CBL-200 Pipe Size Change Measuring Tester/ Longitudinal Reversion Tester suitable to measure various kinds of plastic pipe or plastic materials size change after heating, or used to heat the test sample. It can be used as a heating oven as well.

Constant temperature tank adopts recycle wind heating, leafiness type centrifugal blower, with big wind and low noise, temperature uniform, stable heating field.       
    
The temperature control system is digital control meter, it’s easy operation; and have overheating production function.   
 
Conform with standard ISO 2505.

Principle:
A pipe of specified length is placed in a liquid bath or air oven at a specified temperature for a specified time .  A marked length of this portion of pipe is measured, under identical conditions, before and after heating. The reversion is calculated as a percentage of the change in length in relation to the initial length. The surface appearance of the test piece shall not be changed after heating.

Preparation of Test Pieces

Test may only be performed on pipes 24 hours after production.

Prepare three samples each with a length of 200+/-20mm long. Two circumferential marks are traced 100mm apart at equal distances from two ends.

Air Oven

Air oven must be set to 100/110/120/150 Celsius according the pipe material.

At room temperature, (23 degrees Celsius +/- 2) measure the distance of the two circumferential marks using a caliper.

Then, suspend the test piece in the air oven. The test piece may only be placed in the air oven if the oven has reached the set temperature.

In placing the test sample in the air oven, the actual temperature of the oven must return to the set temperature within 15 minutes.
 

The duration of exposure is according the test sample material and the wall thickness of the sample, generally 60/120/240min.

Calculation of Results

Longitudinal Reversion is calculated as follows

RL,  =  L/Lo x 100

Where,

L =  Lo –L;

L may be positive or negative.

Lo is the distance between the marks before the exposure in mm

L is the distance between the marks after the exposure in mm.

Calculate the value of the longitudinal reversion RL of the three sample pieces. Report the arithmetic mean of the three values.  

Air Oven test specification setting：

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ISO 2505:2005

Thermoplastics pipes -- Longitudinal reversion -- Test method and parameters

GB/T 6671 etc.,