WO2004099891A1

WO2004099891A1 - Pressure regulator apparatus, particularly for moving liquids in irrigation systems

Info

Publication number: WO2004099891A1
Application number: PCT/IB2004/001442
Authority: WO
Inventors: Arno Drechsel
Original assignee: Arno Drechsel
Priority date: 2003-05-09
Filing date: 2004-05-07
Publication date: 2004-11-18
Also published as: ITVI20030094A1

Abstract

A liquid pressure regulator apparatus, particularly for irrigation systems, comprises a liquid inlet body (2) and a liquid outlet body (3) removably connected along a longitudinal axis (L), at least one guide member (4) which is placed in the inlet body (2) to define with the inner wall of the body (2) an annular channel (5), a tubular member (6) moving in the longitudinal direction, for selectively obstructing the annular channel (5), drive means acting on the movable tubular member (6) for automatically adjusting the liquid pressure. The movable tubular member (6) has an upstream portion (7) which is shaped to interact with the guide member (4) to define an opening (7') of varying size to accordingly adjust the liquid pressure at a predetermined value, a downstream portion (8) which is shaped to convey liquid into the outlet body (3), and an intermediate passageway (9), between the upstream portion (7) and the downstream portion (8), for conveying liquid from the opening (7') to the downstream portion (8) in a substantially radial direction, to reduce pressure as well as any axial force acting on the movable tubular member (6) and to stabilize the operation thereof.

Description

PRESSURE REGULATOR APPARATUS, PARTICULARLY FOR MOVING LIQUIDS IN IRRIGATION SYSTEMS

Field of the Invention

The present invention generally finds application in the field of irrigation and liquid distribution systems, and particularly relates to a pressure regulator apparatus as described in the preamble of claim 1.

Background of the Invention

A variety of pressure regulator apparatuses are known in the field of irrigation systems, for ensuring that the irrigation liquid sprinkled on the ground or plants is kept at a substantially constant pressure.

Irrigation systems may have a large size and typically have one or more lines, that may be even several hundred meters long, with multiple liquid outlet pipes brunching off the latter. A distribution device is typically mounted at the end of each outlet pipe to appropriately direct liquid flow.

Pressure regulators are typically mounted at the ends of the outlet pipes upstream from distribution devices. This arrangement provides a constant delivery of liquid to the ground and allows to control liquid flow by varying the size of the distribution device.

US-A-3,948,285 discloses a pressure regulator apparatus comprising an inlet sleeve that may be screwed onto the end of a liquid outlet pipe and an outlet sleeve, with a liquid distribution device screwed thereon. The inlet sleeve and the outlet sleeve are removably connected and house a movable stem therein, whose head is shaped to selectively close a liquid passageway. Any liquid pressure drop occurring in the passageway is regulated by the movable stem, whose position is determined by the biasing action of a spring and by the differential pressure acting on a resilient diaphragm. The spring moves the shaped head of the movable stem away from the passageway and reduces the pressure drop through the passageway.

Furthermore, ambient pressure acts on a first face of the resilient diaphragm, whereas liquid pressure acts on the second face thereof. When liquid pressure is higher than atmospheric pressure, it generates a resultant thrust opposing the spring action which can move the shaped head of the movable stem closer to the passageway until a dynamic equilibrium position is reached, thus controlling the liquid flow and pressure.

An apparent drawback of this solution is that any abrupt liquid pressure variation may easily generate oscillatory motions of the movable stem. Thus, an abrupt liquid pressure increase, for instance when the system is started, compresses the spring and may cause the shaped head of the movable stem to close the passageway. As a result, liquid flow is stopped, the pressure acting on the second face of the resilient diaphragm rapidly decreases and the spring uncovers the passageway again, thereby causing an abrupt pressure increase and the initiation of an oscillatory motion.

The oscillations of the movable stem cause the apparatus to operate irregularly and significantly decrease the life thereof. Also, the oscillations propagate as vibrations to the irrigation system, which may be damaged thereby.

Patents US-A-4,543,985, US-A-5,257,646, US-A-5,881 ,757, US-A-5,875,815 disclose pressure regulators that are substantially similar to the above mentioned regulator. In these regulators an elastic member pushes a movable hollow stem to a position in which liquid passage is enabled, whereas the liquid pressure acting on a resilient diaphragm reduces or even stops the flow.

In order to dampen the oscillations of the movable stem, a face of the resilient diaphragm delimits an annular chamber, which is in fluid communication with the liquid that exits from the apparatus through one or more channels having a relatively small liquid passage section. These channels have the function of a low- pass filter between the outlet liquid pressure and the pressure of the annular chamber which acts on the resilient diaphragm. Therefore, any high frequency liquid pressure oscillations, which are generated, for instance, when the system is started up, are filtered by the channels and only a part of them reaches the diaphragm.

While the above technical features seem to obviate the oscillation problem, other drawbacks may arise during operation. In fact, the liquid generally contains impurities or suspended particles that can obstruct the channels during operation and prevent proper operation of the apparatus.

An additional disadvantage is that, in partly or wholly obstructed channels, the obstructing deposits may be suddenly detached therefrom. In this case, undesired oscillations are not reduced, but increased.

Disclosure of the invention

A general object of this invention is to obviate the above drawbacks, by providing a pressure regulator apparatus which can provide a substantially constant liquid outlet pressure in spite of flow changes.

A primary object is to provide an apparatus that has a regular operation, and is not subjected to undesired oscillations, even in case of abrupt liquid pressure changes or water hammers.

A further object of the invention is to provide a device which combines sturdiness and easy and quick assembly, requiring no special tools.

A particular object is to provide an apparatus that may be calibrated for different pressures and flows in a simple manner, and whose calibration levels may be easily recognized by the user.

Another particular object is to provide a cost-effective apparatus for various types of irrigation systems, and for different liquid flow values.

These objects, as well as other objects that will be more apparent hereafter, are fulfilled, according to claim 1 , by a liquid pressure regulator apparatus, particularly intended for irrigation systems, comprising a liquid inlet body and a liquid outlet body which may be removably connected along a longitudinal axis, at least one guide member which is placed within the inlet body and defines, together with the inner wall of the body, an annular channel, a tubular member moving in the longitudinal direction, for selectively obstructing the annular channel, drive means which act on the movable tubular member for automatically regulating liquid pressure, characterized in that the movable tubular member has an upstream portion which is designed to interact with the guide member to define an opening of varying size, to accordingly regulate liquid pressure to a predetermined value, a downstream portion which is designed to convey liquid into the outlet body, and an intermediate passageway, between the upstream portion and the downstream portion, for conveying liquid from the opening to the downstream portion in a substantially radial direction, to reduce pressure and the axial dynamic thrusts acting on the movable tubular member and regulate the operation thereof.

Thanks to this particular arrangement, any undesired oscillations of the movable tubular member may be dampened, even in case of abrupt liquid pressure changes or water hammers.

Preferably, the guide member has a hollow cylindrical portion for slideably housing the upstream portion of the tubular member. Furthermore, the hollow cylindrical portion is in fluid communication with the downstream portion to be substantially replenished with liquid at the adjusted pressure.

Thanks to these features, the movement of the movable tubular member is further stabilized.

Advantageously, the movable tubular member comprises a longitudinal conduit which is connected to a transverse wall of the upstream portion to put the downstream portion and the hollow cylindrical portion of the guide member in fluid communication with each other. Furthermore, the longitudinal tube extends within the downstream portion along such a predetermined length, as to generate a pressure difference between the opposite faces of the transverse wall.

This allows to partly balance any sudden thrusts by the drive means and to ensure a more regular motion of the movable tubular member.

Brief Description of the Drawings

Further characteristics and advantages of the invention will be more apparent from the detailed description of a few preferred, non-exclusive embodiments of an apparatus according to the invention, which are described as non-limiting examples with the help of the annexed drawings, in which:

FIG. 1 is a sectional view of a first embodiment of an apparatus according to the invention;

FIG. 2 and FIG. 3 are two sectional views of the apparatus of FIG. 1 in two different arrangements;

FIG. 4 is a partially perspective view of the apparatus of FIG. 1 ; FIG. 5 is an axial view of the apparatus of FIG. 1 ; FIG. 6 and FIG. 7 are two partial exploded views of the apparatus of FIG. 1 ;

FIG. 8 is an exploded view of the apparatus of FIG. 1 ; FIG. 9 is a sectional view of a detail of the apparatus as shown in FIG. 1 ; FIG. 10 and FIG. 11 are two sectional enlarged views of a detail of the apparatus of FIG. 1 in two different arrangements; FIG. 12 is a sectional view of a second embodiment of an apparatus according to the invention. Detailed description of a preferred embodiment

Particularly referring to the above figures, an apparatus according to the invention is described, which is generally designated with numeral 1 , for regulating pressure, particularly of flowing liquids in irrigation systems.

The apparatus 1 has a liquid inlet body 2 and a liquid outlet body 3 which may be removably connected along a longitudinal axis L. At least one guide member 4 is placed within the inlet body 2, and its outer surface defines, together with the inner wall of the inlet body 2, an annular channel 5.

A tubular member 6, moving in the longitudinal direction, is also housed within the inlet body 2 and the outlet body 3, and is adapted to receive liquid from the annular channel 5.

Liquid pressure is regulated by drive means which act on the movable tubular member 6, to appropriately change the axial position thereof. The axial displacement of the movable tubular member 6 causes a selective obstruction of the annular channel 5 and, as a result, a change of the moving liquid pressure.

A peculiar characteristic of the invention consists in that the movable tubular member 6 has an upstream portion 7 which is designed to interact with said guide member 4 to define an opening 7' of varying size to accordingly regulate liquid pressure to a predetermined value, a downstream portion 8 which is designed to convey liquid into the outlet body 3, and an intermediate passageway 9, between the upstream portion 7 and the downstream portion 8, for conveying liquid from the opening T to the downstream portion 8 in a substantially radial direction . Thus, the movable tubular member 6 is not subjected to the liquid inlet pressure, but only to an adjusted pressure, with no axial force of the liquid acting thereon.

The guide member 4 may have a hollow cylindrical portion 10 for slideably housing the upstream portion 7 of the tubular member 6. Furthermore, the hollow cylindrical portion 10 may be in fluid communication with the downstream portion 8 to be substantially replenished with liquid at the adjusted pressure. Thanks to this particular arrangement, both the upstream portion 7 and the downstream portion 8 are in contact with a liquid that has substantially the same controlled pressure, which has an advantageous stabilizing effect on the motion of the movable tubular member 6.

Downstream of the hollow cylindrical portion 10, the guide member 4 further has an annular wall 4', perpendicular to the flow direction in the annular channel 5, which wall is joined to a bell-shaped expansion 4" by an axial cylindrical wall 4'". The annular wall 4' acts as a deflector for the flow from the channel 5 to radially divert the flow toward the intermediate opening 9. Furthermore, an O-ring 5' is located in the seat that is formed between the annular wall 4' and the bell-shaped expansion 4" to prevent fluid leakage between the inlet body 2 and the guide member 4, thereby preventing any axial forces on the bell-shaped expansion 4" which might cause excessive mechanical stresses.

Advantageously, the drive means may include a reaction spring 11 and an annular resilient diaphragm 12. The latter may have an inner diametrical portion 13 which is integral with the downstream portion 8 of the movable tubular member 6 and an outer diametrical portion 14 which is integral with the inlet body 2 or with the outlet body 3.

In greater detail, there are provided a first chamber 15 in fluid communication with the movable tubular member 6 and a second chamber 16 at ambient pressure. The first chamber 15 and the second chamber 16 are separated by the annular resilient diaphragm 12, with different pressures acting on opposite faces thereof. The axial thrust exerted by the liquid on the annular resilient diaphragm 12 is balanced by the thrust of the reaction spring 11 , and the balance of these opposed thrusts determines the axial position of the movable tubular member 6 relative to the channel 5. More particularly, in normal operating conditions, liquid flows in the annular tube 5 into the downstream portion 8 of the movable tubular member 6, after passing through the intermediate passageway 9.

If the inlet liquid pressure increases, the pressure in the first chamber 15 will also increase, thereby generating a higher axial thrust of the movable tubular member 6 in the downstream direction. This thrust increase is balanced by a higher compression of the reaction spring 11 , which causes the movable tubular member 6 to be translated in the downstream direction.

In the new position, the upstream portion 7 of the movable tubular member 6 obstructs to a greater extent the annular channel 5 thereby causing a liquid pressure drop and restoring the initial pressure conditions for the liquid that exits from the apparatus 1.

The outer diametrical portion 14 of the annular resilient diaphragm 12 is locked on one side by the outlet body 3 and on the other side by the inlet body 2 and the peripheral edge of the bell-like expansion 4" of the guide member 4. The inner diametrical portion 13 is integrated with the movable tubular member 6 by means of a compression ring 17. The latter is snap fitted in an outer circumferential groove 18 of the downstream portion 8 of the movable tubular member 6.

Advantageously, the movable tubular member 6 may comprise a longitudinal conduit 19 to put the downstream portion 8 and the hollow cylindrical portion 10 of the guide member 4 in fluid communication with each other. Particularly, the longitudinal tube 19 may be connected to a transverse wall 20 of the upstream portion 7 level with a longitudinal hole 21 of the transverse wall 20.

The longitudinal conduit 19 extends inside the downstream portion 8 along such a predetermined length, as to generate a pressure difference between the opposite faces 22, 23 of the transverse wall 20. Hence, a first face 22 is directly in contact with the liquid that exits from the annular channel 5 and flows radially through the intermediate passageway 9, whereas the second face 23 is in contact with the liquid that flows up the longitudinal conduit 19.

Upon a sudden increase of the inlet liquid flow, the second face 23 was found to be exposed to a pressure slightly greater than the pressure that acts on the first face 22. The effect resulting from this difference opposes the increase of pressure acting on the annular resilient diaphragm 12 and further stabilizes the movement of the movable tubular member 6. By appropriately selecting the ratio between the surfaces of the two opposite faces 22, 23, the axial thrust generated by the difference between the pressures exerted on the faces 22, 23 may be adjusted, which allows to use a smaller and less expensive spring 11.

In order to integrate the longitudinal conduit 19 with the movable tubular member 6, the latter has one or more longitudinal radial walls 24, each having an outer edge 25 that is connected to the inner surface of the downstream portion 8 and an inner edge 26 that is connected to the outer surface of the longitudinal conduit 19.

In order to further improve the operation of the apparatus 1 , first seal means 27 are provided between the guide member 4 and the upstream portion 7 of the movable tubular member 6 and second seal means 28 between the downstream portion 8 and the outlet body 3.

According to one embodiment, which is shown in FIG 1 to FIG. 11 , the first and second seal means 27, 28 include O-rings 29 in corresponding annular grooves 30. Moreover, the annular grooves 30 for the first seal means 27 may be formed in the upstream portion 7, as shown in the annexed figures, and/or in the liquid guiding member 4. The annular grooves 30 for the second seal means 28 may be also formed in the downstream portion 8, like in the first embodiment that is shown in the figures , and/or in outlet body 3.

According to a second embodiment, as shown in FIG. 12, the first and second seal means 27, 28 include one or more annular Belleville spring-like elastic members 31, which provide a sealing action against axial motion. The use of washer type or Belleville springs 31 avoids the friction caused by O-rings 29 and increases the sensitivity of the apparatus 1.

Furthermore, the annular resilient diaphragm 12 may be shaped like a washer or Belleville spring, as shown in FIG. 12, and be made of materials that provide an appropriate elastic bias. Here, the annular resilient diaphragm 12 may undergo elastical deformation due to an increase of the inlet liquid pressure and may exert on the movable tubular member 6 an axial force corresponding to the action exerted by the reaction spring 11. Thanks to this characteristic, the opposing spring 11 may have a small size, which involves a reduction of the total costs for the apparatus 1.

In order to removably connect the inlet body 2 and the outlet body 3, suitable locking means 32 are provided.

The locking means 32 may include first teeth 33 which project in the longitudinal direction out of a circular end edge 34 of the inlet body 2. The first teeth 33 may be angularly spaced to allow the insertion of second teeth 35 projecting from the outlet body 3, which are substantially equal to the first teeth 33.

The first teeth 33 and second teeth 35 may have at the ends thereof transverse extensions 36 so shaped to define a circular formation 37.

The locking means 32 may further include a retaining ring 38 to be fitted on the circular formation 37 to prevent the mutual separation of the inlet and outlet bodies 2, 3 thanks to its contact with the transverse extensions 36 of the first and second teeth 33, 35.

In order to engage the retaining ring 38 in the circular element 37, the locking means may include a snap-fitted cover member 39. The inner surface 40 thereof is situated in the proximity of the outer surface 41 of the retaining ring 38, to radially lock the latter and prevent it from being ever separated from the circular seat 37.

From the foregoing description, it is apparent that the apparatus according to the invention achieves the intended object and particularly allows to continuously adjust the outlet liquid pressure, by keeping it substantially steady even in case of transient operation of the plant, where the apparatus is mounted. Also, thanks to the above arrangements, the movable tubular member is displaced in a regular manner, and undesired oscillations and vibrations are dramatically reduced, whereby the apparatus is generally sturdy and reliable.

The apparatus of this invention is susceptible of a number of changes and modification falling within the scope of the appended claims. All the details thereof may be replaced by other technical equivalents, and the materials may vary depending on different needs, without departing from the scope of the invention.

While the apparatus has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

The instant application is based upon and claims priority of patent application no. VI2003A000094, filed on 09.05.2003 in Italy, the disclosure of which is hereby expressly incorporated here in reference thereto.

Claims

1. A liquid pressure regulator apparatus, particularly for irrigation systems, comprising a liquid inlet body (2) and a liquid outlet body (3) which are removably connected along a longitudinal axis (L), at least one guide member (4) placed within said inlet body (2) and defining with the inner wall of said body (2) an annular channel (5), a tubular member (6) moving in the longitudinal direction, for selectively obstructing said annular channel (5), drive means acting on said movable tubular member (6) for automatically controlling liquid pressure, characterized in that said movable tubular member (6) has an upstream portion (7) for interacting with said guide member (4) to define an opening (T) of varying size, to thereby regulate liquid pressure at a predetermined value, a downstream portion (8) for conveying liquid into said outlet body (3), and an intermediate passageway (9), between said upstream portion (7) and said downstream portion (8), for conveying liquid from said opening (7') to said downstream portion (8) in a substantially radial direction, in such a manner to reduce the pressure and the axial forces acting on said movable tubular member (6) and to stabilizing its operation.

2. Apparatus as claimed in claim 1 , characterized in that said guide member (4) has a hollow cylindrical portion (10), for slideably housing said upstream portion (7) of said movable tubular member (6).

3. Apparatus as claimed in claim 2, characterized in that said hollow cylindrical portion (10) is in fluid communication with said downstream portion (8) to be substantially replenished with liquid at the adjusted pressure and to stabilize the motion of said movable tubular member (6).

4. Apparatus as claimed in claim 2, characterized in that, downstream from said hollow cylindrical portion (10), said guide member (4) has an annular wall (4') perpendicular to the flow direction in said annular channel (5), to radially convey the flow, which wall is joined to a bell-shaped expansion (4") by an axial cylindrical wall (4"'), an O-Ring being located between the annular wall (4') and the bell- shaped expansion (4'").

5. Apparatus as claimed in claim 3, characterized in that said drive means include an annular resilient diaphragm (12), having an inner diametrical portion (13) which is integral with said downstream portion (8) of said movable tubular member (6) and an outer diametrical portion (14) which is integral with said inlet body (2) and with said outlet body (3).

6. Apparatus as claimed in claim 5, characterized in that it comprises a first chamber (15), in fluid communication with said movable tubular member (6) and a second chamber (16) at ambient pressure, said first and second chambers (15, 16) being separated by said annular resilient diaphragm (12).

7. Apparatus as claimed in claim 5, characterized in that it comprises a compression ring (17), which is snap fitted in an outer circumferential groove (18) of said downstream portion (8) of said movable tubular member (6), to rigidly attach thereto the inner diametrical portion (13) of said annular resilient diaphragm (12).

8. Apparatus as claimed in claim 2, characterized in that said movable tubular member (6) comprises a longitudinal conduit (19) to put said downstream portion (8) and said hollow cylindrical portion (10) of said guide member (4) in fluid communication with each other.

9. Apparatus as claimed in claim 8, characterized in that said longitudinal conduit (19) is connected to a transverse wall (20) of said upstream portion (7) level with a longitudinal hole (21) of said transverse wall (20).

10. Apparatus as claimed in claim 9, characterized in that said longitudinal conduit (19) extends inside said downstream portion (8) along such a predetermined length, as to generate a pressure difference between the opposite faces (22, 23) of said transverse wall (20) and further stabilize the motion of said movable tubular member (6).

11. Apparatus as claimed in claim 10, characterized in that said movable tubular member (6) comprises at least one longitudinal radial wall (24) having an outer edge (25) that is connected to the inner surface of said downstream portion (8) and an inner edge (26) that is connected to the outer surface of said longitudinal tube (19).

12. Apparatus as claimed in claim 5, characterized in that it has first seal means (27) between said guide member (4) and said upstream portion (7) of said movable tubular member (6) and second seal means (28) between said downstream portion (8) and said outlet body (3).

13. Apparatus as claimed in claim 12, characterized in that said first and second seal means (27, 28) include O-rings (29) located in corresponding annular grooves (30).

14. Apparatus as claimed in claim 13, characterized in that said annular grooves (30) are formed on said upstream portion (7) and/or on said guide member (4).

15. Apparatus as claimed in claim 13, characterized in that said annular grooves (30) are formed on said downstream portion (8) and/or on said outlet body (3).

16. Apparatus as claimed in claim 12, characterized in that said first and second seal means (27, 28) include one or more annular elastic members (31) providing a sealing action responsive to axial movements.

17. Apparatus as claimed in claim 1 , characterized in that it comprises locking means (32) for removably connecting together said inlet body (2) and said outlet body (3).

18. Apparatus as claimed in claim 17, characterized in that said locking means (32) include first teeth (33) projecting a longitudinal direction from a circular end edge (34) of said inlet body (2), said first teeth (33) being angularly spaced to allow the insertion of second teeth (35) projecting from said outlet body (3), which are substantially equal to said first teeth (33).

19. Apparatus as claimed in claim 18, characterized in that said first and second teeth (33, 35) have transverse extensions (36) at their ends to define a circular formation (37).

20. Apparatus as claimed in claim 19, characterized in that said locking means (32) include a retaining ring (38) inserted in said circular formation (37), for preventing the mutual separation of said inlet and outlet bodies (2, 3) upon contact with said transverse extensions (36) of said first and second teeth (33, 35).

21. Apparatus as claimed in claim 20, characterized in that said locking means (32) include a snap-fitted cover member (39) to lock said retaining ring (38) in said circular formation (37).