The branch conduit has a bleed passage with the outlet bleed port.

A bleed isolation valve is disposed in the bleed passage between the main passage and the outlet bleed port.

The manifold body has an inlet (21) and an outlet (22), an outlet bleed port (27) and first and second valve cavities (25,26).

The branch conduit has a bleed passage with the outlet bleed port.

A bleed isolation valve is disposed in the bleed passage between the main passage and the outlet bleed port.

A bleed exit allows the oxygen to escape to the ambient air.

A sneeze valve is connected with the exhaust outlet for inhibiting flow through the exhaust outlet.

A drain is located in the wall downstream from the outlet opening.

A cutting device (14) is arranged at said discharge valve (12) outlet for cutting up into blocks a continuous polymer flow at the discharge valve (12) outlet.

The LNP (2), the output coupler and the wavemeter (14) are contained in sealed chambers each having a purge inlet port and a purge outlet port.

The purging quantity has a value equal to or less than the difference between the maximum quantity and the output quantity, and the purging quantity is controlled based on the output quantity.

The purging quantity has a value equal to or less than the difference between the maximum quantity and the output quantity, and the purging quantity is controlled based on the output quantity.

A variable -bleed valve is in fluid communication with the hydraulic chamber and an outlet channel and configured to selectively vary a bleed rate between the hydraulic chamber and outlet channel.

A heater assembly can be arranged at a purge exhaust output of the vessel bed.

The outlet fitting includes internal insulation to avoid the need for a steam purge.