Tensionmeters

Main information about Hans-Schmidt tensionmeters:

Construction

All Hans-Shmidt strain gauges are equipped with a 3-roller measuring system. The central measuring roller has the ability to bend under the pressure generated by the measured material – this principle of measurement ensures repeatability and the highest accuracy. All rollers are equipped with ball bearings.

1 Measured sample, 2 Centrall measuring roll, 3 Outside guiding rolls, 4 Guidance of measured sample, 5 Measured scale, 6 Slider, 7 Holding element of a sample, 8 Compenser of thiskness of measured sample.

Sample thickness compensator

Hans-Schmidt tensionmeters can be equipped with a compensator for the thickness of the measured sample. This element is responsible for compensating the sample diameter over a given measuring section for a given measuring range.

1 Sample, 2 Holder 3 Holder 4 Handle holding a sample of measured material

Measuring head

The width of the measuring head varies depending on the type of meter and the measuring range. The dimension “X” defines the minimum required space that should be available on the measuring section. This space is expressed by the width of the fiber guide and the distance between the outer guide rollers.

Calibration of Hans-Schmidt Tensionmeters

To ensure maximum precision, each strain gauge is individually calibrated according to the procedure developed by Hans-Schmidt. During calibration, a weight of known mass is hung on a reference sample hooked on the handle and hanging down, as shown in the figure. This method is widely used all over the world – as a standard strain gauge calibration method.

SELECTION CRITERIA

1. Selection of meter type
Available:

• Manual or stationary,
• Analogue or electronic,

2. Selection of measuring range
Measurement range selection based on the table below:

• * Pulling force in N (1 cN = 0,01 N, 1 daN = 10 N)
• ** PA – calibration material, polyamide fiber – calibration is carried out according to the Hans-Schmidt factory procedure.

Note: It is recommended to select a measuring range that is twice the expected value of the measurement – so that it is possible to measure larger values than expected; also makes it easier to read the measured value on an analog scale.

Tex index

Tex is an index determining the linear density of fiber mass expressed in grams per 1000 m (1 tex = 1 g / 1000 m). This parameter describes the delicacy of textile fibers, yarns, cords etc. The tex index is a number: e.g. 120 tex.

In addition, the record 120 tex x 2 means: that the given weave consists of 2 fibers having a tex value of 120 each. To determine delicate yarns, the decitex (dtex) size is used, which refers to a measuring section of 10,000 m in length. The higher the tex or dtex value, the stronger the fiber. In practice, the parameters of chemical fibers are given mainly in dtex units.

3. Selection of guide rollers according to the following criteria:

• Rollers with V-grooves or asymmetrical grooves,
• U-shaped radial or cylindrical rollers,
• Rollers made of aluminum, plastic, steel, etc.,
• Maximum speed of movement of the measured material

4. Additional accesories

• Adjustable attenuators
• Special pressure lever,
• Memory indicator.

5. Special designs on request

The Hans-Schmidt company offers meters to meet individual requirements:

• Personalized measuring ranges
• Customized measuring head widths,
• Adjusted distances between the two outer guide rollers, minimizing material deformation,
• Meter calibration performed in a way other than standard,
• Calibration for different units, such as g or kg

6. Calibration using materials provided by the customer.

It is recommended when the diameter, stiffness or structure of the measured material differs from the calibration material from Hans-Schmidt. For this purpose, it is recommended to provide a sample with a length of about 5 m.

7. Certificates of the factory checking

Calibration certificates 3.1 in accordance with the PN-EN 10204 standard, optionally available, recommended mainly for users using the ISO 9000 quality management system. Certificate of compliance with the order 2.1 in accordance with the EN 10204 standard is included in the delivery with the meter.

In addition, in the event of problems with the selection of a specific strain gauge, Hans-Schmidt provides assistance after providing the following information::

• What is the use of the measured material,
• Description of the measured material (diameter, type, properties, etc.),
• The speed of moving the measured material,
• Approximate value of the stress force,
• Maximum width of the measuring head or possible access space,
• If necessary, send a sample section about 5 m long.

MANUAL, ANALOGUE

Series Z, DX and DN:

• Equipped with a traditional measuring scale with a diameter of 54 mm and an additional linear scale enabling precise reading of the measured value,
• Equipped with V-type guide rollers with precision ball bearings,
• Equipped with a special slider to move the outer guide rollers away while obtaining for measuring the moving material,
• Equipped with a sample thickness compensator, increasing the accuracy of the measurement in the event of changes in diameter on the measured section,
• They have holes for mounting on brackets and continuous measurement in the technological process,
• Individually calibrated to ensure the highest measurement accuracy.

In addition, special versions are available, equipped with small measuring heads, especially useful when access to the material being measured is limited or the fibers are close together. These meters are ideal in situations where standard models cannot be used:

• They have small ball bearings with guide grooves type V (DXE and DXV models),
• They are equipped with ceramic pins useful during measurement when the measured material moves at high speeds (DXP models),
• They can be calibrated using samples provided by the customer (DXE and DXV models),

Other versions of special models are equipped with large, universal measuring rollers with a diameter of 32 mm, minimizing the formation of bends in the material being measured, making them ideal for measuring the tension force of optical fibers, carbon fibers or technical fibers.

Examples:
Z series: available in ranges: from 1 to 5 cN, or from 20 – 300 cN

DX series: available in ranges: from 10 – 50 cN, to 5 – 20 daN

DN series: available in ranges 20 – 120 cN, to 5 – 50 daN

MANUAL, ELECTRONIC

Series ZE, DTMB, DTMX i ET:

• They are easy to use,
• They have a clear LCD display,
• They are equipped with a microprocessor controller enabling obtaining the highest measurement accuracy,
• They have the option of choosing the update interval: 0.5 – 1 -2 or 4 seconds (DTMB and DTMX series),
• They enable the presentation of minimum, maximum and peak values, as well as displaying the measurement result in cN and g units (ET series)
• They have a zeroing function (enabling the meter to be used for measurements in various positions), a built-in sample thickness compensator (increasing the accuracy of measurement when diameter changes over the measured dimension section) and adjustable electronic attenuators ensuring stable reading of the tension force,
• They are equipped with V-type guide rollers with precise ball bearings and a guide roller movement mechanism (ET models are equipped with long rollers, enabling measurement in hard-to-reach places),
• They have holes for mounting on brackets and continuous measurement in the technological process,
• They can be calibrated based on the material provided by the customer (available for two different materials),
• They have a low weight,
• They are battery powered,
• They have a high-strength plastic casing,
• Models equipped with guide rollers and wheels with ball bearings enable the measurement of material moving at speeds up to 2000 m / min,
• Models with ceramic pins allow the measurement of material moving at speeds up to 6000 m / min.

Examples:
ZE Series: available in measuring ranges from 0,5 – 100 cN, do 1- 500 cN

DTMB and DTMX Series: available in measuring ranges from 0 – 200 cN do 5- 50 daN

ET Series: available in measuring ranges from: od 0,5 – 100 cN, do 1 – 500 cN

APPLICATION

Typical application of Tensionmeters:

Tensionmeters are used in monitoring production processes and quality control. The Hans-Schmidt company offers the largest selection of strain gauges – 19 different series, 60 models and over 2,000 possible variants.

Tensionmeters are used in various types of industries:

• In the optical industry,
• In the textile industry,
• In the knitting industry,
• In the carbon fiber processing industry,
• In the automotive industry,
• In the aviation industry,
• In the medical industry,
• In the telecommunications industry,
• In the sewing industry.
• e.t.c