1. The patent refers to an equipment for continuous regulation of the flow of liquids, with direct electric actuation of the element that performs the modification of the flow section, with applications in the control systems of the parameters of working fluid environments used in hydraulic automation installations.

2. Other equipment solutions for regulating fluid flow used in automated processes are known, but, in principle, all solutions for equipment for regulating fluid flow perform this process by changing the flow section of the fluid from the supply source to the supplied installation, section created between a hole drilled in a fixed element and a moving part actuated by an actuator. The differences between the flow control solutions are given by the shape of the orifice through which the fluid passes, by the profile of the moving part in the area of the flow section, by the type of control characteristic, by the type of actuator used, by the way the motion is transmitted from the actuator to the moving part, the fineness of the adjustment and the materials used for the execution of the component parts. In terms of the shape of the orifice through which the fluid passes, some solutions use a cylindrical hole and other solutions use a conical hole.

In terms of the profile of the moving part in the area of the flow section, some solutions use a conical profile, other solutions use a flat profile, and other solutions use a spherical profile. From the point of view of the adjustment characteristic some solutions work according to a linear characteristic, at which the flow varies linearly with the stroke of the moving part, other solutions work according to a characteristic of equal percentages, at which equal increments of the stroke of the moving part produce equal percentages of variation, other solutions work according to a characteristic with parabolic modification, which allows a fine adjustment of the flow at low values and an approximately linear variation, at high values of flow, other solutions work according to a fast opening characteristic, characterized by the installation of a maximum flow as soon as the moving part begins to open, other solutions work according to a hyperbolic characteristic, and other solutions work according to a square roots characteristic.

In terms of the type of actuator used to change the position of the moving part, some solutions use a spring-type actuator, other solutions use a membrane-type actuator, other solutions use an electromagnet-type actuator and other solutions use an electric motor as an actuator.

In terms of how the movement from the actuator to the moving part is transmitted, some solutions, mainly those using spring, diaphragm and electromagnet type actuators, the movement from the actuator to the moving part is transmitted directly and other solutions, mainly those that use electric motor type actuators, the movement from the actuator to the moving part is transmitted indirectly, by means of mechanisms for reduction the movement. Most of the known solutions make the initial adjustment, either of the pressure or of the flow of the working fluid used, an initial adjustment which is made manually. After making this adjustment, the manually adjusted value is kept constant, either by the balance between the force due to the fluid pressure and the force developed by the spring and / or the diaphragm, or by a command transmitted by the electromagnet or electric motor actuators. 3. The solutions we know have the following disadvantages:

- in general, they have a very large number of components, resulting in a very high complexity of the adjustment equipment, a difficult execution and assembly and a high probability of failure or disturbance;

- most known flow control solutions only allow manual adjustment of the fluid flow and maintaining this value constantly;

- most of the solutions we know for flow regulation use spring or diaphragm actuators, elements whose characteristic is difficult to control and which, over time, can be uncalibrated;

- the flow control is not very precise and there is no feedback loop to correct the flow value to the required value in the fluid-fed system whose flow is to be adjusted;

- the actuation of the movable element, which by its movement modifies the fluid flow section, is usually done, not directly from the electric motor type actuator, but by means of mechanisms for reduction the movement; these mechanisms, usually of the geared type with gears or worm - worm wheel, which further complicate the construction of the adjustment equipment and introduce additional losses and inaccuracies.

4. The technical problem solved by the patent is the realization of a flow control equipment with a simple construction and a small number of components and which achieves a continuous adjustment, in a wide flow range, by direct actuation of the element that modifies the section of fluid flow by an electric motor that ensures very small increments of positioning of the moving element, so a very fine adjustment of the flow.

5. The equipment for the continuous regulation of the flow of liquids, according to the patent, removes the mentioned disadvantages of the known solutions, in that it uses an electric motor that transmits a rotational movement with very small increment, directly to the element of modification of the flow section, without using mechanisms of reduction of the movement. The flow section variation element is provided with an area with external grooves which ensures the taking over of the rotational movement transmitted by the electric motor and allows the longitudinal movement of the flow section variation element. This movement is performed with a screw-nut mechanism consisting of the outer thread with fine pitch executed on the element for changing the flow section and the inner thread of a piece with inner thread of movement. The longitudinal movement of the flow section modification element leads to the displacement of the conical portion of this element in relation to the cylindrical orifice through which the fluid exits the regulating equipment, having the effect of changing the fluid flow section and implicitly changing the fluid flow. The fluid outlet is practiced, like the fluid inlet, in a non-metallic part that allows direct contact between the flow section modification element and this non- metallic part, thus allowing the complete closure of the inlet-outlet circuit, obtaining thus zero flow. The non-metallic part with the inlet-outlet openings is fixed in a body on which the fluid inlet and outlet connections are mounted, on which pressure transducers can be mounted which allow the determination of the pressure drop on the flow control equipment and ensure feedback loop to automate the adjustment process. 6. The patent has the following advantages:

- constructive simplicity, due to the small number of mechanical components that make up the adjustment equipment that is the subject of the patent;

- the transmission of the movement from the electric motor to the element that performs the modification of the fluid flow section is done directly, through a coupling with internal grooves, without the need to use intermediate mechanisms to reduction the movement;

- the construction solution of the adjusting equipment, according to the patent, does not contain spring or membrane elastic elements, the characteristic of the equipment being given only by the variation of the pressure drop on the equipment depending on the position of the flow section modification element, controlled by the electric motor;

- the fluid flow can be adjusted in a wide range, from zero to the maximum flow provided by the pump used to supply the installation through which the fluid whose flow is regulated flows;

- the flow adjustment is continuous and is performed automatically and not manually;

- the equipment allows a very fine adjustment of the fluid flow, the electric motor can be controlled to make very small angular displacements, which cause linear displacements of the flow section change element with submicron values, so extremely small changes of the flow section;

- the proposed constructive solution allows the miniaturization of the equipment, which can also be used in the medical and pharmaceutical fields, for the very precise dosing of the liquids used for treatment or for obtaining drugs;

- by using two pressure transducers installed at the inlet and outlet of the control equipment and a flow transducer inserted in the fluid flow circuit, the process requiring the flow control can be fully automated and monitored.

7. The following is a way of making the patent, in connection with Fig. 1 and Fig. 2, which represents:

- Fig.1 - Longitudinal section through the assembly of the equipment for the continuous regulation of the liquid flow, with direct electric actuation of the element that performs the modification of the flow section;

- Fig. 2 - 3D view of the flow section adjustment element.

According to the patent, the equipment for continuous regulation of the liquid flow rate, with the direct electric drive of the element which performs the modification of the flow section, consists of:

The electric motor for actuating the regulating element 1, has the role of transmitting to the flow section adjustment element 4 a rotational movement, by means of a coupling with internal grooves 3. The electric motor 1 is powered from a power supply and controlled by means of a driver which allows the variation in a very wide range of the angle with which the element 4 is rotated, which allows a very fine adjustment of the flow section and implicitly of the fluid flow to be adjusted to a certain value, and then maintained at this value as accurately as possible. The electric motor 1 can be a servomotor type or a stepper motor type, this second type being able to ensure, if for its control a driver with micropass is used, very small angular increments, therefore an extremely fine adjustment of the fluid flow. The electric motor 1 is usually purchased from specialized manufacturers.

The electric motor connecting piece - regulating equipment body 2, has the role of ensuring the attachment of the electric motor 1 , as well as the attachment of the part with internal movement thread 5, on which the body of the adjusting equipment 8 is fixed by screwing. Since both the electric motor 1 and the connecting piece 2 and the inner threaded part 5 and the body of the adjusting equipment 8 are provided with recesses or cylindrical shoulders for centering, the axes of these components will be coaxial, which will lead to a longitudinal movement of the element 4 coaxial with the part with the inlets and outlets of the fluid 6. The electric motor connecting piece - regulating equipment body 2 also has the role of guiding the rotational movement of the coupling with inner grooves 3, as well as the movement of roto-translation of the flow section adjustment element 4.

- The coupling with the inner grooves 3, has the role of transmitting the rotational movement from the axis of the electric motor 1 to the flow section adjustment element 4 and to allow to this element to make a linear movement along its axis, which it has the effect of modifying (decreasing or increasing) the fluid flow section and implicitly changing the fluid flow. The inner grooves of the coupling 3 can be made by EDM, wire or solid electrode or with the help of a 3D printer, on metal or plastic. The coupling 3 rotates inside the connecting piece 2, between the two parts being a close clearance assembly that ensures a very low relative frictional movement. Fixing of the coupling with inner grooves 3 on the electric motor shaft 1 can be done by several methods of mechanical assembly, in the example of Fig. 1 the fixing of the coupling 3 by means of two threaded pins and a cylindrical bushing mounted on the electric motor shaft 1.

- The flow section adjustment element 4, has the role of modifying the flow section of the fluid and implicitly of its flow, modification made by moving it in the longitudinal direction. The longitudinal movement is made by a screw- nut mechanism consisting of the piece with external thread made on element 4 (Fig. 2) and the inner thread made in the piece with internal movement thread 5. The smaller the thread pitch executed on the two parts, the finer the fluid flow adjustment will be, because at the same rotation angle given by the electric motor 1 of element 4, the linear displacement of element 4 will be the smaller by the smaller the thread pitch. Although the electric motor 1 transmits a rotational movement to the element 4, it will also make a linear movement due to the screw-nut mechanism between parts 4 and 5. This linear movement is allowed by the engagement between the inner grooves of the coupling 3 and the grooved portion executed on the element 4 (Fig. 2). In the area of the flow section between the element 4 and the part with inlet-outlet holes 6, the element 4 is provided with a conical portion (Fig. 2). The peak angle of the threaded portion is fabricated at values as small as possible, these allowing a change in the flow section which is the smaller the smaller the angle of the conical portion made on the element 4 is (so a fine flow adjustment is possible). The element 4 is an element that requires a high precision of execution, which requires its realization from materials that allow specific surface finishing processes.

- The part with internal movement thread 5, has the role of transmitting to the flow section adjustment element 4 a linear displacement movement by means of the screw-nut mechanism formed by the piece with external thread made on element 4 (Fig. 2) and from the internal thread performed in the part with internal movement thread 5. The part with internal movement thread 5 is fixed on the connecting piece 2 and is assembled by screwing with the body of the adjusting equipment 8. The inner and outer cylindrical portions performed in part 5 ensure the concentricity between the connecting piece 2 and the body of the adjusting equipment 8, thus contributing to the concentric movement of the element 4 with an outlet hole made in the piece 6.

- The part with fluid inlet - outlet holes 6, has the role of allowing the circulation of the fluid whose flow must be regulated, from the fluid supply source to the supplied equipment or installation. The piece with holes 6 is assembled with the body of the adjusting equipment 8 by means of an interference adjustment, the fluid inlet opening being made after assembling the parts 6 in the body 8. After making the inlet hole and mounting in it the fluid inlet connection 7, the part 6 and the body 8 become solid, thus preventing the relative rotation between the two parts. The outlet hole has a cylindrical shape and together with the element 4 forms the fluid flow section. The hole piece 6 can be made of a non-metallic material, for example polyamide, Teflon, PEEK, etc., a material which ensures a low coefficient of friction in combination with the material from which the element 4 is made. Also the non-metallic material from which it is made the hole part 6 can provide sealing to the body of the adjusting equipment 8. In order to ensure the seal to the element 4, in the part with holes 6 one or more recesses can be provided, in which O-ring type sealing elements are mounted.

- The fluid inlet connection 7, has the role of making the connection between the fluid supply source and the part with holes 6. It is mounted by screwing in the inlet hole made in the subassembly formed between the part with holes 6 and the body of the adjustment equipment 8. This connection can be provided with a hole for mounting a transducer for monitoring the fluid pressure at the inlet to the control equipment.

- Body of the adjusting equipment 8, has the role of allowing the support of the component elements of the adjusting equipment, on the body 8 mounting the part with internal movement thread 5, the part with fluid inlet - outlet 6, fluid inlet connection 7 and outlet connection fluid 9. The part with internal movement thread 5, the fluid inlet connection 7 and the fluid outlet connection 9 are mounted on the body 8 by screwing, and the part with holes 6 is mounted by pressing into the body 8. The inner cylindrical portions performed in the body 8 ensure concentricity between the hole piece 6 and the flow section adjustment element 4, thus contributing to the movement of the element 4 concentric with the outlet hole performed in the piece with holes 6.

- The fluid outlet connection 9, has the role of connecting the part with holes 6 with the installation or equipment supplied with the fluid whose flow is regulated. It is screwed into the outlet hole performed in the body of the regulating equipment 8. As well as the fluid inlet connection 7 and the fluid outlet connection 9 can be provided with a hole for mounting a transducer to monitor the fluid pressure at the outlet of the regulating equipment. In this way it is determined the pressure drop on the control equipment and creates an adjustment loop to automate the adjustment process.

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