Convergence meter JSS30A tunnel hook digital convergence meter

Convergence meter JSS30A tunnel hook digital convergence meterOperation and use

1. Check whether the buried points are damaged or loose, and wipe the dust off the measuring points.

2. Open the steel ruler handle of the convergence meter, pull out the hook of the ruler head and place it in the measuring point hole. Pull the convergence meter to the other end of the measuring point, and hang the hook of the ruler frame into the measuring point hole. Select the appropriate ruler hole, insert the ruler hole pin, and use a ruler card to fix the ruler and the connecting ruler frame.

3. Adjust the adjusting nut and observe carefully to align the engraved line on the plastic window with the two white lines on the ruler inside the tension window.

4. Record the baseline length (Figure 4) and digital reading of the steel ruler at the end of the measuring frame. To improve measurement accuracy, each baseline should be repeated three times and the average value should be taken. When the difference between the three readings is greater than 0.5mm, the test should be retested.

5. During the testing process, if the digital reading exceeds 25mm, the steel ruler should be retracted (replaced with a new ruler hole) by 25mm and retested. The difference between the two sets of average values is the actual distance between the two ruler holes to eliminate measurement errors caused by inaccurate punching distance of the steel ruler.

After completing a baseline measurement, the adjustment nut should be turned counterclockwise in a timely manner, the convergence meter should be removed, the ruler card should be opened to retract the steel tape ruler, and preparation should be made for the next use.

Convergence meter JSS30A tunnel hook digital convergence meter

JSS30A digital convergence meter tunnel convergence meter usage method

1. Hanging instruments and adjusting steel ruler tension

Before measuring, estimate the approximate distance between the two measuring points, fix the steel ruler at the required length (pull out the steel ruler to fix the positioning hole in the positioning pin), rotate the spiral micrometer to the maximum reading position (25mm), hang the two axis holes of the instrument on the pre embedded cylindrical measuring points, hold the instrument with one hand and screw the other hand into the spiral micrometer until the scale line on the inner guide rod coincides with the scale line on the sleeve, and then the reading can be made.

2. Readings

The steel ruler reading at the positioning pin is called the first digit of the length, and the spiral micrometer reading is the last digit.

Distance measurement=first digit+last digit

Generally, the operation should be repeated three times to read three sets of values and calculate the weighted average to determine the measurement value, in order to reduce visual errors during measurement.

3. Calculation of convergence value and convergence speed

The convergence value is the change in distance between two measuring points at a certain time. If the observed value at T1 is L1 and the observed value at T2 is L2, then the convergence value △ L=L1+L2

Convergence speed △ V (t)=△ L/△ T, where △ T=T2-T1

4. Temperature correction calculation

Mechanical convergence meters have temperature errors, so temperature correction values should be added to each measured reading

Actual measurement value=corrected steel ruler length+micrometer reading

即： L′=Ln[1－a(T0-Tn)]

In the formula, L 'is the actual length of the steel ruler after temperature correction

Ln is the length reading of the steel ruler at the nth observation

A is the coefficient of linear expansion of the steel ruler, taken as a=12 × 10-6 ℃

T0 is the locationEnvironmental temperature during observation (℃)

Tn is the ambient temperature at the nth observation (℃)

Characteristics of JSS30A digital convergence meter tunnel convergence meter

Novel structure, easy operation, high measurement accuracy, small size, light weight, and good sealing performance.

The JSS30A series convergence meter is the main instrument used for measuring and monitoring tunnel deformation, consisting of three parts: connection, force measurement, and distance measurement.

We mainly produce four types of convergence meters: JS30A-15, JSS30A-20, JSS30A-30, and JSS30A-40.

JSS30A digital convergence meter tunnel convergence meter structure

1. Connecting steering: Connecting steering is achieved by micro bearings, which can rotate in any direction in space;

2. Force measuring spring: used to calibrate the tension of the steel ruler, thereby improving the accuracy of readings;

3. Distance measuring device: Distance measuring is composed of a steel ruler and a micrometer. Measure distances greater than 20mm with a steel ruler. There are holes every 20mm on the steel ruler, and the minimum reading of the spiral micrometer is 0.01mm. Distance measurement=steel ruler reading+spiral micrometer reading. When measuring, when the convergence meter is suspended between two measuring points and the micrometer is rotated in, the tension of the steel ruler increases until it reaches the specified tension, and then the reading is taken.

maintenance and repair

1. Adjust the nut counterclockwise to the maximum range, and be careful not to expose the thread.

2. The digital display circuit itself has an automatic power-off function to improve battery life. After the display value remains fixed for 7 minutes, the screen will automatically power off. Rotate the adjusting nut, and the value will automatically appear.

3. After using the convergence meter for a period of time, it should be calibrated to zero and checked whether the digital reading is zero. If there is a deviation, the plastic cover can be opened and corrected according to the fourth item. Otherwise, it can continue to be used.

After the convergence measurement is completed, use cotton yarn to wipe away dust and regularly apply engine oil to the steel ruler to prevent rusting.

During use, try to avoid mud and water from entering the convergence meter and steel ruler, and correctly use the rotating parts of the convergence meter to ensure that the steel ruler is straight and not twisted.

6. Mercury thermometers used for temperature measurement should have a score of 0.1 ℃, and other thermometers with a score greater than this value should not be used.

7. When using in coal mines, remember not to replace batteries underground due to errors. Other types of batteries shall not be used as substitutes except for those specified in this manual.

When the displayed characters are dim, unstable, or have no display, the battery should be replaced in a timely manner. When the convergence meter is not used for a long time, the battery should be removed.

9. The method of replacing the steel ruler is to first remove the ruler frame plate on the opposite side of the ruler handle, then insert the new steel ruler into the ruler shaft, and cover the ruler frame plate.