INJECTION DEVICE FOR LIQUIDS SUCH AS CEMENT, RESINS AND OXIDIZING AGENT FOR THE CREATION OF SPECIAL BASES AND FOR SOIL CONSOLIDATION

Description

[0001] This patent concerns piston pumps for fluids, and in particular it concerns a new device for injecting fluids, such as cement, resins and oxidizing agents, for making special foundations and for soil consolidation and reclamation. The new device comprises a piston pump, of the double-acting or plunger type, driven by a worm screw or threaded shaft and a lead screw nut with recirculating balls, operated by means of a brushless motor or a stepping motor. Currently, piston pumps driven by a hydraulic or pneumatic circuit are used to inject fluids (cement, resins and oxidizing agents).

[0002] The technique used in the state of the art has several obvious drawbacks.

[0003] CA 3 143 991 A1 describes an electrically-actuated linear pump using a planetary roller screw drive, powered by multiple electric motors, to move a double-acting rod and pump fluid at high pressure, with a control system for synchronized operation.

[0004] As far as electro-hydraulic devices are concerned, they are not very efficient: a large part of the power is dissipated in heat and for this reason it is necessary to use carefully dimensioned heat exchangers.

[0005] Another drawback is represented by the considerable weight and the large overall dimensions used to withstand the high operating pressures.

[0006] A further major drawback of electro-hydraulic devices is represented by the environmental impact resulting from the oil leaks that occur both during normal operation of the equipment and whenever a technical maintenance operation is performed.

[0007] During operation, in fact, a small portion of oil leaks from the gaskets and joints into the environment, and this portion increases proportionally with use and ageing of the gaskets.

[0008] In addition to the above, during the replacement of a component, for example, even if containment techniques are adopted, some of the hydraulic oil inevitably leaks into the surrounding environment. The use of hydraulic oil also entails costs for the disposal of used oil. There is also a high operating noise due to the fluid hammer of the oil during the change of direction of the piston and to the typical noise emitted by hydraulic pumps.

[0009] Generally speaking, pneumatically operated pumps are also subject to the same problems. The energy efficiency of compressors is even significantly lower than that of hydraulic pumps, with the result that only a small amount of energy is actually used, while the remainder is dissipated in the form of heat.

[0010] Since the operating pressure is much lower than that of hydraulic equipment (8 bar compared to approximately 200 bar in the case of oil), it is necessary to use pistons with a considerably larger bore compared to hydraulic pistons, consequently increasing the overall dimensions of the machine. The overall weight, on the other hand, is reduced, as pneumatic pistons, which have to withstand a lower pressure compared to oil-dynamic pistons, have thinner walls and therefore are lighter.

[0011] Furthermore, in order to prevent oxidation and maintain the optimal sliding movement of the pneumatic components, the equipment must be provided with lubricating devices suited to atomize the lubricating oil into the pneumatic system.

[0012] Part of this oil is deposited on the filters positioned at the outlets of motors and pneumatic pistons and part of it is dispersed into the surrounding environment, especially if regular maintenance, which cannot always be guaranteed on site, is not carried out.

[0013] When technical operations must be carried out on site, it is necessary to dismantle the pneumatic system, which increases the risk of the oil accumulated in the pipes being dispersed into the environment.

[0014] In addition to the above, despite the silencers arranged in the air outlets, the pneumatic pumps emit much noise, due to the high expansion speed of compressed gases.

[0015] Finally, in the event of accidental failure to disconnect the pneumatic supply, a technical operation is always dangerous, as there is the risk of components being ejected against the operators at high speed.

[0016] In order to overcome all the aforementioned drawbacks, a new device for injecting fluids, such as cement, resins and oxidizing agents, has been designed and constructed, which is particularly suitable for making special foundations and for soil consolidation and reclamation.

[0017] The main object of the present invention is to solve the problems observed in the state of the art, first of all by eliminating the risk of dispersing polluting hydraulic / lubricant oils into the environment and eliminating the waste oil disposal cost.

[0018] Another object is to provide a device which significantly reduces the risk of the operators being injured due to bursting hydraulic and pneumatic pipes.

[0019] Another object is to provide a device made up of a smaller number of components, which simplifies and speeds up repair work as technicians can easily detect any malfunctions.

[0020] The use of correctly dimensioned mechanical parts ensures a significant increase in efficiency compared to corresponding hydraulic and pneumatic components.

[0021] Another advantage of the present invention lies in that the speed of the piston of the device can be precisely controlled, particularly in proximity to the ends of stroke, thus reducing noise and the intensity of fluid hammering.

[0022] Another advantage of the present invention is represented by the fact that the overall size and weight of the device are reduced thanks to the use of fewer components.

[0023] Another advantage of the present invention is represented by the fact that it makes it possible to use a smaller generator to supply power to the motor, as no starting power is required to start the motor. In fact, the latter is managed by an inverter that regulates its power absorption.

[0024] Another advantage of the present invention is represented by the fact that it has sufficient speed and torque for the required flow rates and pressures.

[0025] These and other direct and complementary objects are achieved by the new device for injecting fluids, such as cement, resins and oxidizing agents, particularly suitable for making special foundations, and for soil consolidation and reclamation.

[0026] The new device comprises: at least one electric motor of the brushless or stepping type; at least one fluid-dynamic cylinder for the injection of fluids; means for transmitting motion between said at least one electric motor and the piston of said at least one fluid-dynamic cylinder, and wherein said transmission means in turn comprise: at least one worm screw or threaded shaft; connection means for connection between said electric motor and said threaded shaft; said connection means comprise, for example, at least one flexible coupling; at least one lead screw nut with recirculating balls coupled with said threaded shaft and suited to transform the rotary motion of said threaded shaft into a linear motion; means for transmitting said linear motion between said at least one lead screw nut with recirculating balls and said at least one fluid-dynamic cylinder; said transmission means comprise, for example, a hollow transmission cylinder in which said threaded shaft is at least partially inserted, said hollow transmission cylinder having a first end directly or indirectly constrained to said lead screw nut with recirculating balls and a second opposite end directly or indirectly constrained to said piston of the fluid-dynamic cylinder. Said transmission means are conveniently configured to prevent the undesired rotation of said hollow transmission cylinder, and for this purpose said transmission means comprise, for example, linear guides sliding on bars that are parallel to the sliding direction of the hollow transmission cylinder.

[0027] Said fluid-dynamic cylinder can, for example, be of the known type, and thus comprise a cylinder provided with at least one opening for fluid intake and at least one opening for fluid outlet, said piston being slidingly housed within said cylinder.

[0028] Said fluid-dynamic cylinder can, for example, be of the plunger type or of the double-acting type.

[0029] Said fluid-dynamic cylinder is, for example, part of a known plunger or double-acting pump, or it can be integrated in the device in a single frame or containment structure and equipped with special gaskets, further reducing the overall dimensions of the entire device.

[0030] The overall dimensions of the device are further reduced in comparison to the known devices thanks to the fact that said hollow transmission cylinder has a cavity whose dimensions are such as to allow said threaded shaft, or at least part of the latter, to be inserted therein when the upper end-of-stroke position is reached.

[0031] Since the device operates by means of said threaded shaft with lead screw nut with recirculating balls, which is driven by said brushless or stepping motor, it is possible to accurately manage the speed of the piston in proximity to the ends of stroke.

[0032] In this way, the piston is prevented from hitting the end-of-stroke elements due to inertia, and moreover the noise is eliminated every time the motion of the piston is reversed. In addition to the above, there will no longer be any sound leakage due to fluid hammering, which normally occurs in the known hydraulic devices.

[0033] The new device is also extremely compact and comprises a containment frame which is sized to hold the machine body and an electrical panel, conveniently equipped with an inverter to control said electric motor.

[0034] The characteristics of the new device are better clarified by the following description, which makes reference to the drawings that are attached hereto by way of non-limiting example. Figure 1 shows a side view of the new device 100 in the lower end-of-stroke position (A), while Figure 1a shows a sectional view of the device 100 shown in Figure 1. Figure 2 shows a side view of the new device 100 in the upper end-of-stroke position (B), while Figure 2a shows a sectional view of the device 100 shown in Figure 2.

[0035] The new device 100 comprises a brushless or stepping motor 1, connected by means of a flexible coupling 2 to a threaded shaft 3 supported by a bearing 4 and locked by a ring nut 10. Said threaded shaft 3 is coupled with lead screw nut with recirculating balls 5 which in turn is connected to a plate 6 provided with a seat for one or more linear guides 7 which slide on one or more bars 8 oriented parallel to the threaded shaft 3.

[0036] Said lead screw nut with recirculating balls 5, therefore, moves linearly in both directions, depending on the direction of rotation of the threaded shaft 3.

[0037] Said plate 6 is connected to the upper end 91 of an internally hollow flanged cylinder 9, hereinafter referred to as hollow transmission cylinder 9.

[0038] The special connection with plate 6 - linear guides 7 and bars 8 is useful to avoid the undesired rotation of said hollow transmission cylinder 9.

[0039] Said hollow transmission cylinder 9 is provided with an internal seat 93 for the insertion of the threaded shaft 3.

[0040] The opposite lower end 92 of said hollow transmission cylinder 9 is preferably threaded or in any case connected to a piston 24 of a fluid-dynamic cylinder 20.

[0041] The device 100 comprises a containment frame in turn comprising a first casing 14, with upper flange 15 and lower flange 16, which contains said flexible coupling 2.

[0042] Said frame also comprises a second casing 11, with an upper flange 13 and a lower flange 12, which contains the assembly made up of the threaded shaft 3 and the lead screw nut with recirculating balls 5.

[0043] Said fluid-dynamic cylinder 20 can be of the single-acting or double-acting type.

[0044] According to the invention, the device can comprise one or more additional threaded shafts with corresponding motors connected to the same fluid-dynamic cylinder 20.

[0045] According to the invention, the device can alternatively comprise a single assembly made up of the motor, the threaded shaft and the lead screw nut connected to two or more fluid-dynamic cylinders 20. This solution is particularly effective for injecting two-component resins with a 1:1 ratio between the components.

[0046] Said motor 1 is controlled by means of an inverter suited to manage the operation of the motor to selectively reverse its direction of rotation as well as to vary its torque and speed to manage the movement of the piston accordingly.Operation

[0047] Thus, said inverter controls the operation of said motor 1, whose number of revolutions is defined by the stroke of the piston 24 and the pitch of the threaded shaft 3.

[0048] Once the set number of revolutions has been completed in one direction, for example from the upper end-of-stroke position to the lower end-of-stroke position, the inverter reverses the operation of the motor 1, which will make the same number of revolutions in the opposite direction, in such a way as to reverse also the sliding direction of the piston 24, for example from the lower end-of-stroke position to the upper end-of-stroke position.

[0049] The flow rate of the device is defined by the angular speed of the motor 1, which is selected by the operator by means of a potentiometer or by means of an interface communicating with said inverter.

[0050] The pressure is defined by the torque delivered by the motor 1 and is also set by the operator through said inverter.

[0051] The maximum pressures and flow rates are defined by the power of the selected motor, that is, the maximum angular speed and the maximum torque that can be delivered.

[0052] The device 100 can also comprise suitable end-of-stroke sensors and / or absolute encoders, the latter, for example, integrated in said motor 1, to ensure the correct operation of the device 100. Furthermore, said inverter can be conveniently connected to a PLC so that all site variables can be managed, and their values recorded.

Claims

1. Device (100) for the injection of fluids such as cement, resins and oxidizing agents, in particular for making special foundations and for soil consolidation and reclamation, characterized in that it comprises: - at least one electric motor (1) of the brushless or stepping type; - at least one fluid-dynamic cylinder (20) for the injection of fluids; - motion transmission means suited to transmit motion between said at least one electric motor (1) and the piston (24) of said at least one fluid-dynamic cylinder (20), and wherein said transmission means in turn comprise: - at least one threaded shaft (3); - connection means for connection between said electric motor (1) and said threaded shaft (3); - at least one lead screw nut with recirculating balls (5) coupled with said threaded shaft (3) and suited to transform the rotary motion of said threaded shaft (3) into a linear motion; - means for transmitting said linear motion between said at least one lead screw nut with recirculating balls (5) and said at least one fluid-dynamic cylinder (20), and wherein said means for transmitting said linear motion between said at least one lead screw nut with recirculating balls (5) and said at least one fluid-dynamic cylinder (20) comprise a hollow transmission cylinder (9) having: - one seat (93) for the at least partial insertion of said threaded shaft (3), - a first end (91) directly or indirectly constrained to said lead screw nut with recirculating balls (5); - a second opposite end (92) directly or indirectly constrained to said piston (24), and wherein said lead screw nut with recirculating balls (5) has a linear motion in both directions according to the rotation direction of said threaded shaft (3), and wherein the dimensions of said seat (93) of said hollow transmission cylinder (9) are such that it can contain the entirety or part of said threaded shaft (3) when said cylinder (9) is in an upper end-of-stroke position (A).

2. Device (100) according to claim 1, characterized in that said lead screw nut with recirculating balls (5) is connected to a plate (6) provided with a seat for one or more linear guides (7) which slide on one or more linear bars (8) arranged so that they are parallel to said threaded shaft (3) itself.

3. Device (100) according to claim 1, characterized in that said connection means for connection between said electric motor (1) and said threaded shaft (3) comprise at least one flexible coupling (2) and at least one bearing (4) provided with a locking metal ring (10).

4. Device (100) according to claim 1, characterized in that said fluid-dynamic cylinder (20) is of the plunger type or of the double-acting type.

5. Device (100) according to any of the preceding claims, characterized in that it comprises a containment frame in turn comprising a first casing (14) which contains at least said flexible coupling (2) and a second casing (11) which contains at least said threaded shaft (3) and said lead screw nut with recirculating balls (5).

6. Device (100) according to any of the preceding claims, characterized in that it comprises an inverter suited to manage the operation of said at least one motor 1 in order to selectively reverse its rotation direction as well as to vary its torque and speed.