The document describes Brazed Plate Heat Exchangers (BPHEs) manufactured by Xylem, under the Bell & Gossett brand. These devices are designed to efficiently transfer heat between two fluids.
Function Description:
Brazed Plate Heat Exchangers are compact and highly efficient heat transfer devices. They consist of a series of thin, corrugated metal plates brazed together to form a strong, pressure-resistant unit. The corrugations on the plates create turbulent flow, which enhances heat transfer efficiency. The two fluids involved in the heat exchange process flow in alternate channels, separated by the plates, allowing heat to be transferred from the hotter fluid to the colder fluid without direct mixing. This design makes BPHEs suitable for a wide range of applications where efficient heat transfer in a compact footprint is required.
Important Technical Specifications:
The manual provides tables for mounting stud torque values and design pressure.
For 150 psig design pressure:
- Models 400, 405, 410, 411, 412:
- T (lbs): 280
- F (lbs): 130
- Mb (in-lbs): 27
- Mv (in-lbs): 300
- Model 200:
- T (lbs): 200
- F (lbs): 100
- Mb (in-lbs): 20
- Mv (in-lbs): 200
Mounting stud torque values:
- Stud size ¼”-20: Torque 8 in-lb, 24 ft-lb
- Stud size 3/8”-16: Torque 8 in-lb, 24 ft-lb
- Stud size ½”-13: Torque 8 in-lb, 30 ft-lb
The document also mentions that the brazed plate heat exchangers are designed to maintain a leak-tight condition under various operating pressures, temperatures, and flow conditions. The design allows for high pressure and temperature applications.
Usage Features:
- Installation:
- BPHEs should be mounted vertically with ports facing up or down.
- Connections should be made using appropriate fittings and piping, ensuring proper alignment to avoid stress on the exchanger.
- For single-phase fluids, the heat exchanger can be mounted in any orientation that is convenient and should be piped in a counter-current, parallel flow arrangement.
- For two-phase fluids, the heat exchanger should be mounted vertically and piped as shown in Figure 1 and Table 1.
- Air vent valves and temperature alarms should be installed to ensure proper operation and safety.
- Do not use pipe dope or thread sealants containing solvents that could damage the brazing material.
- For soldering type connections, use 45% silver solder or higher, with a 1000°F minimum recommended pre-heat.
- For MIG or TIG welding, avoid overheating.
- The brazed connections are designed for normal torque and force during installation.
- Ensure that all plugs and shipping covers are removed before installation.
- Verify that the heat exchanger is clean and free of debris before installation.
- Operation:
- Before start-up, ensure the entire system is clean to prevent fouling. Flushing the system with a 20-24 mesh strainer is recommended.
- Follow the specified start-up and shut-down procedures for the specific design limits shown on the product data sheet.
- Gradually fill and drain the heat exchanger to avoid thermal shock.
- Start-up procedures vary based on the type of fluid (liquid, gas, condensing gas, vaporizing gas) and temperature (hot, cold). Generally, it involves gradually introducing the cold fluid first, then the hot fluid, to prevent thermal shock.
- Shut-down procedures also vary, typically involving shutting down the hot fluid first, then the cold fluid, to prevent thermal shock.
- Always ensure the heat exchanger is completely drained when shutting down to eliminate possible freeze-up or corrosion issues.
Maintenance Features:
- Cleaning Procedures:
- Regular cleaning is crucial to maintain efficiency and prevent fouling.
- The frequency of cleaning depends on the application and fluid conditions.
- Cleaning methods include:
- Flushing: For light fouling, flush with water in the opposite direction of normal flow.
- Chemical Cleaning: For more stubborn deposits, use a cleaning solution compatible with the heat exchanger materials. Xylem recommends specific cleaning compounds.
- Mechanical Cleaning: Not explicitly detailed, but the warning about not exceeding design conditions of heat exchanger during maintenance suggests care.
- Inspection: Periodically inspect the heat exchanger for leaks, corrosion, and signs of fouling.
- Troubleshooting: The manual implies that Xylem provides support for troubleshooting and repairs.
- Warranty:
- Xylem products are high-quality and come with an expected reliable operation and long life.
- The warranty covers defects in design, materials, or workmanship.
- The warranty is limited to sales and service representatives within the Xylem network.
- The product must be used under the conditions described in the manual.
- Any unauthorized repair work voids the warranty.
- Xylem assumes no liability for bodily injury, material damages, or economic losses resulting from misuse or improper maintenance.
The manual emphasizes safety throughout, using WARNING, CAUTION, and NOTICE labels.
- WARNING: Indicates a hazardous situation that, if not avoided, will result in death or serious injury.
- CAUTION: Indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.
- NOTICE: Indicates a potential situation that, if not avoided, could result in undesirable conditions.
Key safety rules include:
- Always keep the work area clean.
- Be attentive to the risks presented by gas and vapors in the work area.
- Avoid all electrical dangers.
- Always keep in mind the risk of drowning, electrical accidents, and burn injuries.
- Use appropriate safety equipment, including hard hat, safety glasses/goggles, protective shoes, protective gloves, gas mask, hearing protection, first-aid kit, and safety devices.
- Read and understand the manual before installation, operation, or maintenance.
- The operator must be aware of safety precautions to prevent physical injury.
- Operating, installing, or maintaining the unit in any way that is not covered in this manual could cause death, serious personal injury, or damage to the equipment.
- Do not change the service application without the approval of an authorized Xylem representative.
- Many heat exchangers circulate fluids that are irritating or dangerous to humans. These fluids could cause problems if bolted or threaded joints are not maintained in a leak-tight condition.
- Even if fluids are not irritating or dangerous, a leak could cause a slippery situation on the floor below.
- Since one fluid in the heat exchanger is at a higher temperature, any leaks may cause burns.
- Brazed plate heat exchangers have exposed sharp metal surfaces. Protective gloves are recommended when handling.
- A heat exchanger is a pressure vessel designed for operation at certain specific limits of pressure and temperature. The cooling or process system, which includes the heat exchanger, must be safeguarded with safety valves and controls.
- Do not exceed design conditions of heat exchanger during maintenance.
The manual is an essential resource for anyone involved with the installation, operation, and maintenance of Xylem Brazed Plate Heat Exchangers, ensuring safe and efficient performance.
Need help?
General
To Next Page
