Micro-metering device with constant flow rate

A micro-metering device with a constant flow rate, comprising:

• a rotary shear valve;
• a mounting seat;
• a rotation drive assembly;
• an injection drive assembly;
• and
• a controller;
• wherein the rotary shear valve comprises a valve main body and a valve spool;
• the valve main body is provided with a main flow channel and a plurality of branch flow channels;
• and the valve spool is rotatably arranged inside the valve main body, and is configured to communicate the main flow channel with at least one of the plurality of branch flow channels;
• a pressure sensor is provided inside the valve main body, and is communicated with the main flow channel;
• and the pressure sensor is configured for detecting a pressure inside the main flow channel;
• the valve main body comprises a valve head cover, a valve head and a valve head housing arranged sequentially from one side to the other side, wherein the main flow channel and the plurality of branch flow channels are provided on the valve head;
• a first side of the valve head is provided with a mounting groove communicated with the main flow channel, and the mounting groove is configured to accommodate the pressure sensor;
• a sealing ring is provided between a first side of the pressure sensor and the mounting groove;
• and the valve head cover is configured to seal the mounting groove, and is detachably connected to the valve head;
• a lead wire of the pressure sensor is connected with a probe;
• and the probe passes through the valve head and the valve head housing successively and extends to an outside of the valve head housing;
• the valve spool is rotatably arranged in an inner cavity of the valve head housing, and is located on a second side of the valve head;
• and a valve body is arranged between the valve head and the valve spool;
• a valve spool base, a bearing and a disc spring are provided in sequence in the inner cavity of the valve head housing from one side to the other side;
• the valve spool base is rotatably provided in the inner cavity of the valve head housing via the bearing;
• the valve spool is fixedly arranged on a first side of the valve spool base;
• a sealing gasket is provided between the valve spool and the valve spool base;
• a connection port is provided on a second side of the valve spool base, and a through hole aligned with the connection port is provided on a side of the valve head housing;
• and a first end of the disc spring is connected to the bearing, and a second end of the disc spring is connected to the valve head housing;
• the rotary shear valve is arranged on a first side of the mounting seat, and the rotation drive assembly, the injection drive assembly and the controller are arranged on a second side of the mounting seat;
• the rotation drive assembly is configured to drive the valve spool to rotate;
• the injection drive assembly comprises an injector and an injection drive member;
• an output end of the injector is communicated with the main flow channel;
• the injection drive member is configured to drive the injector to realize liquid suction and discharge;
• and the pressure sensor, the rotation drive assembly and the injection drive member are electrically connected to the controller;
• the injection drive member comprises an injection drive motor, a transmission component, a ball screw, a push plate and a linear encoder;
• the ball screw is rotatably arranged on a side of the mounting seat away from the rotary shear valve;
• the injection drive motor is in transmission connection with the ball screw through the transmission component, so that the ball screw is driven by the injection drive motor to rotate;
• the ball screw runs through the push plate and is threadedly connected to the push plate;
• the push plate is capable of sliding along an axial direction of the ball screw;
• the mounting seat is provided with an avoidance opening fitting the push plate;
• an input end of the injector is connected to the push plate;
• the linear encoder is configured to detect a position of the push plate;
• and the injection drive motor and the linear encoder are electrically connected to the controller;
• the linear encoder comprises a code rail and a read head assembly;
• the code rail is fixedly provided on the push plate and is parallel to the ball screw;
• the read head assembly is fixedly provided on the mounting base, and is electrically connected to the controller;
• and
• during the liquid suction and discharge, the controller is configured to dynamically adjust an output power of the injection drive motor according to the pressure in the main flow channel detected by the pressure sensor.