DK202100003U4 - Pressure compensating flow regulating valve - Google Patents

Abstract

The present invention relates to a type of pressure compensated flow control valve which delivers a preset constant flow rate, in a liquid or gas medium, using an elastomeric bellows with folds following a helical shape along the bellows. The valve invention can deliver a stable flow rate, down to a few liters per hour, from supply pressures corresponding to pressure levels, which i.a. found in water supply installations in homes, horticulture and industry. The valve invention can also handle fluctuating changes in the pressure drop across the valve without changing the set flow rate that the valve delivers. The valve also functions as a shut-off valve (non-return valve), and is relatively resistant to particle penetration. The primary component of the invention is a flexible bellows of elastomeric material designed for this purpose, which is closed at one end, and when installed in the cylindrical chamber of the valve housing, flexible passage-limiting channels are formed between the folds of the bellows and the cylindrical wall of the valve chamber. With varying pressure drops across the valve, the bellows will either expand or compress, thereby changing the cross-sectional openings in the ducts, thereby maintaining the set flow rate.

Description

Technical Field The present invention relates to a type of pressure compensating flow control valve which is a pressure independent flow valve capable of delivering a preset small constant flow rate in a medium which is either in liquid or gaseous form. .

Technical field Pressure-compensating flow-regulating valves are designed to be able to supply a constant flow rate themselves, by being able to adjust the size of their valve openings themselves, based on the pressure drop size above the valve unit.

A typical pressure-dependent flow valve will have a flow rate that varies if the supply pressure or load on the outlet side of the valve varies.

This is because the size of the valve opening is constant, which results in varying pressure drops across the valve.

In the event of pressure changes, the valve opening, in a pressure-independent flow valve, must vary in order to maintain a continuous constant pressure drop across the valve unit and thereby ensure a constant flow rate.

The lower the flow rate that the valve has to deliver, the higher the pressure drop across the valve opening, so it requires a very restrictive flow restriction (small opening) in the valve construction, in order to achieve relatively small flow rates.

A common use of pressure-compensated flow control valves is in hydraulic systems, where they ensure a smooth and constant speed, of hydraulic motors or cylinders, under varying loads.

A simple compact valve variant is shown schematically in fig. In this, the main valve opening (41) has a fixed size, where a certain amount of flow is supplied, depending on the given pressure drop between the valve inlet (42) and the outlet (43). To accommodate pressure drop changes, a compensated spring-actuated control slider (44) is included in the valve construction, which adjusts an additional opening (45), thereby ensuring an even pressure difference between the valve inlet (42) and outlet (43). This type of valve construction is simple and efficient, but reacts unstable if set to deliver a relatively small amount of flow, in addition to the fact that the valve is very sensitive to the penetration of polluting particles.

An example of a known simple designed pressure compensated flow control valve type which can handle fluctuating pressure drop values, polluting particles and obstruction of return is the rubber ring valve, shown schematically in fig. This type of valve uses a flexible rubber ring (51), with a predetermined opening diameter, loosely installed in the valve housing.

If the pressure drop increases over the valve, the rubber ring is pressed up against a conically shaped end wall (52) in the chamber of the valve housing, thereby forcing the rubber ring to deform and causing the opening diameter of the rubber ring to decrease.

Likewise, when the pressure difference decreases, the opening widens again when the rubber ring returns to its original shape and position.

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Page 2 of 5 The valve has a limited pressure drop range in which it can be adjusted, due to the rubber ring's limited ability to deform its opening, but the valve is suitable for use in liquid containing contaminating particles, due to the flexible rubber ring that is loose in the valve body.

In addition, a version of this valve can act as a shut-off valve (non-return valve) that prevents backflow by sliding the rubber ring to the opposite end of the valve chamber and closing a circle of small inlet holes (53). However, this closure requires a relatively large backflow before the rubber ring is pushed to the opposite end of the valve body and seals the inlet holes.

All flow control valves have some form of constriction, to limit the flow rate down to the desired level.

When the flow rate is limited down to a relatively small level, the pressure difference is significantly raised above the valve, making it more difficult to ensure a constant and controllable amount.

Micro-irrigation installations that supply water to the plants in small quantities use different ways to deal with this.

A general method is to reduce the supply pressure, to minimize the pressure drop outside the individual drip valves (emitter), but it is limited how much the supply pressure can be lowered, to overcome the pressure drop, created by long supply lines and height difference in installations.

Several known types of micro-irrigation emitters include equipped with a maze of small channels with flow obstructions, which help to create vortices in the flowing medium, thereby inducing a flow resistance.

A maze of ducts provides a more stable and controllable flow rate instead of using a very small short valve opening, and the smaller the valve opening, the more the valve is exposed to clogging of polluting particles.

However, clogging can be minimized by installing filters in the supply system, but it is not always sufficient if contamination occurs later in the installation or that there is an intentional supply of particles, such as plant fertilizers, etc., into the water.

The object of the invention The object of the presented valve invention is to provide a valve construction which delivers a preset constant flow rate down to a few liters per hour, from supply pressures corresponding to pressure levels, which i.a. found in water supply installations in homes, horticulture and industry.

The valve invention must also be able to handle fluctuating changes in pressure without changing the set flow rate that the valve delivers.

The medium which the valve invention is to handle is in liquid form, but is also intended to be able to be used in a medium which is in gaseous form.

In addition to regulating the flow, the valve invention must also function as a shut-off valve (non-return valve), in order to avoid backflow in the valve and possible contamination in the supply system.

Presented valve construction must be able to handle a certain degree of penetration and deposition of smaller particles, without appreciable degradation of the intended function of the valve, and the possibility of loosening and flushing the particles out of the valve.

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Page 3 of 5 The valve invention must be of a simpler design than other known valves with the same function, in addition to the fact that it must consist of few components and have relatively low production costs.

BACKGROUND OF THE INVENTION The present invention relates to a type of pressure compensating flow control valve which delivers a preset constant flow rate in a liquid or in a gas medium, using a bellows made of elastomeric material closed at one end and whose folds follow a spiral shape along the bellows.

The valve invention can supply a stable flow rate, down to a few liters per hour, from supply pressures corresponding to pressure levels, which are found, for example, in water supply installations in homes, horticulture and industry.

The valve invention can also handle fluctuating changes in the pressure drop across the valve due to any changes in the supply pressure or changes in the pressure resistance at the outlet of the valve, without changing the set flow rate that the valve delivers.

The valve also functions as a shut-off valve (non-return valve), with the option of being set to a given opening pressure (crack pressure), using the installed spring.

The flexible bellows of the valve invention can also handle a certain degree of minor particle penetration, without appreciable degradation of the intended function of the valve, in addition to the possibility of being able to loosen trapped and deposited particles, and then flush them out of the valve, by performing a expanding and compressing procedure. the bellows.

Description of the figures Fig. 1 is a cross-sectional view of the presented valve construction, consisting of a bellows with a spring designed for this purpose installed in a simple representative valve housing design with an inlet and an outlet opening.

Fig. 2 shows two perspective views of the bellows designed for this purpose, which is the primary component in the relay valve invention.

Fig. 3 is a cross-sectional view of the bellows shown in Fig. 2. Fig. 4 is a schematic cross-sectional view of a known pressure compensating flow regulating valve type with a fixed size valve opening, including a compensating opening adjusted by a spring-actuated regulating slider.

Fig. 5 is a schematic cross-sectional view of a known pressure-compensating flow-regulating valve type with flexible rubber ring which acts as a valve opening.

Technical effect The pressure-compensating flow control valve provided, as schematically shown in Fig. 1, consists of a bellows designed for this purpose, shown in Fig. 2 and Fig. 3, and a spring (09), installed in a valve housing, the valve housing consisting of a cylindrical chamber (19), in addition to an inlet (17) and an outlet (23).

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Page 4 of 5 The bellows shown in Fig. 2 and Fig. 3, is the primary component of this invention, which is made of a flexible elastomeric material.

In order for this bellows to perform its function, it is installed in a cylindrical chamber (19) in a valve housing (10), with the closed end (16) of the bellows located opposite the inlet side (17) of the valve. To achieve a desired limited flow rate, the medium flows into the chamber from the valve inlet (17) and passes through one or more smaller openings (14) around the outer edge of the closed end of the bellows, and then into one or more passage restricting channels (18). These channels, which follow a helical shape on the outside of the bellows between the folds, are closed inside the cylindrical chamber wall (19). Along the back of the folds is a set of small combs (11) which are pressed against the cylindrical chamber wall (19) and create a relatively tight seal which forces the medium to follow the enclosed channels (18) along the entire length of the bellows. | the other end of the bellows, where the channels end, the medium comes out of one or more openings (15) and into the inner cavity of the bellows.

From there, the medium moves towards the outlet opening (23) of the valve and out of the valve.

The flow rate is regulated by varying the cross-sectional area of the ducts, which is achieved by changing the length of the bellows, by means of the pressure drop between the valve inlet (17) and its outlet (23). As the pressure drop across the valve increases, the bellows is further compressed, forcing the medium to have to climb through narrower channels, thereby maintaining a preset flow rate.

A compression spring (09) can be installed internally in the bellows to ensure that the bellows expands when the pressure drop is equalized between the valve inlet (17) and the outlet (23). If the pressure equalization drops further to close to zero or becomes negative, the bellows, by means of the spring (09), will expand sufficiently to press against the end wall of the cylindrical chamber on the inlet side (17), thereby closing the inlet opening.

A round raised collar (20) on the bellows helps to seal around the inlet, and thus the valve can act as a shut-off valve (non-return valve) that prevents backflow.

There are many conditions of the presented valve construction that can be changed to deliver the desired flow rate.

By changing the size of the bellows, the design and the softness of the elastomeric material from which the bellows is made, the flow rate can be set in a given pressure drop range.

In addition, the force applied to the spring by the bellows (09), which is defined by the spring constant of the spring and how much the spring is tightened when it is installed, can also determine the flow rate.

The valve housing (10), shown in Fig. 1, is only shown in a simple outlined design, to emphasize only its function and has no possibility of being able to immediately preset a desired flow rate, unless the spring or bellows is replaced with something else.

If an adjustable spindle is integrated in the valve housing, which presses on the spring (09) at the opposite end of the bellows, it is possible to adjust the flow rate while the valve is in use.

By adjusting the spindle, the tightening of the spring changes, and thus also the set flow rate changes, for a given pressure drop across the valve.

Instead of using a valve opening with a short length, the relatively long channels of the bellows ensure a more stable and controllable flow rate under varying pressure drops.

The flow through a short opening gives a large pressure drop over the short distance, resulting in large speed changes of

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Page 5 of 5 the medium.

This entails i.a. stronger turbulent flow conditions around the valve opening, which influences the actual flow dynamic size of the opening, which provides a more unstable control of the flow rate.

This ratio is amplified the lower the desired flow rate is preset to.

By using instead a restrictive channel, which can be defined as an opening of a relatively large length, the pressure drop will be distributed more along the length of the channel, which results in smaller velocity changes in the medium, and thereby a more stable and controllable state.

The presented valve invention, with a bellows designed for that purpose, can also handle a certain degree of particle penetration and deposition, without diminishing the intended function.

This is due to the flexibility of the thin and soft helical folds on the bellows that are able to enclose the penetrating particles.

Typical particles that accompany the medium into the valve are small metal shavings, contaminating deposits of ocher or lime, or an intentional addition of particles such as plant fertilizers, foods or dyes.

The use of a bellows also has the advantage that it can open the passage-limiting channels, to a very large extent, by expanding the bellows, and thereby loosening and flushing out the penetrated particles.

This can be done, for example, by first equalizing the pressure difference between the inlet and outlet of the valve, whereby the bellows is expanded by means of the installed spring (09). Then the pressure drop across the valve increases again, which compresses the bellows and flushes out the loosened particles through the valve outlet (23). This expansion and compression of the bellows may need to be done more than once, in order to adequately loosen and flush all particles out of the valve.

Exploitation of the invention Product ranges in which submitted valve invention can be integrated are, for example, in dosing units for the process or medicine industry, micro-irrigation systems for plants and as flow restrictors in shower taps or kitchen water taps.

The advantage of the present valve invention is to make use of channels which limit the flow rate, in order to be able to better maintain a preset stable small flow rate, under a relatively high supply pressure, which may also vary.

Emitters used in micro-irrigation installations utilize ducts to limit the flow rate, however, these ducts are not flexible and therefore they have a limited pressure drop range in which they can be operated, and where flushing of penetrated and clogged particles in the valve is more difficult to perform.

The simple design of the valve invention, consisting of a small number of parts and with relatively low production costs, will not only be able to replace some of the flow valves that are installed in current product units, but also provide the opportunity to perform functions and construct installations in other and new ways.

For example, by integrating water saving functions into more consumption units in a simpler and more affordable way, or building simpler micro-irrigation installations where reduction of the supply pressure and requirements for adequate filtration of the water are not necessary.

Claims (4)

DK 202100003 U4 Page 1 of 1 Utility model requirements Pressure compensating flow regulating valve, shown in Fig. 1, containing a flow restricting element with a helical channel, shown in Fig. 2 and Fig. 3, characterized in that the flow restricting element is shaped like a bellows, made of a flexible elastomeric material , consisting of one or more folds following a helical shape along the entire length of the bellows, in addition to terminating walls (12 & 13) around the outer edges at each end of the bellows, and between the folds on the outside of the bellows there are one or more helical channels (18 ), where each channel has smaller openings (14, 15) at each end, in addition there is on the outside of the bellows, along the back of the folds, a set of small ridges (11), and furthermore there is a pouch (21) in the bellows cavities in the closed end, in addition to a circular raised collar (20) on the outside of the closed end of the bellows. Pressure compensating flow regulating valve, according to claim 1, characterized in that the bellows is installed in a cylindrical valve chamber (19), which is part of a valve housing (10), the ridges (11) on the back of the folds on the bellows being pressed against the cylindrical wall of the valve chamber. (19), thereby forming a seal enclosing the helical channels (18), and at each end of the cylindrical valve chamber there is an inlet opening (17) and an outlet opening (23), respectively, the installed bellows having its closed end against the inlet opening, while, at the opposite end of the valve chamber, a compression spring (09) is installed, which is supported at each end by the bagging (21) of the bellows and by a part of the outlet opening (22), respectively. Pressure compensating flow control valve, according to claim 2, characterized in that the spring (09) can be replaced by a second spring having a different spring constant value, and / or the bellows can be replaced by a second bellows consisting of an elastomeric material with a different softness, and / or the design of, for example, the helical shape which the folds of the bellows follow can be changed. Pressure compensating flow regulating valve, according to claim 2 or 3, characterized in that an adjustable spindle can be integrated in the valve housing, which presses on the spring (09) at the opposite end of the bellows, in order thereby to be able to adjust the flow rate, by changing the force which the spring applies to the bellows while the valve is in use.