Sage-Tips

What type of reducers designer must select at pump suction?

Eccentric reducers are traditionally recommended for the pump suction reducer fitting to allow for transportation of air through the fitting to the pump. The ability of a concentric reducer to provide an improved approach flow to the pump while still allowing air to be transported through the fitting is investigated.

Can we use concentric reducer in pump suction?

Concentric reducer is recommended for vertical inlet (suction) piping or horizontal installations where there is no potential for air vapor accumulation. When the source of supply is above the pump, then the eccentric reducers must be placed with the flat side down.

Why reducer is used?

A reducer is a kind of pipe fitting used in process piping that reduces the pipe size from a larger bore to a smaller bore (inner diameter). A reducer allows for a change in pipe size to meet hydraulic flow requirements of the system, or to adapt to existing piping of a different size.

Why does pump discharge reducer?

The primary reason for using reducer and expander in inlet/ outlet piping is to join the respective pipe sizes with smaller pump nozzles. Larger upstream pipe on the suction side joins with a smaller suction nozzle using a reducer. And a small discharge nozzle continues into a larger outlet pipe via an expander.

Why suction is bigger than discharge?

The discharge pipe may be larger than the suction pipe. The purpose of the lines is to keep the losses to a minimum. This is done to make sure there is enough Net Positive Suction Head available to meet the requirements of the pump.

What is the suction side of a pump?

The inlet, or suction side of a pump is the point of lowest pressure in a given pump. For positive displacement pumps, the lowest pressure occurs just prior to rotor meshing; for centrifugal pumps, lowest pressure is near the eye of the impeller.

Why eccentric reducer is used in pump suction?

Eccentric reducers are used at the suction side of pumps to ensure air does not accumulate in the pipe. The gradual accumulation of air in a concentric reducer could result in a large bubble that could eventually cause the pump to stall or cause cavitation when drawn into the pump.

What is difference between eccentric and concentric reducer?

Concentric reducers reduce the pipe in the center. So, if you’re looking at the reducer head-on, you can see the smaller section is formed in the direct center of the larger side. Eccentric reducers reduce the pipe to the side. Eccentric reducers are used when the pipes have to maintain the same top or bottom level.

What is the purpose of reducer in pipe?

First, let’s keep it simple: A pipe reducer is a pipe fitting that connects a larger pipe to a smaller pipe. Thus, it reduces the size of the pipe in the pipe system, from one size to another. Pipe reducers may frequently be used to connect pipes of different sizes.

When would you use a concentric reducer?

A concentric reducer is used to join pipe sections or tube sections on the same axis. The concentric reducer is cone-shaped, and is used when there is a shift in diameter between pipes. For example, when a 1″ pipe transitions into a 3/4″ pipe and the top or bottom of the pipe doesn’t need to remain level.

What prevents a pump from drawing air suction?

Preventing discharge cavitation

1. Keep reducers as close to the pump as possible.
2. Install control valve, if needed, on the discharge side–never on the suction side.
3. Avoid pockets where air or vapors can accumulate.

Why eccentric reducers are placed at the bottom of the pump?

This results in higher liquid velocity in the pump suction, increasing frictional losses. It also affects the overall performance and long term reliability of the pump. When the source of supply is above the pump, then the eccentric reducers must be placed with the flat side at the bottom.

Can I use a concentric reducer on the suction side?

Concentric reducers are only permitted on the discharge side of the pump. It is the sloping quality of the reducer that has the potential for an air pocket to form if used on the suction side and oriented with the sloping side facing up. Wayne, I was only asking in reference to a vertical supply feeding the pump.

How do you reduce the size of a suction pipe?

It’s standard practice to employ suction-side piping one or two sizes bigger than the pump inlet. A reducer fitting is typically used in pump suction piping to reduce the size of the suction pipe to match the size of the pump suction end flange.

Why do we need reducers and expanders at pump suction and discharge piping?

Normally the pump nozzles are smaller than inlet / outlet piping. That is why we need to use reducers and expanders at the pump suction and discharge piping. We have a choice of using concentric or eccentric reducers.