Information on Machines for Making Concrete Building Blocks

Block Machine History

• Harmon Palmer invented the hollow concrete block-making machine in 1900. His machine used molds with removable cores and adjustable sides, principles that are still used in modern machines. Palmer made improvements, including collapsible mold sides that facilitated the removal of finished blocks. In 1909, Herman Besser invented a power tamper for compressing the concrete in the block machines’ molds, allowing for more consistent quality by eliminating hand tamping. In 1939 Besser’s company introduced vibration tamping, which further improved quality while reducing wear on the tamping apparatus.

Basic Principle

• Originally, block making machines were set up at a job site, made enough concrete blocks to complete the job at hand, and were moved on to the next site. This practice is still followed with small manual machines in underdeveloped countries. In developed countries, blocks are made in commercial blockyards on automated machines and shipped to the job site. Modern block-making machines cover a wide range of types and prices. But they all work on the same basic principles. Wet concrete is poured into block molds and is compressed by tamping. The fresh blocks are freed from the molds and exit the machine for hardening, which occurs via drying under controlled conditions. Then the blocks are cured for up to two weeks before being used.

Manual Machines

• Manual machines for making concrete blocks are produced mainly in China and India. These machines make one or two blocks at a time and can produce 300 to 600 blocks per day. Modern manual machines use a vibrator driven by an electric motor or small diesel engine. The vibrator works with a hand-pumped or motor-driven hydraulic tamper to compress the concrete blocks. The concrete is mixed and poured into the molds by hand, and the finished blocks are unmolded and removed from the machine on a hand pallet for drying and curing. These machines can be dismantled and moved from one job site to another. They weigh around 1,000 pounds when assembled for work.

Automated Machines

• In developed countries, concrete block machines are highly automated stationary devices used in blockyards to produce thousands of blocks per day. Most models offer computer controlled ingredient blending and block manufacture, allowing a blockyard to produce a great variety of concrete brick and block from a single machine. Because of their automation, these machines can be run with a few as six people. Automated block making machines are produced in the United States, Europe and Asia. These machines incorporate automated batching and mixing of the concrete, automated production of eight to 16 blocks at a time, conveyors and other handling equipment for the finished blocks, and the capability to produce different types of hollow and solid blocks, paving blocks, curbstones and other specialty concrete block products