An extensive range of instruments to help identify electrostatic hazards and solve processing problems. These instruments can determine how readily static charge can be conducted away from a material and the likely risk of undesirable static build up. Each is designed to test materials in different forms including liquids, powders, films and fully fabricated equipment (e.g. FIBC's, gloves, etc.).
 

Charge relaxation time measurement apparatus (JCI 155v5)
for powders, textiles and liquids.

Charge Relaxation Time (JCI 155v5)

For measuring charge relaxation times of powder products, films, solids and liquids. Manufactured to permit testing in accordance with BS and IEC test standards.

Data from this apparatus complements conductivity and resistivity measurements. Relaxation time measurements are especially useful in differentiating between higher resistivity materials, both as regards to the risk of occurrence of problems and in relation to applications with static electricity.

A compact self contained and portable instrument with digital storage of observations and the opportunity for graphical presentation of results.

Humidity Controlled Workstation

Electrostatic properties are substantially affected by relative humidity, so it is often imperative to test under known and controlled environmental conditions. This work station provides a simple means of achieving controlled humidity by means of saturated salts and can be used for conducting all of the resistivity, conductivity and charge relaxation time tests described on this page.

Instead of manually controlling humidity by means of saturated salts, a fully automated humidity control option is available. 

Humidity Controlled Workstation for resistivity, conductivity and charge relaxation tests. Various sizes available.

Liquid Conductivity

Manufactured in accordance with BS, although test cells can be manufactured to comply with other standards if required. A compatible power supply and picoammeter are also supplied with the apparatus.

A portable Liquid Conductivity test rig (EX approved) is also available.

Powder Chargeability

Whenever one material moves against another, electrostatic charging will result. The net rate of charge acquisition will depend on both the rate of charge generation and the rate of charge dissipation. While measurements of resistivity and charge relaxation time reveal a material's ability to dissipate charge, chargeability indicates its propensity to generate it.

Chilworth have developed this apparatus for measuring powder chargeability directly. The apparatus is based upon BS electrostatic principles.

Powder Resistivity

Manufactured in accordance with BS standard, although test cells can be manufactured to comply with other standards if required. A Custom manufactured multirange high voltage power supply and a compatible picoammeter are also supplied with the apparatus.

High Voltage Power Supply

Ranges – 500V, 1kV, 2kV,3kV and 0-10kV adjustable (variable in 0.1kV steps) Current capability - 500µA.

Application: resistivity test cell supply (dependent on test standard) or calibration of gas probe in conjunction with capacitive storage unit.

Concentric ring electrode to EN standards.
Inset: Concentric rings test electrode -compliant with BS or EN standards.

Textile fabric tester to DIN standards.
Tests electrical resistance of strips of textile fabric.

Resistivity for Film and Solids 

An ohm square test cell and/or a concentric ring type test electrode can be supplied for conducting tests in accordance with BS, BS EN and IEC guidelines if required, depending on whether tests are to be performed on film, textile fabric or solid electrical insulating materials.

The measurement apparatus and power supply supplied with the apparatus will depend upon the material to be tested and the test standard to be complied with.

A few examples (by no means exhaustive) of test cells which can be supplied are shown in the adjacent photos.
 

Spark Incendivity Probe and Gas Mixing

Chilworth manufacture a gas ignition probe to enable static discharges to be drawn from a surface through a gas mixture of known ignition energy. This is a means of estimating discharge energy in a way that is extremely demonstrative and practical. A gas mixing unit and calibration table is provided with the ignition probe and covers a wide range of gases.

An optional spark ignition calibration unit is also available which permits the operator to calibrate the probe to a gas of known Minimum Ignition Energy.

Electrostatic Field Meter (JCI 140)

A compact and easy to use instrument for detection and measurement of static electricity in practical situations. This instrument measures surface voltages without contact at a separation distance of 100mm. Full scale sensitivities are 2000 volts and 20,000 volts and measurements can be made to 1V on the 2000V scale. Connections for long term continuous monitoring operation and for signal recording.

Ranges Floor, Footwear & Glove Testing

Permits testing in accordance with BS standard and comparison of results to be compared to the guidelines mentioned within the current CENELEC standard.

Consists of floor electrodes, high resistance range insulation tester, hand electrode, foot plate, insulated backing sheet, calibration resistors and test guidance manual, all located within a convenient carry/storage case.

Spark Detection

A field study tool manufactured for remote detection of electrostatic spark activity on plant using radio frequency monitoring principles. 

Static Electricity Neutraliser

Chilworth can also supply electrostatic neutralisers and power supply equipment for solving clients on-site electrostatic hazards or to provide a solution to production problems caused by electrostatics. We can also provide off-the-shelf or custom fabricated solutions.