Grease Worker

What is the Grease Worker?

A grease worker shears a grease sample by forcing a perforated plate up and down in a closed cup, 60 or more strokes at a set rate. It prepares grease for worked penetration testing and can be used for prolonged working to assess mechanical stability per ASTM D217.

Overview

The worker consists of a standard cup holding about 400 g of grease, a lid with a shaft, and a perforated plunger plate with holes that shear grease as it passes through. A motor drives the plunger at 60 double strokes per minute for 60 strokes in the worked penetration procedure, or up to 100,000 strokes for prolonged worker testing. A temperature-controlled jacket or pre-conditioning keeps grease at 25 °C. After working, the grease is transferred to the penetrometer cup within a defined time. Automatic counters and stop functions prevent variation. The difference between unworked and prolonged worked penetration quantifies shear stability of the thickener and is important for greases in bearings and chassis.

How does it work?

Grease is a dispersion of a thickener, such as lithium or calcium soap, polyurea or clay, in base oil with additives. Its behavior is non-Newtonian, so tests measure structure rather than viscosity. Consistency is measured by letting a standard cone sink into the sample for five seconds and reading the penetration depth in tenths of a millimeter, usually after working the grease in a standard worker. Dropping point is the temperature at which the first drop falls from a heated cup, indicating thermal limit of the thickener structure. Oil separation measures how much base oil bleeds through a wire cone under storage conditions. Oxidation tests heat grease in oxygen and record pressure drop, and water washout tests spray or immerse grease to find the percentage lost. Standard cup, cone and temperature geometry give comparable results.

What are the key features?

• Standard cup and perforated plunger plate
• Motorized 60 double strokes per minute
• Stroke counter with preset stop
• Optional temperature jacket
• Prolonged working capability to 100,000 strokes

What are the technical specifications?

A typical grease worker configuration offers sample mass of ≈ 400 g per cup, stroke rate of 60 ± 10 double strokes/min, stroke count of 0–99,999 preset, plunger stroke of ≈ 67 mm, plate hole diameter of ≈ 2.4 mm, 51 holes and temperature control of 25 ± 1 °C (jacket option). 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 Grease Worker is used in worked penetration sample preparation, mechanical stability testing of greases and bearing and chassis grease qualification. Across the wider Grease Testing class, laboratories also deploy it for grease batch quality control, NLGI grade determination and high-temperature grease development.

Which standards and certifications apply?

Relevant standards and methods include ASTM D217, ISO 2137, ASTM D566, ASTM D2265, IP 396, ASTM D942, ASTM D1264 and ASTM D6184. 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.

Grease tests are sensitive to sample handling. Fill cups without air pockets, and bring samples to 25 °C in a bath before penetration testing. Keep cones and worker plates clean and undamaged, and verify penetrometer zero and cone mass and dimensions. Calibrate temperature sensors in dropping point blocks. For oxidation bombs, check pressure transducers and leak tightness, and treat oxygen with care: use clean, oil-free regulators and a ventilated area. Replace consumables such as wire cones and cups per the method. Keep grease waste separate from solvents, and record reference grease checks with certified materials to support laboratory accreditation.

How do I select the right Grease Worker?

A grease worker is required with any penetrometer that reports worked penetration or NLGI grade. Specify the number of cups, stroke counter, prolonged-work capacity and whether temperature control is included. Laboratories testing mechanical stability should add roll stability equipment per ASTM D1831.

How does it compare with other Grease Testing variants?

Choose equipment according to the grease properties in your product specification. Every grease plant needs a penetrometer and grease worker for NLGI grade, plus a dropping point apparatus. Formulators of high-temperature and long-life greases add oxidation stability testing. Storage and bearing-application tests such as oil separation and water washout support quality control and complaint handling. Consider whether the penetrometer needs automatic operation, full-scale or quarter-scale cones, and heating capacity for the dropping point block, which is often 260 to 400 °C for high-temperature greases. Check compatibility with the standard edition cited by customers, and whether consumables such as wire cones, cups and wheel bearings are available. In the RFQ, list methods, sample throughput and the thickener types tested.