As one of the most favored pump types in the API 610 standard "Centrifugal Pumps for Petroleum, Heavy Chemical, and Gas Industry Services", the OH4 centrifugal pump, with its unique vertical inline structure, outstanding reliability, and convenient installation and maintenance features, has become an ideal choice for fluid transfer in numerous fields such as chemical engineering, power generation, pharmaceuticals, and water treatment — many engineering friends around me have reported that this pump is "easy to use and space-saving", and it’s truly a good choice.
OH4 is a standardized designation for vertical inline centrifugal pumps in the API 610 standard. Among them, "OH" stands for "Overhung Impeller" — simply put, the impeller is mounted at the end of the shaft, with the bearing behind the impeller; the number "4" specifically refers to its vertical installation structure where the inlet and outlet flanges are aligned on the same axis. This design is really ingenious.
Unlike common horizontal pumps, the OH4 pump is vertically oriented, with the motor mounted above the pump body and the pump shaft installed vertically. The inlet and outlet flanges are exactly on a central line, allowing it to be directly connected in series to the process pipeline without the need for additional elbows or support bases. It’s a proper "plug-and-play" solution, saving a lot of trouble.
The most surprising feature of the OH4 pump is its compact design! Since the inlet and outlet are on a straight line, the entire unit is highly integrated, occupying much less space than horizontal pumps — it’s perfect for places with limited space such as high-rise pump rooms and offshore platforms, or where the pipeline layout is complex. I’ve seen many modular skid-mounted equipment prioritize its use.
Moreover, it usually doesn’t require a separate concrete foundation; it either uses a shared base or is directly supported by the pipeline, eliminating the complex alignment process required for traditional pump sets. I remember a project with a tight schedule — using the OH4 pump directly cut the installation time by half and saved a lot of civil engineering costs.
Maintenance is an even bigger plus. Many OH4 pumps support a top pull-out structure — there’s no need to disassemble the pipeline or remove the motor; the rotor assembly can be pulled out from above, and replacing mechanical seals or bearings can be done in minutes. Maintenance technicians all praise it as "easy and efficient".
Despite its compact size, the OH4 pump’s performance is not compromised at all. Its hydraulic model is optimized through CFD, featuring high efficiency and low net positive suction head required (NPSHr), making it calm in handling different operating conditions. Depend
ing on the fluid being transferred, materials such as 304/316 stainless steel, duplex steel, or even Hastelloy can be selected, combined with appropriate sealing solutions. Whether it’s clean water, hot water, organic solvents, or high-temperature, high-pressure corrosive fluids, it can all be safely transferred.
More importantly, it strictly complies with the API 610 standard, meeting international industrial-grade standards in terms of vibration control, bearing life, and temperature rise limits. In industries such as petrochemicals and power generation that require continuous and stable operation of equipment, it’s extremely reliable with few failures.
The OH4 centrifugal pump has an extremely wide range of applications and can be seen in various industries:
In particular, the "pipeline-as-pump-base" design is simply a "timely rain" for projects that require rapid deployment or renovation and upgrading. Now, many modular factories and skid-mounted equipment use it as a standard configuration.
As a reliable core in fluid transfer systems, the OH4 vertical inline centrifugal pump is not only a guarantee for the stable operation of process flows but also an important cornerstone for modern factories to move towards intensification, efficiency, and intelligence.
In this field, Teffiko has always adhered to the rigorous API 610 standard, crafting each OH4 pump with ingenuity — from hydraulic optimization to intelligent integration, from material selection to full-life-cycle services, committed to providing quieter, more energy-efficient, and more durable fluid solutions.
Choosing the Teffiko OH4 vertical inline centrifugal pump means choosing a simpler, more efficient, and more sustainable industrial future. Enterprises that have used it have basically become repeat customers, and its reputation is truly excellent.
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