Pressurisation Stations sometimes known as Pressurised Pumping Stations or Fill & Spill units are mostly used on the larger systems that may also include District Chilled Water or Heating circuits. The operating range from “Cold to Hot” on these types of systems can be significantly smaller than with traditional pressurisation systems and Pressure Maintenance can often be within +/- .2 bar, which is particularly useful on systems where limiting the final maximum working pressure is important to protect older plant or retain the working pressure below a certain PN rating.
Only Expansion Vessels designed specifically for the Pressurisation Unit may be used with these systems. These Expansion Vessels are always operate at or around atmospheric pressure hence they can accommodate more thermal expansion than a “Pre-charged” Expansion vessel of the same size. Subsequently the foot print of these Expansion vessel/s are smaller providing valuable space saving in modern cramped plantrooms.
As with Traditional systems the Expansion vessel is responsible for accommodating thermal changes, however the pumps on this type of Pressurisation Unit are now also responsible for not only “topping up” the system, but also to return the expanded water from the Expansion vessel back into the system upon cooling.
Calculation, Sizing and commissioning of Pressure Maintaining Stations is a little more complex than with traditional Pressurisation units, so please view the products on our site but contact us to discuss any specified units or for advice on your design and build projects.