Pressure measurement and control of plastic extruder die
1、 Objective: extrusion is one of the most important methods in plastic processing. In the process of extrusion, the extruder head is the key component, especially in the new development of precision extruder, the design technology level of the head is an important factor to realize precision extrusion. Because of the existence of viscosity and friction force in the melt, the melt flow along the flow channel will cause the change of melt pressure, resulting in a certain pressure drop. The high temperature melt pressure sensor such as pt124 or pt123 of our company is used, and the pressure transmitter measures the online pressure data of the head, providing reliable basis for the head design; the improvement of pressure control accuracy is the final guarantee for the product quality and output stability.
2、 Model of supporting products:
1. Pt123-35m-3.3mv-0.5-1 / 2-20unf-8m replaces imported high temperature melt pressure sensor
2. Rkc-fb900 with 4-20mA PID negative feedback intelligent pressure control instrument
3、 Functions of supporting products:
1. Pt123 replaces the imported high temperature melt pressure sensor to change the die head online measurement pressure into a 0-3.33mv/v sexual wire electrical signal output to the control instrument.
2. Fb900 instrument collects the signal transmitted by pt123, displays it in digital form, outputs a 4-20mA PID signal to the frequency converter as the input feedback of the frequency converter, so as to control the motor speed to balance the screw extrusion pressure and ensure the quality and stability of the product.
4、 Main technical parameters of supporting products:
A. Pt123-35m-3.3mv-0.5-1 / 2-20unf-8m replaces imported high temperature melt pressure sensor:
1. Product overview and features:
A. Imported resistance strain gauge chip is used;
B, flat diaphragm design, dedicated to melt pressure measurement;
C. The SMT technology has zero point, full range compensation and temperature compensation;
D. High precision and high stability amplifier IC;
E. The sensor has 80% self calibration function;
F. Full seal welding structure, impact resistance, fatigue resistance and high reliability;
2. Product application:
A. Pressure measurement of high temperature melt in rubber equipment, plastic equipment, chemical fiber polyester nylon equipment and polyester equipment;
B. High temperature steam measurement and control;
C. High temperature boiler pressure measurement;
3. Main product parameters:
Tested medium: gas, melt, liquid and vapor (weak corrosivity)
Pressure type: gauge pressure
Range: 35MPa
Output: 3.33mv/v (six wire system, 4-wire bridge output, the other two are 80% calibrated)
Comprehensive accuracy: ± 0.5% FS
Power supply: 10V DC (5-12vdc)
Insulation resistance: ≥ 1000m Ω / 100VDC
Medium temperature: - 20 ～ 450 ℃
Ambient temperature: - 20 ～ 85 ℃
Storage temperature: - 40 ～ 90 ℃
Relative humidity: 0-95% RH
Sealing grade: IP65
Overload capacity: 150% FS
Response time: ≤ 10ms
Stability: ≤± 0.15% FS / year
Vibration impact: ≤± 0.15% FS / year (mechanical vibration frequency 20Hz ～ 1000Hz)
Electrical connection: six core standard aviation connector; standard wiring 8M
Pressure connection: 1 / 2-20unf
Connecting thread material: 304 / 316L stainless steel
B. Rkc-fb900 instrument or py900pid negative feedback pressure control meter of general measurement company
Rich input and output
Automatic / manual, local / remote direct switching
Multi storage area function: you can log in up to 8 different settings, such as the main settings, and make complex settings and changes in a package.
You can also switch the area through the optional external pin input.
Through the combination of multi storage functions to connect the number of the opposite area, the duration of the area, and set the rate of change limit, the program operation of the maximum 16 segments (8 steps) can be realized
The frequently used data (up to 16 items) can be freely listed in a continuous address, so the data transmission can be greatly reduced and high-speed communication can be realized.
Communication can be used for joint operation
PID control: the sampling period can be switched to 0.05s, corresponding to the high-speed heating process. A new type of heating and cooling PID is used to strengthen the suppression of the downrush on the cooling side.
It can be switched between "heating, cooling, heating cooling, position proportion" controls.
5、 Product related pictures:
