• COMPRESSOR

    CHENG

    Q. How to take air compressor bumping clearance without opening the head ? Ans.) Open c/case remove bottom end bearings put magnetic type dial guage on connecting rod n lift […]

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  • REFRIGERTION CONTD.

    CHENG

    Q) Give refrigerant properties. ANS.)1.Non toxic, non flammable, non explosive, non corrosive 2.economical, easy leak detection, easily available, environment friendly 3.low sp. heat, low boiling pt., low sp. vol. 4. […]

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  • BOILER WATER TEST

    CHENG

    P-ALKALINITY:- THIS TEST IS CARRIED TO FIND OUT THE PRESENCE OF ALKALINE IN BOILER WATER. BOILER WATER SHOULD BE ALKALINE TO SAVE IT FROM CORROSION.ALKALINITY IS DUE TO HYDROXIDE AND […]

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  • BOILER CORROSION

    CHENG

    ELECTROCHEMICAL CORROSION:-  WHEN IRON COMES IN CONTACT WITH WATER, HYDROGEN IONS TAKES ELECTRONS FROM METAL AND BECOMES HYDROGEN WHILE OH(-) REACT WITH METAL TO FORM HYDROXIDE OF METAL. THIS LEAD […]

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  • BOILER SAFETY VALVE

    CHENG

    SAFETY VALVE:- BOILER ARE TO BE FITTED WITH NOT LESS THAN 2 SAFETY VALVES EACH HAVING A MINIMUM INTERNAL DIAMETER OF 25MM. BUT THOSE HAVING HEATING SURFACE < 50 SQM. […]

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  • PUMPS

    CHENG

    Q.) Draw the characteristics of centrifugal pump? Ans.)   Q.) Why Q drops when H increases? Ans.)Q is directly related to flow velocity and following Bernoulli’s equation, if H increases, kinetic […]

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  • PURIFIER

    CHENG

    PURIFIER LINE DIAGRAM Q) What are the different processes by which fuel oils can be purified? A) 1. Gravitational method i.e. put the oil in settling tank and then draining […]

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  • REFRIGERATION

    CHENG

    REFRIGERATION SYSTEM UNLOADING MECHANISM OF REFRIGERATION COMPRESSOR When the compressor is not running then the control piston is not exposed to the lub oil pressure and the spring press the […]

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