Sagility Interview Questions and Answers

Duplex stainless steel is good for NaCl 2500 ppm fluid due to its high corrosion resistance and strength.

• Duplex stainless steel has a high resistance to corrosion and pitting

• It has a high strength and toughness

• Other materials like carbon steel and copper alloys may corrode in NaCl solutions

Total head required for a pump can be calculated using Bernoulli's equation

• Determine the flow rate required

• Calculate the friction loss in the piping system

• Determine the elevation difference between the pump and the discharge point

• Add the three values to get the total head required

• Consider any additional losses due to fittings or valves

Accessories used in a pump suction and discharge line

• Strainers or filters to prevent debris from entering the pump

• Valves to control the flow of fluid

• Pressure gauges to monitor the pressure

• Flanges to connect the pump to the piping system

• Flexible connectors to absorb vibrations

• Check valves to prevent backflow

• Expansion joints to compensate for thermal expansion

• Flow meters to measure the flow rate

Standard oxygen transfer efficiency for fine bubble diffusers is typically around 30-40%.

• Fine bubble diffusers are commonly used in wastewater treatment plants to transfer oxygen to the water.

• Factors that can affect oxygen transfer efficiency include bubble size, diffuser design, and water temperature.

• Efficiency can be improved by optimizing these factors and ensuring proper maintenance of the diffusers.

• Typical oxygen transfer rates for fine bubble diffusers range from 1.5 to...read more

Designing a wet well pumping station involves several steps and considerations.

• Determine the flow rate and head requirements

• Select appropriate pumps and piping

• Design the wet well and sump

• Include safety features such as alarms and backup power

• Consider maintenance and accessibility

• Ensure compliance with regulations and standards

The gradient required for free flow in a sewage pipe depends on the pipe diameter, flow rate, and type of material used.

• The gradient should be steep enough to ensure that the sewage flows freely without any blockages or backups.

• The gradient is typically expressed as a percentage or ratio of the vertical drop to the horizontal distance.

• For example, a gradient of 1:100 means that for every 100 meters of horizontal distance, the pipe should drop 1 meter vertically.

• The required g...read more

NPSH is calculated by subtracting the vapor pressure of the fluid from the absolute pressure at the pump suction.

• NPSH stands for Net Positive Suction Head.

• It is a measure of the pressure required at the suction of a pump to avoid cavitation.

• NPSH is calculated by subtracting the vapor pressure of the fluid from the absolute pressure at the pump suction.

• NPSH is important to ensure the pump operates efficiently and does not suffer from cavitation damage.

• Factors affecting NPSH in...read more

Affinity laws describe the relationship between pump performance and speed, flow rate, and head.

• Affinity laws state that if the speed of a pump is changed, the flow rate and head will also change proportionally.

• The laws can be used to predict the performance of a pump at different speeds without having to conduct actual tests.

• The three affinity laws are: 1) Flow rate is proportional to speed, 2) Head is proportional to the square of speed, and 3) Power is proportional to the ...read more