ES2329714T3 - IMPROVED OPEN CIRCUIT OLEODYNAMIC SYSTEM TO OPERATE AND CONTROL A CONCRETE PISTON PUMP. - Google Patents

Abstract

An actuating oleodynamic system for pumps pumping viscous material, and in particular concrete, of the open-circuit and high-pressure type supplied by one or more hydraulic pumps, with direct, automatic-sequence driving system for the actuation of the hydraulic cylinders which displace the pistons in the liners of said pump and of the cylinders of a deviation valve through which said liners are alternately put in communication with a loading hopper and with a supply pipe. The system comprises a hydraulic valve assembly to control the displacement direction of said pistons, consisting of two hydraulic distributors, each actuated by a 5-way electrovalve to invert said direction between a pumping function and an intake function. The hydraulic circuit driving the hydraulic cylinders of the pump is symmetrical with respect to a plane transversal to the centreline of the two cylinders arranged side by side, in correspondence of which the hydraulic supply assembly is also arranged, resulting in a simple and quick switching of the supply from "shaft side" to "piston side" and viceversa.

Description

Open Circuit Oleodynamic System improved to drive and control a piston pump concrete.

The present invention relates to a system Open circuit oleodynamic, with a drive system Direct automatic sequence for drive and control of alternating piston pumps, in particular pumps for pump concrete or other viscous materials.

In particular, said pumps are generally of the type comprising two cylindrical sleeves that receive the material to be pumped, inside which the corresponding pistons capable of pushing the viscous material For the shirts. Each of the pistons mentioned above represents the work element of a hydraulic jack, whose drive element is the piston of a set hydraulic piston / cylinder, the two pistons of each cat (the one that moves in the shirt and the one of the hydraulic jack) in opposite ends of the same axis.

The pump is started by operating the two hydraulic cylinders, such that the axles respective may have an alternate steering movement opposite, so that while the piston in one of the shirts of the pump returns and sucks the viscous material inside the jacket, the other piston advances simultaneously, causing expulsion of the shirt material, that is, precisely the action of desired pumping.

A flow valve mechanism, known in the field as S-valve, is used in combination with axles / pistons and in sync with its movement to get the alternate connection of the outputs of the shirts through a hopper that feeds the material to be pumped and, respectively, through the pump supply line, thus ensuring a substantially outflow constant of the pumped material (concrete).

State of the art

In order to direct the movement of hydraulic cylinders of the piston pumps, have long since they know complex oleodynamic systems, characterized because present controlled automatic work sequences of the proper way. These systems can be divided into two categories main, according to the type of hydraulic circuit used in the same, and specifically:

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closed circuit oleodynamic systems;

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open circuit oleodynamic systems.

The open circuit oleodynamic systems they are the ones that are most frequently adopted, due to their relative simplicity of construction, ease of finding the components, ease of maintenance, and finally, due to the fact that repair operations, in case of malfunction, They can also be carried out by non-qualified personnel with the basic equipment normally available.

The automatic work sequences of the Open circuit hydraulic systems are usually controlled by means of an auxiliary hydraulic circuit, capable of switching automatically between the two pistons the fluid flow pressurized, according to the signals received from the electrical or, preferably, hydraulic limit devices, able to detect the displacement of the hydraulic pistons of the pump precisely in the vicinity of its dead spots upper and lower.

In particular, two types can be distinguished different from said control circuits: a first type of low pressure uses a fluid characterized by an auxiliary pressure, generally of the order of 40 bar, conversely, a second type of said control circuit takes advantage of the same pressure of supply of the main control circuit of the cylinders pump hydraulics and therefore is a high circuit pressure, whose pressure can reach for example 350 bar.

In low pressure control systems there is the need to create and maintain a fluid at an auxiliary pressure reduced by means of a separate circuit intended for it and that It usually consists of a pump, a relief valve pressure, a pressure regulating valve, and possibly a accumulator. All this increases the complexity of the system as well. as the resulting costs, both for the purchase, and for its installation. Another method to obtain a fluid at a pressure reduced auxiliary is to reduce the fluid pressure of main supply to hydraulic cylinders by means of a pressure regulating valve. A substantial inconvenience of said system is that the auxiliary pressure remains constant, only while the main supply fluid pressure remain above the calibration value of the valve pressure regulation. When this case does not occur, for example usually during the inlet phase of the concrete pump in the one that returns to the supply hopper to try to release an obstruction in the concrete supply duct, the auxiliary fluid pressure falls below the calibration value altering the proper functioning of the functions of control.

This inconvenience does not take place natural in high pressure control circuits, where take advantage of the same pressurized fluid from the main supply to the hydraulic cylinders, in fact, to power the circuit control that triggers the investment of hydraulic distributors and, by cascade effect, that of the pumping cylinders and the flow bypass valve. However, in this case it turns out necessary to select suitable hydraulic components for withstand the maximum pressure that the auxiliary pressure can reach, which, according to the exercise pressure of the machine in operation, can be of the order of 350 bar.

The operation of a concrete pump always provides two characteristic work stages different, exactly:

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a concrete supply stage which is properly the stage of pump operation; Y

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a concrete entry stage that takes place, well at the end of the supply stage, to carry out the cleaning of the duct, or even during that stage, to try to free an obstruction that could plug the duct.

The two stages mentioned above are they carry out, according to the current state of the art, in two ways different.

According to a first provision, between the hydraulic pump that supplies the circuit with pressurized fluid and distributors of hydraulic pump cylinders (pumping cylinders and cylinders for valve switching deviation in S) a directional valve is installed deviation, by means of which you can directly reverse the supply and return to distributors, when desired switch from one of the pump's work stages to another. Without However, this solution implies that said directional valve of deviation consists of a 4-step distributor that can support 350 bar in its four holes.

A hydraulic distributor of this type is not normally available in the market, so it is necessary to provide a specific design. Thus, this solution is currently not preferred, both because of its high costs, and because its maintenance requirements make it much more practical and attractive.
for users the use of standard components that are readily available in the market.

However, in a second provision of the design, switching between input and supply phases of the pump is achieved by reversing the flow direction in the drive lines of the hydraulic cylinders that drive the concrete pump to the diverter valve distributor and in the cylinders of the diverter valve to the distributor of the pump cylinders. This investment is usually get in correspondence with supply distributors hydraulic of said cylinders, by means of two solenoid valves of the commercial type, normally installed for the sake of convenience in a single base block, which in turn is connected mechanically with its respective hydraulic distributor.

The need to use two solenoid valves for each hydraulic distributor (and consequently four solenoid valves in total to control the two distributors hydraulic circuit) depends on the fact that, in the commercial solenoid valves, the four existing holes, mentioned with the reference letters P (fluid inlet pressurized), T (fluid return hole to the tank collection), A and B (pressurized fluid supply holes and back to equipment) cannot be used interchangeable for high pressure flows.

In fact, precisely because of the structure specific mechanics of commercial solenoid valves, holes P, A, B are all suitable for supporting the nominal valve pressure, for example 350 bar for the type of solenoid valve used in the systems described herein memory. However, the hole T can generally withstand a pressure below 50% of the nominal valve pressure, per example in this case a maximum pressure of 160 bar, so that hole cannot be used to receive one of the flows of the pressure fluid that, as shown, can reach a 350 bar pressure. For this reason, in each solenoid valve only holes P, A and B are used, so that for direct the four fluid flows provided in each of the two hydraulic distributors that supply a respective cylinder, two coupled solenoid valves must be used.

This design layout is widely currently adopted, since it allows compliance with control desired of the oleodynamic system using solenoid valves Cheap and readily available commercials. Not however It lacks disadvantages, because the use of two solenoid valves, which must be connected electrically and hydraulically, it determines a high volume of components, a greater complexity of the circuit and, as a consequence, a risk of malfunction due to improper assembly or connection of the components during maintenance operations in the construction site

Finally, one last point should be indicated. circumstance in connection with the methods of using the concrete pumps, that is, they are used in a variety of applications in the construction industry, in particular the pumps can be used in combination with a distributor arm mounted on the same vehicle as the pump to supply concrete to buildings of medium height or large slab foundations. On the contrary, in other cases, especially in tall buildings, the distributor arm is disengaged from the vehicle where the pump is and It is installed in a specific tower. In that case, the pump concrete should pump the concrete up to the arm distributor, through a connection duct installed in a way adequate.

In the first case, characterized by modest heights and small losses of hydraulic load in the conduit which, in fact, is only the distributor arm, a flow rate is usually required for the concrete pump high and a relatively low pressure. In the second case, characterized in that it presents great heights and high losses hydraulic load in the duct, which also includes the connecting duct, the concrete pump, on the contrary, should be develop a high pressure and a relatively high flow rate low.

This work flexibility is usually gets moving the supply of hydraulic cylinders that operate the pump, from the "shaft side" to the "side piston "and vice versa. In fact, feeding the cylinders Hydraulic "shaft side", that is, on the side of the chamber ring formed between the cylinder and the piston shaft, and keeping the synchrony of the displacement between the two cylinders by means of the connection between the respective piston chambers, are reached high pressures with a relatively low flow rate. To the opposite, feeding the hydraulic cylinders on the "side piston ", that is on the side of the cylindrical chamber formed on the piston, and maintaining the synchrony between the two cylinders by means of the connection between the respective annular chambers, reach high pressures with a relatively high flow rate low.

Thus, the option of switching the pump to one or the other of these two configurations is a prevailing necessity for users of concrete pumps, so that they can always run close to maximum pump efficiency, despite of very different operating conditions. Particularly, the need for such a change of point prevails supply to hydraulic cylinders take place so quickly and easily as possible.

EP-0167635 documents, US-A-3994627 and GB-A-1192657 unveil circuits of concrete pump control according to the prior art. He EP-A-0167635 is the closest prior art, and its main features they form the introductory part of the main claim.

Thus, the main objective of the present invention is to provide an oleodynamic system that allow to overcome the above mentioned inconveniences, typical of the solutions known in the market.

In particular, a first objective of the present invention is to provide an oleodynamic system as defined in claim 1 for the drive and control of a open circuit piston pump for pumping concrete, and that includes automatic sequences to make the investment powered by hydraulic distributors powered by hydraulic stops, in which the volume of the sets of solenoid valves associated with such distributors is reduced substantially and the hydraulic connections of the same.

A second objective of the present invention is provide an oleodynamic system of the aforementioned type previously, which also allows changing the supply of "shaft side" to the "piston side" quickly and easily.

In accordance with the present invention, said objectives are achieved through an oleodynamic system for the drive and control of a piston pump to pump concrete, which presents the characteristics defined in the attached claim 1.

In the subordinate claims are defined other features of the invention.

Brief description of the drawings

In any case, they will be revealed other features and advantages of the present invention from of the following description of an embodiment thereof, provided only by way of non-limiting example, referring to the attached drawings, in which:

Figure 1 shows a schematic view of the circuit diagram of an oleodynamic system according to the technique previous;

Figure 2 is a scheme of the system oleodynamic for the drive and control of a pump concrete according to the invention, with a "shaft side" supply, during a work stage;

Figure 3 is a diagram similar to that of the Figure 2, at the same stage of work, with a supply of "side piston";

Figure 4 is a sectional view of a known 4-way solenoid valve; Y

Figure 5 is a sectional view of the 5-way solenoid valve according to the present invention, which is shows, in two opposite halves, in its two positions of job.

Detailed description of a preferred embodiment of the invention

Referring to Figure 1, a system Oleodynamic according to the prior art consists of: two main hydraulic cylinders 1 and 2, whose pistons are strongly connected to the pistons (not shown) that they push the viscous material pumped (usually concrete) into the cylindrical pump sleeves; two hydraulic cylinders 3 and 4 which actuate the movement of the distributor valve, by means of of an S level set at the center of its shared axis; a first 5 mobile sliding hydraulic valve to supply the hydraulic cylinders 1 and 2 of the pump; a second valve 6 mobile sliding hydraulics to supply the cylinders 3 and 4 hydraulic distribution valve; four solenoid valves 7, 8 and 9, 10, for the remote operation of the distributors 5 and 6, respectively, in the pumping and entry; a hydraulic pump P for the supply of the circuit; a pressure limiting valve 11 with a solenoid valve 12 connected to the drain, for the control and protection of the  oleodynamic circuit; an F filter, usually installed in the sewer system; one-way valves 13 and logical seat valves 14 of the auxiliary circuit, capable of ensuring the synchrony of operation of hydraulic cylinders 1, 2 and 3, 4 and the refilling oil leaks. A known oleodynamic system Presenting this type of architecture is, for example, the one shown in document EP-0 167 635.

Figure 2 shows an oleodynamic system according to the invention, in which the components with the same function they are mentioned with the same reference numbers used in the Figure 1.

As can be seen immediately through a comparative analysis of the two diagrams, the system oleodynamic according to the present invention also shares the general architecture of previous systems known in what Concerning the layout and hydraulic connections of the circuit main hydraulic, that is, pump P and filter F, the hydraulic cylinders 1 and 2 pump, hydraulic circuits 3 and 4 distribution valve, and distributors hydraulic 5 and 6.

On the contrary, differences are found substantial in the realization of the auxiliary circuit that makes displacement sequences are determined automatically synchronized of the hydraulic cylinders and that allows switching the operation of the concrete pump in the opposite cycles of pumping / input cycles to the side, as well as quick change from the supply point of the "shaft side" to the "side piston".

Referring to the switching of the pump operation between pumping and inlet cycle, the function that is carried out in the conventional system by The two pairs of 4-way solenoid valves are now carried out through two innovative 5-way solenoid valves 15 and 16, mounted directly at hydraulic distributors 5 and 6.

The structure of said solenoid valves is shown schematically in Figure 5, and is characterized for a greater number of interior compartments than that of conventional solenoid valves, of which an example is shown in Figure 4. In particular, said known solenoid valves they comprise five interior compartments V, the central one being V_ {P}, connected to the pressure source P, capable of communicating alternately with one of the two side compartments V_ {A} and V_ {B} connected to equipment A and B, respectively. Finally, the two peripheral compartments V_ {T} are interconnected and connected to drain T, as well as in communication alternately with one of the two compartments V_ {A} and V_ {B}, who at that time is not in communication with the V_ {P} compartment. As is known, the switching of the AP / BT connection to the AT / BP connection is achieved by sliding a slide C in which two cylindrical elements R are formed with a double perimeter seal that can alternately seal one or another of the corresponding cylindrical seats that delimit the compartments V_ {A} and V_ {B}, in which the elements are housed cylindrical

The 5-way valve structure according to the The present invention differs from that described above in that it comprises seven V compartments, instead of the five mentioned above, as well as a slide C equipped with four cylindrical sealing elements R, of which the ends R_ {Y} They are double. From a functional point of view, the 5-way valve according to the invention repeat, in the five central compartments VP, VA, VB and VT the same function as the four-way valve described above. However, unlike the conventional solenoid valve, the compartments V_ {T} are divided from the solenoid D chamber and the spring chamber M return via double cylindrical sealing elements R_ {Y} that are in permanent hermetic contact with the cylindrical seats that delimit the two compartments of outermost valve V_ {Y}. These compartments are also interconnected and communicate with the drain branch through the central drain And formed in hydraulic distributors 5 and 6, to drain the excess oil that seeps into them adjacent compartments V_ {T}.

Thanks to this valve distribution, the T hole can also operate at the maximum nominal pressure, being divided from the solenoid D and spring chambers of return M by means of the two pairs of sealing elements cylindrical R_ {Y} that support in a symmetrical and balanced way the pressure received through the slide C and allow to maintain a higher working pressure in holes A, B, P and T, as well  as a permissible reduced pressure in the outer chambers of the solenoid D and return spring M. In this way, you can carry out the different connections required by the hydraulic distributors 5 and 6 by means of the single element of solenoid valve mentioned above 15, 16, with advantages significant from the point of view of the rationalization of electrical and hydraulic systems that, in the prior art, they are necessary to comply with the correct connection between 4-way solenoid valves that drive each distributor hydraulic. In a preferred configuration, solenoid valves 15 and 16 have three of the five holes arranged in a plane machined in accordance with ISO / CETOP 03, suitable for your arrangement so that they fit in a similar plane of the hydraulic distributors, so that only two remain connections pending to be made, through the ducts exterior of the block formed by the solenoid valve and its respective distributor. Conveniently, the components of the 5-way solenoid valves of the slide C are identical to those of commercial 4-way solenoid valves, of so that the cost is reduced and its maintenance is facilitated.

In addition, as regards the option of Quickly vary the pump supply point from the "shaft side" to the "piston side", according to the present invention the hydraulic circuit that drives the cylinders hydraulic 1 and 2 that drive the pump, is achieved in a way symmetric with respect to a plane transverse to the central line of the two cylinders arranged next to each other, more than with with respect to a plane parallel to the axes of the cylinders and willing among them. In other words, while in the known technique both cylinders 1 and 2 are equipped with a identical control circuit, in the system according to the present invention each of the cylinders is equipped with a circuit of identical control at both ends of the same and different from the adjacent cylinder circuit. Thus, the pair of ends on the same side of the two cylinders together presents the same control structure and thus the switching of the point of Supply can be carried out very quickly and easily, such as It will be shown below.

In fact, in particular the first cylinder Hydraulic 1 is equipped at its two opposite ends with two one-way valves 13a and 13b, capable of automatically guaranteeing the synchronization of the pumping cylinders, while the second cylinder 2 is equipped at its two opposite ends with two logical seat valves 14a and 14b, preferably joined in a only small block, capable of driving the flow inversion of the hydraulic distributor 6 of the cylinders 3 and 4 of the valve deviation On the contrary, the inversion of the flow of distributor 5 of the hydraulic cylinders 1 and 2 of the pump is operated by means of two drive lines from the Bypass valve cylinders passing through a mechanical switching valve and tracks 17.

The hydraulic circuit described above allows to make the regular flow inversion to the cylinders 1 and 2 of the pump and up to cylinders 3 and 4 of the valve deviation without the need to supercharge the slave circuit as it happened in the prior art, thanks to the fact that provide for two one-way valves 13a and 13b, one of which fills the oil in the slave circuit, and the other drains the oil from said slave circuit, automatically maintaining synchrony between the pumping cylinders. Two additional one-way valves 18, arranged in branch branches connecting the branches of hydraulic distributor 6 drive (from the valves 14) with the supply branches of cylinders 1 and 2 of the pump, provide alternate drainage of a branch of drive on the supply branch of cylinders 1 and 2, which It is alternately in communication with the drain (T). In prior art, the drive branch that It is designed to go in the drainage force to run through the logic valves under considerable back pressure. Thus, the one-way valves 18 reduce the peaks of pressure and increase the speed of distributor switching hydraulic 6.

In addition, the specific symmetry imparted to the control circuit allows switching the supply of "side shaft "(Figure 2) to" piston side "(Figure 3) in one way particularly simple. In fact, making the supply of pressurized fluid reaches a central location in the cylinders 1 and 2, can be changed, to get the change of supply, the two flexible connections that connect the supply of a pair of cylindrical ends 1 and 2 (the right one in Figure 2) to the opposite, simultaneously switching the bypass conduit 20 in order to connect the pair of cylinder ends Disconnected from the supply. This switching results extremely fast, intuitive, does not require having different special components for the two types of supply and, above all, it makes a connection virtually impossible Incorrect pump.

From the following description, it turns out evident how you have achieved the present invention in its entirety the established construction objectives in the management of the switching between pumping and input functions, and of ease of use and speed in the management of the change of supply from the "piston side" to the "cylinder side" and vice versa.

However, it is obvious that, although the present invention has been described with reference to a particular embodiment, a person skilled in the art can carry out a plurality of changes and improvements thereto, even using equivalent devices already known for hydraulic systems for piston pumps, all of them within the scope of protection of this invention, as defined in the appended claims.

Claims (15)

1. Oleodynamic pump drive system that pumps a viscous material, said high pressure open circuit type system being provided with one or more hydraulic pumps that supply said viscous material, with a direct, automatic sequence drive system , for actuating hydraulic cylinders (1, 2) that move the pistons by pushing said viscous material in cylindrical sleeves of said pump, and of the cylinders (3, 4) of a bypass valve (S) through which said sleeves communicate alternately with a loading hopper and with a supply conduit, said pump drive system comprising a hydraulic valve assembly for controlling the direction of travel of said pistons, which is constituted by two hydraulic distributors (5 , 6) actuated by solenoid valves (7 to 10) to reverse said direction between a pumping function and a function of trada, characterized in that said hydraulic distributors (5, 6) are operated by means of five-way solenoid valves (15, 16), of which four are connected to the corresponding distributor drive lines and the fifth is connected to a solenoid chamber ( D) and with a solenoid valve return spring chamber (M) for the circulation of pressurized fluid
reduced 2. Oleodynamic system according to claim 1, in which said solenoid valves (15, 16) are installed directly in contact with a surface of said hydraulic distributors (5, 6). 3. Oleodynamic system according to claim 2, in which three communication holes of said solenoid valves (15, 16) open on a machined surface smooth, said surface being intended for mounting in contact with said surface of hydraulic distributors (5, 6) that incorporates a corresponding amount of holes complementary. 4. Oleodynamic system according to claim 3, in which two of the communication holes of said solenoid valves (15, 16) are threaded holes arranged in one side of said solenoid valve. 5. Oleodynamic system according to claim 1, wherein said solenoid valve (15, 16) comprises seven coaxial compartments (V_ {Y}, V_ {T}, V_ {A}, V_ {P}, V_ {B}, V_ {T}, V_ {Y}) in which a single slide (C) is slides, equipped with suitable cylindrical sealing elements (R) to seal the corresponding seats that separate said compartments 6. Oleodynamic system according to claim 5, in which the three central compartments (V_ {A}, V_ {P}, V_ {B}) are connected to solenoid valve holes respective, the fourth hole being connected together to the pair of compartments (V_ {T}) adjacent to the three central compartments 7. Oleodynamic system according to claim 6, wherein said solenoid valves (15, 16) comprise, in the opposite sides of said seven compartments, a solenoid chamber (D) and a return spring chamber (M), both in a bath of oil, and in which the pair of compartments (V_ {Y}) that is found respectively between said solenoid chamber (D) or said return spring chamber (M) and the five compartments central, are interconnected and communicate with a branch of drainage of the circuit by means of a drainage channel provided in hydraulic distributors (5, 6) operated by said solenoid valves (15, 16). 8. Oleodynamic system according to claim 7, in which each of the compartments (V_ {Y}) respectively adjacent to the solenoid chamber (D) and the chamber spring return (M) is separated from the compartment adjacent (V_ {T}) internally by one of said elements cylindrical sealing (R) of the slide (C), said elements (R) constantly in contact with the housing corresponding in any position of the slide (C). 9. Oleodynamic system according to any of the previous claims, wherein the hydraulic circuit that drives the hydraulic cylinders (1, 2) that drive the pump is symmetric with respect to a plane transverse to the central line of said two cylinders (1, 2) arranged next to each other, is that is, each cylinder is equipped with a drive circuit identical to the two opposite ends of it. 10. Oleodynamic system according to claim 9, wherein the previous one (1) of said hydraulic cylinders (1, 2) which drives the pump is equipped at its two opposite ends with one-way valves (13a, 13b) to control the slave circuit, while the last (2) of said cylinders is equipped in its two opposite ends with logical seat valves (14a, 14b) capable of driving the flow inversion of the distributor hydraulic (6) of the cylinders (3, 4) of the bypass valve (S) 11. Oleodynamic system according to claim 10, wherein said logical seat valves (14a, 14b) are grouped together in a single block. 12. Oleodynamic system according to claim 9, in which they are taken from the cylinders (3, 4) of the valve deviation (S) two drive lines that drive the inversion of distributor flow (5) of the hydraulic cylinders (1, 2) of the pump, by means of a mechanical switching valve of four way (17). 13. Oleodynamic system according to preceding claims 9 to 12, wherein two are provided additional one-way valves (18) arranged on branches of branch connecting the drive branches of the hydraulic distributor (6) of the valve cylinders deviation (S), from said logical seat valves (14a, 14b), with the supply branches of the cylinders (1, 2) that drive the pump. 14. Oleodynamic system according to claim 9, in which the supply of pressurized fluid to the cylinders hydraulic (1, 2) takes place by means of a hydraulic block principal arranged in correspondence with the central line of said cylinders arranged next to each other. 15. Oleodynamic system according to claim 14, in which the supply switching from the "axis side" to the "piston side", and vice versa, takes place by changing the two flexible supply connections (19) of a pair of ends of the hydraulic cylinders (1, 2) to the opposite, changing shape inverse the bypass duct (20) that interconnects the pair of ends of the hydraulic cylinders (1, 2) not connected to the supply.