Flanged air separator Termojet DN65 110°C/10bar

Flanged air separator Termojet DN65 — a steel vessel for removing air from heating and cooling systems in boiler rooms, heat substations and industrial circuits. The connection is flanged DN 65 (GOST 12820-80, PN16, flange outside diameter 180 mm), so the unit is built into steel pipework without adapters and is removed for service without cutting.

How the air separator works. Inside a body far wider than the pipe the flow velocity drops several times over. In this calm zone the water passes through a stainless steel spiral coalescing mesh: microbubbles that travel with the water in a pipe and never get the chance to rise catch on the coils, merge into larger bubbles and float up into the top chamber. From there the air leaves through the automatic air vent. The mesh also strips dissolved gas: water passing through it releases the excess into bubbles, and after a few circulation cycles the system becomes practically air-free.

Why it is needed. Air in a system means cold spots on radiators and underfloor loops, noise, cavitation and premature wear of pump bearings, plus oxygen corrosion of steel. Sludge means blocked boiler heat exchangers, seized valves, worn impellers and falling heat output. An air separator is installed once and then works on its own: air is vented automatically. The best result comes from a pair — an air separator on the flow right after the boiler, where the water is hottest and gives up gas most readily, and a dirt separator on the return ahead of the boiler and pumps that need protecting.

Advantages of the Termojet DN65 air separator:

• the spiral insert is stainless steel — it does not rust itself and never becomes a source of dirt, unlike inserts made of carbon steel;
• DN 65 flanges to GOST 12820-80 PN16 — a demountable joint, the unit comes off for inspection without welding;
• the body opens for cleaning the mesh — servicing without replacing the unit;
• a top chamber with an automatic air vent — air leaves the system with no operator involvement;
• minimal hydraulic resistance: the unit does not eat into the pump head;
• made by Termojet in Ukraine, manufacturer’s warranty.

Where it is used. Boiler rooms and heat substations of commercial and industrial buildings, boiler cascades, district heating systems, cooling circuits, heat pump installations. The flanged series starts at DN50 and covers up to DN100; for smaller circuits the catalogue offers threaded models — threaded DN50 air separator and combined DN50 air and dirt separator. Neighbouring sizes in the same series — DN50 and DN80. The full list is in the Termojet air and dirt separators section.

What it is installed with. In a boiler room the air separator pairs with the flanged dirt separator DN65 — together they remove both gas and sludge. If the scheme includes a hydraulic separator, part of this work is already done for you: the body of a Termojet low-loss header has a built-in air vent and sludge trap. Pump circuits downstream of the separators are easiest to assemble from ready-made Termojet pump groups. For heat pump installations see Termojet heat pumps.

Technical data: flanged DN 65 connection (GOST 12820-80, PN16, flange outside diameter 180 mm), branch bore 67.5 mm, nominal flow 19.3 m³/h at a velocity of 1.5 m/s, maximum working pressure 10 bar, maximum medium temperature 110 °C, medium — water or a glycol solution up to 50%, coalescing element — stainless steel spiral mesh, body — structural steel, dimensions 380×487×208 mm (W×H×D), mounted on a horizontal pipe with the body vertical, facing up.

Frequently asked questions

Why is an air separator better than an ordinary automatic air vent?
An automatic vent at the high point releases only the air that has already gathered into a bubble and reached that point. A separator deals with microbubbles and dissolved gas, which simply flow past an ordinary vent along with the water. That is why a system with pumped circulation needs both.

Where exactly should it be installed?
An air separator goes on the flow right after the boiler: that is where the water is hottest and releases dissolved gas most readily. The body is mounted vertically on a horizontal run of pipe, with free access to the air vent on top.

Can it be used on a system with glycol?
Yes. The unit is rated for water or a glycol solution up to 50% — that covers both heat pump circuits and cooling systems, where antifreeze is mandatory. Glycol is denser than water and gives up gas less readily, so a margin on flow is worth having: on a glycol circuit it is better not to run right at the nominal figure.

What flow can DN65 handle?
The nominal flow is 19.3 m³/h. This is not a strength limit but the flow at which the velocity in the branch stays at 1.5 m/s — the same figure European separator manufacturers take as nominal. Push more through and the flow shoots past the calm zone, letting some of the bubbles through; up to roughly 3 m/s is acceptable for short periods, at the cost of separation efficiency.