein the latter is attached with a key to the fixed tube for protection against rotation. In this way, the spring drive element can be advanced to further compress the spring or retracted to reduce compression by correspondingly rotating the motor and lead screw.

Further downstream from the outlet 7 is the pipeline 8 of the local distribution network. In it, near the outlet, a flow meter 32 and a pressure sensor 33 are located. They are electronically connected to the controller 34. Also connected to the controller is a remote pressure sensor 35, located at the farthest point 36 of the pipeline 8. The controller 34 is also connected to the main remote control panel 39. The main control panel typically controls a plurality of local distribution networks, each of which is equipped with its own controller and a pressure reducing valve device. As an alternative to each local distribution network having its own controller, the pressure reducing valves can be controlled directly from the main control panel.

There are various leak points 37 in the pipeline, the flow rate at which increases with increasing pressure and the number of user taps 38, etc. It is they that primarily determine the flow rate at the pressure regulator 1. If it were of the type that was constantly set to a pressure that maintained sufficient pressure at the furthest point 36 of the network, the pressure would be such that, regardless of the user flow rate at the taps 38, the leaks 37 would worsen.

In this embodiment of the invention, the entire pressure reducing valve device includes not only the pressure reducing valve 1 and the flow meter 32, but also a controller 38 designed to control the regulator by means of a servomotor in accordance with the flow measured by the flow regulator, as well as a remote pressure sensor 35, which is not strictly necessary for this invention.

Many local distribution networks, such as network 8, have been previously measured and have pressure/flow characteristics such as those shown in Fig. 4, when the regulator is adjusted to provide the required pressure at the furthest point at varying flows. The ideal low pressure point 41 for zero flow is rarely encountered, due to leaks. A practical low pressure point 42 can be measured at night, when the users' demand for water is low. Other flow and pressure readings 43 can be obtained during periods of more or less intensive use by adjusting the pressure reducing valve to provide sufficient pressure at the furthest point.

In practice, the pressure-flow graph is essentially a straight line with a slope or gradient and an offset equivalent to the zero flow offset. The graph can be represented by the following equation:

Required regulator pressure = Pressure at zero flow + measured flow x graph gradient (in terms of pressure per unit flow).

This is surprising because one would expect that adjustment by means of a regulator would change the measured flow. However, this is a second order effect because the main factor determining flow is the consumer's water use. By comparison, the flow resulting from leakage is small and is kept lower than it would otherwise be by keeping the network pressure lower than it would be if it were set to the value that would ensure sufficiency at the furthest point at maximum flow. This value results in too much flow and too much leakage at all other flow rates.

The spring 21 in the pressure reducing valve counteracts the force acting on the side of the diaphragm 10, which is subject to the pressure to be adjusted, while the pressure force upstream acting on the regulating plate 9 is essentially constant and small compared to the force acting on the side of the diaphragm. Thus, this change can provide a shortening of the spring by an amount proportional to the required pressure change, if we take into account that only a small movement of the regulating plate is required for a significant change in the pressure drop at the outlet. Thus, for practical purposes, the linear displacement of the end of the spring under the action of the servomotor causes a linear change in the regulated pressure. Accordingly, the controller can be set to linearly shift the end of the spring in accordance with the flow rate.

If the pressure at zero flow and the gradient of the measured flow graph are unknown, the controller can be configured to periodically adjust the controlled pressure for different flow values in order to set the pressure values necessary to achieve sufficient pressure at the most remote point. For this purpose, a connection is made to the remote pressure sensor 35 and the near pressure sensor 33, in the first case the connection is carried out in a suitable wireless manner.

The controller may be equipped with a memory capable of recording a pressure and flow map, as opposed to recording only the offset and gradient in memory, and using that data as a lookup table to determine the value to which the controller should adjust the downstream pressure based on the measured flow rate.

Sensor 33 can be used to fine-tune the servomotor control to achieve the desired pressure in accordance with the measured flow rate.

The manner in which the device according to the present invention is configured to control the water pressure in the network will be described in more detail with reference to Figs. 5-8.

The pressure/flow characteristics of a local water supply network will vary depending on a number of variables, such as the length of the pipeline, the number of consumers, the number of leaks in the network and the location of the most remote user. Therefore, when setting up the device according to the invention, the initial step is to establish a pressure/flow relationship for the network and, in particular, to establish the flows into the network that are necessary to maintain the required water pressure at the most remote user at different times during twenty-four hours. For this purpose, during twenty-four hours, the water flow and pressure are measured using a flow meter 32 and a pressure sensor 33, and the water pressure at the remote user is measured using a remote pressure sensor 35 and, if necessary, adjusted using a pressure reducing valve to maintain the required minimum pressure at the remote user. The pressure and flow data are transmitted from the flow meter and pressure sensors to the controller, and the relationship between the flow and pressure is established, as described above.

A set of pressure and flow data for one local distribution containing a pressure reducing valve device according to the invention is shown in Table 1 below.

In the table, the water pressure data for the upstream side (i.e. the high pressure main) relative to the pressure reducing valve are shown in the columns under the heading I/L Pressure, while the water pressure downstream relative to the pressure reducing valve is shown in the columns under the heading O/L Pressure. The pressure figures are given in both bars and as water head in metres. The flow rate (given in both cubic metres per hour and litres per second) is the flow rate measured by the flow meter 32. The data represent the pressures required to maintain a water pressure of 1 bar at the remote user. The pressure and flow rate profiles over a 24 hour period are shown in graphs 7A to 7D in Fig. 7. The relationship between pressure and flow rate obtained from the data is shown in the graph in Fig. 4.

Table 1

Time Flow ^m3 per hour I/L Head pressure in m I/L Pressure Bar O/L Pressure head in m Consumption Liters per second O/L Pressure Bar 0 5.50 54.92 5.38 26,575 1,5279 2,60435 1 4.80 53.76 5.27 25.42 1,3334 2,49116 2 4.60 53.43 5.24 25.09 1,2779 2,45882 3 4.70 53.60 5.25 25,255 1,3057 2,47499 4 5.30 54.59 5.35 26,245 1,4723 2,57201 5 6.30 56.24 5.51 27,895 1,7501 2,73371 6 7.70 58.55 5.74 30,205 2,1391 2,96009 7 8.90 60.53 5.93 32,185 2,4724 3,15413 8 8.50 59.87 5.87 31,525 2,3613 3,08945 9 7.30 57.89 5.67 29,545 2,0279 2,89541 10 7.30 57.89 5.67 29,545 2,0279 2,89541 11 7.80 58.71 5.75 30.37 2,1668 2,97626 12 8.20 59.37 5.82 31.03 2,278 3,04094 13 9.30 61.19 6.00 32,845 2,5835 3,21881 14 8.80 60.36 5.92 32.02 2,4446 3,13796 15 9.00 60.69 5.95 32,35 2,5002 3,1703 16 9.40 61.35 6.01 33.01 2,6113 3,23498 17 10.30 62.84 6.16 34,495 2,8613 3,38051 18 12.00 65,64 6.43 37.3 3,3336 3,6554 19 12:30 66.14 6.48 37,795 3,4169 3,70391 20 11.40 64,65 6.34 36.31 3,1669 3,55838 21 9.70 61.85 6.06 33,505 2,6947 3,28349 22 10.20 62,67 6.14 34,33 2,8336 3,36434 23 8.40 59.70 5.85 31,36 2,3335 3,07328 24 5.30 54.59 5.35 26,245 1,4723 2,57201

Applying the relationship Y=mX+c to the data and graph gives a gradient (m) of 1.65 and a theoretical low pressure point (c) at zero flow of 17.5 (water head in meters). However, since in practice there is never zero flow (e.g. due to leaks), the practical low pressure point is a pressure of about 25 meters (water head).

Once the pressure/flow ratio has been established empirically as described above (although it is also possible to obtain the ratio by theoretical calculations), this ratio serves as the basis for controlling the pressure reducing valve according to the algorithm shown in Fig. 6.

Thus, as shown in the algorithm in Fig. 6, the pressure reducing valve is initially adjusted by means of a servomotor to position the spring 21 in such a way that if the flow measured by the flow meter 32 were the flow rate F ^D at the peak load on the consumption side, then the water pressure P ^D measured by the sensor 33 would be such as to provide the desired minimum pressure P ^R at the remote location. Then, data is collected on the actual flow rates in the pipeline 8 further downstream. A first measurement F ^N of the flow rate is made at time 1 and compared with the peak value F ^D of the flow rate. If F ^N is less than F ^D , then the water pressure is reduced by actuating the servomotor to move the position of the spring actuator 24 and the spring 21 to increase the pressing force of the spring with respect to the regulating plate 9. At the second time, the flow rate is measured again to obtain the flow rate F ^N+1 . If the flow rate has dropped, further movement of the spring drive element 24 and the spring 21 to increase the spring pressing force with respect to the regulating plate 9 is carried out in such a way as to further reduce the water pressure measured by the sensor 33. On the other hand, if the flow rate F ^N+1 has increased, the spring drive element 24 and the spring 21 move in the opposite direction to reduce the spring pressing force with respect to the regulating plate, thereby increasing the water pressure in the pipeline 8. Thus, by carrying out flow rate measurements at regular intervals and comparing each new flow rate measurement F ^N+1 with the previous flow rate measurement, the water pressure in the pipeline 8 can be constantly adjusted so that the pressure measured by the sensor 33 is maintained at the minimum level necessary to ensure the required minimum pressure P ^R at the remote location 36.

In conventional local water supply networks, pressure reducing valves are typically configured in such a way that the water pressure measured immediately downstream of the pressure reducing valve is the minimum water pressure required to ensure a given pressure at a remote location 36. As a result, an excess pressure is created in the network most of the time, which, among other things, significantly increases water losses due to leakage. This problem can be eliminated by using a pressure reducing valve device according to the present invention. The advantages of the pressure reducing valves according to the present invention over conventional pressure reducing valves installed to ensure a constant water pressure are illustrated by the graphs shown in Fig. 8. The lower graph shows the flows at different times of the day. The flows measured in a network equipped with a conventional pressure reducing valve are shown in dotted lines, while the flows measured when the conventional pressure reducing valve was replaced by the pressure reducing valve device according to the present invention are shown in solid lines. The uppermost graph in Fig. 8 shows the water pressure in the network for the same period. As can be seen, the water pressure in the network equipped with a conventional PRV valve remains constant, and therefore the pressure is much higher than it should be. In contrast, the pressure in the same network equipped with the pressure reducing device according to the invention is significantly lower throughout the tested period of time, but is still sufficient to maintain the required water pressure at the remote location.

In the network shown in Fig. 5, the controller 34 is connected to a main control panel 39 (remote control panel) - a place from which the network can be controlled remotely. The main control panel can be connected to a plurality of local networks fed by a high-pressure main, wherein each of the local networks is provided with a valve device for reducing the pressure according to the invention. As an alternative or in addition, flow meters and pressure sensors in each local network can be connected to the main control panel, and when abnormal flow values are detected (for example, indicating a serious failure in the network or a serious leak, such as a pipe rupture), alarm signals are generated in the main control panel. By connecting the controller 34 to the remote control panel, it is possible to remotely control the pressure and flow further downstream, where this is required for operational purposes.

Claims (50)

1. A valve device for reducing the pressure of a fluid medium, comprising: - a spring-loaded pressure-reducing valve having: - a housing containing a chamber for the flow of a fluid medium, - an opening for feeding fluid into the chamber and an opening for removing fluid from the chamber, - a control plate located opposite the opening and exposed during use to the action of the supplied fluid acting on it, - a spring, under the action of which the possibility of shifting the plate towards the hole is ensured, and - a diaphragm between the control plate and the housing for closing the chamber between them, which is subjected to the controlled pressure in the chamber during use, - a controlled drive with a motor acting between the housing and the end of the spring farthest from the control plate, - a flow meter located downstream of the outlet, and - a controller configured to receive flow data from the flow meter and control a controlled motor drive to retract the far end of the spring in accordance with the flow rate measured by the flow meter; wherein, in order to increase the flow rate on the consumption side measured by the flow meter, the controller is configured to control the controlled drive with a motor to move the far end of the spring to reduce the force pressing the spring against the control plate to increase the pressure of the fluid further downstream relative to the outlet, and vice versa. 2. A valve device for reducing the pressure of a fluid medium according to claim 1, in which the body has an internal cavity divided by a diaphragm into a chamber for the flow of a fluid medium on one side of the diaphragm and a dry chamber on the other side of the diaphragm. 3. A valve device for reducing the pressure of a fluid medium according to paragraph 1 or 2, wherein the device is designed with the possibility of reducing the water pressure. 4. A valve device for reducing the pressure of a fluid medium according to claim 1 or 2, wherein the device is designed with the possibility of reducing the pressure of both liquid and gaseous hydrocarbon fluids. 5. A valve device for reducing the pressure of a fluid medium according to any one of paragraphs. 1-4, in which the controlled drive with a motor is a drive with a servomotor. 6. A valve device for reducing the pressure of a fluid according to claim 5, in which the controller is configured to calculate the action of the servomotor in positioning the spring in accordance with a substantially linear relationship between the pressure and the flow rate downstream. 7. A valve device for reducing the pressure of a fluid medium according to claim 6, in which the calculation is based on the pressure that must be achieved depending on the servo positioning of the spring. 8. A valve device for reducing the pressure of a fluid medium according to claim 7, in which the calculation is based only on the servo positioning of the spring. 9. A valve device for reducing the pressure of a fluid according to claim 8, in which the calculation is based on a downstream pressure and flow reference table. 10. A valve device for reducing the pressure of a fluid according to claim 9, wherein the reference table includes pressure values that must be achieved. 11. A valve device for reducing the pressure of a fluid medium according to claim 10, in which the reference table includes spring positions depending on the number of revolutions of the servo drive. 12. A valve device for reducing the pressure of a fluid medium according to any preceding claim, in which the regulating plate is designed to abut against the central region of the diaphragm, and a guide rod passes into the centering guide in the hole. 13. A valve device for reducing the pressure of a fluid medium according to any one of paragraphs. 1-11, in which the regulating plate is located at a distance from the diaphragm on a guide rod extending from the diaphragm into a centering guide in the opening. 14. A valve device for reducing the pressure of a fluid according to any preceding claim, wherein the spring is a compression spring acting on the side of the diaphragm remote from the orifice. 15. A valve device for reducing the pressure of a fluid medium according to any one of paragraphs. 1-13, in which the spring is an extension spring acting on the side of the diaphragm closest to the opening. 16. A valve device for reducing the pressure of a fluid according to any preceding claim, in which the controlled actuator with a motor includes a device with a nut and a lead screw, adapted to act on the end of the spring remote from the diaphragm, and driven by the actuator motor. 17. A valve device for reducing the pressure of a fluid according to any preceding paragraph in combination with a remote pressure sensor for measuring downstream the pressure to be maintained. 18. A fluid pressure reducing valve device according to claim 1, wherein the fluid is water and the fluid pressure reducing valve device is connected to a local water supply network, wherein the controller is programmed or has a command from a remote control center to vary the flow rate such that the minimum water pressure provided to a remote user in the network, such as the user experiencing the greatest pressure drop, is in the range of from 0.5 bar to 2 bar. 19. A valve device for reducing the pressure of a fluid according to claim 18, in which the controller is programmed or has a command from a remote control center to vary the flow rate so that the minimum water pressure provided to a remote user in the network is in the range of from 0.6 bar to 1.5 bar, most often from 0.7 bar to 1.2 bar, for example approximately 1 bar. 20. A valve device for reducing the pressure of a fluid medium, comprising: - a spring-loaded pressure-reducing valve having: - a housing having an internal cavity divided by a diaphragm into a chamber for the flow of fluid on one side of the diaphragm and a dry chamber on the other side of the diaphragm, - an opening for feeding a fluid into a fluid flow chamber and an opening for removing a fluid from a fluid flow chamber, - a control plate located opposite the opening and exposed in use to the action of the supplied fluid acting on it, wherein the control plate is connected directly or through a connecting element to the said one side of the diaphragm, and the diaphragm used is exposed in use to the action of the controlled pressure in the chamber for the flow of the fluid, - a compression spring located in the dry chamber on said other side of the diaphragm, the compression spring being positioned so as to apply pressure through the diaphragm and push the plate towards the opening, and - a controlled drive with a motor acting between the housing and the end of the compression spring farthest from the control plate, - a flow meter located downstream from the outlet; - a controller and an electronic data storage located within or associated with the controller, wherein the data storage contains data defining the relationship between the flow rate of the fluid and the pressure of the fluid in a downstream pipeline network to which the spring-loaded pressure reducing valve is connected; wherein the controller is configured to receive flow data from the flow meter and to increase the flow on the consumption side measured by the flow meter, control the controlled drive with a motor for moving the far end of the spring to reduce the force pressing the spring to the control plate to increase the pressure of the fluid further downstream relative to the outlet, and vice versa. 21. A valve device for reducing the pressure of a fluid medium according to any one of paragraphs 1-20, wherein the valve device for reducing the pressure of the fluid medium is connected to remote control equipment, by means of which the possibility of remote control of the operation of the device is ensured. 22. A valve device for reducing the pressure of a fluid medium according to claim 21, in which only the controller is connected to the remote control equipment. 23. A valve device for reducing the pressure of a fluid medium according to claim 21, in which both the flow meter and the controller are connected to remote control equipment. 24. A valve device for reducing the pressure of a fluid according to claim 21, in which the controller is programmed to send alarm signals to a remote control if the fluid flows exceed a certain threshold level. 25. A water supply system comprising a plurality of local networks, wherein each of the local networks is provided with a valve device for reducing the pressure of the fluid according to any one of paragraphs 1-24. 26. A method for controlling water pressure in a local water supply network having a spring-loaded valve for reducing pressure according to any of paragraphs 1-24, connecting the local water supply network to a high-pressure main, comprising: (i) providing a spring-loaded pressure reducing valve with an actuator with a motor which is designed to change the flow of water into the network upon receiving control signals from the controller; (ii) providing the network with a flow meter and a pressure sensor downstream of the spring loaded pressure reducing valve, the flow meter and sensor being in communication with the controller; (iii) measuring flows and pressures to establish the relationship between the flow and pressure of water entering the network and storing the data establishing this relationship in the controller and/or at the remote control location; (iv) using the specified relationship to establish a pressure reducing valve setting at a given time that maintains the required minimum pressure at a given remote location in the network; and (v) monitoring changes in flow rate in the network detected by the flow meter and actuating the motorized actuator to change the setting of the pressure reducing valve in response to changes in flow rate to maintain the required minimum pressure at a specified remote location in the network.