STRAINER

Strainers are devices that help to remove the particulate matter from entering the steam line equipment. Strainers are provided with a device like a simple Stainless Steel screen to trap all physical impurities and keep the internals of these components clear for optimum performance. All steam line equipment like Control Valves, Steam Traps, Pumps, and flow meters must have a strainer fitted at the inlet to prevent dirt particles from reaching the fine pressure areas like valve seating. A control valve or a trap will start leaking in case such dirt particles get deposited on the internals of these fittings.

Installation:

Strainers are fitted in front of every trap, flow meter, reducing valve, and regulating valve.

1. Strainers should always be installed in steam lines with their baskets to the side, in steam or gas application (a)

2. On the liquid system, the pocket should point vertically downwards, this ensures that the removed debris is not drawn back into the stream pipework during low flow conditions. (B)

3. It is advisable to install strainers in horizontal lines, it not always possible and they can be installed in vertical pipelines if the flow is downwards, in this case, the debris is naturally directed and collected into the pocket. (C)

4. Installation in the upward direction is not possible.

Operation:

Pipeline works installed are common to have fragments of casting sand, rust, carbonate, etc to deposit inside the pipe. These deposits can pass

along pipework with steam and rest inside a piece of steam using equipment. Steam using equipment may also suffer permanent damage.

Strainer

Steam flows from inlet A through the perforated screen ‘B’ to outlet ‘C’. While stem and water will pass readily through the screen, dirt cannot. The cap ‘D’ can be removed, allowing the screen to be withdrawn and cleaned at regular intervals. A blowdown valve can also be fitted to cap D to facilitate regular cleaning.