SubscribeInditherm plc has developed a number of innovative solutions for heating in the water utilities sector using its patented carbon based conductive polymer technology (CPT). Heating multiple chemical dosing lines in water and waste water treatment plants is one area where the technology has proved itself to be particularly cost-effective.
The Concept
Some chemicals start to crystallise at low temperatures and it is necessary to apply heat to keep them liquid. For example, 50% Caustic solution starts to thicken at around 16°C and starts crystallising at around 8°C. Traditionally, electrical trace heating has been used to keep chemicals liquid. The individual lines are then lagged to prevent heat loss.
There are several limitations to this solution:
- Each line needs to be individually traced and clad.
- Installation time is significant.
- Power consumption is high (typically 10-25 W/m/line).
- Voltage (110V or 230V) requires special safety considerations.
- It is not possible to examine or maintain the lines without removing the insulation.
- It is often necessary to put in underground channels to protect the lines.
- Different parts of the lines cannot easily be individually temperature controlled.
Laying the dosing lines inside Inditherm heated jackets solves these problems:
- Multiple lines can be laid inside a single jacket, saving space.
- Installation time is cut dramatically (typically by a factor of 3 or more), due to jackets being manufactured off site and holding multiple lines. This also reduces the health & safety exposure for contractors.
- Power consumption is reduced significantly, and depending upon the number of lines in each jacket and the average ambient temperature, can be reduced to between 24W/m/tray and 50W/m/tray. For example, the energy saving in a 100m dosing line run (with an average of 8 lines per tray) would be around 70,000kWh per year (worth approximately £2,500).
- Low voltage (24Vac) is very safe, particularly in wet environments.
- Jackets can be fitted into standard cable trays, which do not need to be laid below ground, again saving overall project time and cost.
- Each pad has an individual temperature control, so will switch on automatically when needed, even if other parts of the line are switched off because they are in a warmer area.
A typical arrangement is shown in Figure 1.
Figure 1 - Typical Inditherm Dosing Line Heated Jacket Arrangement
System Features
The Inditherm heated jacket system consists of the following:
- Base unit comprising Inditherm heated pad mounted on PU foam insulation and encased in heavy-duty, black PVC welded cover. Available in standard sizes that are suitable for most situations, installation can be completed very rapidly.
- Integral insulated hinged cover that folds over to enclose the dosing lines and is then fitted to the other side of the base unit with continuous Velcro strips.
- Heated pipe jackets that are wrapped around pipes where they are not supported in cable trays, e.g., draw chambers or change-of-direction chambers.
Typical Heated Jacket around Multiple Chemical Dosing Lines
- Electrical control panel, manufactured in accordance with the client’s standard specification. They are typically powered from the 415/230/110Vac mains input to a 24Vac output transformer housed in an IP55 rated enclosure with hinged doors and lockable handle assembly. The panels have power-on LED indication and mains isolator switches. All power outlets are protected by individual 16A DIN-rail mounted circuit breakers. Panel wiring is in accordance with BS6231. kWh meters can be fitted, as required. There are several sizes of panel, depending upon the length of the dosing line runs. One panel can power up to a maximum of 250m.
Typical Control Panel
- Cables and junction boxes that power the heated jackets. Junction boxes are mounted every 10 to 15m, depending upon the rating of the system.
- Covers to catchpots and points of application boxes. Inditherm supplies both standard sized or custom-made insulated and heated covers for catchpots and points of application boxes. These can be fitted quickly by the Inditherm installation team.
Catchpots Heated with Inditherm Jackets
Installation
Jacket heaters are laid in standard metal or plastic perforated cable trays, 200mm, 400mm or 500mm wide. They may also be laid into standard channels of the same widths, or wider.
Dosing lines are laid onto the based units and secured at intervals with ties, as necessary. The covers are then placed over them and secured with Velcro. The closed covers may be secured to the cable trays at intervals with straps or ties, as required.
Jacket heaters are made in standard lengths of 3m, 1m and 0.5m. These can be run around corners, both in the same plane or in other planes. 300mm long unheated fill-in sections are used to cover exposed spaces.
Heated jackets are wired together in parallel and terminated at intervals into junction boxes. Cables are laid and secured in the tray to the side of the heated jackets or can be laid within the jacket when installed in ducts.
Specification
- Operating Temperature: The system has two temperature options:
· Frost protection: Operating temperature 15°C in ambient down to -10°C.
· Heating: Operating temperature 40°C in ambient down to -10°C. - Cover material: High tenacity polyester with matt black plasticized PVC coating on both sides. Weight to BS3424/5A: 560g/m2 ± 25g/m2. RF welded to ensure completely waterproof. Cable entry though a waterproof grommet.
- Maintenance: The system has no moving parts, so maintenance is minimal. Users have the ability to examine dosing lines, simply by undoing the Velcro-secured cover.
- Cables: 2.5mm to 25mm PVC coated. Cables are sized to provide 16A with the minimal possible voltage drop.
For further information contact Bob Worton at +44 (0)1709 761000 or rworton@indithermplc.com