HWL/HGL ParallelConstant Power Electric Trace HeatingAvailable in two types: reinforced and standard. The reinforced version features an additional protective sheath over the standard type's electric heating tape.Electric Heating TapeThere are three-core electric heat tracing cables, two-core electric heat tracing cables, and the two-core cables are further divided into 380V and 220V versions. The power range is 10W to 60W per meter. The HWL/HGL parallel constant power electric heat tracing cable specifications are the same as the standard RDP type, and are superior to the general RDP type. The HGL constant power parameters are the same as the standard RGP type, and are also superior to the general RGP type.
Product Structure
The resistance wire is connected in parallel, and it heats the pipe by relying on the wire's heat generation during operation.
Woven layer options: "Alloy wire" and "Tinned copper wire"; materials vary, so do the prices.
Product Applications
The HWL/HGL parallel constant power electric tracing heater is mainly used for the heating, frost prevention, or maintenance of process temperatures in pipeline systems, storage tanks, valves, and pump bodies in the oil, chemical, power, and metallurgy industries. It is suitable for long-distance, large-diameter pipelines for tracing and insulation. It can be used in both ordinary and explosion-proof areas of Class I and II, Zone 2.
Working Principle
Two parallel degree nickel-copper braided wires are encapsulated in a fluorine-insulating layer, serving as the power bus, and nickel-chromium alloy heating wires are wrapped around the outer insulation layer at fixed intervals, with each wire being welded at these intervals to form a continuous parallel resistance. Once the copper power bus is energized, the individual parallel resistances heat up, creating a continuous heating traceable heat tape that can be cut to any length.
The power bus consists of two or three parallel insulated copper conductors, wrapped with heating wires on the surface of the main insulation layer. These heating wires are connected to the bus at regular intervals (i.e., the length of the heating section), forming a continuous parallel resistance. Once the bus is powered, the individual parallel resistances heat up, thereby creating a continuous heating strip. It can be cut to any length during use, but overlapping is not permitted. It is used in conjunction with a temperature control device. As shown in the diagram, the parameters of the constant power electric heating tape mainly consist of the bus, insulation layer, inner sheath, heating core, outer sheath, shielding layer, and reinforcing layer, etc.
Product Features
No starting current, constant power;
2. Long length usage, one-way length up to 300 meters, bidirectional up to 600 meters.
3. No degradation; lifespan is approximately 3 years longer under the same conditions.
4. In terms of medium to long pipelines and large tanks, due to the longer length of this electric trace heating, there are fewer circuits, resulting in a lower overall cost.
5. This electric heat trace must be used in conjunction with a thermostat or other temperature control device.
6. The electric heating tape must not be crossed or overlapped during installation, and knotting is strictly prohibited to prevent the resistance wires from getting tangled together.
7. This electric heating tape has a minimum recommended installation length, typically not less than 3 meters.
8. Do not mix with steam heating.
High temperature resistance, capable of withstanding up to 255 degrees Celsius.
Installation Instructions
Design Drawing
A complete set of design drawings should be available prior to construction, including the following information:
Line Number, power supply points are indicated by squares.
Electrical trace length required per meter of pipeline length (unit: meters) is the winding factor.
Heating system accessories and material list.
Design considerations include parameters and specifications of the insulation material used.
(Part Two) Pre-construction Preparation
(P) Pipeline and Tank System
The pipeline and tank system, along with the equipment, have been fully installed.
The rust and corrosion preventive coating has dried completely.
The pipeline and tank system construction specifications are consistent with those shown in the design drawings.
Remove all burrs and sharp edges.
(B) Electric Heat Trace and Accessories
Is the surface of the electric tracing tape damaged or broken?
The electrical heating tape has good insulation properties (insulation resistance ≥ 100MΩ when tested with a 1000VDC megger).
The electric tracing heating and all accessories are of the same model and design specifications.
(3) Specific Construction Methods
Single-strand electric heat tracing installation method
Secure the electric heat trace tape to the pipeline using pressure-sensitive tape at intervals of approximately every 50 cm.
When laying flat, attach the electric heat tracing as close as possible to the lower 45-degree side of the pipe.
预留 100cm long electric heat tracing at the power supply points and end points of the line.
Wiring according to the designed twist factor (for integer coefficients, lay flat to minimize connection points).
All heat sinks (such as brackets, valves, flanges, etc.) should be pre-drilled to the required length of electric tracing as per design specifications, wrapped around the heat sink body, and secured. The following points should be noted:
The heat sink should have the required length of electric tracing for the design.
Heating cables with constant power must not be overlapped or crossed.
The wrapping method should be designed to allow the heat sink to be easily removed for maintenance or replacement without damaging the electric tracing or affecting other circuits.
At the locations where two-way or three-way fittings are used, each end of the electric heating tape should have a reserved length of 100 cm.
Helically Wound Wire
If the wrapping coefficient is 1.5, a 4m pipe requires 6m of electric tracing. During installation, first secure the ends of the 6m electric tracing to a 4m section of the pipe. Then, wrap the loose electric tracing around the pipe and secure it in place.
Multiple electric tracing installation method
Design drawings specify a winding factor of (n=1, 2…), commonly used on large-diameter pipelines, with the following method:
The electric tracing heating is routed from one end of the pipeline to the end and then back to the starting point, with the number of turns equal to the coefficient. (But note the maximum length used.)
The electric tracing heating is installed by sequentially wiring from one end of the pipeline to the end, with the number of wiring cycles equal to the coefficient or by using a winding installation method.
Parts Installation
* The sealing rings used must be compatible with the electric tracing heater and combined with waterproof sealant.
Power junction boxes should be as close as possible to the power supply end of the pipeline circuit.
Prepare wire ends according to the accessory installation instructions.
Each line should have a small segment of electric heating tape reserved for future maintenance purposes.
Inspection and testing of thermal insulation materials prior to installation:
Inspect the surface of the electric tracing heater for any damage.
Inspect all accessories for complete installation.
Test each individual circuit end with a megger to ensure good insulation performance.
Record the shake test results on the installation record sheet.
Insulation layer installation
Immediately install the insulation layer after the electric tracing heating system is tested, and pay attention to the following points:
The insulation material, thickness, and specifications used comply with the design drawings.
Insulation materials must be dry during construction.
The thermal insulation should be covered with a waterproof outer shell.
Avoid damaging the electric tracing heating during the installation of the insulation layer.
After the insulation layer is installed, an immediate insulation test should be conducted on the electric heat tracing system.
Additional warning labels indicating "Contains Electric Heat Trace" should be applied to the insulation layer, and the locations of all accessories must be clearly marked.
Design Description
I. Design Parameters to Be Determined
1) Maintain temperature requirement for pipeline, T_v (°C), take 10°C.
2) The extreme low temperature for many years is -25℃.
3) Outer Diameter of Pipe (mm)
4) Type and thickness (mm) of insulation material for pipelines; Rock wool δ=50mm
5) The pipeline is located outdoors (or indoors)
6) Is the environment explosion-proof: Non-explosion-proof
7) Does it have steam cleaning or heating (or high operating temperature of the medium)?
II. System Heat Dissipation Calculation:
For example, with the DN108 pipeline.
Step 1: Calculate the actual heat dissipation of the pipeline, QT.
QT=1.3×2π×（Tv-Td）/[1/λ•Ln（Do/Di）+2/(Do×α)]
QT - Heat loss per unit length of pipeline, W/m
Tv—Pipe maintenance temperature in °C
Td - Low environmental temperature in °C
λ - Thermal conductivity coefficient of insulation material, W/(m•℃)
Do — Outer Diameter of Insulation (Do = Di + 2δ) mm
Di - Insulation inner diameter mm
δ - Insulation thickness mm
α – Heat transfer coefficient (W/㎡℃) from the outer surface of the insulation to the atmosphere is related to wind speed ω (m/s)
α=1.163(6+3ω1/2) W/( ㎡℃ )
The calculated actual heat dissipation of the DN108 pipe is QT = 50.5 W/m.
Step 2: Electric Trace Heating Wrapping Factor
Select HBL3-J3-30 electric heat tracing. At 10°C, the pipe dissipates 50.5W/m of heat. Since the electric heat tracing is applied to the exterior of the pipe, the heat transfer efficiency is lower, around 70~85%. Considering a safety margin of 20~40% on the calculated heat loss for maintaining temperature, a constant power electric heat tracing with a rating of 30W/m is chosen. Therefore, for every meter of DN108 pipe, 2 meters of HBL3-J3-30 type electric heat tracing are required.
Step 3: Electric Trace Heating Installation Coefficient
1) The required hot line length for the valve equals the valve coefficient multiplied by the hot line length required per meter of pipe
2) The required热线 length for each flange is twice the diameter of the flange multiplied by the number of electrical heating tapes needed per meter of pipeline.
3) At other large pipe fittings with significant quantities of pipe, additional electric tracing should be installed to ensure freezing is prevented at these locations.
Each electric heat tracing accessory requires a reserve of at least 1 meter for wiring and future maintenance.
During installation, varying tension of the electric tracing heating tape can cause a certain degree of error in the actual installed quantity.
In summary of the above five points: The installed quantity of electric tracing heating tape is the design quantity multiplied by the installation coefficient of 1.20 to 1.50.
Step 4: Electric Trace Heating Cable Quantity Count
Based on the pipe count, determine the total quantity of electric heat tracing required, and compile the total count of electric heat tracing for all pipes.
Step 5: Determine the number of power distribution circuits and accessories
Based on the drawings, determine the quantity of circuit breakers and accessories, and ascertain the location of the distribution box according to the pipeline layout on-site. The selection of the distribution box must fully consider the on-site power capacity and the number of electric tracing heaters, as well as the maximum usage length of the electric tracing heaters. When determining the circuit, it is not only necessary to consider the on-site layout but also the maximum usage length of the electric tracing heaters, as well as the rated current of the power connection box and the thermostat.
Determine the quantity of power junction boxes
The number of power junction boxes is determined by the number of circuits. Generally, the number of power junction boxes (ZDJH) required should match the number of circuits needed for electric tracing design. For instance, if an electric tracing project is designed with 40 circuits, then 40 power junction boxes are needed. Considering spares, an additional 10% should be added, which means a total of 45 power junction boxes are designed.
Determine the quantity of intermediate junction boxes
The determination of the intermediate junction box quantity typically depends on site-specific conditions. For instance, the number of pipe tees determines the quantity of T-type junction boxes (ZJH-3). As for straight-type junction boxes (ZJH-2), it is generally taken as 20% of the power junction box quantity, with the actual site usage being the final criterion.
On-site Temperature Controller Selection
Field temperature controllers are determined based on the number of loops. Generally, the number of field temperature controllers (BJW51) required for electric heating design should match the number of loops. This also depends on engineering design requirements; some projects require the addition of field temperature controllers, while others may necessitate digital temperature controllers. Therefore, different design schemes should be adopted according to the client's specific requirements. For instance, a certain electric heating project was designed with 40 loops and required the addition of field temperature controllers, hence 40 field temperature controllers (BJW51 model) were needed. Considering spares, an additional 10% should be included, meaning a total of 45 field temperature controllers (BJW51 model) were designed.
Fixed Pressure Sensitive Tape
The determination of the fixed pressure-sensitive tape (20mm x 20m) typically hinges on the diameter and quantity of engineering pipelines or tanks. For instance, if there are DN100 pipelines totaling 100 meters, approximately 198 meters of pressure-sensitive tape would be required: L = d * 3.14 * K1 * K2 * K3 * L1 = 0.1 * 3.14 * 1.5 * 1.4 * 3 * 100 = 198 meters.
diameter (d), K1 safety allowance is 1.5, K2 engineering allowance is 1.2~1.5, K3 approximately three wraps of pressure-sensitive tape around a one-meter pipe (i.e., secure every 30~50cm), generally take 3 or 4, L1 is the actual length (height) of the pipe or tank body
Aluminum Foil Tape Selection
Aluminum foil tape (50mm x 20m) quantity determination: The quantity of aluminum foil tape is determined based on the length of the electric heating tape. For instance, if a project specifies 1000 meters of electric heating tape, the aluminum foil tape quantity would be L = L1 * K1 = 1000 * 1.3 = 1300 meters. L1 is the length of the electric heating tape, and K1 is the project coefficient (usually taken as 1.2 to 1.5).
Determination of the quantity of end junction boxes
The quantity of terminal junction boxes (ZJH) is generally determined based on the number of power junction boxes and tee junction boxes, usually calculated as N = n1 + n2, where n1 is the number of power junction boxes and n2 is the number of tee junction boxes.
Stainless steel tape and bolted couplings
The determination of the stainless steel band quantity is primarily based on the number of power junction boxes and temperature controllers. Each power junction box and temperature controller requires two sets of stainless steel bands and bolt caps. The length of each set of stainless steel bands depends on the pipe diameter, for instance, if a power junction box is mounted on a DN100 pipe, the required quantity of stainless steel bands for that junction box would be:
L=d*3.14*k1*2=0.1*3.14*1.5*2=0.942m,
d is the diameter of the pipe, k1 is the safety factor, set at 1.5, and 2 refers to two sets per power junction box.
Warning Labels and Silicone (or Explosion-Proof Putty)
Warning Labels (110*180) - one per 30 meters of electric heating tape, one at each end and power junction box. Silicone (TM441) quantity - one-third of the power junction box at the end. Explosive-proof mortar (1kg/bag) - one kilogram used for every 5 power junction boxes or explosion-proof thermostats.
