Pneumatic breakers

A summary of the properties and categories of hand held pneumatic breakers is given in Vorster et al. (1992). For concrete repair work breakers usually range from about 10 to 45 kg, or a maximum of about 20 kg... 

Typical production rates for pneumatic breakers range from about 0.025 to 0.25 m per hour for breakers ranging from 10 to 45 kg. Breakers are well suited for jobs with small, discontinuous areas of concrete removal, but not for large scale removal. 

Pneumatic breakers will not clean the rebars and are operator sen. itive in the finish achieved. Work at the UK Transport Re.search Laboratory (Vassie, 1987) hasshowm that inadequate rebar cleaning w ill allow corm.sion to proceed. Hydrojetting or grit blasting the rebars may be needed to remove all chloride contamination. 

Techniques for Concrete Removal and Bar Cleaning on Bridge Rehabilitation Projects. Addresses the partial removal of concrete from decks and other parts of bridge structures. Three technologies are identified and studied in detail pneumatic breakers, milling and hydrodemolition analysis addresses work characteristics, production, cost and quality of product. 135 pages. SHRP-S-336, 15... 

Figure 19.16(a) An SFg circuit breaker 123-145 kV, 31.5 kA. It can also be pneumatic or spring operated, depending upon the arc quenching technique adopted and energy required to extinguish 2 the arc (Courtesy BHEL) 3... 

A defect in rubber products where a component has been misaligned in relation to the centre line, e.g., conductor in a cable, breaker strip in a conveyor belt or pneumatic tyre. 

Formerly termed braced tread, rigid breaker or belted tyre. A pneumatic tyre in which the cords of the casing plies run directly across the tyre section from bead to bead, and not at an angle as in a cross-ply tyre the breaker in a radial-ply tyre is an inextensible band which runs circumferentially round the tyre between tread and casing. It is made up of layers of bias cut fabric set at discrete angles to confer the required stability in the tread but maintain the flexibility in the sidewall. 

Q standard low voltage circuit breaker at the grid side M two-pole cage induction motor, rated power 250 kW P cable guillotine with a pneumatic drive to cut the cable under explosive hydrogen-air atmosphere... 

Isolation, which involves the closing of valves, shutting down main disconnects and circuit breakers, and disconnecting pneumatic, electric, hydraulic, and compressed gas and liquid lines. 

Pneumatic drills, or road breakers, are powered by compressed air produced by a compressor. Compressed-air power is cheap and safe. An air device does not risk creating sparks in an explosive atmosphere and can be used under wet conditions without danger of electric shocks. Compressed air is therefore the only type of power used in some mining or construction operations. 

The decision logic is made up of solid-state circuitry that compares with various inputs. When a combination of inputs requires action, the logic circuitry provides a signal that seals into turn on a solid-state power gate that operates activation devices, such as contactors, circuit breakers, and solenoid pilot valves. Actuation devices in turn control power to the motors that operate valves and drive pumps, or control the air supply to pneumatically operated valves. 

The power supply circuit breakers actuated by the excessive pressure in the pneumatic control valve of the emergency heat removal system ... 

Before processing, wool has to be scoured to remove contaminating particles such as dirt, sweat, and wool fat. The wool is dried in perforated cylinder driers and then opened in the breaker card. After these stages the fibers are oiled to alter the frictional properties of the fibers and to prevent electrostatic charging. The fibers are then pneumatically transported to the mixing chamber. Because raw wool scouring systems are very expensive and subject to strict environmental protection laws, most worsted spinning mills purchase scoured wool, card slivers, or combed slivers. 

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