UT2071 Pipe inner diameter measuring instrument is used for the inner diameter measurement of the corrugated pipe ring stiffness test for prestressed concrete bridges, which meets the requirements of the Ministry of Communications "JT/T529-2004 Plastic Bellows for Prestressed Concrete Bridges" and "GB/T9647-2003 Determination of Ring Stiffness of Thermoplastic Pipes". 

1. LED digital display screen

2. linear guide, higher precision,

3. extended rod design

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.