API Plan 23

• Product in seal chamber is isolated from pumping area using a close clearance throat bushing.
• Increases product temperature margin in the seal chamber thus avoiding vaporization.
• Seal runs at a lower stabilized temperature of the media.
• Removes only the generated seal face heat and the heat soak from the pump area, thus the cooler is smaller and more effective as compared to an equivalent Plan 21.
• Uses a pumping ring for circulation in running condition.
• In idle condition, thermosiphon effect ensures circulation.
• A distributed flush is not recommended for this plan.

• Hot hydrocarbons.
• Hot water services above 80 °C (176 °F).
• Boiler feed water.
• Applications where increasing seal chamber pressure to improve vapor pressure margin is not possible.

• For media with high viscosities and higher freezing points, steam must be used in the cooling lines instead of water.
• A high-point vent valve to be provided to vent the system before start-up.
• A close clearance throat bushing must always be in place to reduce the heat soak from the pump.
• Avoid sharp bends and 90° elbows in piping. Piping should be smooth and continuously rising.
• Cooler to be installed approx. 500 mm (20 ”) above pump centerline.
• Good quality cooling water is recommended to avoid deterioration of cooler efficiency.
• Flush outlet from seal chamber should be in the top half of the seal gland plate or the seal chamber.

• High temperature, clean non-polymerizing fluids.
• Close to vaporization point.

• Process side
• Flushing and cooling

1CW-FL, 1CW-FX, 2CW-CW, 2CW-CS, 3CW-FB