How does a high temperature pump work?
Most high-temperature process pumps adopt the centrifugal pump principle: the motor drives the impeller to rotate, and the liquid enters from the impeller inlet and obtains energy, and is discharged after collecting through the flow channel of the pump casing. Its main design differences from normal temperature pumps focus on thermal expansion control, seal temperature control and bearing protection.
For example, the pump casing and the rotor heat up at different speeds, and the internal gap may change; after the heat medium enters the sealing cavity, the temperature of the sealing surface may also be too high. Therefore, high-temperature pumps need to design support structures, operating clearances, seal chambers, and cooling or flushing systems based on working conditions. The specific configuration should be based on the medium and start and stop conditions.
What key parameters must be confirmed during model selection?
Media and temperature
First clarify the name and composition of the medium, and provide normal, minimum startup and maximum design temperatures. Also confirm the density, viscosity, vapor pressure, corrosiveness at operating temperature, and whether it contains particles, is prone to crystallization or solidification. Merely providing a "maximum temperature" is not enough to complete the selection: when starting from a cold state, the fluidity of some media may be very different from that during normal operation.
Flow, head and pressure
Provides normal, minimum and maximum flow, as well as system head corresponding to each working condition. The lift should take into account the equipment height difference, pipeline friction loss and the pressure required at the end; the design pressure needs to be checked against the highest possible pressure in the system. When selecting the model, the operating point, power and allowable operating range should be checked to avoid the pump being in a low flow state for a long time. Too small a flow rate may cause local heating of the liquid, affecting operational reliability.
Inlet conditions and NPSH
High-temperature liquids need to check the inlet pressure, liquid level, suction pipeline loss and medium vapor pressure. The available NPSH of the system should be calculated and compared with the NPSHr required by the selected pump to leave a margin suitable for actual working conditions. Only checking the outlet head and ignoring the inlet conditions can easily cause cavitation, noise or flow reduction.
How to determine the pump type, material and seal?
For hot oil and petrochemical process media, horizontal process pumps can be evaluated based on temperature, pressure, and device requirements; for media such as molten salt to be transported in storage tanks, it is necessary to focus on evaluating the liquid level, immersion depth, and vertical pump structure. Material selection must also check the corrosiveness of the medium, the strength at the design temperature, and the applicable conditions of seals and bearing components. The material cannot be determined based on the words "high temperature resistance" alone.
The sealing plan needs to confirm whether the medium may vaporize, coke or solidify in the sealing cavity, and then determine the single-end or double-end sealing, as well as auxiliary configurations such as cooling and flushing. For high-temperature hot water and hot hydrocarbon working conditions, a sealing cycle scheme with a cooler can be evaluated, but the specific scheme must still be determined according to the conditions of the seal chamber.
Key points in selection for different engineering applications
Petrochemical and thermal oil circulation: focus on checking the continuous operating temperature, pressure, seal chamber temperature and device requirements for pump structure.
High-temperature hot water transportation: focus on checking the inlet pressure, vaporization risk, and sealing cooling conditions.
Molten salt energy storage and circulation: In addition to flow rate and head, the medium composition, solidification risk, start-stop method, liquid level change and thermal expansion must also be checked. Thermal oil pumps and molten salt pumps should not be substituted for each other just because their design temperatures are close.
Buyer Frequently Asked Questions
The rated temperature meets the requirements, why is it still possible to choose the wrong one?
The rated temperature is only one of the boundary conditions. The corrosiveness of the medium, cold start, inlet cavitation conditions and seal chamber temperature may all determine whether the pump can operate stably.
What should be provided to the manufacturer before quoting?
It is recommended to provide the medium composition, temperature at each stage, flow range, system head, inlet and outlet pressure, liquid level or suction conditions, operating time, start and stop frequency, and available cooling or heating conditions on site. The more complete the information, the easier it is to accurately determine the pump type and sealing scheme.
How do Feiyue high-temperature pump products match needs?
Feiyue website lists products such as OH2 high-temperature oil pump, high-temperature hot water pump and high-temperature molten salt pump. The upper temperature limit indicated on its OH2 high-temperature oil pump page is 450°C; molten salt pumps have different structures and parameter ranges. When purchasing, the specific working conditions should be submitted to the manufacturer, requiring performance curves, material configurations, sealing and auxiliary system solutions, and then checking the applicable scope of the final model to avoid taking the upper limit parameters of the product series as the guaranteed value of any model.
