Quenching medium cooling performance measurement system

　　The measurement system shall be capable of providing a permanent record of the cooling performance of each sample of quenching oil to be tested, obtaining a record of the temperature change and time of the probe and the cooling rate and temperature.

　　Records can be obtained using any 1 of two methods: computer technology or standard recording technology with electronic differentiators.

　　① Computer technology. The output signal of the probe thermocouple is collected, digitized and stored in the computer memory, and the sampling frequency is not less than 20 times/s. During or after the experiment, a plotter was used to plot temperature as a function of time.

& nbsp; & nbsp; The cooling rate can be calculated by the digital differential of the probe thermocouple output signal and the corresponding time, and the function relationship between the cooling rate and the probe temperature can be drawn.

　　② Standard recording technique. The relationship between temperature and time can be obtained by recording the output signal of the thermocouple of the probe with a recorder.

　　Plotting the cooling rate as a function of probe temperature requires an electronic differentiator. For detailed instructions, please refer to the figure. It produces a proportional to the probe thermocouple output value over time changes in the speed signal, the use of a recorder, plotting the relationship between the speed signal and the probe temperature.

Figure  Typical Circuit with Differentiator

Note: Temperature coefficients of all registers and capacitors: & plusmn;100 & times;10-6/℃

& nbsp; & nbsp; The total accuracy of the measurement system shall not be less than & plusmn;2.5% of the recorded value that has taken into account the effect of thermocouple calibration.