Gujarat Alkalies & Chemicals Assistant Engineer Mechanical Interview Questions and Answers

Refrigeration cycle is a process in which refrigerant absorbs heat from a low-temperature space and rejects it in a high-temperature space.

• Refrigerant absorbs heat from the low-temperature space (evaporator)

• Refrigerant is compressed to increase its temperature and pressure

• High-temperature refrigerant releases heat in the condenser

• Refrigerant expands in the expansion valve to lower its temperature and pressure

• Cycle repe...read more

Various types of pumps with characteristics curves

• Centrifugal pumps: high flow rates, low pressure, used in HVAC systems

• Reciprocating pumps: high pressure, low flow rates, used in hydraulic systems

• Diaphragm pumps: positive displacement, used for metering and dosing applications

• Gear pumps: used for lubrication systems, constant flow rate

• Axial flow pumps: high flow rates, low head, used in irrigation systems

The range of a cooling tower typically varies based on the size and capacity of the unit.

• The range of a cooling tower can vary from small residential units to large industrial units.

• Smaller cooling towers may have a range of a few tons of cooling capacity, while larger industrial cooling towers can have a range of hundreds or even thousands of tons.

• The range of a cooling tower is typically measured in terms of cooling ...read more

Cooling towers are heat rejection devices that use water to transfer heat from a system into the atmosphere.

• Cooling towers work on the principle of evaporation to remove heat from the water being circulated through the tower.

• The hot water is pumped to the top of the tower and distributed over the fill or packing, where it is exposed to air.

• As the water flows over the fill, some of it evaporates, which removes heat from...read more

Deaerator is placed at higher elevation to create a pressure difference for efficient removal of dissolved gases from feedwater.

• Higher elevation creates a pressure difference which aids in the removal of dissolved gases from feedwater

• This helps in preventing corrosion in the boiler system

• It also improves the efficiency of the boiler by reducing the amount of oxygen in the feedwater

LP dosing refers to the process of injecting a low pressure chemical solution into a system or process.

• LP dosing is commonly used in water treatment plants to add chemicals such as chlorine or coagulants to the water supply.

• It is also used in industrial processes to introduce additives or inhibitors into pipelines or equipment.

• LP dosing systems typically consist of a pump, piping, and injection point where the chemical...read more

Stroke length of a reciprocating compressor is the distance the piston travels from top dead center to bottom dead center.

• Stroke length is an important parameter in determining the displacement volume of the compressor.

• It is typically measured in inches or millimeters.

• For example, a reciprocating compressor with a stroke length of 4 inches will have a piston that travels 4 inches up and down within the cylinder.

• Stroke ...read more

Surging and choking are two common operating conditions in centrifugal compressors.

• Surging occurs when the flow rate through the compressor is reduced to the point where the compressor cannot maintain a stable flow and pressure. This leads to a pulsating flow and can cause damage to the compressor.

• Choking happens when the flow rate through the compressor is increased to the point where the compressor cannot handle the ...read more