COMPRESSION TESTING MACHINE:

AS PER IS-516, B.S.S. 1610, 1881

INTRODUCTION:

Strength of Concrete is a very important aspect during construction. Strength of concrete Is obtained by crushing the specimen in form of cubes or cylinders. Concrete is carefully designed for a particular compressive strength by the Engineers and specimen is tested by applying load in a compression Testing Machine. Range of Compression Testing Machines from 10 Tons to 300 Tones in different models. Portable models are very convenient and useful for site use where carrying frequently the specimens for testing in a standard laboratory is inconvenient and uneconomical. With special attachments the machines can also be used for bricks. Hallow or solid concrete blocks, using appropriate capacity machine. In general a Compression Testing Machine consists of a Load Frame with suitable platens and a Pumping Unit with Pressure Gauge, either hand operated or electrically cum- hand operated or Digital or Computerized. Load Frame and Pumping unit are connected by pressure pipe.

PILLAR TYPE LOAD FRAME

• These are two/ Four pillar type load frames.
• Two solid pillars are vertically fixed to a sturdy base and at other end is fixed across-head.
• The height of the cross head is also slightly adjustable.
• A lead screw passes through the center of cross-head.
• To the lower end of this lead screw is fixed upper platen with a spherical seat for self alignment.
• At the center of the base plate is fixed a jack, on the top of which the lower platen with the help of a centering pin is kept.
• The distance between the upper end platen is variable by means of the lead screw.
• A spacer block is also supplied with the load frame.
• This spacer block which can be fitted on the top of the jack and below the lower platen by means of centering pins helps reduce the distance between the two platens.
• The platens are well machined, polished and hardened.
• The lower platen has concentric grooves to centrally place the specimen.

OR

CHANNEL TYPE LOAD FRAME

• In these load frames “C” channels are used, they are welded at the top as well as bottom and with stand high loads.
• A hydraulic jack is fitted at the center of the base of the load frame, over which can be fitted lower platen and spacer block with the help of centering pin.
• A lead screw passes through the top of the frame.
• To the lower end of this lead screw is fixed the upper platen with spherical seat for self alignment.
• The platens are accurately machined, hardened and polished.
• The lower platen has concentric grooves to correctly place the specimen.

Note: The platens are normally circular in shape, but on special request square platens or rectangular platens can be supplied.

ELECTRICALLY CUM HAND OPERATED PUMPING UNIT

• This is a separate console housing an oil tank, electric motor, relay etc.
• Inside the oil tank are mounted two pumps which are worked with the help of a cam rotating inside the tank.
• The cam is rotated by the electrical motor and belt.
• Above the tank is fitted a hand pump.
• All plungers are accurately machined and no oil seals are used.
• Special non- return valves are fitted in the pumping system for trouble free long service, A dip stick is provided to know the oil level in the tank.
• A drain to remove oil is fitted at the base of the tank.
• The pumping unit has on its front panel a slow-fast lever to control the rate of loading, a release valve and a slit to enable a rod to be inserted in the hand pump to operate the pumping unit manually.
• A pressure gauge is fitted in front at a convenient angle.
• The pressure gauge has 200 divisions for its full capacity, Inside the pressure gauge is fitted a micro switch.
• This micro switch automatically cuts off electrical supply to the pumping unit on reaching full capacity of the pressure gauge.
• A red dummy pointer is fixed on the cover glass of the pressure gauge to record maximum load at the failure of the specimen.
• The pumping unit works on 230 volts A.C. or 415 volts, 3 phase supply.
• This pumping unit is connected to the load frame by means of pressure pipes.
• Additional pressure gauges (maximum 2 Nos.) of lower capacities with isolation valves can be fitted on the pumping unit.

Note:

Digital & Computerized versions of electrically operated Compression Testing Machines can also be supplied.

The digital versions have 0.5% accuracy Various Models of Compression Testing Machine are available listed in the following table.

Note: Standard Machines are supplied for operated for operation on 415 volts, Three phase, 50 H2 supply. Can be supplied for operation on 230 volts, single Phase, A.C. Supply on specifying, while placing orders, at extra cost