Flash Vessels | Gestra

GESTRA VD – Condensate Flash Vessels

GESTRA VD flash vessels are utilized in steam networks where hot condensate, boiler blowdown, or hot water is depressurized to produce flash steam. The vessel separates low-pressure steam from liquid condensate, directing steam to a low-pressure network or deaerator, while returning condensate to the feed system.

Operating Principle

In the VD series, condensate entry is tangential. The flow rotates within the vessel, functioning as a cyclonic separator. Flash steam is collected at the top, while condensate is directed to a float steam trap. This arrangement reduces droplet presence in steam and limits wire drawing phenomena at the inlet.

VD Technical Specifications

• Vessel volumes: 50, 100, 400, 850, and 1400 L.
• Design pressures available: 0.5 / 1.0 / 2.5 / 8 / 10 / 12 bar.
• Typical VD series flow rate: approximately 1.2 to 40 t/h, depending on operating data.
• Materials: S235JRG2 or P265GH, with stainless steel construction option.
• Connections: flanges, condensate inlet, flash steam outlet, condensate outlet, safety, drainage, pressure gauge, and level indicator.

Versions and Equipment

The VD can be delivered as a simple vessel or a complete skid with safety valve, pressure gauge, visual level indicator, UNA steam trap, isolation valves, bypass, and base. For sizes 850–1400 L, two steam traps are arranged in parallel. A compact version VD 45h/VD 45v is available for horizontal or vertical piping.

Selection Criteria

Required: condensate flow, pressure before depressurization, desired flash steam pressure, backpressure at condensate outlet, temperature, and media quality. For proper operation of the compact version: pHP > pLP > pSD. In stainless steel construction, chlorides in condensate must not exceed 50 mg/L.

FAQ

Where is it applied?
In continuous boiler blowdowns, process condensate returns, and low-pressure steam recovery.

Is a safety valve required?
Yes, the vessel must be protected against overpressure according to design pressure and installation operating data.