Purpose:

The instrument is used to determine diameter of geology borehole and engineering borehole. You can get diameter data of borehole after measuring borehole diameters and calculating average value of borehole diameters. It is one of auxiliary instruments of Detection System for Borehole of Concrete Pile. The borehole diameter curve measured can be applied in the following aspects:

1. To determine quantity of cement used for well cementing;

2. Provide borehole diameter data for lateral curve logging and radioactive logging;

3. To find position of wall collapse through borehole diameter curve;

4. To select suitable fixed position of casing tube as per borehole diameter change;

5. To determine sectional surface of borehole;

Technical parameters

1. Borehole diameter range: Φ500mm～1200mm; If equipped with a extending leg of 200 mm, its measurement range can be extended to 1600 mm;

2. Diameter measurement error: ＜±15mm;

3. Maximum working pressure: 20 MPa;

4. Maximum working temperature: 90 ℃;

5. Sensitivity: It is not lower than 10 mV/10 cm when current is at 1 mA;

6. Insulation: Resistance of its shell is not less than 100 MΩ/500V in normal; and it is not less than 2MΩ/500V at moisture environment.