Using steam to heat and agitate liquids inside tanks
Tank Heaters & Mixers
Tank heaters are relatively simple devices which can be used to heat and agitate fluids in tanks and vessels. As with our Pipeline Heaters steam is fully condensed in to the liquid being heated which allows the liquid to reach a tempetature within 5 degrees Celsius of the liquids saturation temperature, of course if required these unit can be also used to boil the liquid for sterilisation purposes etc. As these heaters have no moving parts to wear, the liquids passing through them can be clear or have suspended solids or can be viscous slurries. Our range of Tank Heaters & Mixers can be seen below:
Type 301 Quiet Heater
Quiet Heaters are designed to heat liquids in tanks by condensing steam into a liquid and causing circulation of the heated liquid within the tank. These heaters mix high velocity steam and atmospheric air with a liquid to reduce the noise and vibration characteristic of the injecting steam in to a cold liquid. Atmospheric air is entrained by the steam as it passes through an annular nozzle, this cushions the steam bubbles and prevents their sudden collapse as the steam is condensed. This helps to reduce the loud cracking noise usually accompanying this process to a low hum, in addition the air increases the agitation of the liquid.
Usually these heaters are placed near the tank bottom to obtain maximum circulation. Steam pressure must be high enough to overcome the static head of the liquid, yet not so great that live steam escapes from the surface of the liquid. The steam pressure can be set by a valve to provide the desired liquid temperature and the air line should be throttled if agitation is greater than required. While this type of heater will entrain atmospheric air, compressed air may be used if additional agitation is desired.
Typical materials of construction are stainless steel or bronze and unit sizes range from 0.5 Inch to 4 Inch, all units are equipped with screwed connections.
Type 314 Sparger Nozzle
Sparger nozzles are used in place of drilled holes in sparger pipes as these nozzles require fewer pipe openings and can improve circulation to provide more uniform heating. Type 314 Sparger Nozzles are designed to be submerged in the liquid to be heated and are usually installed in at the bottom of the vessel in a pattern designed to give good circulation and heat coverage.
Heaters of this type are recommended for use in cases where:
- It is desired to start heating from a shallow level
- Uniform agitation and heating is required over a large shallow tank area
- Steam pressures are relatively low
- Solids in the liquid might tend to clog the small passages in other types of heaters
Sparger Nozzles are operated by the flow of steam through the nozzle, the steam jet entrains the liquid through the suction opening which is immediately condensed and discharged through the diffuser at a high velocity. The agitating action of the sparger nozzle provides thorough mixing of steam and liquid in the diffuser which breaks up any steam bubbles to provide quieter operation. Agitation of tank liquid is also considerable, for example a 0.75 Inch Sparger Nozzle passes approximately 82Kg/Hr steam at 2.8 BarG, it will entrain a minimum of 6M3/Hr of liquid and raises the temperature by 8 Degrees Celsius in one passage through the nozzle.
Typical materials of construction are stainless steel and carbon steel, with unit sizes ranging from 3/8 Inch to 3 Inch for units with screwed or flanged connections, 4 Inch and 6 Inch units are fitted with flanged connections.
Type 315 Circulating Heaters
Type 315 Circulating Heaters are recommended for use where heating and a strong directional circulating action is required, this type of heater must also be totally submerged in the liquid it heats.
Typical applications for these heaters can be seen below:
- Heating and agitating solutions used in pickling tanks in steel plants and foundries
- Sterilising molasses in the fermentation tanks used in alcohol plants
- Dissolving chemical salts in the various liquids used in chemical plants
- Heating and agitating liquids where vigorous agitation is required
This heater is designed to provide vigorous circulation, agitation, and quick large capacity heating. The Circulating Heater is simple in construction and relatively easy to install however due to the jet discharging in a single direction there is a back thrust that is likely to cause vibration of the steam pipe unless the unit as securely anchored in some way. As per the Sparger Nozzle above, Circulating heaters are operated by the flow of steam through a nozzle, the steam jet then entrains liquid through the suction opening which is immediately condensed and discharged through the diffuser at a high velocity. The agitating action of the nozzle provides thorough mixing of the steam and liquid in the diffuser which breaks up any steam bubbles to provide quieter operation.
Typical materials of construction are stainless steel and carbon steel and unit sizes range from 0.5 Inch to 2 Inch, all units are equipped with either screwed or flanged connections.