What does a mixer's nominal size (e.g., 200T) signify?

It indicates the volume of mixed concrete in liters per batch (200 liters) and the type of mixer (T for Tilting).

What are the three types of batch mixers covered?

Tilting (T), Non-tilting (NT), and Reversing (R) drum types.

What is the permissible error in the water measuring tank?

The water measuring equipment must be accurate to within ± 3 percent of the required quantity.

IS 1791

: 1968

Batch Type Concrete Mixers - Specification

CurrentSpecializedSpecificationGeneral · Scaffolding, Formwork and Construction Equipment

Archive.org BIS Portal Google

This standard lays down the requirements for the design, manufacture, and testing of free-fall batch type concrete mixers. It categorizes mixers into tilting, non-tilting, and reversing types based on their discharge mechanism, and defines standard nominal capacities based on the volume of mixed concrete.

Specifies requirements for batch type concrete mixers used for construction purposes.

Quick Reference Values

tilting mixer nominal sizes100, 140, 200, 250 liters

non tilting mixer nominal sizes200, 280, 375, 500, 1000 liters

reversing mixer nominal sizes200, 280, 375, 500, 1000 liters

water measuring tank accuracy± 3 percent

minimum mixing time1.5 to 2.5 minutes depending on capacity

Practical Notes

The nominal size (capacity) of the mixer refers to the volume of compacted mixed concrete per batch, not the dry unmixed volume.

Regularly inspect and calibrate the water measuring equipment to maintain accurate water-cement ratios and prevent strength loss.

Ensure mixer blades are inspected for wear; worn blades significantly reduce mixing efficiency and homogeneity of the concrete.