A parallel double LVDT anti-torsion device

Abstract

The utility model discloses a parallel double LVDT anti-twist device, which belongs to the main steam regulating valve feedback device of the steam turbine of the power plant, and comprises a first LVDT device, a second LVDT device, a connecting piece and a connecting rod installed in the fixed bottom plate of the bracket, wherein the middle part of the connecting piece is connected to the connecting rod; the connecting rod is connected to the movable end of the valve; a torsion spring is installed between the movable iron core of the LVDT device and the LVDT connecting rod, and when the valve opening is large and the position of the valve stem is offset, the wear between the movable iron core and the coil assembly of the LVDT device can be eliminated by deformation of the torsion spring. The torsion spring has an automatic recovery function, and can automatically adjust the steam turbine regulating valve feedback device to adjust the offset of the valve stem. The device has a simple structure, low cost and convenient installation.

Description

Technical Field

[0001] The utility model relates to the technical field of a main steam regulating valve feedback device for a steam turbine in a power plant, in particular to a parallel double LVDT anti-twist device. Background Art

[0002] When the opening of the high and medium pressure main steam regulating valve of the steam turbine is large, the valve stem will have a certain degree of deviation, and the larger the opening, the greater the deviation, which will cause the core of the LVDT device of the main steam regulating valve feedback device of the steam turbine to be subjected to greater pulling force, and the core is easily damaged. Once the LVDT feedback device fails, the main steam regulating valve cannot be adjusted normally, affecting the power output of the steam turbine. The existing technology utility model patents "Automatic deviation correction LVDT device" (authorization announcement number CN 214008262 U) and "Valve LVDT anti-wear device" (authorization announcement number CN 217380663U) solve the above problems in the "Valve feedback device based on dual LVDT displacement sensors" (authorization announcement number CN 215831270 U) is improved, the patented improved technical features of the "automatic deviation-correcting LVDT device" are as follows: "the feedback rod on the LVDT sensor is connected to the connecting plate via a universal connector; the universal connector includes a fixed cover, a ball and a lower ball sleeve, the ball is located in the lower ball sleeve, and the top of the ball is fixed to the fixed cover"; the patented improved technical features of the "valve-adjusting LVDT anti-wear device" are as follows: "the LVDT core (1) is connected to the core fixing plate (2) via a shockproof buffer joint (4); the shockproof buffer joint (4) includes a lower connector (41), the top of the lower connector (41) is provided with a ball movable groove, and the ball movable groove is provided with a A steering ball (42) is provided, the steering ball (42) is connected to a connecting column (43), the connecting column (43) is connected to an upper connector (44), the upper connector (44) is used to connect to an LVDT core (1), and a buffer layer (45) is provided between the outer wall of the connecting column (43) and the movable groove of the ball body. That is, a universal connector or a shockproof buffer joint is added to the "valve feedback device based on a dual LVDT displacement sensor". The added structures of the two improved utility model patents are more complicated, which increases the cost, and the automatic adjustment effect of the added structures is poor. The automatic deviation correction function of the valve feedback device of the dual LVDT displacement sensor is difficult to play, and the anti-wear effect of the valve adjustment LVDT is difficult to achieve. Summary of the invention

[0003] The utility model aims to provide a parallel dual LVDT anti-twist device to solve the problems in the prior art that the LVDT iron core of the high and medium pressure main steam regulating valve feedback device of the steam turbine is easily damaged when the pulling force is large, the main steam regulating valve stem is difficult to adjust automatically, and the power output of the steam turbine is affected.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a parallel dual LVDT anti-twist device, including a bracket fixing base plate, a first LVDT device, a second LVDT device, an LVDT device fixing bracket, a connecting piece and a connecting rod, the first LVDT device includes a first LVDT device coil assembly and a first movable iron core, the second IVDT device includes a second IVDT device coil assembly and a second movable iron core, the first LVDT device and the second LVDT device are fixed to the bracket fixing base plate through an LVDT device fixing bracket; the middle part of the connecting piece is connected to the connecting rod; the connecting rod is connected to the movable end of the valve; it also includes a first LVDT connecting rod, a first torsion spring, a second LVDT connecting rod, and a second torsion spring, the first movable iron core of the first LVDT device assembly and the second movable iron core of the second LVDT device assembly are respectively connected to the lower parts of the first torsion spring and the second torsion spring, the upper parts of the first torsion spring and the second torsion spring are connected to the lower parts of the first LVDT connecting rod and the second LVDT connecting rod; the upper parts of the first LVDT connecting rod and the second LVDT connecting rod are connected and fixed to the two ends of the connecting piece.

[0005] Furthermore, a connecting rod fixing hole is provided at the center of the connecting member, and a first connecting rod fixing hole and a second connecting rod fixing hole are respectively provided at both ends of the connecting member.

[0006] Furthermore, the first connecting rod fixing hole and the second connecting rod fixing hole are equidistantly distributed on both sides of the connecting rod fixing hole, and the first connecting rod fixing hole, the second connecting rod fixing hole and the connecting rod fixing hole are on the same horizontal plane.

[0007] Furthermore, the lower end of the connecting rod is provided with an external thread and is inserted into the connecting rod fixing hole. The upper locking nut of the connecting rod and the lower locking nut of the connecting rod are respectively abutted against the upper surface and the lower surface of the connecting piece and are tightened and fixed.

[0008] Furthermore, one also includes a first torsion spring lower connecting piece and a first torsion spring upper connecting piece, the upper part of the first movable iron core is provided with an external thread, the lower connecting piece of the first torsion spring is provided with an internal thread, and the first movable iron core is threadedly connected to the lower connecting piece of the first torsion spring; the lower end of the first torsion spring is coaxially welded to the lower connecting piece of the first torsion spring, and the upper end of the first torsion spring is coaxially welded to the upper connecting piece of the first torsion spring; the upper connecting piece of the first torsion spring is provided with an internal thread, and both ends of the first LVDT connecting rod are provided with external threads, the lower end of the first LVDT connecting rod is threadedly connected to the upper connecting piece of the first torsion spring, the upper end of the first LVDT connecting rod is inserted into the first connecting rod fixing hole of the connecting piece, the upper locking nut of the first connecting rod and the lower locking nut of the first connecting rod are respectively abutted against the upper surface and the lower surface of the connecting piece, and are tightened and fixed;

[0009] The second also includes a second torsion spring lower connecting piece and a second torsion spring upper connecting piece. The upper part of the second movable iron core is provided with an external thread, the lower connecting piece of the second torsion spring is provided with an internal thread, and the second movable iron core is threadedly connected to the lower connecting piece of the second torsion spring; the lower end of the second torsion spring is coaxially welded to the lower connecting piece of the second torsion spring, and the upper end of the second torsion spring is coaxially welded to the upper connecting piece of the second torsion spring; the upper connecting piece of the second torsion spring is provided with an internal thread, and both ends of the second LVDT connecting rod are provided with external threads, the lower end of the second LVDT connecting rod is threadedly connected to the upper connecting piece of the second torsion spring, and the upper end of the second LVDT connecting rod is inserted into the second connecting rod fixing hole of the connecting piece, and the upper locking nut of the second connecting rod and the lower locking nut of the second connecting rod are respectively abutted against the upper surface and lower surface of the connecting piece and tightened and fixed.

[0010] Furthermore, the upper locking nut of the first connecting rod adopts a double nut, the upper locking nut of the second connecting rod adopts a double nut, and the lower locking nut of the connecting rod adopts a double nut.

[0011] Furthermore, the first LVDT device and the second LVDT device are fixed on the bracket fixing base plate in parallel with each other.

[0012] Furthermore, the centers of the first LVDT device, the second LVDT device, and the connecting rod are located in the same plane.

[0013] Compared with the prior art, the utility model has the beneficial effect that a torsion spring is added between the movable iron core of the LVDT device and the LVDT connecting rod. When the opening of the high and medium pressure main steam regulating valve of the steam turbine is large, the valve opening is too large, and the position offset of the valve stem is also large, the large force transmitted by the valve stem to the LVDT connecting rod connected thereto can be eliminated by deformation of the torsion spring, and the wear between the movable iron core and the coil assembly of the LVDT device is alleviated. The torsion spring has an automatic recovery function and can automatically adjust the turbine regulating valve feedback device to adjust the offset of the valve stem. The device has a simple structure, low cost and is easy to install. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the utility model.

[0015] Figure 2 This is a schematic diagram of a fixing bracket for an LVDT device of the present utility model.

[0016] Figure 3 This is a schematic diagram of the first LVDT device of the utility model.

[0017] Figure 4 This is a schematic diagram of the second LVDT device of the present utility model.

[0018] Figure 5This is a schematic diagram of the connector of the LVDT device of the present utility model.

[0019] 1. Bracket fixing base plate, 2. Connecting piece, 3. LVDT device fixing bracket, 4. LVDT device fixing bracket fixing hole, 5. Connecting rod, 6. Connecting rod fixing hole, 7. Connecting rod upper locking nut, 8. Connecting rod lower locking nut, 10. First LVDT device coil assembly, 11. First movable iron core, 12. First torsion spring, 13. First torsion spring lower connecting piece, 14. First torsion spring upper connecting piece, 15. First LVDT connecting rod, 16. First connecting rod fixing hole, 17. First connecting rod upper locking nut, 18. First connecting rod lower locking nut Mother, 19, first LVDT device, 20, second LVDT device coil assembly, 21, second movable iron core, 22, second torsion spring, 23, second torsion spring lower connecting piece, 24, second torsion spring upper connecting piece, 25, second LVDT connecting rod, 26, second connecting rod fixing hole, 27, second connecting rod upper locking nut, 28, second connecting rod lower locking nut, 29, second LVDT device, 30, valve movable end, 31, LVDT device fixing hole, 32, first LVDT device signal output line, 33, second LVDT device signal output line. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings in the embodiments of the present invention. However, the embodiments described below through the accompanying drawings are intended to be used to explain the present invention and should not be understood as limiting the present invention.

[0021] like Figure 1As shown, a parallel dual LVDT anti-twist device includes a bracket fixing base plate 1, a first LVDT device 19, a second LVDT device 29, an LVDT device fixing bracket 3, a connecting piece 2 and a connecting rod 5; the first LVDT device 19 includes a first LVDT device coil assembly 10 and a first movable iron core 11, and the second IVDT device 29 includes a second IVDT The device coil assembly 20 and the second movable iron core 21 are fixed to the first LVDT device 19 and the second LVDT device 29 on the bracket fixing base plate 1 by using the LVDT device fixing bracket 3 through the LVDT device fixing bracket fixing hole 4 with bolts; the middle part of the connecting piece 2 is connected to the connecting rod 5; the connecting rod 5 is connected to the valve movable end 30; the first LVDT connecting rod 15, the first torsion spring 12, the second LVDT connecting rod 25, and the second torsion spring 22 are also provided; the first movable iron core 11 and the second movable iron core 21 are respectively connected to the lower parts of the first torsion spring 12 and the second torsion spring 22, and the upper parts of the first torsion spring 12 and the second torsion spring 22 are connected to the lower parts of the first LVDT connecting rod 15 and the second LVDT connecting rod 25; the upper parts of the first LVDT connecting rod 15 and the second LVDT connecting rod 25 are connected and fixed to the two ends of the connecting piece 2.

[0022] like Figure 1 , Figure 5 As shown, a connecting rod fixing hole 6 is provided at the center of the connecting member 2, and a first connecting rod fixing hole 16 and a second connecting rod fixing hole 26 are respectively provided at both ends of the connecting member 2, and the first connecting rod fixing hole 16 and the second connecting rod fixing hole 26 are equidistantly distributed on both sides of the connecting rod fixing hole 6, and the first connecting rod fixing hole 16, the second connecting rod fixing hole 26 and the connecting rod fixing hole 6 are on the same plane; the upper end of the first LVDT connecting rod 15 is penetrated into the first connecting rod fixing hole 16 of the connecting member 2, and the first connecting rod upper locking nut 17 and the first connecting rod lower locking nut 18 are respectively abutted against the upper surface and the lower surface of the connecting member 2, wherein the first connecting rod upper locking nut 17 adopts a double nut design to prevent the vibration caused by large The first LVDT connecting rod 15 may fall off due to large vibration; similarly, the upper end of the second LVDT connecting rod 25 is inserted into the second connecting rod fixing hole 26 of the connecting piece 2, and the second connecting rod upper locking nut 27 and the second connecting rod lower locking nut 28 are respectively abutted against the upper surface and lower surface of the connecting piece 2, wherein the second connecting rod upper locking nut 27 adopts a double nut design to prevent the second LVDT connecting rod 25 from falling off due to large vibration; similarly, the lower end of the connecting rod 5 is inserted into the connecting rod fixing hole 6, and the connecting rod upper locking nut 7 and the connecting rod lower locking nut 8 are respectively abutted against the upper surface and lower surface of the connecting piece 2, wherein the connecting rod lower locking nut 8 adopts a double nut design to prevent the connecting rod 5 from falling off due to large vibration.

[0023] As attached Figure 1 , Figure 2 As shown, the first LVDT device 19 and the second LVDT device 29 are fixed to the bracket fixing base plate 1 in parallel with each other through the LVDT device fixing holes 31 on the LVDT device fixing bracket 3 .

[0024] As attached Figure 3 , Figure 4 As shown, in the first LVDT device 19, the first torsion spring 12 is a spring with relatively strong stiffness, that is, when the first torsion spring 12 is not subjected to force, it does not deform, and the first movable iron core 11, the first torsion spring 12, the first torsion spring lower connecting piece 13, the first torsion spring upper connecting piece 14, and the first LVDT connecting rod 15 are on the same axis, wherein the upper end of the first torsion spring 12 is coaxially welded to the first torsion spring upper connecting piece 14, and the first torsion spring upper connecting piece 14 is provided with an internal thread, which is connected to the external thread of the lower end of the first LVDT connecting rod 15; the lower end of the first torsion spring 12 is coaxially welded to the first torsion spring lower connecting piece 13, and the first torsion spring lower connecting piece 13 is provided with an internal thread, which is connected to the external thread of the upper part of the first movable iron core 11. Similarly, in the second LVDT device 29, the second torsion spring 22 is a spring with relatively strong stiffness, that is, when the second torsion spring 22 is not subjected to force, it does not deform, and the second movable iron core 21, the second torsion spring 22, the second torsion spring lower connecting piece 23, the second torsion spring upper connecting piece 24, and the second LVDT connecting rod 25 are on the same axis, wherein the upper end of the second torsion spring 22 is coaxially welded to the second torsion spring upper connecting piece 24, and the second torsion spring upper connecting piece 24 is provided with an internal thread, which is connected to the external thread of the lower end of the second LVDT connecting rod 25; the lower end of the second torsion spring 22 is coaxially welded to the second torsion spring lower connecting piece 23, and the second torsion spring lower connecting piece 23 is provided with an internal thread, which is connected to the external thread of the upper part of the second movable iron core 21.

[0025] Working principle: When the valve opening is greater than 80%, the position of the valve stem is prone to deviation, and the first movable iron core 11 and the second movable iron core 21 are deviated through the valve movable end 30. At this time, the first torsion spring 12 is deformed to prevent the first movable iron core 11 from rubbing against the first LVDT device coil assembly 10. Similarly, the second torsion spring 22 is deformed to prevent the second movable iron core 21 from rubbing against the second LVDT device coil assembly 20. At the same time, the design of the dual LVDT device can prevent the entire LVDT device from having no valve position signal feedback due to the drop of the single-side movable iron core, that is, when the first movable iron core 11 falls into the first LVDT device coil assembly 10, the second LVDT device signal output line 33 still has a valve position feedback signal output; when the second movable iron core 21 falls into the second LVDT device coil assembly 20, the first LVDT device signal output line 32 also has a valve position feedback signal output.

[0026] The LVDT displacement sensor is composed of an iron core and a coil assembly. It uses the electromagnetic induction principle to convert the measured physical displacement into the induced voltage of the coil through mutual inductance, thereby realizing displacement measurement. When working, inside the LVDT displacement sensor, as the iron core continues to move, the magnetic field will change. When the primary coil senses it, it will provide an alternating voltage according to the different positions of the iron core. Then the secondary coil starts working to generate an induced electromotive force. However, due to the different positions of the iron core, the induced electromotive force generated is also different. At this time, the displacement of the iron core provides a voltage output signal. The automatic adjustment effect of the main steam regulating valve feedback device of the steam turbine can be detected to ensure good regulation.

[0027] In the present embodiment, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0028] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A parallel dual LVDT anti-twist device, comprising a bracket fixing base plate (1), a first LVDT device (19), a second LVDT device (29), an LVDT device fixing bracket (3), a connecting piece (2) and a connecting rod (5), wherein the first LVDT device (19) comprises a first LVDT device coil assembly (10) and a first movable iron core (11), the second LVDT device (29) comprises a second LVDT device coil assembly (20) and a second movable iron core (21), the first LVDT device (19) and the second LVDT device (29) are fixed to the bracket fixing base plate (1) via an LVDT device fixing bracket (3); the middle portion of the connecting piece (2) is connected to the connecting rod (5); the connecting rod (5) is connected to a valve movable end (30), characterized in that It also includes a first LVDT connecting rod (15), a first torsion spring (12), a second LVDT connecting rod (25), and a second torsion spring (22); the first movable iron core (11) and the second movable iron core (21) are respectively connected to the lower parts of the first torsion spring (12) and the second torsion spring (22); the upper parts of the first torsion spring (12) and the second torsion spring (22) are connected to the lower parts of the first LVDT connecting rod (15) and the second LVDT connecting rod (25); and the upper parts of the first LVDT connecting rod (15) and the second LVDT connecting rod (25) are connected and fixed to the two ends of the connecting member (2).

2. A parallel dual LVDT anti-torsion device according to claim 1, characterized in that A connecting rod fixing hole (6) is provided at the center of the connecting piece (2), and a first connecting rod fixing hole (16) and a second connecting rod fixing hole (26) are respectively provided at both ends of the connecting piece (2).

3. A parallel dual LVDT anti-torsion device according to claim 2, characterized in that The first connecting rod fixing hole (16) and the second connecting rod fixing hole (26) are equidistantly distributed on both sides of the connecting rod fixing hole (6); the first connecting rod fixing hole (16), the second connecting rod fixing hole (26) and the connecting rod fixing hole (6) are on the same horizontal plane.

4. A parallel dual LVDT anti-twist device according to claim 2 or 3, characterized in that The lower end of the connecting rod (5) is provided with an external thread and is inserted into the connecting rod fixing hole (6). The upper locking nut (7) and the lower locking nut (8) at the thread of the connecting rod (5) are respectively abutted against the upper surface and the lower surface of the connecting piece (2) and are tightened and fixed.

5. A parallel dual LVDT anti-torsion device according to claim 2 or 3, characterized in that The first movable iron core (11) further comprises a first torsion spring lower connecting piece (13) and a first torsion spring upper connecting piece (14); the first movable iron core (11) is provided with an external thread on its upper portion; the first torsion spring lower connecting piece (13) is provided with an internal thread that matches the external thread on the upper portion of the first movable iron core (11); the first movable iron core (11) and the first torsion spring lower connecting piece (13) are connected via threads; the lower end of the first torsion spring (12) is coaxially welded to the first torsion spring lower connecting piece (13); the upper end of the first torsion spring (12) is coaxially welded to the first torsion spring lower connecting piece (13); The spring upper connecting piece (14) is coaxially welded; the first torsion spring upper connecting piece (14) is provided with an internal thread, and both ends of the first LVDT connecting rod (15) are provided with external threads. The lower end of the first LVDT connecting rod (15) is threadedly connected to the first torsion spring upper connecting piece (14), and the upper end of the first LVDT connecting rod (15) is inserted into the first connecting rod fixing hole (16) of the connecting piece (2). The first connecting rod upper locking nut (17) and the first connecting rod lower locking nut (18) are respectively abutted against the upper surface and the lower surface of the connecting piece (2) to be screwed. The parallel dual LVDT anti-twist device further comprises a second torsion spring lower connecting piece (23) and a second torsion spring upper connecting piece (24); the upper part of the second movable iron core (21) is provided with an external thread, the second torsion spring lower connecting piece (23) is provided with an internal thread, and the second movable iron core (21) is threadedly connected to the second torsion spring lower connecting piece (23); the lower end of the second torsion spring (22) is coaxially welded to the second torsion spring lower connecting piece (23), and the upper end of the second torsion spring (22) is coaxially welded to the second torsion spring upper connecting piece (24). The connecting piece (24) is coaxially welded; the second torsion spring upper connecting piece (24) is provided with an internal thread, and both ends of the second LVDT connecting rod (25) are provided with external threads; the lower end of the second LVDT connecting rod (25) is threadedly connected to the second torsion spring upper connecting piece (24); the upper end of the second LVDT connecting rod (25) is inserted into the second connecting rod fixing hole (26) of the connecting piece (2); the second connecting rod upper locking nut (27) and the second connecting rod lower locking nut (28) are respectively abutted against the upper surface and the lower surface of the connecting piece (2) and tightened and fixed.

6. A parallel dual LVDT anti-torsion device according to claim 5, characterized in that The first connecting rod upper locking nut (17) is a double nut, the second connecting rod upper locking nut (27) is a double nut, and the connecting rod lower locking nut (8) is a double nut.

7. A parallel dual LVDT anti-torsion device according to claim 1, characterized in that The first LVDT device (19) and the second LVDT device (29) are fixed on the bracket fixing base plate (1) in parallel with each other.

8. The parallel dual LVDT anti-torsion device according to claim 1, characterized in that The centers of the first LVDT device (19), the second LVDT device (29), and the connecting rod (5) are located in the same plane.

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