What are the standard capacities for pan mixers as per IS 12119?

The standard nominal capacities are 100, 200, 300, 500, 750, 1000, 1500, 2000, 2500, and 3000 litres (Table 1).

What is the main performance criterion for a pan mixer?

The coefficient of variation of the coarse aggregate content between different samples from a batch shall not exceed 5% (Clause 8.2.4).

What overload must the mixer be able to handle on start-up?

The mixer must be capable of starting with a 15 percent overload by weight of its nominal rated capacity (Clause 6.1).

What information should be marked on the mixer?

The mixer should be marked with the Manufacturer's name, mixer type (pan), model/serial number, nominal capacity, and recommended mixing speed (Clause 9.1).

IS 12119

: 1987

General requirements for pan mixers for concrete

CurrentFrequently UsedSpecificationBIMMaterials Science · Cement, Concrete, Aggregates and RCC

Download PDF BIS Portal Google

This standard specifies the requirements for the materials, construction, performance, and testing of batch-type pan concrete mixers. It covers various nominal capacities and outlines the criteria for ensuring uniform mixing, such as through a performance test measuring the variation of coarse aggregate.

General requirements for pan mixers for concrete

Quick Reference Values

Nominal capacities100, 200, 300, 500, 750, 1000, 1500, 2000, 2500, and 3000 litres

Performance test CV limitCoefficient of Variation of coarse aggregate content shall not be more than 5%

Starting overload capacityCapable of starting with 15% overload on nominal capacity

Performance test mixing time90 seconds (Clause 8.2.3)

Blade and arm tip speedShall be between 1.25 and 2.0 m/s

Practical Notes

Pan mixers provide a more intensive shearing action than drum mixers, making them ideal for stiff, low-slump mixes common in precast concrete production and for producing high-strength concrete.

Regular inspection and timely replacement of wear plates and mixing blades are critical to maintain the mixing efficiency specified by the performance requirements in Clause 8.

The performance 'washout test' (Clause 8.2) is the definitive method to certify a mixer's capability but is complex; end-users often rely on manufacturer's type-test certification.