Jiangsu Haifa Machinery Manufacturing Co., Ltd.

When selecting and designing API610 chemical process pumps, the OH2 pump is a type I often prioritize. Especially in applications such as oil refining, petrochemicals, coal chemicals, fine chemicals,-temperature heat transfer oil, high-temperature acid liquids, hot water, demineralized water, hydrocarbons, aromatics, sulfuric acid, and nitric acid, customers typically focus not only on flow rate and head but also whether the pump can operate stably over the long term under high temperature, high pressure, flammable, explosive, and media conditions. Structurally, the API610 OH2 pump is a horizontal, single-stage, overhung, centerline-support chemical process pump. to conventional foot-mounted pumps, the OH2 pump offers a distinct advantage under high-temperature conditions: the direction of thermal expansion is more controllable when the pump casing heats up, resulting in relatively smaller changes in coupling alignment. During workshop assembly and field service, we have found that many high-temperature pump failures are not issues but rather stem from details like hot alignment, nozzle stress, mechanical seal cooling, and bearing temperature rise not being handled properly. The centerline support structure of the OH2 pump is specifically designed to serve these complex operating conditions.

In high-temperature media transport, the first challenge for the pump is thermal deformation. For instance, when the media temperature reaches °C, 300°C, or even higher, the pump casing,, shaft, impeller, and seal chamber all experience varying degrees of thermal expansion. If the structural rigidity is insufficient, it can easily lead to wear rings rubbing, shaft seal leakage, and increased bearing vibration. In our OH2 pump design, we focus on controlling the casing wall thickness, cover rigidity, shaft diameter safety factor, and hot-state clearances of the rotating components. For high-temperature media, it is not enough to only consider cold assembly dimensions; the actual state during hot operation must also be taken into account.

The second challenge is sealing. Under high-temperature and high-pressure conditions, mechanical seals simply be configured as for standard water pumps. We typically select API682 seal plans based on the media characteristics, such as Plan 11, Plan 21, Plan 23, Plan 32, Plan52, Plan 53A, and Plan 54 For media prone to vaporization, we focus on seal chamber pressure and cooling effectiveness; for high-temperature crystallizing media, we consider insulation, flushing, and anti-crystallization zones; for toxic, odorous, or flammable media, we generally recommend double mechanical seals with corresponding auxiliary seal systems. In my experience, the reliability of high-temperature pumps largely depends on whether the mechanical seal plan truly matches the on-site media.

The third challenge is material selection. High-temperature and high-pressure pumps are not simply about making the casing thicker. example, when handling high-temperature sulfuric acid, high-temperature nitric acid, chloride-containing media, molten salt, urea melt, or highly corrosive chemical liquids, material selection directly determines the pump's lifespan. Based on conditions such as temperature, concentration, chloride ion content, solid content, pH value, NPSHa, and operating cycle, we choose materials like WCB, ZG230-450, 304, 316L, 2205, 2507, 904L, Alloy 20, Hastelloy, and titanium. For critical components like the impeller, shaft sleeve, wear rings, and pump shaft, different configurations are made depending on erosion and corrosion conditions.

Jiangsu Haifa Machinery Manufacturing Co., Ltd. produces API610 chemical process covering structures such as OH1, OH, OH3, OH4, OH6, BB1, BB2, BB3, BB4, BB5, as well as VS1, VS4, VS5, and VS6. Taking our HES series chemical process pumps as an example, products are used in like petrochemicals, chemicals, salt chemicals, metallurgy, power generation, pharmaceuticals, environmental protection, and fine chemicals. Some product parameters cover flow rates from 2 to 2600 m³/h, heads up to 300 m, applicable temperatures from -80 to 450°C, and design pressures from 2.5 to 26 MPa. For-flow, high-head conditions, we also offer the API610-OH2-HES(X) low-flow chemical process pump, with a flow range of .8 to 12.5 m³/h, head of 12 to 125 m, applicable temperature from -80 to 450°C, and design pressure up to 2.5 MPa.

From a field application perspective, the OH2 pump is suitable for many high-temperature, high-pressure process points, such as hot oil circulation pumps in refining units, high-temperature solvent pumps in chemical plants, nitric acid unit transport pumps, sulfuric acid unit process pumps, heat transfer oil circulation pumps, high-temperature demineralized water transport pumps, urea unit media pumps, and alternatives for high-temperature magnetic drive pumps. When selecting a pump, customers are advised not to provide only the three parameters of "flow rate, head, and motor power." It is best to also include media name, density, viscosity, temperature, inlet pressure, outlet pressure, vapor pressure, NPSHa, corrosiveness, solid content, operating mode, and on-site installation conditions. The more complete the parameters, the more reliable the pump type, material, and seal plan we can provide.

When working on OH2 pumps, we pay special attention to details: first, the pump inlet flow path should minimize cavitation risk; second, the impeller hydraulic model should balance efficiency and stable operating range; third, the pump shaft rigidity must ensure rotor stability under high temperatures; fourth, the bearing housing must have adequate heat dissipation and lubrication conditions; fifth, loads must meet API610 requirements; sixth, the chamber structure should facilitate flushing, cooling, and venting; seventh, the baseplate rigidity and coupling alignment must ensure long-term on-site operation.

Many customers ask whether the OH2 pump be used for high-pressure conditions. In my understanding, the OH2 pump is suitable for medium-to-high temperature, medium-to-high pressure process conditions where a single-stage head can meet the requirements. If the head needs to be higher, or if the system pressure is very high and the continuous operation level is stringent, we would recommend customers consider BB2, BB4, BB5, or other between-bearing or multi-stage structures In other words, the OH2 is not the answer for all high-pressure conditions, but for many high-temperature chemical process points, it a balanced choice among structure, maintenance, cost, and stability.

As a manufacturer's technical staff, I prefer to view the OH2 pump as a "field-oriented product." It is not a simple standard component but requires detailed design based on the media operating habits of each unit. When conditions like high temperature, high pressure, corrosion, flammability, explosiveness, small amounts of solids, and easy crystallization are combined, pump reliability cannot be solved by a single material or structure alone. It must be ensured through hydraulic design, material selection, seal systems, cooling and flushing, manufacturing precision, and on-site installation working together.

Jiangsu Haifa Machinery Manufacturing Co., Ltd. has long focused on the design and manufacturing of API610 chemical process pumps, high-temperature and high-pressure pumps, corrosion-resistant pumps,-temperature molten salt pumps, high-temperature nitric acid pumps, high-temperature sulfuric acid pumps, petrochemical pumps, deep-sea chemical pumps, and high-temperature magnetic drive pumps. For complex conditions provided by customers, can perform pump selection, material recommendations, mechanical seal plan design, drawing confirmation, and non-standard customization based on on-site parameters. We hope that every OH2 pump not only meets the flow rate and head on the data sheet but also operates stably, reliably, and safely over long term in the customer's unit.