FR2511446A1 - METHOD AND HYDRAULIC CIRCUIT FOR DISPENSING A LIQUID FLOW PRODUCED BY A PUMP WITH MULTIPLE ACTUATION DEVICES - Google Patents

Abstract

THE INVENTION CONCERNS A PROCESS AND A HYDRAULIC CIRCUIT FOR DISTRIBUTING A FLOW OF LIQUID Q PRODUCED BY A PUMP 2 UNIFORMLY BETWEEN SEVERAL HYDRAULIC ACTUATION DEVICES 9, THE FLOW OF LIQUID DELIVERED BY THE PUMP BEING DIVIDED BY A ROTATING DISTRIBUTOR A 4 IN PARTIAL FLOWS Q WHICH ARE EACH CHANNEL TO THE RESPECTIVE ACTION DEVICES; BETWEEN EACH BLOCK 5 OF THE DISTRIBUTOR AND THE ASSOCIATED ACTUATION DEVICE, A PRESSURE CONTROL VALVE 7 IS PROVIDED WITH THE HELP OF WHICH THE PRESSURES P OF THE PARTIAL FLOWS Q ARE SET TO THE SAME VALUE WHICH IS GREATER THAN THE PRESSURE OF WORK P OF THE ACTUATION DEVICES 9 IN ORDER TO MAINTAIN THE PRESSURE DIFFERENCE PP CONSTANT IN THE INDIVIDUAL BLOCKS OF THE DISTRIBUTOR INDEPENDENT OF VARIATIONS IN THE WORKING PRESSURES OF THE ACTUATION DEVICES. APPLICATION TO OIL PLATFORMS.

Description

The present invention relates to a method of dispensing a flow

  of liquid produced by a pump uniformly to a plurality of hydraulic actuators, wherein the flow of liquid discharged by the pump is divided by means of a dispenser

  turning into partial flows which are each

  to respective operating devices.

  In practice, it is often necessary to

  operate simultaneously several operating devices

  hydraulic system to which a liquid under pressure is

  supplied with a common pump To prevent the flow of

  fluid produced by the pump to be principally

  to the actuator (s) that are subject to the minimum load and to

  uniform distribution of the flow between all

  operating devices so as to operate simultaneously

  all actuating devices, it is known in

  the prior art than the distribution of a liquid flow.

  by a pump can be controlled by various means, including the following: 1 Flow control valves provided for each actuator This solution is affected by the disadvantages of difficult and imprecise control and large loss of energy, especially if the flow rate of the pump varies; 2 Drawer type dispensing valves; this solution is affected by the disadvantages of a distribution only in two partial flows and a difficult and inaccurate control which varies in relation to the load;

  3 A rotating dispenser; this solution

  the disadvantage that the control varies in relation to the load; 4 Actuators connected in series; this solution has the disadvantage of a multiplication of errors and excessive service pressure or massive actuators; A reaction timing; this solution has the drawbacks of being expensive, complicated and of unsafe operation under difficult ambient conditions; 6 individual control valves for each actuating device, each of said valves comprising

  both his own command element; the inconvenience

  it is difficult for the operator to order

  simultaneously several actuators.

  It is an object of the invention to provide a method which overcomes the above-mentioned drawbacks and which allows a uniform distribution of liquid flow produced by the pump with three individual actuating devices in spite of

  differences between the charges on the

  This problem is solved by means of the method according to the invention which is characterized in that

  the pressures of the partial flows leaving the

  are set by throttling of said partial flows at control pressures higher than the working pressure required by an actuating device.

any.

  In the process according to the invention, a rotating distributor is used in a known manner to ensure the distribution of the pump flow. This distributor comprises, for each actuating device, a block of

  flow distribution and it divides the volumetric flow-

  from the pump in partial flows corresponding to

  However, the same load is established for all the blocks of the distributor by throttling of the partial flows leaving the distributor. The invention is based on the idea that, by arranging the charges of the individual blocks of the distributor so that they remain constant regardless of changes in

  actuators, also the distribution report

  distributor remains constant By throttling

  partial flows so that the pressures of

  parts of the dispenser are greater than the

  working pressure required by an operating device

  In any case, the pressure differences in the individual distributor blocks remain unchanged and in correspondence to the distributor's distribution ratio.

  also remains unchanged, even if the pressures from

  partial changes after the throttling point due to variations in the working

  The distribution ratio of the distribution

  scorer is easily maintained if the differences

  pressures in the individual blocks remain unchanged.

  However, if the pressure difference varies, the distribution ratio also varies because the volumetric efficiency of the blocks, i.e. the outflow, is very strongly dependent on the pressure difference, due to the process according to the present invention. invention, the debit provided by

  the pump is safely distributed between the

  individual actuators independently of variations

loads soliciting them.

  The invention also relates to a hydralic circuit using the methods described above, this

  characterized in that in the fluidic connection

  existing between the distributors and each actuating device, there is provided a throttling element which adjusts the pressure of each partial flow leaving the distributor to a value greater than the pressure of

  required by any actuating device

  With the aid of the throttling element it is possible to adjust the partial flow pressures leaving the distributor to a value which, in use, remains constant

  because it is always greater than the maximum pressure

  In this way, the same constant load is obtained for the blocks.

  of the distributor in order to establish for this

  a constant distribution ratio irrespective of

  variations in the working pressures of the

  ment. The invention can be applied for example to the lifting of supports of a drilling platform resting on the ground and actuated by hydraulic cylinders. In particular the invention is suitable for devices equipped with telescopic stands, in which case the supports At the lowest level each is provided with a control lever while the remaining supports are lifted using the same lever. In addition, the invention is generally applicable to the synchronization of hydraulic actuators, such as that cgàindres or engines,

  if absolute precision is not necessary.

  Other advantages and features of the invention will be highlighted later in the

  description, given by way of non-limiting example, in

  reference to the attached single drawing which

  a hydraulic circuit to which the process is applied

according to the invention.

  In the drawing, a pump 2 driven by a motor 1 is connected by a duct 3 to a rotating distributor 4 which comprises in this embodiment, four individual blocks 5 Distributors of this type equipped

  2, 3 or 4 blocks are commercially available.

  Each block of the distributor is connected by a conduit 6 to a pressure control valve 7 which is

  connected in turn by a conduit 8 to an action device

hydraulically 9.

  The opening pressures p 1 of the pressure control valves 7 are set to the same value which is greater than the working pressure P 2 required by any actuating device 9 but which is lower than the operating pressure p 5 of the pump 2 The tank pressure of the actuating device has been designated Pt. The pump delivers at the operating pressure ps a

  flow of liquid Q which is divided by the indi-

  4 of the dispenser valves in four partial flows Qj, whose pressures in the ducts 6 are equal to the opening pressures p 1 of the valves Since all the valves have the same opening pressure, the pressure differences ps p 1 between the distributor blocks are also equal in that the partial flows Q 1 have in a continuous manner the same values. The partial flows pass through the valves 7 in the ducts 8 and furthermore in the actuating devices 9 of FIG. way

to ensure their maneuver.

  It should be noted that all the other pressures, with the exception of the working pressures P 2 of the dispenses

  actuators, are the same for all the blocks in the distri-

  scorer In a state of continuity, each pressure control valve ensures the throttling of the flow of liquid leaving the block so that Pl remains constant, even if the pressure loss p 1 P 2 varies when the working pressure

  P 2 of the corresponding actuating device changes.

  Naturally, the invention is not limited to the embodiments described above and shown, from which we can provide other modes and other embodiments, without departing from the scope of the invention.

2511446-

Claims (4)

  A method of distributing a fluid flow produced by a pump uniformly to a plurality of hydraulic actuators, wherein the flow of liquid (Q) delivered by the pump (2) is divided by a dispenser rotating (4) partial flows (Q 1) which are each channeled to respective actuating devices (9), characterized in that the pressures (pl) of the partial flows (Q 1) coming out of   distributor (4) are regulated by throttling the   parts, at values higher than the working pressure (p 2) required by an actuating device any (9).   Method according to Claim 1, characterized in that the difference between the operating pressure (ps) of the liquid flow (Q) produced by the pump (2) and the pressure (pl) of each partial flow (Q 1 ) leaving the   distributor (4) is set to the same value.   3. Method according to one of claims 1 or 2,   characterized in that each partial flow (Q 1) is   throttled using a pressure control valve (7).   4 Hydraulic circuit for supplying liquid under pressure to the actuating devices, this circuit comprising a pump (2), a rotating distributor (4) receiving a flow of liquid (Q) flow through the pump and dividing this flow into partial flows ( OQ 1), as well as several actuating devices (9) each receiving one of the partial flows through a respective fluidic connection (6, 8), characterized in that it is provided in the fluidic connection ( 6, 8) existing between the distributor (4) and each actuating device (9), a throttling means (7) which adjusts the pressure (pl) of each partial flow (Q 1) coming out of the distributor to a value greater than the working pressure (p 2) required   by any actuating device (9).   A hydraulic circuit according to claim 4, characterized in that said throttling means (7) comprises pressure control valves, the opening pressures (pl) of said valves being set to the same value which is greater than the pressure of (p 2) required by any actuating device (9) so that the   pressure differences (ps Pl) between the indi-   viduals (5) of the equivalent distributor.