Hydraulic Bursting Strength Tester for Paper

What is the Hydraulic Bursting Strength Tester for Paper?

A hydraulic bursting strength tester for paper applies increasing fluid pressure behind a rubber diaphragm to burst a clamped specimen. It is the reference configuration for ISO 2758 and TAPPI T403 testing of paper and light board.

Overview

A motorised pump raises the hydraulic pressure at a controlled rate, typically 95 mL per minute of fluid displacement, and the specimen is clamped over a circular aperture of defined area. The diaphragm, whose thickness and elasticity are specified, transmits the pressure to the specimen, and a pressure transducer or precision gauge records the maximum value at rupture. The lower clamping platen is usually the fixed reference, and the upper platen is loaded by a lever and weight system or by a calibrated spring so that the clamping force can be verified. Because pressure rise rate and clamping force both affect the result, the instrument includes separate verification points for each, and a reference pressure gauge is used to check the transducer over its range.

How does it work?

A circular specimen is clamped between two platens under a defined clamping pressure and a rubber diaphragm expands against it as hydraulic or pneumatic pressure increases at a controlled rate. The maximum pressure reached at rupture is recorded as the bursting strength, and the value is affected by clamping pressure, diaphragm condition, the rate of pressure rise and specimen conditioning. Standards define the clamping force, the free test area, the pressure rise rate and the diaphragm material and thickness, so the instrument must be configured exactly as the method specifies. Because the diaphragm stretches with every test, it must be replaced at defined intervals and its condition checked, since a stiff or hardened diaphragm gives high and erratic readings. Corrugated board requires a larger test area and a support plate to prevent local crushing.

What are the key features?

• Motorised hydraulic pump with controlled rise rate
• Specified rubber diaphragm and test area
• Pressure transducer with digital maximum hold
• Lever and weight or spring clamping system
• Reference gauge port for pressure verification
• Rupture pressure display in kPa

What are the technical specifications?

A typical hydraulic bursting strength tester for paper configuration offers measuring range of 0–1600 kPa, resolution of 1 kPa, test area diameter of 30.5 mm per ISO 2758, pressure rise rate of 95 ± 10 mL/min fluid displacement, clamping pressure of About 700–1200 kPa, specified by method and diaphragm thickness of 0.9 mm typical for paper. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Hydraulic Bursting Strength Tester for Paper is used in bursting strength testing of paper and light board, paper bag and sack grade verification, incoming inspection of packaging papers and mill process control of furnish changes. Across the wider Burst Analysis class, laboratories also deploy it for bursting strength of packaging papers and boards, corrugated board quality control and paper bag and sack grade verification.

Which standards and certifications apply?

Relevant standards and methods include ISO 2758, ISO 2759, ISO 12625-11, ASTM D774, TAPPI T403, TAPPI T810 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Condition specimens to the standard atmosphere, since bursting strength changes markedly with moisture content. Clamp each specimen centrally and without creases, since edge positions and wrinkles cause premature rupture and low readings. Replace the diaphragm at the interval stated in the method or whenever it shows hardening, cracking or permanent deformation, and record the replacement in the instrument log. Verify the clamping pressure and the pressure rise rate periodically, and check the pressure gauge or transducer against a reference. After each test, inspect the rupture pattern: an off-centre or irregular burst usually indicates a clamping or centring problem rather than a material fault.

How do I select the right Hydraulic Bursting Strength Tester for Paper?

Choose the hydraulic configuration when testing paper or light board to ISO 2758 or TAPPI T403, and confirm the test area, diaphragm specification and pressure rise rate match the standard edition. Verify the pressure transducer with a reference gauge at several points, since a single point check does not reveal scale errors.

How does it compare with other Burst Analysis variants?

Choose the instrument from the standard and the product. Paper and tissue use the smaller hydraulic test area, board uses the larger area with a higher pressure range, and corrugated board needs a pneumatic or hydraulic instrument with a support plate and a sufficiently wide clamping ring. Confirm the pressure range covers the expected bursting strength with adequate headroom, since a range that is too low prevents reaching rupture and one that is too wide reduces resolution. Specify automatic clamping if many specimens are tested, and always choose an instrument whose diaphragm and pressure rise rate match the standard edition you follow, because values from different configurations are not interchangeable.