Flow throttle valve

Abstract

A flow throttle valve particularly suitable as a reject valve for keeping constant the pressure of the flow pumped into the system by the high pressure pump and for maintaining the system pressure of a reverse osmosis device at a pressure level below 20 bar. The flow pressure is controlled by a spring-driven cone (3) which is partially in the outlet channel (2) of the throttle valve at a given time. A motion restrictor (7, 8) is supported on the wide end of the cone (3) such that in its lowest position, the cone (3) allows a bypass flow of a given flow rate up to the target pressure of the system. A further increase in flow rate results in the cone (3) rising and the force exerted by the flow pressure on the restrictor member (7) contributes to preventing the valve from closing.

Description

[Technical Field]

[0001] This application relates to a flow throttle valve particularly suitable as a reject valve for maintaining a constant pressure of the flow rate pumped into a system by a high-pressure pump, and for maintaining the system pressure of a reverse osmosis apparatus at a pressure level of less than 20 bar. [Background technology]

[0002] It is known that the pressure in a reverse osmosis module can be adjusted by controlling the amount of water released from the module as a reject, while water is simultaneously supplied to the module by a high-pressure pump. A module refers to a conventional standardized tubular pressure vessel and the reverse osmosis membrane contained within it. As a stream of saline solution passes through the module, the membrane separates fresh water from the saline solution. The remaining concentrate separated from the fresh water is called the reject.

[0003] In reverse osmosis systems, the number and type of membranes determine the limiting of the supply.

[0004] The higher the concentration of solids dissolved in water, mainly salts (TDS = total dissolved solids), the higher the osmotic pressure of the water. For the membrane to separate fresh water from the saline solution, the pressure within the module must be at least equal to the reverse osmotic pressure of the concentrate flowing through the module. The amount of fresh water separated by the membrane is called the output. The sum of the output and the rejected amount is equal to the supply amount.

[0005] When constant adjustments, such as those made by flau restrictor holes, are used on the reject side, a problem arises: as the salinity of the water changes, the pressure within the system also changes. The temperature of the water being treated also significantly affects the membrane output, and consequently, the rejection rate changes. Another problem with constant adjustments is that as the membrane degrades, the membrane output decreases, and the amount of rejection increases relative to the supply rate. Constant adjustments are only appropriate when the supply rate and membrane output are constant.

[0006] In small brackish water reverse osmosis systems with output of several tens of liters per hour, the reject flow is typically adjusted using a manually adjustable needle valve, which is set to the desired level once the system's pressure pump is started. The main problem with this system is that the membrane output only begins to stabilize after the system has been in use for some time.

[0007] In particular, when the reverse osmosis system operates on energy obtained from solar panels without an intermediate battery, manual adjustment of the reject valve is always necessary. This is because the solar irradiance (kW / m 2 This is because as the temperature changes, the amount of electricity obtained from the solar panels changes. As a result, the rotational speed of the inverter-controlled high-pressure pump in the system also changes, and consequently, the supply and rejection rates of the system change. [Overview of the Initiative]

[0008] The purpose of the throttle valve according to the present invention is to maintain a constant pressure in the reverse osmosis system regardless of changes in the supply rate, and to make it functionally reliable at a predetermined system pressure.

[0009] The valve according to the present invention is spring-driven. The valve comprises a cone that adjusts the flow opening of the outflow channel and has a narrow end on the inflow side. As described below, the cone rises as it moves toward the outflow channel in the flow direction, and the cross-sectional area of ​​the outflow opening of the outflow channel also increases.

[0010] Spring-driven valves such as check valves, pressure relief valves, safety valves, and bypass valves are structurally similar to each other, but their operating principles and intended uses differ.

[0011] Structurally, the throttle valve according to the present invention is similar to a check valve, but its function and intended use differ from those of check valves, pressure relief valves, throttle valves for refrigerators, and other valves mentioned above. It is a valve in which the flow path cross-sectional area is stably adjusted in response to changes in flow rate, and the valve maintains a constant system pressure. This cannot be achieved with the other valves mentioned above.

[0012] Publication JP3079258U describes a check valve whose structure is similar to that of the throttle valve according to the present invention. In this valve, a spring pushes a valve-closing cone against the wall of the conical valve seat. The cone is set deep within the valve seat and has a sealing ring fitted around it. The purpose of the valve is to prevent inflow from the opposite direction to the inflow direction when it is closed. Since the cone is mostly within the seat, the inflow pressure that attempts to open the valve mainly acts on the stem end of the cone and hardly on the cone itself. When the force acting on the cone and its stem due to the inflow exceeds the opposite force acting on the cone by the spring, the cone suddenly rises, thereby opening the channel. Immediately thereafter, the flow pressure between the cone and the conical seat of the cone becomes almost zero. This is because the flow velocity increases significantly between the walls which are located close to each other. In the type of valve disclosed in the publication, the inflow pressure acting on the cone is so small that when the valve opens, the spring force pulls the cone back to the seat. To prevent this from happening, the inflow rate must be sufficiently large and the spring force small. Otherwise, the cone will begin to strike the seat (disturbance). The greater the spring force acting on the cone, the worse this disturbance becomes. Therefore, the spring should be as loose as possible and designed to return the cone to the seat only after the flow has stopped. In fact, this type of check valve is always either fully open or completely closed. The structure of this check valve is not suitable for maintaining inflow pressure as the flow rate changes.

[0013] Publication WO2014168768 describes a valve structurally similar to the valve according to the present invention. This is for the sudden release of internal gas pressure in a high-pressure environment underwater when the pressure in the system rises for any reason. It is not intended for the maintenance of liquid flow or inflow pressure. Due to the flow of liquid, it faces the same problems as the check valve described in the above publication.

[0014] Publication US2017 / 0030616A1 describes a valve that operates as a throttle valve for a refrigeration unit, where pressurized refrigerant liquid flows through the valve and evaporates. The valve cone is positioned relative to the edge of the outlet channel. In an attempt to prevent the valve cone from clogging the outlet channel, a small groove is provided at the edge of the outlet channel to allow the refrigerant liquid to flow continuously. The problem with the proposed solution is that as the amount of liquid pumped by the compressor increases, the force on the cone decreases due to the pressure of the liquid flow, while the force on the cone due to the spring trying to close the valve increases. In the absence of other forces, the valve closes abruptly and then immediately opens, causing the cone to begin hitting the edge of the outlet channel (disturbance). The valve in the publication attempts to mitigate this phenomenon by adding an additional channel with a fixed hole next to the flow channel closed by the cone, thereby reducing the cone's rise at maximum flow rate. The publication notes that the proposed solution fails to eliminate the disturbance at maximum flow rate. However, it is clear that the problem occurs at all flow rates where the cone begins to rise.

[0015] The throttle valve according to the present invention solves the above-mentioned problem (disturbance phenomenon) based on the features described in attached claim 1. The spring-driven cone of the throttle valve according to the present invention rises and falls in accordance with changes in flow rate, maintaining a constant preset system pressure.

[0016] The throttle valve according to the present invention has an outlet channel located centrally within the body and having a flow-perpendicular cross-sectional area smaller than the flow-flow cross-sectional area of ​​the tubular body of the throttle valve. The narrow diameter end of a cone that adjusts the flow opening of the outlet channel is on the inlet side. The large diameter end of the cone has a motion restrictor supported at the diameter end, which consists of a restrictor member that is openably supported by a stem passing through the cone and is positioned perpendicular to the stem. The restrictor member has restrictor legs supported by the restrictor member, which extend from the restrictor member to a plane surrounding the outlet end of the outlet channel.

[0017] The restrictor legs limit the movement of the cone so as not to be pressed against the periphery of the end of the outflow channel by the force applied to the outflow channel by the spring, thereby enabling a uniformly surrounding bypass flow that allows the cone to always flow between the restrictor legs and further through the channel between the restrictor member and the body. The flow rate of this bypass flow can be adjusted by adjusting the length of the restrictor legs. Figure 2.

[0018] The support plate, which is almost in contact with the inner surface of the main body, is supported by the stem of the inlet cone, and one end of the pressurized compression spring is supported by the support plate, although the other end is supported by the main body.

[0019] The flow generates a pressure difference across the motion restrictor, exerting a force on the restrictor member of the motion restrictor in the flow direction. This force increases as the flow rate increases, and its magnitude can be adjusted by adjusting the cross-sectional area of ​​the channel between the restrictor member and the main body in the flow direction. Additionally, the flow generates dynamic pressure on the restrictor member, which imparts an additional force to the restrictor member in the flow direction.

[0020] The support plate is provided with channels that allow flow. The cross-sectional area of the channels perpendicular to the flow is arranged such that a pressure difference of a desired magnitude is generated across the support plate by the flow, and a force is exerted on the support plate in the flow direction as well. This force increases as the flow rate increases and contributes to resisting the increase in the spring force attempting to close the valve.

[0021] The aforementioned forces exerted on the motion restrictor and the support plate in the flow direction resist the increase in the force generated by the rising cone and the decrease in the force exerted on the cone by the flow pressure. Due to these resistance forces, the rising height of the cone is automatically adjusted to maintain a constant system pressure, thereby preventing surging phenomena from occurring.

[0022] When operated as a reject valve for a reverse osmosis system, the throttle valve according to the present invention can directly operate the electric motor of the high-pressure pump of the reverse osmosis unit using electricity obtained from a solar panel via an inverter. The rotational speed of the motor, and correspondingly the supply flow rate, vary according to the electric power obtained from the solar panel. The change in the rotational speed of the motor causes the flow rate of permeate water and, correspondingly, the flow rate of the reject produced by the reverse osmosis system per unit time to change.

[0023] Next, the structure and operation of the throttle valve according to the present invention will be described in detail with reference to FIGS. 1 to 3.

Brief Description of the Drawings

[0024] [Figure 1] Shows a prior art check valve in which the valve cone is supported on a conical seat. [Figure 2] Shows a longitudinal cross-section of the structure of the throttle valve according to the present invention with a cone 3 in the lowest position. [Figure 3] Shows the operation of the valve according to the present invention.

Modes for Carrying Out the Invention

[0025] Figure 2: - The throttle valve includes a tubular body 1 into which the flow enters from one end, and the body 1 is provided with an outlet channel 2 having a circular cross-section. - The cone 3 is positioned in the outflow channel 2 such that its narrow end faces the inflow side, and the cone is axially supported on a stem 4 that passes through the cone 3. - The support plate 5 is supported by the stem 4 on the inlet side, and the support plate 5 is movable along the stem 4 and is in close contact with the inner surface of the main body 1. - A pressurized compression spring 6 surrounding the stem 4 is provided between the outlet channel 2 and the support plate 5, with one end of the compression spring 6 supported by the support plate 5 and the other end supported by the body 1. - The support plate 5 is provided with one or more channels 10 that allow for flow. - The motion restrictor is supported at the large diameter end of the cone 3, and the motion restrictor is releasably supported on a stem 4 passing through the cone 3, and consists of a restrictor member 7 having restrictor legs 8 that are supported on a restrictor member extending from the restrictor member 7 to a plane 9 surrounding the outflow end of the outflow channel 2. - The channel 11 that allows flow is formed between the restrictor member 7 and the main body 1. - The restrictor legs 8 and spring 6 restrict the movement of the cone 3 so as not to be pressed against the periphery of the end of the outflow channel 2 by the force applied. The restrictor legs 8 allow the cone 3 to always have a uniformly surrounding bypass flow when the cone 3 is in its lowest position, so that the flow can pass between the restrictor legs 8 and further through the channel 11. The flow rate of the bypass flow can be adjusted by adjusting the length of the restrictor legs 8.

[0026] Figure 3: - The pressure generated by the throttle valve is p1. - The pressure between the outlet end of outlet channel 2 and the restrictor member 7 is p2. The pressure difference across outlet channel 2 is (p1-p2). - The pressure difference across the restrictor member 7 is (p2 - p0), and the magnitude of the pressure difference and the force applied on the restrictor member 7 can be adjusted by adjusting the cross-sectional area of the restrictor member 7 perpendicular to the flow. - The magnitude of the force applied on the support plate 5 by the flow can be adjusted by adjusting the cross-sectional area of the channel 10 perpendicular to the flow.

[0027] The flow pressure in the outflow channel 2 is mainly converted into velocity (Bernoulli's theorem). The flow velocity at the end of the outflow channel 2 is given by the formula v = C D (2gH) 1 / 2 obtained from. The pressure head H corresponds to the pressure difference across the channel that adjusts the flow.

[0028] The flow rate in the outflow channel 2 is approximately obtained from the formula Q = C D ·A·(√(2g·H)) 1 / 2 where Q is in [m 3 / s], C D is a constant depending on the channel shape, A [m 2 is the cross-sectional area of the channel, g is 9.81 m / s 2 , and H [m] is the pressure head, for example, the pressure difference (p1 - p2) across the outflow channel 2.

[0029] Similar formulas are also used to obtain the flow pressure difference across the restrictor member 7 and the support plate 5.

[0030] Next, an embodiment of the valve according to the present invention will be described.

[0031] Problems to be solved in the embodiment: Note: In the translation of the flow rate formula in item , the square root symbol is added in the English translation according to the correct formula. The original text seems to be missing the square root symbol. The correct formula for the flow rate of a fluid through an orifice or channel is \(Q = C\cdot A\cdot\sqrt{2gH}\).When cone 3 completely closes outlet channel 2, the pressure generated by the high-pressure pump forces cone 3 to open the valve. An equal resistance force must be generated by the preload spring 6 for cone 3 to begin rising only when the system's target pressure is reached. As the valve opens, the cross-sectional area of ​​cone 3, to which the flow pressure is applied, decreases, while the force generated by spring 6, which tries to close the valve, increases. If no other force acts on cone 3, the valve will close abruptly and then immediately open (a turbulent phenomenon).

[0032] Solution: The restrictor member 7 and, if necessary, the support plate 5 of the throttle valve of the present invention, are subjected to a force parallel to the direction of flow, which resists the increase in the force that would otherwise close the valve.

[0033] In this exemplary embodiment, the flow rate pumped by the high-pressure pump is 5-8 m³ 3 The system's target pressure is 10.5-11 bar. The flow from the throttle valve is 0 bar. g It continues up to the ambient pressure.

[0034] Throttle valve dimensions: - The inner diameter of body 1 is 30 mm. -Outflow channel 2 has a diameter of 16 mm and 2 cm 2 It has the following cross-sectional area. - The cone angle of cone 3 is 34 degrees. - Compression spring 6 has a free length of 185 mm, a wire diameter of 3.76 mm, and a spring constant of 3.55 N / mm. - The cross-sectional area of ​​the restrictor member 7 perpendicular to the flow is 3.7 cm². 2 That is the case. - The cross-sectional area of ​​the channel 11 between the restrictor member 7 and the main body 1 is 1.5 mm². 2 That is the case.

[0035] The length of the restrictor leg 8 of the motion restrictor is 5m when the cone 3 is at its lowest position and p1-p2=10 bar. 3The flow rate is defined so that it can pass through the cone at a rate of / h (Figure 2). In this case, the cross-sectional area of ​​the cone 3 at the outlet end of the outlet channel 2 is 1.7 cm². 2 Therefore, the allowable flow cross-sectional area of ​​the annular flow opening after passing cone 3 is 0.3 cm². 2 The flow imparts a force of 170 N to cone 3 in the direction of flow. The pressure difference across restrictor member 7 (P2-P0=0.4 bar) imparts a force of 15 N to restrictor member 7. For cone 3 to remain in the correct position, the force generated by spring 6 must be equal to the sum of the aforementioned forces, i.e., 185 N. This means that spring 6 is preloaded to a length of 133 mm. Since the inlet end of the stem 4 of cone 3 is subjected to the same pressure as cone 3, the cross-sectional area of ​​cone 3 at the outlet end of outlet channel 2 is used in the calculation.

[0036] -5.5m 3 At a flow rate of / h, that is, immediately after the valve opens, the cross-sectional area 2 of cone 3 at the outlet end is 1.67 cm². 2 In this case, it is subjected to a force of 167N generated by the flow pressure. Since the pressure difference across the restrictor member 7 is 0.5 bar, the restrictor member 7 is subjected to a force of 19N. The spring 3 is compressed by a further 0.25 mm, so the force generated by the spring increases by 1N, i.e., to 186N. 167N + 19N = 186N, and in particular, the restrictor member 7 is subjected to additional dynamic flow pressure, so the valve remains open.

[0037] -Maximum flow rate 8m 3 When the pressure difference across the outflow channel 2 is 10 bar at 1 / h, the cone 3 rises 1.5 mm, and the cross-sectional area of ​​the annular flow opening surrounding the cone is 0.5 cm². 2 It increased to 1.50 cm². Accordingly, the cross-sectional area of ​​cone 3 at the outlet end of outlet channel 2 was 1.50 cm². 2 The force decreases, and as a result, the force generated by the flow pressure, applied to cone 3, is 150N. The force generated by spring 3 increases by 5N, to 189N. 8m 3A flow rate of / h generates a pressure difference exceeding 1.1 bar across the restrictor member 7 of the motion restrictor. In this case, the force exerted by the flow on the restrictor member 7 is 41N. Since 150N + 41N > 189N, and the restrictor member 7 is also subjected to the dynamic pressure of the flow, an additional force parallel to the direction of the flow is generated, so the valve does not close.

[0038] Flow rate is 8m 3 If the value is / h, the pressure difference across the restrictor member is 1.1 bar, so the pressure on the inlet side of outlet channel 2 must be 11.1 bar, so that the pressure difference across outlet channel 2 becomes 10 bar.

[0039] The size of the channel 10 within the support plate 5 may be such that it affects the pressure difference across the support plate 5. Since the support plate 5 is supported on the stem 4 of the cone 3, the magnitude of the force applied on the support plate 5 in the flow direction may be used to resist the force applied to the cone 3 by the spring 6 as needed.

[0040] As a result of the aforementioned forces, cone 3 automatically enters an equilibrium state at different flow rates, and the throttle valve according to the present invention maintains the system pressure essentially constant at a desired level.

Claims

1. A flow throttle valve particularly suitable as a reject valve for maintaining a constant pressure of a flow rate pumped into a system by a high-pressure pump and maintaining the system pressure of a reverse osmosis apparatus at a pressure level of less than 20 bar, wherein the valve comprises a tubular body (1), the flow enters from one end of the tubular body, the body (1) is provided with a central outflow channel (2) of circular cross-section, and has a cone (3) within the body with a narrow end positioned on the inflow side, and a support plate (5) movable along a stem (4) is axially supported on the stem (4) which is supported on the inflow side. The outer end of the support plate (5) is in substantially contact with the inner surface of the main body (1), The support plate (5) is provided with a channel (10) for the flow through it. A pressurized compression spring (6) surrounding the stem (4) is provided between the outflow channel (2) and the support plate (5), with one end of the compression spring (6) supported by the support plate (5) and the other end supported by the main body (1). The motion restrictor (7, 8) is supported at the large diameter end of the cone (3), and the motion restrictor (7, 8) consists of a restrictor member (7) and a restrictor leg (8) supported by the restrictor member (7) and extending from the restrictor member (7) to a plane (9) surrounding the outlet end of the outlet channel (2), wherein the restrictor leg (8) is applied to restrict the movement of the cone (3) so as to prevent the cone from being pressed against the periphery of the outlet end of the outlet channel (2) by the force generated by the spring (6), thereby enabling a uniformly surrounding bypass flow that allows the cone (3) to always flow between the restrictor leg (8) and further to flow through the channel (11) that allows flow between the restrictor member (7) and the body (1), The aforementioned flow throttle valve.

2. The valve according to claim 1, characterized in that the position of the support plate (5) on the stem (4) is adjustable in the axial direction of the stem.

3. The valve according to claim 1 or 2, characterized in that the stem (4) passes through the cone (3) and the restrictor member (7) is releasably supported on the stem (4).

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