Low-liquid-level protection device for lubricating oil tank of steam turbine

Abstract

According to the technical scheme, the low-liquid-level protection device is characterized by comprising a main oil tank, a control unit, a signal processing module and an alarm device, a floating plate assembly is arranged in an oil cavity and slidably connected with the inner wall of the oil cavity through a sliding structure, and a high-liquid-level detection position and a low-liquid-level detection position are arranged on a sliding rail; first sensors are arranged on the high liquid level detection position and the low liquid level detection position of the sliding rail, a first trigger is arranged on the floating plate assembly, and when the floating plate assembly reaches the corresponding position, the first trigger triggers the first sensors; the sensor sends a signal to enable the control unit to control the alarm device to start and enable equipment on the steam turbine to stop or supplement oil into an oil tank; the floating plate assembly is always attached to the liquid level of the oil through the buoyancy effect and slides up and down along with lifting of the liquid level of the oil. The mechanical direct measurement mode can avoid the interference of external factors such as vibration and improve the measurement accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine oil tanks, and in particular to a low liquid level protection device for a steam turbine lubricating oil tank. Background Art

[0002] When the steam turbine is operating normally, lubricating oil is usually needed to lubricate and clean the bearings inside the turbine, and to remove the heat generated by the friction of the turbine rotor to prevent the turbine bearings from overheating. The steam turbine lubricating oil tank is responsible for storing lubricating oil in the lubrication system of the steam turbine, thereby ensuring the normal supply of lubricating oil to the turbine bearings.

[0003] During the normal operation of the turbine lubrication system, if the oil in the oil tank is too low, the main oil pump will be sucked empty, which may cause serious accidents such as turbine bearing burnout and rotor dynamic / static friction. Therefore, in the prior art, a low liquid level protection device is set in the oil tank to monitor the height of the oil in the tank. When the oil is detected to be at a low level, an alarm will be triggered and the device will be handled by either adding oil or shutting down the machine.

[0004] The current low liquid level protection device usually monitors the oil level in the oil tank through an oil level sensor or an oil level gauge. The above-mentioned devices all measure the oil level in the oil tank to obtain the oil level; however, in actual use, since the oil tank is connected to equipment such as an oil pump and a range hood, these equipment will vibrate when working, causing the oil tank to vibrate as well. The vibration of the oil tank will cause the oil level to fluctuate, thereby affecting the measurement results of the oil level sensor or the oil level gauge, and easily leading to erroneous operations such as false alarms or false shutdowns of the equipment, affecting the normal operation of the turbine lubricating oil system. Summary of the invention

[0005] The present invention provides a low liquid level protection device for a steam turbine lubricating oil tank, which solves the problem in the related art that the fluctuation of the oil level affects the measurement result of the sensor and causes erroneous operation.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a low liquid level protection device for a steam turbine lubricating oil tank, comprising a main oil tank with an oil chamber, a control unit connected to steam turbine equipment, a signal processing module arranged on the control unit, and an alarm device electrically connected to the control unit, wherein a floating plate assembly in contact with the oil liquid surface is arranged in the oil chamber, and the floating plate assembly is slidably connected to the inner wall of the oil chamber through a sliding structure, the sliding structure comprises a plurality of slide rails vertically arranged on the inner wall of the oil chamber and a slider arranged on the floating plate assembly and slidably matched with the slide rails, a high liquid level detection position and a low liquid level detection position are arranged on the slide rail, and a first sensor electrically connected to the control unit through the signal processing module is arranged on the high liquid level detection position and the low liquid level detection position of the slide rail, and a first trigger matched with the sensor is arranged on the floating plate assembly, and when the floating plate assembly reaches the corresponding position, the first trigger triggers the first sensor, so that the sensor sends a signal to let the control unit control the alarm device to start and shut down the equipment on the steam turbine or replenish the oil in the oil tank.

[0007] The present invention is further configured such that the floating plate assembly includes a connecting frame slidably arranged on the inner wall of the oil chamber, the sliding block is fixedly arranged on the peripheral side of the connecting frame, and the first trigger is arranged on the connecting frame; a connecting hole is arranged in the middle of the connecting frame, a floating block that can float on the surface of the oil is detachably connected to the connecting hole, and a gap is formed between the floating block and the connecting frame for the oil to flow through.

[0008] The present invention is further configured such that the top surface of the floating block is provided with a conical guide surface which is inclined downward from the middle to the peripheral side.

[0009] The present invention is further configured such that the floating block comprises a hollow floating pad, a solid center of gravity block immersed in oil is arranged below the floating pad, and the guide surface is arranged on the top of the floating pad.

[0010] The present invention is further configured such that a plurality of the center of gravity blocks are provided and evenly distributed below the floating pad; and a plurality of air holes for exhausting air are provided on the floating pad.

[0011] The present invention is further configured such that a plurality of needle-shaped protrusions inserted into the oil are protruding from the lower surface of the floating pad, and the plurality of needle-shaped protrusions form a defoaming layer on the lower surface of the floating pad.

[0012] The present invention is further configured such that a shutdown liquid level section is also provided on the slide rail, and the shutdown liquid level section is provided between the high liquid level detection position and the low liquid level detection position; the shutdown liquid level section includes a sensing position and a trigger position located below the sensing position, and the sensing position and the trigger position are respectively provided with a second sensor and a third sensor connected to the control unit through a signal processing module; a second trigger cooperating with the second sensor and the third sensor is provided on the connection frame, and also includes a timer provided on the control unit and connected to the second sensor and the third sensor; when the second trigger passes through the second sensor, the second sensor will send a signal to the timer, and the timer will send a pulse signal to the third sensor by presetting a time period, and when the second trigger passes through the third sensor within the pre-set time period, the third sensor will send a signal to the control unit to shut down the equipment.

[0013] The present invention is further configured such that the second sensor and the third sensor are Hall effect sensors, and the trigger is a magnetic block arranged on the connection frame and corresponding to the Hall effect sensor.

[0014] The present invention is further configured such that the first sensor is a Hall effect sensor, and the first trigger is a magnetic block arranged on the connection frame.

[0015] The present invention is further configured such that the slide rail is hollow, the oil tank is provided with a mounting hole connected to the interior of the slide rail, the Hall effect sensor is installed on the slide rail through the mounting hole and the sensing end of the Hall effect sensor is arranged toward the interior of the oil chamber; the magnetic block is fixedly arranged on the path of the connecting frame relative to the Hall effect sensor.

[0016] In summary, the beneficial effects of the present invention are:

[0017] Compared with the prior art, the float plate assembly of the present application always keeps in contact with the oil surface through the action of buoyancy, and slides up and down with the rise and fall of the oil surface; when the oil shakes, the float plate assembly is slidably arranged in the oil chamber through the slide rail and the slider, so the float plate assembly will encounter a certain resistance when sliding, and this resistance will consume the energy of the oil shaking, thereby reducing the amplitude and frequency of the shaking; at the same time, the oil will be blocked and confined in a small space by the float plate assembly, thereby reducing the fluidity and impact force of the oil, so it can be ensured that the float plate assembly can descend as the oil decreases, but when the oil tank is vibrated and the oil level fluctuates, the float plate assembly will not shake up and down; compared with relying solely on the oil level sensor or the oil level gauge, this mechanical direct measurement method can better avoid interference from external factors such as vibration and improve measurement accuracy.

[0018] In addition, sensors are provided at the high liquid level detection position and the low liquid level detection position of the slide rail, and a trigger cooperating with the sensor is provided on the floating plate assembly. Therefore, the stable floating plate assembly reduces the possibility of false alarm or false shutdown and improves the reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional structural diagram of this embodiment.

[0020] Figure 2 It is a diagram of the internal structure of this embodiment.

[0021] Figure 3 It is a partial schematic diagram of the back of this embodiment.

[0022] Figure 4 yes Figure 3 An enlarged schematic diagram of .

[0023] Figure 5 is a bottom schematic diagram of the floating plate assembly.

[0024] Figure 6 It is a schematic diagram of the top structure of the floating plate assembly.

[0025] Figure 7 It is a module connection block diagram of this embodiment.

[0026] Figure numerals: 1. main oil tank; 11. oil chamber; 2. alarm device; 3. floating plate assembly; 31. connecting frame; 32. connecting hole; 33. floating block; 34. gap; 35. guide surface; 36. floating pad; 37. center of gravity block; 38. defoaming layer; 4. sliding structure; 41. slide rail; 42. slider; 43. high liquid level detection position; 44. low liquid level detection position; 50. first sensor; 51. first trigger; 52. second sensor; 53. third sensor; 54. second trigger; 6. shutdown liquid level section; 61. sensing position; 62. trigger position; 7. mounting hole. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0028] Embodiment 1

[0029] like Figure 1-7As shown, this embodiment discloses a low liquid level protection device for a steam turbine lubricating oil tank, comprising a main oil tank 1 with an oil chamber 11, a control unit connected to the steam turbine equipment, a signal processing module arranged on the control unit, and an alarm device 2 electrically connected to the control unit, wherein the control unit is used to connect the equipment on the steam turbine, including a PLC circuit board, the PLC circuit board is connected to the actuator of the equipment, and the signal processing module can process the signal of the sensor, so that the control unit can receive and process the signal of the sensor; and the alarm device 2 includes a buzzer arranged on the oil tank, the buzzer is connected to the control unit, when the signal of the sensor is sent to the control unit through the signal processing module, the control unit will control the buzzer to make it sound and can also send information to the control system of the equipment so that the staff can find the fault in time.

[0030] like Figure 2-3 As shown, a floating plate assembly 3 that is in contact with the oil surface is provided in the oil chamber 11 of the oil tank, and the floating plate assembly 3 is slidably connected to the inner wall of the oil chamber 11 through a sliding structure 4. The sliding structure 4 includes a plurality of slide rails 41 vertically arranged on the inner wall of the oil chamber 11 and a slider 42 arranged on the floating plate assembly 3 and slidably matched with the slide rails 41. A high liquid level detection position 43 and a low liquid level detection position 44 are provided on the slide rail 41. A first sensor 50 that is electrically connected to the control unit through a signal processing module is provided on the high liquid level detection position 43 and the low liquid level detection position 44 of the slide rail 41, and a first trigger 51 that cooperates with the sensor is provided on the floating plate assembly 3; when the floating plate assembly 3 reaches the corresponding position, the first trigger 51 triggers the first sensor 50, so that the sensor sends a signal to allow the control unit to control the alarm device 2 to start and shut down the equipment on the turbine or replenish the oil in the oil tank.

[0031] The float plate assembly 3 is slidably arranged in the oil chamber 11 and adheres to the surface of the oil, so it can slide up and down in the oil chamber 11 when the oil rises or falls. Since a plurality of slide rails 41 are arranged in the oil chamber 11, and a plurality of sliders 42 slidably matched with the slide rails 41 are arranged on the float plate assembly 3, it is ensured that the float plate assembly 3 can slide up and down smoothly in the oil chamber 11. Transparent glass is arranged on the oil tank to clearly see the position of the float plate assembly 3, so that the float plate assembly 3 can be used to stably measure the oil level height.

[0032] like Figure 3As shown, a high liquid level detection position 43 and a low liquid level detection position 44 are provided on one of the slide rails 41, a first sensor 50 is provided at two positions, and a first trigger 51 is provided on the floating plate assembly 3. When the floating plate assembly 3 reaches the corresponding position, the first trigger 51 triggers the first sensor 50, so that the sensor sends a signal to the control unit to control the alarm device 2 to start and shut down the equipment on the steam turbine or replenish the oil in the oil tank; since the floating plate assembly 3 can only slide up and down along the slide rail 41, when the oil in the oil tank is vibrated in the oil tank and the liquid level fluctuates up and down, due to the uncertainty of the fluctuation position of the liquid level, This floating plate assembly 3 is difficult to be subjected to a uniform upward force, so the friction force generated between the floating plate assembly 3 and the slide rail 41 will consume the force generated by the fluctuation of the oil, thereby ensuring that the up and down fluctuation of the oil will not affect the position of the floating plate assembly 3 on the slide rail 41, thereby ensuring the accuracy of the position of the floating plate assembly 3 and thus ensuring the accuracy of the liquid surface position; and the floating plate assembly 3 limits the space for the oil to move and fluctuate in the oil chamber 11, thereby reducing the amplitude of the oil shaking, thereby ensuring the accuracy of the oil level height when the floating plate assembly 3 moves to the low liquid level detection position 44 and the high liquid level detection position 43, avoiding false touches caused by oil shaking.

[0033] like Figure 5-6 As shown, the floating plate assembly 3 includes a connecting frame 31 slidably arranged on the inner wall of the oil chamber 11, a slider 42 is fixedly arranged on the peripheral side of the connecting frame 31, and a first trigger 51 is arranged on the connecting frame 31; a connecting hole 32 is arranged in the middle of the connecting frame 31, and a floating block 33 that can float on the surface of the oil can be detachably connected in the connecting hole 32, and the floating block 33 can be connected to the connecting hole 32 in the middle of the connecting frame 31 by bolts or snaps, so as to reduce the weight of the floating plate assembly 3 and facilitate the staff to disassemble and assemble the floating plate assembly 3; and a plurality of floating blocks 33 can be provided, which are installed in the connecting hole 32 after assembly, so as to facilitate installation and disassembly for some large oil tanks. A gap 34 is formed between the float 33 and the connecting frame 31 for the oil to flow through; the top surface of the float 33 is provided with a conical guide surface 35 which is inclined downward from the middle to the circumference. The setting of the guide surface 35 can allow the filtered oil to flow back from the surface of the float 33 into the oil, thereby realizing the recycling of the oil. At the same time, the gap 34 between the float 33 and the connecting frame 31 can also be used for the oil generated by the oil to be discharged from the oil tank by the range hood through the gap 34.

[0034] At the same time, in order to ensure the stability of the floating block 33 in the oil, it includes a hollow floating pad 36, and a solid center of gravity block 37 immersed in the oil is arranged below the floating pad 36. The guide surface 35 is arranged on the top of the floating pad 36. The center of gravity block 37 can provide the floating block 33 with a certain weight, so that the floating pad 36 can always fit on the surface of the oil and descend in time with the descending of the oil, thereby improving the accuracy of the oil height measurement; at the same time, it can also ensure the stability of the floating pad 36 in the oil.

[0035] There are several center of gravity blocks 37, which are evenly distributed below the floating pad 36; the floating pad 36 is provided with several air holes for exhaust, and the setting of the air holes can ensure that the oil smoke and air in the oil can be discharged through the floating pad 36; the lower surface of the floating pad 36 is protruding with several needle-shaped protrusions inserted into the oil, and several of the needle-shaped protrusions form a defoaming layer 38 on the lower surface of the floating pad 36, and the needle-shaped protrusions can destroy the tension on the surface of the oil, thereby reducing the foam layer on the surface of the oil and improving the accuracy of the oil level.

[0036] like Figure 3-4 As shown, the slide rail 41 is also provided with a shutdown liquid level section 6, and the shutdown liquid level section 6 is arranged between the high liquid level detection position 43 and the low liquid level detection position 44; the shutdown liquid level section 6 includes a sensing position 61 and a trigger position 62 located below the sensing position 61, and the sensing position 61 and the trigger position 62 are respectively provided with a second sensor 52 and a third sensor 53 connected to the control unit through a signal processing module; the connection frame 31 is provided with a second trigger 54 that cooperates with the second sensor 52 and the third sensor 53, and also includes a delay device that is arranged on the control unit and connected to the second sensor 52 and the third sensor 53; when the second trigger 54 passes through the second sensor 52, the second sensor 52 will send a signal to the delay device, and the delay device will send a pulse signal to the third sensor 53 by presetting a time period, and when the second trigger 54 passes through the third sensor 53 within the pre-set time period, the third sensor 53 will send a signal to the control unit to shut down the equipment.

[0037] Through the setting of the shutdown liquid level section 6, including the second sensor 52 and the third sensor 53 set on the slide rail 41 and the second trigger 54 set on the connecting frame 31, the staff can set the time of the delayer according to the speed of oil consumption through the delayer set on the control unit. When the liquid level drops to the connecting frame 31 and the second trigger 54 arrives at the second sensor 52 position, the second sensor 52 will send a signal to the delayer, and the delayer will send a pulse signal to the third sensor 53. The third sensor 53 will be started in a standby state. If the floating plate assembly 3 passes the position of the third sensor 53 within the time set by the delayer, it proves that the speed of the oil level dropping is too fast and there is a leak in the lubricating oil system. Therefore, the third sensor 53 will send a signal to the control unit through the signal processing module, so that the alarm module will alarm and control the equipment to stop and the valve to close, thereby preventing the oil from continuing to leak. If the floating plate assembly 3 passes the third sensor 53 after the set time period, the third sensor 53 will not be triggered. Among them, the second trigger 54 and the first trigger 51 can be the same trigger.

[0038] The second sensor 52 and the third sensor 53 are Hall effect sensors, and the trigger is a magnetic block arranged on the connection frame 31 and corresponding to the Hall effect sensor; the first sensor 50 is a Hall effect sensor, and the first trigger 51 is a magnetic block arranged on the connection frame 31. The use of Hall effect sensors can prevent the sensors from being exposed to oil, thereby avoiding damage to the sensors.

[0039] The slide rail 41 is hollow, and the oil tank is provided with a mounting hole 7 connected to the inside of the slide rail 41. The Hall effect sensor is mounted on the slide rail 41 through the mounting hole 7, and the sensing end of the Hall effect sensor is arranged toward the inside of the oil chamber 11. The magnetic block is fixedly arranged on the path of the connection frame 31 relative to the Hall effect sensor. The magnetic block can be directly fixed on the peripheral side of the connection frame 31, and the hollow slide rail 41 can facilitate the staff to install the Hall effect sensor.

[0040] Embodiment 2

[0041] On the basis of the first embodiment, the PLC circuit board can adopt the Siemens S7-1200 series, which supports a variety of input and output modules, including digital input / output modules and analog input / output modules. These modules can be directly connected to the sensor to process and convert the signal. The signal processing module is integrated on the circuit board, and there is no need to add an additional signal processing module to connect to the PLC circuit board, and the connection and installation are more convenient and quick.

[0042] The actuators on the equipment include but are not limited to the power supply of the equipment, valves in the oil circuit and oil pumps. These actuators are connected to the PLC circuit board. When there is a problem with the oil level and the sensor is triggered, the equipment can be powered off to stop the operation of the equipment or control the opening and closing of the equipment oil circuit and replenish the oil in the tank.

[0043] The alarm device is a buzzer. When there is a problem with the sensor, the PLC circuit board will control the buzzer to start, thereby prompting the staff that there is a problem with the oil level.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the design concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A steam turbine lubricating oil tank low liquid level protection device, comprising a main oil tank (1) with an oil chamber (11), a control unit connected to the steam turbine equipment, a signal processing module arranged on the control unit, and an alarm device (2) electrically connected to the control unit, It is characterized in that The oil chamber (11) is provided with a floating plate assembly (3) in contact with the oil surface. The floating plate assembly (3) is slidably connected to the inner wall of the oil chamber (11) via a sliding structure (4). The sliding structure (4) comprises a plurality of slide rails (41) vertically arranged on the inner wall of the oil chamber (11) and a sliding block (42) arranged on the floating plate assembly (3) and slidably matched with the slide rails (41). The slide rails (41) are provided with a high liquid level detection position (43) and a low liquid level detection position (44). The slide rails (41) A first sensor (50) electrically connected to a control unit via a signal processing module is provided at a high liquid level detection position (43) and a low liquid level detection position (44); a first trigger (51) cooperating with the sensor is provided on the floating plate assembly (3); when the floating plate assembly (3) reaches a corresponding position, the first trigger (51) triggers the first sensor (50), causing the sensor to send a signal to cause the control unit to control the alarm device (2) to start and stop the equipment on the steam turbine or to replenish the oil in the oil tank.

2. A steam turbine lubricating oil tank low liquid level protection device according to claim 1, It is characterized in that The floating plate assembly (3) comprises a connecting frame (31) slidably arranged on the inner wall of the oil chamber (11), the sliding block (42) is fixedly arranged on the peripheral side of the connecting frame (31), and the first trigger (51) is arranged on the connecting frame (31); a connecting hole (32) is arranged in the middle of the connecting frame (31), a floating block (33) that can float on the surface of the oil is detachably connected in the connecting hole (32), and a gap (34) for the oil to flow through is formed between the floating block (33) and the connecting frame (31).

3. A steam turbine lubricating oil tank low liquid level protection device according to claim 2, It is characterized in that The top surface of the floating block (33) is provided with a conical guide surface (35) which is inclined downward from the middle to the peripheral side.

4. A steam turbine lubricating oil tank low liquid level protection device according to claim 3, It is characterized in that The floating block (33) comprises a hollow floating pad (36), a solid center of gravity block (37) immersed in oil is arranged below the floating pad (36), and the guide surface (35) is arranged on the top of the floating pad (36).

5. A steam turbine lubricating oil tank low liquid level protection device according to claim 4, It is characterized in that A plurality of center-of-gravity blocks (37) are provided and are evenly distributed below the floating pad (36); and a plurality of air holes for exhausting air are provided on the floating pad (36).

6. A steam turbine lubricating oil tank low liquid level protection device according to claim 5, It is characterized in that The lower surface of the floating pad (36) is provided with a plurality of needle-shaped protrusions for inserting into the oil, and the plurality of needle-shaped protrusions form a defoaming layer (38) on the lower surface of the floating pad (36).

7. A steam turbine lubricating oil tank low liquid level protection device according to claim 2, It is characterized in that The slide rail (41) is also provided with a stop liquid level section (6), and the stop liquid level section (6) is provided between a high liquid level detection position (43) and a low liquid level detection position (44); the stop liquid level section (6) comprises a sensing position (61) and a trigger position (62) located below the sensing position (61), and the sensing position (61) and the trigger position (62) are respectively provided with a second sensor (52) and a third sensor (53) connected to the control unit via a signal processing module; the connection frame (31) is provided with a second sensor (52) and a third sensor (53) connected to the control unit via a signal processing module. (53) and a second trigger (54) that cooperates with the second sensor (52) and the third sensor (53), and also includes a delay device that is arranged on the control unit and connected to the second sensor (52) and the third sensor (53); when the second trigger (54) passes the second sensor (52), the second sensor (52) will send a signal to the delay device, and the delay device will send a pulse signal to the third sensor (53) after a preset time period. When the second trigger (54) passes the third sensor (53) within the preset time period, the third sensor (53) will send a signal to the control unit to stop the device.

8. A steam turbine lubricating oil tank low liquid level protection device according to claim 7, It is characterized in that The second sensor (52) and the third sensor (53) are Hall effect sensors, and the trigger is a magnetic block arranged on the connection frame (31) and corresponding to the Hall effect sensor.

9. A steam turbine lubricating oil tank low liquid level protection device according to claim 1, It is characterized in that The first sensor (50) is a Hall effect sensor, and the first trigger (51) is a magnetic block arranged on the connection frame (31).

10. A steam turbine lubricating oil tank low liquid level protection device according to claim 8 or 9, It is characterized in that The slide rail (41) is hollow, the oil tank is provided with a mounting hole (7) connected to the interior of the slide rail (41), the Hall effect sensor is mounted on the slide rail (41) through the mounting hole (7), and the sensing end of the Hall effect sensor is arranged toward the interior of the oil chamber (11); the magnetic block is fixedly arranged on a path of the connection frame (31) relative to the Hall effect sensor.

Images