The process
Mechanical vapour recompression raises the pressure of the vapour leaving an evaporator so it can heat the calandria, replacing live steam. The blower handles saturated, often corrosive vapour at a precise pressure ratio, in stainless steel, with a knock-out vessel ahead of it.
The gas at the fan
Saturated vapour, often with dissolved solids and a low pH. Wetted parts in stainless steel, a shaft seal rated for the vapour, drain points and a casing designed for condensate.
Selection for this duty
| Blade form | Backward curved, in stainless steel, at the tip speed the pressure ratio demands |
| Material of construction | Stainless steel on all wetted parts, grade to suit the gas analysis |
| Drive and bearings | Direct coupled or belt driven; belt drive where the duty point may need tuning at site |
| Also specified | Casing drain at the lowest point |
| Density at the fan | At about 90°C the gas density is close to 0.97 kg/m³, 81% of standard air. Pressure developed and power drawn fall in the same ratio, so the selection is made at this density and the motor is checked at cold start. |
Recompresses the vapour leaving an evaporator so it can be reused as the heating medium. Handles wet, often corrosive vapour, so wetted parts are in stainless steel. Client-stated blade types for the MVR Blower in general: Backward curved.
Industries
Other fans in mvr evaporators
MVR Blower in other processes
Services on this fan
Information needed to select or quote
- Duty point. Volume flow and static pressure at the fan inlet, with the gas density and temperature or the conditions to derive it.
- Operating conditions. Site altitude, normal operating temperature and continuous or intermittent duty.
- Gas stream. Dust loading and particle size, corrosive species, moisture, upset temperature and any tendency of the material to deposit on the impeller.
- Mechanical. Rotation viewed from the drive end, discharge orientation and motor power.