Introduction

1.1. Performance: The proving ring is a grade 0.3(3‰)”force value” measuring

instrument. It is designed to calibrate material testing machine and compression testing machine. It can also be used to test and calibrate "force value” for other apparatus, equipment and components. It is characterized by reliable readouts, zero drift, good quality, aging-resistant, and zero worn-out. It is inexpensive, easy to operate, accurate and safe, and is suitable for applications in quality monitoring, metrological testing. scientific institutes, colleges and universities, and quality inspection.

1.2. Standard: The proving ring is manufactured and inspected in accordance with JJG-144-92 “The standard Proving Ring”

1.3. Principle: It has a mechanical mechanism. and comes in the direct measurement type and the lever magnification type.

1.3.1. Direct measurement(Fig.1):The proving ring produces a deformation under a force which causes the needle of the measuring meter to move to make a direct measurement

1.3.2.: The proving ring produces a deformation under a force, which is magnified via a lever before a measurement is made

1.4. Main parameters:

1.4.1. The scope of measurement:10% of the max testing force ~ the max test force

1.4.2. Both the repetitive error and the long - term stability of the displayed value:≤0.3

1.4.3. The relative error of the displayed value produced between advance and return: ≤1.5%

2. Operation

2.1. Ambient temperature:10℃~35℃

2.2. It should be kept away from moisture, dirt and vibration

2.3. The upper seat and the supporting arm should be assigned the same number as the elastomer.

2.4. For the lever magnification proving ring make sure both ends of the supporting arm has been fitted into, the spherical sockets of the upper and lower seats respectively. At the time of installation, to keep the ends of the ball in contact with the seats, raise the lever slightly with your fingers, fit the supporting arm, and then release the fingers, so the ends of the supporting arm are driven into the socket of the two seats under a spring force. Turn round the supporting arm gently (never turn round it in operation). And be sure it can turn round readily and remains in place, otherwise, install it again.

2.5. Make sure the symmetry axis of the proving ring is in alignment with the axis of the loading device.

2.6. The mark assigned to the dial indicator should be consistent with that is given in the calibration certificate.

2.7. Loading or unloading should be carried out slowly and steadily.

2.8. Preloading test with the max testing force should be performed at least three times before a measurement is made. When taking “Zero” readout, tap the central part of the dial indicator with the eraser of a pencil (Stop tapping if the displayed value remains unchanged after the initial tap) until the needle of the dial indicator points to zero and remains there after unloading.

2.9. For the proving ring with a threaded lower seat, make sure it has been screwed over full thread length. To remove the lower seat, strike the bottom with a small mallet to unscrew it.

2.10. The calibration results given in the calibration certificate are the standard data and they are corresponding to the loading points for the proving ring. If the data of an object to be measured fail to match any standard data, the force exerted on the object can be calculated according to the parameters corresponding to calibration results.

3. Maintenance

3.1. Keep the proving ring dry and clean, and handle it carefully lest its accuracy be affected.

3.2. Make sure the loading force does not exceed the max testing force.

3.3. It should be used in conformity with the expiration date as given in the “Calibration certificate”. After the deadline, it should be sent for recalibration. In case of overloading, it should be sent to the metrological department for recalibration before being used again.

3.4. The components of the proving ring must not be adjusted or changed, otherwise it should be recalibrated by the metrological department before being used again.

3.5. When conducting a tension test a connecting rod, with spherical ends made of high tensile alloy, should be prepared by users themselves (the tensile connector  coming with the proving ring is used to calibrate the proving ring )