Aastrid Life Sciences Maintenance Engineer Interview Questions, Process, and Tips

MTTR is the average time to repair a failed system, while MTBF is the average time between failures.

• MTTR measures downtime and repair time, while MTBF measures reliability and uptime.

• MTTR is a measure of how quickly a system can be restored after a failure, while MTBF is a measure of how long a system can operate without failing.

• MTTR is typically used to evaluate maintenance performance, while MTBF is used to evaluate ...read more

Enthalpy is the sum of internal energy and the product of pressure and volume.

• Enthalpy is a thermodynamic property of a system.

• It is represented by the symbol 'H'.

• It is defined as the sum of internal energy and the product of pressure and volume.

• Enthalpy change is the heat absorbed or released during a chemical reaction.

• Enthalpy is used in various fields including chemistry, physics, and engineering.

Validation ensures that a process or system meets the intended requirements, while qualification ensures that the equipment or system is installed and operates correctly.

• Validation is focused on the process or system, while qualification is focused on the equipment or system.

• Validation ensures that the process or system meets the intended requirements, while qualification ensures that the equipment or system is install...read more

Pressure differential is the difference in air pressure between two points in an HVAC system.

• It is important for maintaining proper airflow and ventilation.

• It can be measured using a manometer.

• A high pressure differential can indicate a clogged filter or duct.

• A low pressure differential can indicate a malfunctioning fan or blower.

• It is often used in cleanroom environments to prevent contamination.

There are several types of pumps including centrifugal, positive displacement, and axial flow pumps.

• Centrifugal pumps use a rotating impeller to create a flow of fluid.

• Positive displacement pumps move fluid by trapping a fixed amount and forcing it through the discharge port.

• Axial flow pumps move fluid parallel to the pump shaft.

• Other types of pumps include reciprocating pumps, peristaltic pumps, and jet pumps.

There are two main types of compressors: positive displacement and dynamic.

• Positive displacement compressors work by trapping air in a chamber and reducing the volume of the chamber to compress the air. Examples include reciprocating, rotary screw, and rotary vane compressors.

• Dynamic compressors work by imparting velocity to the air and then converting that velocity into pressure. Examples include centrifugal and axial...read more

HVAC stands for Heating, Ventilation, and Air Conditioning.

• HVAC is a system used for regulating temperature, humidity, and air quality in buildings.

• It includes components such as furnaces, air conditioners, ductwork, and thermostats.

• HVAC systems can be found in residential, commercial, and industrial buildings.

• Proper maintenance of HVAC systems is important for energy efficiency and indoor air quality.

A typical water system diagram includes a water source, treatment plant, distribution network, and end-users.

• Water source can be a river, lake, or groundwater well

• Treatment plant removes impurities and disinfects water

• Distribution network includes pipes, pumps, and storage tanks

• End-users can be residential, commercial, or industrial

• Backflow prevention devices are installed to prevent contamination

Breakdowns in chillers can be caused by various factors such as electrical issues, refrigerant leaks, and mechanical failures.

• Electrical issues such as faulty wiring or blown fuses can cause breakdowns in chillers.

• Refrigerant leaks can occur due to corrosion or damage to the chiller's components.

• Mechanical failures such as worn out bearings or broken belts can also cause breakdowns in chillers.

• Dirty or clogged filters ...read more

Boiler efficiency is the ratio of energy output to energy input.

• Efficiency is important for reducing fuel consumption and costs.

• Factors affecting efficiency include combustion efficiency, thermal efficiency, and fuel-to-steam efficiency.

• Regular maintenance and cleaning can improve efficiency.

• For example, reducing excess air can improve combustion efficiency.

• Another example is using economizers to recover heat from flue...read more

There are various types of seals used in different industries and applications.

• Mechanical seals: used to prevent leakage between rotating and stationary parts, commonly used in pumps and compressors.

• Hydraulic seals: used to prevent fluid leakage in hydraulic systems, commonly used in cylinders and valves.

• O-ring seals: used to create a seal between two mating surfaces, commonly used in plumbing and automotive applicatio...read more

There are several types of pumps used in mechanical engineering.

• Centrifugal pumps

• Reciprocating pumps

• Rotary pumps

• Diaphragm pumps

• Gear pumps

• Vane pumps

• Screw pumps

• Jet pumps

• Peristaltic pumps

• Piston pumps

The parts of a pump include impeller, casing, shaft, bearings, seals, and motor.

• Impeller: Rotating component that imparts energy to the fluid.

• Casing: Encloses the impeller and directs the flow of fluid.

• Shaft: Transmits the rotational motion from the motor to the impeller.

• Bearings: Support the shaft and reduce friction.

• Seals: Prevent leakage of fluid along the shaft.

• Motor: Provides the power to drive the pump.