Three-way rotary valve

Abstract

A three-way rotary valve comprises a valve head, a valve element, a photoelectric switch, a coded disc, a speed reducer, a stepping motor and a control unit with an encoder, an output shaft of the stepping motor is connected with an input shaft of the speed reducer, an output shaft of the speed reducer is connected with the valve element through a coupler, and the coded disc is arranged on the coupler. A channel A, a channel B and a channel C are formed in the valve head at equal intervals in the circumferential direction, a flow channel is formed in the valve element, openings are formed in the positions, on the side wall of the valve element, of the two ends of the flow channel respectively, the flow channel can communicate with the channel A and the channel B, the channel A and the channel C or the channel B and the channel C, and the encoder is used for detecting the rotating position of an output shaft of the stepping motor. According to the three-way rotary valve, the torque of the stepping motor is increased through the speed reducer, so that when the valve head and the valve core of the three-way rotary valve face different resistances, the problem of step loss or jamming of the stepping motor cannot be caused. The connection between the two switching ports of the three-way rotary valve is opened, a conducting state is added, and the application flexibility and convenience of the three-way rotary valve are greatly improved.

Description

Technical Field

[0001] The utility model relates to the field of machinery, in particular to a valve, in particular to a three-way rotary valve, a reduction ratio identification method, and a hole position precision control method. Background Art

[0002] As a valve body that controls the switching of fluid or gas in different pipelines, the three-way rotary valve is widely used in sample collection, liquid sampling or flow path conversion. In the prior art, the three-way rotary valve adopts a method of directly connecting the stepper motor to the valve body or connecting through a reducer. The method of directly connecting the stepper motor to the valve body is relatively simple in structure, but the torque requirement of the stepper motor is high, and the stepper motor is prone to losing steps or getting stuck. Especially in the case where a large pressure liquid needs to flow through the three-way rotary valve, the valve head and the valve core need to be closely matched, which will inevitably increase the friction between the valve head and the valve core. At this time, the torque requirement of the stepper motor becomes higher, which means that a three-way rotary valve of the same specification requires a larger stepper motor, which undoubtedly increases the volume and cost of the three-way rotary valve, and cannot fundamentally solve the problem of losing steps or getting stuck of the stepper motor; the method of connecting through a reducer has a low torque requirement for the stepper motor, which means that a three-way rotary valve of the same specification can meet the requirements with a smaller stepper motor. However, there are many specifications of reducers, and the probability of replacing reducers according to different loads is relatively high. Reducers of different specifications require different drivers for control, and the control program modification is not flexible. Each time a reducer of a specification is replaced, the driver must be re-adapted, which invisibly increases the cost of management and after-sales maintenance. In addition, the valve core of the three-way rotary valve in the prior art cannot be accurately rotated to the target position, and the hole position of the three-way rotary valve cannot be accurately connected.

[0003] In addition, the three-way rotary valve in the prior art includes a common port and two switching ports. Liquid can only be introduced or discharged from the common port and discharged or introduced from the other two switching ports. Special needs, such as introducing liquid from one switching port and discharging liquid from another switching port, cannot be met and the flexibility is poor. Utility Model Content

[0004] The utility model aims to provide a three-way rotary valve, which solves the technical problems in the prior art that the stepping motor loses steps or gets stuck, the driver of the three-way rotary valve with a reducer is frequently replaced, the two switching ports cannot be connected, and the three-way rotary valve hole position cannot be accurately connected.

[0005] The utility model provides a three-way rotary valve, comprising a valve head, a valve core, a photoelectric switch, a code disk, a reducer, a stepper motor, and a control unit with an encoder, wherein the output shaft of the stepper motor is connected to the input shaft of the reducer, the output shaft of the reducer is connected to the valve core through a coupling, the coupling is provided with a code disk, the photoelectric switch is arranged above the code disk, the valve core is arranged in the valve head, the valve head is provided with channels A, channel B and channel C at equal intervals along the circumferential direction, a flow channel is arranged in the valve core, openings are respectively arranged on the side wall of the valve core at both ends of the flow channel, the radial angle of the two openings is 120°, the flow channel can connect channel A with channel B, channel A with channel C, or channel B with channel C, the control unit with an encoder comprises an encoder and a control unit, the encoder is installed on the stepper motor for detecting the rotation position of the output shaft of the stepper motor, the output end of the photoelectric switch, the output end of the encoder, and the control end of the stepper motor are all connected to the control unit.

[0006] Furthermore, a pressure sensor is arranged on the valve head.

[0007] The utility model also provides a method for controlling the operation of the three-way rotary valve, including a reduction ratio recognition program and a precise hole position control program.

[0008] Wherein, the reduction ratio identification procedure includes:

[0009] Step 1: After the three-way rotary valve is powered on, the control unit with the encoder controls the stepper motor to rotate through the stepper motor drive module, and then drives the code disk and the valve core to rotate through the reducer and the coupling;

[0010] Step 2: The control unit with the encoder detects the falling edge of the upper notch of the code disk through the photoelectric switch. When the notch on the code disk rotates to the bottom of the photoelectric switch, the photoelectric switch is triggered, and then a falling edge signal is sent to the control unit with the encoder. When the photoelectric switch is not triggered, the stepper motor continues to rotate until the photoelectric switch is triggered, at which time the encoder value in the control unit with the encoder is reset to zero.

[0011] Step 3, continue to control the stepper motor to rotate until the code disk triggers the photoelectric switch again, indicating that the reducer has rotated one circle. At this time, the control unit with the encoder controls the stepper motor to stop rotating through the stepper motor drive module, and collects the encoder value through the encoder signal acquisition module and records it as E1;

[0012] Step 4: Set the encoder line number to E0, then the reduction ratio of the reducer Ei=(E1 / E0):1;

[0013] The precise hole position control procedure includes:

[0014] Set the initial position and target position of the spool valve. Set S1 as the number of pulses that the control unit with an encoder should send to the stepper motor when the spool valve rotates to the target position. Set V1 as the number of pulses actually rotated by the stepper motor detected by the encoder. Set Δ as the allowable error pulses of the three-way rotary valve. The number of encoder lines is set to E0, and the reduction ratio of the speed reducer is Ei;

[0015] Step 10: The control unit with an encoder calculates the number of pulses S1 that need to be sent to the stepper motor for the spool valve to rotate to the target position, and the encoder detects the number of pulses V1 actually rotated by the stepper motor. The angle that the spool valve needs to rotate when the three-way rotary valve rotates to the target position is α, so S1 = E0 * Ei * α / 360;

[0016] Step 20: The control unit controls the stepper motor drive module to send S1 pulses to the stepper motor to make the stepper motor start to rotate;

[0017] Step 30: After the stepper motor stops, use the control unit to determine whether (S1 - Δ) < V1 < (S1 + Δ) holds. If it holds, the number of pulses V1 actually rotated by the stepper motor is within the allowable error range of S1, and the current position of the three-way rotary valve is the target position, and the process of the hole position precise control method ends;

[0018] Step 40: If (S1 - Δ) < V1 < (S1 + Δ) does not hold, the control unit with an encoder controls the stepper motor drive module to send S1 - V1 pulses to make the stepper motor rotate S1 - V1 pulses, and jumps back to Step 20.

[0019] Compared with the prior art, the effects of the present utility model are positive and obvious.

[0020] 1. The present utility model increases the torque of the stepper motor through a speed reducer, so that when the valve head and spool of the three-way rotary valve face different resistances, it will not cause the problem of the stepper motor losing steps or jamming.

[0021] 2. The present utility model打通了三通旋转阀的两切换口之间的连接,增加了一种导通状态,满足了切换口之间连通的特殊需求,三通旋转阀的通道A、B、C都可作为公共口或切换口,极大的提高了其应用灵活和方便性。

[0022] 3. The reduction ratio identification method of the present utility model can automatically identify the reduction ratio of the speed reducer, so there is no need to upgrade the drive program of the three-way rotary valve after replacing the speed reducer, greatly reducing the management and after-sales maintenance costs.

[0023] 4. The hole position precise control method of the present utility model can accurately drive the spool to rotate to the target position, so that the hole position of the three-way rotary valve is accurately conducted. Description of the Drawings It should be noted that there is an unclear expression in the original text for item 21 which is translated as "打通了三通旋转阀的两切换口之间的连接,增加了一种导通状态,满足了切换口之间连通的特殊需求,三通旋转阀的通道A、B、C都可作为公共口或切换口,极大的提高了其应用灵活和方便性。" Please check and correct this part in the original text for a more accurate translation.

[0024] Figure 1 It is a schematic diagram of a three-way rotary valve of the utility model.

[0025] Figure 2 The utility model is a schematic diagram of a valve core and a valve head in a three-way rotary valve.

[0026] Figure 3 It is a schematic diagram of a control unit in a three-way rotary valve of the utility model.

[0027] Figure 4 It is a flow chart of the reduction ratio identification procedure in the utility model.

[0028] Figure 5 It is a schematic diagram of the flow of the precise hole position control program in the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with an embodiment, but the present invention is not limited to the embodiment. Any similar structure and similar changes of the present invention should be included in the protection scope of the present invention. The use of directions such as up, down, front, back, left, and right in the present invention is only for the convenience of clear description and is not a limitation on the technical solution of the present invention.

[0030] like Figure 1-Figure 5 As shown, a three-way rotary valve of the utility model comprises a valve head 2, a valve core 3, a photoelectric switch 4, a code disk 7, a reducer 8, a stepping motor 9, and a control unit 10 with an encoder, wherein the output shaft of the stepping motor 9 is connected to the input shaft of the reducer 8, and the output shaft of the reducer 8 is connected to the valve core 3 through a coupling 6, on which a code disk 7 is arranged, the photoelectric switch 4 is arranged above the code disk 7, the valve core 3 is arranged in the valve head 2, and the valve head 2 is provided with channels A, channel B and channel C at equal intervals along the circumferential direction, a flow channel is arranged in the valve core 3, and openings are respectively arranged on the side wall of the valve core at both ends of the flow channel, and the radial angle of the two openings is 120°, and the flow channel can connect channel A with channel B, channel A with channel C, or channel B with channel C, and the control unit 10 with an encoder comprises an encoder and a control unit, and the encoder is installed on the stepping motor 9 for detecting the rotation position of the output shaft of the stepping motor 9, and the output end of the photoelectric switch 4, the signal output end of the encoder, and the control end of the stepping motor 9 are all connected to the control unit.

[0031] Furthermore, a pressure sensor 1 is provided on the valve head 2 .

[0032] Specifically, the photoelectric switch 4, code disk 7, reducer 8, stepper motor 9, coupling 6, encoder, control unit, etc. in this embodiment all adopt well-known solutions in the prior art, which are well understood by those skilled in the art and will not be described in detail here.

[0033] The pressure sensor 1 is an optional function of the three-way rotary valve, which can monitor the pressure in the current pipeline of the three-way rotary valve in real time, and can realize pipeline pressure closed-loop control in conjunction with other pressure adjustable devices (such as injection pumps).

[0034] The valve head 2 and the valve core 3 are used in combination, wherein the valve head 2 is fixed, and the valve core 3 is driven to rotate by a stepper motor 9, a reducer 8 and a coupling 6, and rotates to different positions corresponding to different channels, such as Figure 2 Channels A, B or C can all be common ports or switch ports and are spaced 120° apart. The flow path can be

[0035] The photoelectric switch 4 is responsible for detecting the falling edge of the notch 5 on the code disk 7, that is, the code disk 7 rotates under the drive of the stepper motor 9, the reducer 8 and the coupling 6. Whenever the notch 5 rotates to the right below the photoelectric switch 4, the photoelectric switch 4 detects a falling edge, indicating that the valve core 3 rotates one circle. The photoelectric switch 4 can be a proximity switch, a laser sensor, a Hall sensor, etc.

[0036] The code disk 7 is used to detect the number of steps of the stepping motor when the valve core 3 rotates one circle and to determine the position of the origin of the valve core 3.

[0037] The coupling 6 is used to compensate for the installation deviation between the shafts, that is, to compensate for the installation deviation between the reducer 8 and the valve core 3. The coupling 6 can be a cross universal coupling, a universal joint coupling, a floating coupling, etc.

[0038] The reducer 8 is used to increase the torque of the stepper motor 9, especially in the case where a high pressure liquid needs to flow through the three-way rotary valve, at which time the valve head 2 and the valve core 3 need to be closely matched. Adding the reducer 8 can increase the torque of the stepper motor 9 without changing the model of the stepper motor 9, effectively avoiding the risk of step loss and stalling of the stepper motor 9. The reducer 8 can be a gear reducer, a worm reducer, a planetary gear reducer, etc.

[0039] The stepper motor 9 is a driving component of the three-way rotary valve, providing power for the rotation of the valve core 3; the stepper motor 9 can be a servo motor, a DC brushless motor, a DC brush motor, etc.

[0040] The control unit 10 with encoder includes an encoder and a control unit, wherein the encoder is responsible for recording the rotation position of the output shaft of the stepper motor 9, and the control unit is responsible for precise control of the three-way rotary valve and external communication, mainly including a control unit, an encoder signal acquisition module, a stepper motor drive module, a photoelectric switch signal acquisition module, a pressure sensor signal acquisition module, and a communication module. Figure 3 As shown. The encoder signal acquisition module is responsible for collecting encoder data and transmitting it to the control unit; the stepper motor drive module sends pulses to the stepper motor through the control unit, thereby driving the stepper motor to rotate; the photoelectric switch signal acquisition module is responsible for collecting photoelectric switch data and transmitting it to the control unit; the pressure sensor signal acquisition module is responsible for collecting the pressure in the current pipeline and transmitting it to the control unit; the communication module is responsible for sending the current pipeline pressure and the current hole position of the three-way rotary valve to other systems, and its communication mode is not limited, and can be 485 communication, 232 communication, CAN communication, Ethernet communication or other communication.

[0041] The control unit is mainly responsible for the reduction ratio identification of the reducer and the precise control of the hole position of the three-way rotary valve. Figure 4 As shown, the reduction ratio identification method of the reducer includes:

[0042] Step 1: After the three-way rotary valve is powered on, the control unit 10 with the encoder controls the stepper motor 9 to rotate through the stepper motor drive module, and then drives the code disc 7 and the valve core 3 to rotate through the reducer 8 and the coupling 6;

[0043] Step 2, the control unit 10 with the encoder detects the falling edge of the upper notch 5 of the code disk 7 through the photoelectric switch 4. When the notch 5 on the code disk 7 rotates to the bottom of the photoelectric switch 4, the photoelectric switch 4 is triggered, and then the falling edge signal is sent to the control unit 10 with the encoder. When the photoelectric switch 4 is not triggered, the stepper motor 9 continues to rotate until the photoelectric switch 4 is triggered. At this time, the encoder value in the control unit 10 with the encoder is reset to zero. This process is used to eliminate the hidden danger of the uncertain position of the code disk 7 when it is powered on for the first time;

[0044] Step 3, continue to control the stepper motor 9 to rotate until the code disk 7 triggers the photoelectric switch 4 again, indicating that the reducer 8 has rotated one circle. At this time, the control unit 10 with the encoder controls the stepper motor 9 to stop rotating through the stepper motor drive module, and collects the encoder value through the encoder signal acquisition module and records it as E1;

[0045] Step 4: Set the encoder line number to E0, that is, the number of pulses sent by the encoder when it rotates one circle is E0, then the reduction ratio of the reducer is Ei=(E1 / E0):1.

[0046] like Figure 5 As shown, the method for accurately controlling the hole position of a three-way rotary valve includes:

[0047] Set the initial position of the valve core as The target position of the valve core 3 is Set S1 as the number of pulses that the control unit 10 with an encoder should theoretically send to the stepper motor 9 when the valve core 3 rotates to the target position. Set V1 as the number of pulses actually rotated by the stepper motor 9 detected by the encoder. Set Δ as the allowable error pulses of the three-way rotary valve. It is recommended that Δ is not greater than 5;

[0048] Step 10: The control unit 10 with an encoder calculates the number of pulses S1 that need to be sent to the stepper motor 9 for the valve core 3 to rotate to the target position, and the encoder detects the number of pulses V1 actually rotated by the stepper motor 9; The angle that the valve core 3 needs to rotate when the three-way rotary valve rotates to the target position is 120°, so S1 = E0 * Ei * 120 / 360 = E0 * Ei / 3;

[0049] Step 20: The control unit controls the stepper motor drive module to send S1 pulses to the stepper motor 9 to make the stepper motor 9 start to rotate;

[0050] Step 30: After the stepper motor 9 stops, use the control unit 10 to judge whether (S1 - Δ) < V1 < (S1 + Δ) holds. If it holds, the number of pulses V1 actually rotated by the stepper motor 9 is within the allowable error range of S1, and the current position of the three-way rotary valve is the target position, and the process of the hole position precise control method ends;

[0051] Step 40: If (S1 - Δ) < V1 < (S1 + Δ) does not hold, the control unit 10 with an encoder controls the stepper motor drive module to send S1 - V1 pulses to make the stepper motor 9 rotate S1 - V1 pulses, and jumps back to Step 20.

[0052] Generally, after Step 20 is repeated 1 - 2 times, the current position of the three-way rotary valve can be precisely controlled at the target position. One more margin can be left to make the control more stable and reliable.

[0053] The precise control of the positions of other holes of the three-way rotary valve is the same as the above process and will not be elaborated here.

[0054] Advantages of the present utility model:

[0055] 1. The present utility model increases the torque of the stepper motor 9 through the speed reducer 8, so that when the valve head 2 and the valve core 3 of the three-way rotary valve face different resistances, it will not cause the problem of the stepper motor 8 losing steps or jamming.

[0056] 2. The present utility model打通了三通旋转阀的两切换口之间的连接,增加了一种导通状态,满足了切换口之间连通的特殊需求,三通旋转阀的通道A、B、C都可作为公共口或切换口,极大的提高了其应用灵活和方便性。 It should be noted that there is an unclear part in the original text for translation in the last sentence of item 32. It seems there is some incorrect or unclear expression. You may want to check and correct it for a more accurate translation. The above translation is based on the existing text as much as possible.

[0057] 3. The reduction ratio identification method of the utility model can automatically identify the reduction ratio of the reducer, so there is no need to upgrade the three-way rotary valve driver after replacing the reducer, which greatly reduces the cost of management and after-sales maintenance.

[0058] 4. The hole position precise control method of the utility model can accurately drive the valve core 3 to rotate to the target position, so that the hole position of the three-way rotary valve is precisely conducted.

Claims

1. A three-way rotary valve, characterized in that: It includes a valve head, a valve core, a photoelectric switch, a code disk, a reducer, a stepper motor, and a control unit with an encoder. The output shaft of the stepper motor is connected to the input shaft of the reducer, and the output shaft of the reducer is connected to the valve core through a coupling. The coupling is provided with a code disk, the photoelectric switch is arranged above the code disk, the valve core is arranged in the valve head, and the valve head is provided with channels A, channel B and channel C at equal intervals along the circumferential direction. A flow channel is arranged in the valve core, and openings are respectively arranged on the side wall of the valve core at both ends of the flow channel. The radial angle of the two openings is 120°. The flow channel can connect channel A with channel B, channel A with channel C, or channel B with channel C. The control unit with an encoder includes an encoder and a control unit. The encoder is installed on the stepper motor for detecting the rotation position of the output shaft of the stepper motor. The output end of the photoelectric switch, the output end of the encoder, and the control end of the stepper motor are all connected to the control unit.

2. A three-way rotary valve according to claim 1, characterized in that: A pressure sensor is arranged on the valve head.

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