Plastic pipe scriber scribe

  Plastic pipe scriber jl-12 I
product introduction of plastic pipe scriber:
Longitudinal retraction rate is an important index for the performance of plastic pipe products
It reflects the stability of plastic pipe products under the influence of heat
Its measurement is of great significance to improve the bearing capacity of the product to the change of temperature, sunshine and other heat sources during use, and to improve the service life of the product
However, due to the diversity of measurement methods of longitudinal retraction rate, we often affect the accuracy of detection due to improper operation or carelessness

2、 Application scope of plastic pipe scriber:
The product is produced in accordance with GBT 6671-2001 determination of longitudinal shrinkage of thermoplastic pipes and is applicable to the determination of longitudinal shrinkage of plastic pipes

3、 Technical parameters of plastic pipe scriber:
1
Blade thickness: 2mm
2
Blade roller spacing: 100mm & plusmn; 0
1mm
3
Net weight: 9kg
4
Gross weight: 12kg
5、  Overall dimension: 420 * 360 * 300mm
6
Wooden packing
3、 Application method of plastic pipe scriber:
1
Lift the roller carefully, place the standard specimen to be drawn under the two rollers (the roller spacing has been adjusted to 100mm & plusmn; 0
1 in advance), hold one end against the baffle, then put down the roller, and gently press the center of the two rollers with your hand

2
Slowly rotate the pipe test piece, and two closed circumferential lines with an equal distance of 100mm can be drawn on the surface of the test piece
If the lineation feels shallow and unclear, it can be rotated repeatedly for one week

3
At (23 & plusmn; 2) ℃, measure the marking line spacing l0 with an accuracy of 0
25mm

4
Adjust the oven temperature to the value tr specified in Appendix A
(see GBT 6671-2001 determination of longitudinal shrinkage of thermoplastic pipes for Appendix A)
5
Put the test piece into the oven so that the sample does not touch the bottom and wall of the oven
If the specimen is suspended, the suspension point shall be at the end farthest from the marking line
If the sample is placed horizontally, it shall be placed on a flat plate padded with a layer of talc powder
Slice the sample with the convex surface facing down

6
Put the sample into the oven and keep it for the time specified in Appendix A
this time shall be calculated from the time when the oven temperature rises to the specified temperature

7
Take out the sample from the oven and place it on a smooth plane
When it is completely cooled to (23 & plusmn; 2) ℃, measure the maximum or minimum distance Li between the marking lines along the bus on the sample surface, accurate to 0
25mm

Note: for slice samples, the four slices cut from each pipe section shall be used as one sample to measure Li, and the influence of the notch edge shall be avoided during slice measurement

4、 Treatment of test results of plastic pipe scriber:
(Note: the longitudinal shrinkage rate RLI of each section of sample is expressed as a percentage
)
RLi  = △L / L0 × one hundred
Where: △ L = l0 － Li
 & Nbsp& Nbsp& Nbsp& Nbsp L0 —& mdash; Distance between two marking lines of the sample before putting it into the oven (unit: mm)

 & Nbsp& Nbsp& Nbsp& Nbsp Li —& mdash; The distance between two marking lines measured along the bus after the test (unit: mm)

Select Li to maximize the value of △ L

Calculate the arithmetic mean value of RLI of three samples, and the result is taken as the longitudinal retraction rate RL of the pipe

5、 Precautions for plastic pipe scriber
When the sample is completely cooled to (23 & plusmn; 2) ℃, measure the maximum or minimum distance between the markings
Multiple measurements should be carried out
Select Li , Make it the value with the largest change relative to the original gauge distance, and then calculate it