Customized nitrogen generators are ready for installation in greenhouses

Nitrogen generators ready for installation

14 July 2022

Presscon specializes in the design, construction and maintenance of nitrogen expansion systems, among others. The system we developed and built in-house protects plants and products from corrosion, oxidation, fire and explosion hazards.

Our nitrogen expansion system monitors and controls the nitrogen pressure prevailing in the expansion chamber of a central heating system. It applies to central heating systems in the horticultural industry.

Complete system

The system consists of a nitrogen generator with:

a compressed air copressor,
a set of pressure sensors that measure the water level and pressure at the top of a buffer tank,
a vacuum overpressure protector for the buffer tank,
and a control module that controls the nitrogen generator.

Expansion and contraction in expansion space

A central heating system in the horticultural industry stores its heat in a vertical or horizontal buffer tank. The buffer tank is not completely filled with water. There is an expansion space above the water. With a vertical buffer tank, this space is directly above the water in the tank. In a horizontal heat storage tank, the expansion chamber is also directly above the water in the heat storage tank, but it can also be in a separate expansion tank.

The expansion space is designed to give the water in the central heating system room to expand and contract as the water heats or cools. When this happens, the pressure in the expansion chamber also changes.

Preventing rust

Our VERNIT HORNIT expansion system monitors the pressure in the expansion chamber. If the pressure is too high, a pressure relief valve allows additional air to escape. If the pressure is too low, the VERNIT HORNIT expansion system supplies nitrogen to re-pressurize the expansion chamber. The nitrogen generator of the VERNIT HORNIT expansion system delivers an air mixture with a nitrogen concentration of 99.0 vol. % N2. The system uses nitrogen because it is an inert gas. Inert gas prevents rust at high concentration.

Pressure sensors determine water level

The VERNIT HORNIT expansion system always ensures that a blanket of nitrogen is present in the expansion chamber within the buffer tank and that it is maintained at a constant overpressure.

In addition to pressure management of the nitrogen blanket, the VERNIT HORNIT expansion system is also a monitoring device for the water level in the buffer tank. By using pressure sensors, the system determines the height of the water level. If the water level is too high or too low, the VERNIT HORNIT expansion system gives the appropriate error or alarm message. It also sends a stop signal to other relevant devices.

Monitoring the water level is important for maintaining the buffer tank. It prevents the water level from getting too high and damaging the buffer tank roof. It also prevents the water level from getting too low. This leads to air in the heat supply spray tube and in the central heating network.

Two types

We make our expansion system in 2 types:

VERNIT, the expansion system regulates the pressure of the nitrogen blanket in the vertical heat storage tank.
HORNIT, the expansion system regulates the total system pressure in a horizontal heat storage tank. This is done directly or through an external expansion vessel.