GB2140535A - Pressure regulator - Google Patents

Abstract

An automatic pressure regulator which can be connected in a liquid conduit to provide a substantially constant pressure comprises a hollow body (1) with an inlet (3) and an outlet (6) and an overflow stand (8) coupled to a tube (9). A pivotal member (11) is located inside the body and has a sealing surface (15) and an end coupled to a wire (10) which is connected to the end of the lever arm (17). The other end of the lever supports a hollow vessel (22) which can communicate with the outlet tube (7) through its base by means of a tube (23). As the liquid level in the vessel (22) rises or falls the lever (17) pivots to operate the member (11) and thereby control flow through the body 1. <IMAGE>

Description

SPECIFICATION Automatic pressure regulator for liquid conduits The present invention relates to an automatic pressure regulator for controlling the pressure of liquid in a conduit. It particularly, but not exclusively, relates to an automatic controller for providing a substantially constant pressure which can be applied to localised irrigation systems based on pipes and porous membranes through which flow liquids such as water containing fertilizing substances.

The present pressure regulator allows automatic maintenance of a substantially constant pressure in a liquid conduit where it is to be applied and independently from the oscillations in pressure that may exist in the liquid supply. It furthermore permits pressure regulation of the installation which the mechanism controls, and is capable of operating over a wide pressure range from a few centimetres water column (w.c.) up to several metres water column irrespective of the pressure before the mechanism, as it can always decrease and/or maintain it according to the requirements of use for which it is intended.

The automatic regulating mechanism which can be interconnected in a liquid conduit in which a substantially constant pressure is to be achieved basically comprises a hollow body equipped with two sleeves for connection to corresponding inlet and outlet tubes, and a third sleeve, to which an overflow stand is coupled, a tiltable sealing member within the body which is linked to a wire extending through the overflow stand and which is fixed at its other end to a lever from which is supported a vessel that is coupled through a tube to said outlet tube.

With this arrangement and at the beginning of a cycle, liquid passes through the body, which is completely open, and fills up the entire installation that is to be regulated. As the liquid continues flowing in, its level begins to rise in the tube connected to the outlet until it reaches the position of the upper vessel.

The weight increase to which the vessel is submitted then causes operation of the lever, from which it is hanging, and this pulls the wire to tilt the sealing member located in the body which closes the inlet for liquid into the body. In this way a condition of static balance can be achieved.

If consumption of liquid subsequently occurs in the installation, the level of liquid in the vessel drops and hence its effective weight also drops so that the sealing member opens again allowing more liquid to pass through. This will be more than the consumption that is being produced and thus will cause the level of the liquid in the vessel to rise again increasing its weight which again operates the lever to cause the sealing member to close and decrease the quantity of liquid entering the body. Thus a balanced situation is reached at the end of the cycle in which the sealing member successively opens and closes to allow the quantity of liquid to pass through corresponding to that being consumed.The mechanism can remain indefinitely in this situation of dynamic balance, in which its operating base is a loss of charge which automatically varies lowering any inlet pressure down to the one that is required for the particular consumption.

The invention will be described now by way of example only with particular reference to the accompanying drawing which is a longitudinal section of the mechanism and installation of an automatic pressure regulator in accordance with the present invention.

An automatic pressure regulator has a central element comprising a hollow body (1 ) which is provided in its front plane (2) with an inner frusto conical sleeve (3) and an outer striated edge (4) located at its upper angular point. An inlet tube for liquid (5) is coupled to the sleeve (3). Diagonally opposite the sleeve (3) the body (1) has a further cylindrical sleeve (6) which is also striated on its outer surface and provides an outlet for liquid to which a corresponding tube (7) is connected. The two sleeves (3,6) extend generally horizontally at different heights from the body (1); a further generally vertically extending sleeve (8) is located in the upper plane and rear part of the body. The sleeve (8) is cylindrical on its inner surface and striated on its outer surface and a vertical tube (9) is coupled to the sleeve (8) and operates as an overflow stand.A wire or pulling device (10) extends through the tube (9) for the operation of a closing mechanism.

A sealing or closing element is pivotally mounted inside the body (1). The element (11 ) extends in a generally horizontal direction in the central part of the body and is mounted at its forward end between lugs (12) which are formed integrally with a wall of the body. The element (11 ) is carried on a pin shaft (13) about which the element can pivot. The closing element has an upwardly extending limb (14) whose front part is equipped with an elastic platelet (15) which is arranged to seal the inlet mouth (16) for liquid when the mechanism is in its closed position.

The seal operates hermetically due to its own elasticity as well as due to the pressure within the system.

In the upper part of the mechanism and above the overflow stand (9) a lever (17) is mounted on a rigid support (18). The lever is mounted on an intermediary pin (19) about which the lever can pivot. The lever has a series of longitudinally spaced holes (20) drilled therein. One end of the lever is connected to the wire (10) which extends through one of its drilled holes. The wire (10) extends through the tube (9) and is connected to one end of the sealing element (11).

At the other end of the lever (17) and hanging from an appropriate hook (21) suspended from one of the drilled holes there is a vessel (22) which is used to regulate the pressure level to be established in the installation. The base of the vessel (22) is coupled to the outlet tube (7) for liquid by a pipe (23) through which liquid from the outlet (7) can rise into the vessel.

In operation the mechanism begins to function at the moment when the liquid to be expanded begins to ascend through the pipe (23) in such a way that it reaches the inside of the vessel (22). As the vessel is hanging in a balanced position, there will be a moment at which its own weight causes it to move downwards tilting the lever (17) and thereby pulling the wire (10). The sealing member (11) is thus pivoted so that its front part moves towards the inlet mouth (16) for liquid until the tension in the wire (10) is sufficiently strong so that the elastic platelet (15) hermetically seals the mouth (16). The member (15) stays in this position as long as no further demand for liquid is generated on the outlet side of the apparatus.

If consumption does occur the liquid level in the vessel (22) drops thus reducing its weight. The lever (17) thus pivots back allowing the sealing member (11) to open and permitting more liquid to flow through the body. The liquid level rises again in the vessel and the sealing member (11) closes as described above. Thus a situation is reached at which the sealing member successively opens and closes to provide a liquid pressure in the system which is determined by the height of the vessel (22).

The pressure of liquid in the conduit controlled through the mechanism corresponds to the height of water within the vessel (22). This pressure can be varied simply by locating the vessel to the appropriate height.

No matter how high the pressure is in the system it can always be controlled simply by changing the length of the lever arm (17).

Claims (9)

1. Apparatus for controlling the pressure of a liquid flowing in a conduit comprises a body through which liquid can flow between an inlet port and an outlet port, said body having a third port coupled to an overflow pipe, pivotally operable means in said body for controlling flow from said inlet to said outlet, means coupling the flow control means to a lever arrangement which supports a vessel coupled to receive liquid from said outlet, the arrangement being such that variations in the weight of said vessel as the liquid level therein changes causes pivotting of said lever thereby operating said flow control means to regulate the amount of liquid flowing through said outlet.

2. Apparatus according to Claim 1,wherein the flow control means comprises a pivotally mounted sealing member which is located in the body and has an elongate shape, its front part being supported between two lugs on the body on a pin which acts as a pivot axis.

3. Apparatus according to Claim 2 wherein the sealing member carries an elastic sealing piece which is arranged to be positioned against the inlet mouth for liquid during closing of the sealing member.

4. Apparatus according to Claim 1, wherein said lever is located on a rigid support to which it is fixed by means of a pin that acts as a pivot axis.

5. Apparatus according to Claim 4, wherein the effective length of the lever arm from which the vessel is suspended can be varied.

6. Apparatus according to Claim 1, wherein the inlet to the body has a frusto conical form which converges towards the inside of the body.

7. Apparatus according to Claim 1, wherein the outlet port for liquid and said third port have substantially the same internal cross-section.

8. Apparatus according to any preceding claim wherein the height of said vessel is variable so that the regulated liquid pressure can be varied.

9. Apparatus for controlling the pressure of liquid in a conduit substantially as hereinbefore described with reference to and as shown in the accompanying drawing.