Main Uses

This testing machine is used to determine the compressive strength of bricks, stones, concrete, and other building materials.
This machine features electric hydraulic loading, force measurement by sensor, digital display of force values, printing of force data by printer, and calculation of compressive strength. It complies with the national standard "Standard Test Methods for Mechanical Properties of Ordinary Concrete." The loading speed should be manually controlled, and it is equipped with a loading speed indicator, peak value hold, and overload protection functions. It is essential testing equipment for construction, building materials, and highway bridge engineering units.
This testing machine and its accessories comply with the requirements of standards GB/T2611 and GB/T3159.

Main Technical Parameters

1. Maximum range: 2000KN
2. Grade: Level 1
3. Minimum resolution: 0.1KN
4. Maximum distance between pressure plates: 320mm
5. Upper/lower pressure plate specifications: 220*250mm
6. Piston diameter × maximum stroke: φ250mm × 50mm
7. Motor power: 0.75KW
8. Input voltage: 380V
9. Overall dimensions: 950×370×1200mm
10. Total weight: 600Kg

Structure Overview

The testing machine mainly consists of the machine body, hydraulic control box, and force measuring instrument.

1. Machine Body Part

The machine body connects the cylinder and upper beam with four columns. On the upper beam of the testing machine, there is an adjusting screw, a large handwheel, and a nut screw to adjust the no-load height of the machine. The lower end of the screw is equipped with a ball seat and upper pressure plate. The lower pressure plate is placed on the piston of the oil cylinder. When the specimen contacts the upper pressure plate, the ball seat of the upper pressure plate can self-adjust to balance, keeping the specimen and upper pressure plate level. The lower pressure plate is marked with positioning lines for the specimen. During testing, the specimen should align with these lines. Below the lower pressure plate is a dust cover to prevent or reduce dust from entering the cylinder during piston movement, which could damage the cylinder or oil seal. There is a sealing device between the piston and cylinder to prevent oil leakage, but a small amount of oil leakage may still occur during use. At the top of the cylinder, there is an annular oil groove and an oil discharge channel to return oil to the main oil tank.

2. Hydraulic Control Part

The control box of this testing machine mainly consists of an oil tank, oil pump, oil filter, motor, speed valve, and return oil valve. The oil pump is a direct-drive axial five-plunger pump. During loading, the loading speed valve should be manually controlled to regulate the piston rising speed (this speed valve is integrated with the safety valve). When unloading, the return oil valve can be turned to allow the cylinder to slowly descend. The safety valve is preset to an appropriate position at the factory, and users should not adjust it during normal use. 3. For the instrument part, please refer to the instrument manual.

Installation of the Testing Machine

1. When hoisting the testing machine, pass the lifting wire rope through the lifting ring screw at the top of the screw rod.
2. Install the testing machine on a stable foundation about 20 centimeters above the ground, with two embedded M16 anchor bolts.
3. When installing the testing machine, use a 1/1000 frame level to measure the flatness of the lower pressure plate to ensure it is level. If not level, adjust with shims (shims placed under the nut at the bottom of the column).

Maintenance

1. Install the testing machine in a clean, dry, temperature-stable environment without vibration or corrosive gases.
2. Keep the testing machine clean. Parts on the surface without protective coating should be regularly oiled to prevent rust.
3. Use 46# anti-wear hydraulic oil.
4. The piston rising position should not exceed 30mm. The control box is equipped with a limit calibration. When the arrow reaches the limit, immediately slowly release the return oil valve to lower the piston before restarting the motor for the next test.

Calibration of the Testing Machine

1. This testing machine should be calibrated once a year.
2. Calibration should be performed under the following conditions:
(1) Room temperature within 20±10℃.
(2) Relative humidity ≤ 80%.
(3) In a vibration-free environment.
(4) Power supply voltage fluctuation within ±10% of rated voltage, with relatively stable voltage.
3. After powering on the instrument, preheat for 30 minutes and zero it according to the usage instructions.
4. Start the motor and repeat loading to maximum load three times, then set the load display to zero and begin calibration.
5. This testing machine only performs process indication relative error and relative variability calibration.