AB Lorentzen & Wettre Paper Bursting Strength Tester

L&W Bursting Strength Tester

Bursting strength tester for extremely rapid testing of paper, paperboard and corrugated board

L&W Bursting Strength Tester from Lorentzen & Wettre measures not only bursting strength of paper, paper board, and corrugated board, but also bursting energy absorption (BEA) and diaphragm-compensated bursting strength. Bursting strength is a traditional measure of paper strength.

Measurements are simple to make with the Mullen-type L&W Bursting Strength Tester. There are two versions of the instrument; one for paper, and one for paper board and corrugated board.


Fast automatic measurements

Measurement starts automatically once a test piece has been placed in the measuring gap. The clamping foot descends, and a bursting strength measurement is made. The sample is then quickly released and is ready for the next measurement at a new position.
To maximize the sample measurement rate, L&W Bursting Strength Tester takes a minimal amount of time between bursts, so that a series of 10 measurements can be done in less than 45 seconds. The actual measuring time depends, of course, on the type of paper or paper board being tested. Three different test results can be reported after a single measurement; bursting strength standard, bursting strength compensated, and bursting energy absorption (BEA).

Bursting strength can be compensated for the stiffness of the diaphragm

For low bursting strength levels, the stiffness of the diaphragm can account for a large portion of the bursting strength value. If desired, the device can also measure, calculate, and report effective bursting strength compensated from the effects of the diaphragm.

Measurement of Bursting Energy Absorption (BEA)

BEA is used to determine the energy absorption capability of a material. Strong, flexible paper has higher energy absorption values, while brittle, stiff paper has lower values. L&W Bursting Strength Tester calculates and reports BEA according to the SCAN P 24 standard (applies to the paper version).

Function control

The ability to confirm that an instrument is properly set up is of outmost importance. That is why L&W Bursting Strength Tester allows important parameters such as diaphragm resistance and density to be automatically compared to a set of check values. Once the parameters are compared to the control values a report is generated, indicating the differences between measured parameter values and check values.
Measurement results are shown on an easy-to-read display. Individual results and statistical information is reported on the built-in printer. The results can also be transferred to a PC.

Automatic test strip feeding is more effective

Traditional methods for measuring bursting strength are time consuming for both laboratory technicians and mill staff. For this reason, Lorentzen & Wettre has improved L&W Bursting Strength Tester with a new measurement function which both reduces the time an operator needs to spend at the instrument and gives a more reproducible measurement process.

With the new sample feeder function, all the technician needs to do is place the test strip on the measurement table, lower the measurement mechanism, and press the start button. The clamping foot descends, and a bursting strength measurement is taken. The sample is released quickly and automatically fed to the next measurement position. In this way, several measurements can be completed with minimum involvement from the operator, and the measurement results are more reliable.

  • Mullen-type
  • Fastest on the market
  • Easy to use
  • Possible to compensate for the diaphragm’s own stiffness
  • Fast check of main functions
  • Built-in printer
  • Available with automatic test strip feeder

L&W Bursting Strength Tester – Code 180 for paper/181 for board and corrugated board
Extra diaphragms, extra glycerol, equipment for bleeding, and refilling the hydraulic system, bulge height template, PC connection cable, PC program for settings and calibration via PC, paper rolls



50–2000 kPa, 7–300 psi, 0.51–20.4 kgf/cm² (code 180)
250–6000 kPa, 36–900 psi, 2.55–61.2 kgf/cm² (code181)


Display and printer
Four significant digits reported
Pump flow

95 ± 5 ml/min (code 180),
170 ± 15 ml/min (code 181)

Clamping force
Adjustable between 1000–6000 N,
(225–1350 lbf)
Test piece

Thickness: max. 3 mm (0.12 in) (code 180)
Thickness: max. 9 mm (0.35 in) (code 181)
Step length: 48-500 (1,9-19,5 in) (cod 180F)
Step length: 63-500 (2,5-19,5 in) (Code 181F)


 Measurement values
- bursting strength standard
- bursting strength adjusted to compensate for the stiffness of the diaphragm
- bursting energy absorption (BEA) (only for code 180)
- individual values
- mean value
- standard deviation
- coefficient of variation
- maximum and minimum values of the series



- connectable to L&W Autoline Data Acquisition Workstation


Installation requirements

120 W
Instrument air
 >0.5 MPa, (75 psi)



0.5 × 0.5 × 0.5 m
20 × 20 × 20 in


0.34 m³
12 ft³

Net weight

45 kg
100 lb

Gross weight

65 kg
144 lb


Applicable standards

Code 180
1301.403, ASTM D774,
CPPA D.8, JIS 8112,
SCAN P 24, TAPPI T 403

Code 181
1301.438, FEFCO no. 4, SCAN P 25,
TAPPI T 807, T 810


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