The [Screw-Locking" tangless insert provides self-locking torque on the male member by a series of [chords" on one or more of the insert coils. With tangless inserts, no loose tangs are left behind, and they are the solution when foreign object debris (FOD) cannot be present in critical applications. Screw Locking Tangless Insert,Tangless Screw-Locking Inserts,Key-Locking Screw Thread Inserts,Tangless Screw Locking Coil Threaded Insert Shenyang Helisert Technology Co., Ltd , https://www.helisert.com
In the ethylene plant, multistage pumps of the BB5 and BB4 series are selected for the ultra-high pressure boiler feed water pump, magnetic pump, and high-pressure boiler feed water pump. Their working principle and structure are similar to conventional multistage pumps, but their design is primarily determined by the specific operating conditions. The double-shell multistage pump structure is illustrated in Figure 3-11. Don't miss out on the latest order updates—free information available now! Get the most recent buyer details instantly! Grab your chance here!
①Shell Structure: Both single-shell and double-shell pumps can operate under high pressure, but they differ in terms of thermal and thermal shock resistance. A standard single-shell pump typically operates within a temperature range of 180–320°C, while some specially designed high-temperature magnetic pumps can handle up to around 400°C. Double-shell pumps, on the other hand, can operate at temperatures between 400–450°C and offer better resistance to thermal shock. However, double-shell pumps are heavier, take up more space, are more complex to manufacture, and come with a higher cost. They are generally used in large-scale, high-pressure, and thermally demanding applications.
The ultra-high pressure boiler feed water pump in the ethylene plant experiences certain levels of thermal shock and operates at very high discharge pressures, making the double-shell pump an appropriate choice.
â‘¡ Axially Split vs. Radial Split Pumps: In the petrochemical industry, many single-shell, high-lift, low-flow multistage pumps that meet temperature and pressure requirements are designed with an axial split structure. This allows for easier assembly and disassembly during maintenance. Pump models such as Y, YD, and MC, however, use a radial split structure. Although these pumps can meet other technical specifications, their flow rate may be too high, so they are often modified for smaller flow applications. Radial split pumps are more suitable for high-pressure and harsh operating environments.
â‘¢ Shaft Seal: Although the requirements for shaft seals are high, a single mechanical seal is usually sufficient. However, due to the high pressure and low viscosity of the medium, it is generally recommended to use an internally balanced mechanical seal. For hydrocarbon media, which can be flammable and explosive, a dual mechanical seal system is typically employed to enhance safety and reliability.
④ Centerline Support with Horizontal Key Positioning: When the temperature of a horizontal pump exceeds 150°C, it is common to use centerline support to prevent one-sided expansion after heating, which could affect normal operation. Additionally, the support surface should include a horizontal key to fix the pump's axial position.
⑤ Bearing Cooling: Effective bearing cooling is essential to ensure the long-term performance and reliability of the pump. Depending on the application, various cooling methods such as external cooling jackets or internal lubrication systems may be used to maintain optimal bearing temperatures and prevent overheating.