Flowserve PVML API 610 OH5 Vertical In-Line Pump

Flowserve PVML API 610 OH5 vertical in-line diffuser pump

The Flowserve PVML is a vertical in-line pump built to ISO 13709/API 610 (OH5) and BS 4082R. The pump and motor shaft form a single unit with no coupling, so the pump is alignment-free and takes very little floor area compared with a similar OH2 pump. Flowserve describes it as a conventionally sealed, space-saving alternative to many overhung process pumps in upstream and downstream services. Seven Star LLC supplies the PVML in Oman and the GCC as an independent supplier in Muscat; the exact casing size and materials are fixed against your duty point.

Its other distinguishing feature is the milled, interchangeable diffuser channels, customised to each duty point. A total of 150 hydraulics can be achieved from the 13 casings in the family, and the performance can be re-tuned in the field by replacing impellers and diffusers without changing the casing.

PVML in the API 610 vertical in-line family

The brochure lists these options so the right category can be chosen for the motor and speed range. The PVML is the diffuser-style OH5 pump; its OH3 counterpart is the PVXM, which has its own bearing housing and is covered on another page of this site.

PVML technical specifications

How the PVML diffuser design works

A milled diffuser collects flow around the impeller through several channels, which Flowserve says gives low vibration at any flow, very low shaft deflection and virtually zero radial hydraulic thrust. The suction box has a unique design intended to give low NPSH requirements, and the sealed dry shaft design protects the carbon steel against corrosion. Cartridge seal mounting gives precise seal-face setting and quick replacement. Impellers are dynamically balanced and the impeller nut is positively locked and anti-rotation, with its threads kept out of the pumped fluid.

Where the PVML fits among Flowserve API pumps

The brochure names the PHL, HDX and PVXM among the complementary API designs. The PVML can replace an overhung OH2 pump where floor space is limited and a conventional seal is acceptable. Compared with the HPX or PHL horizontal designs it needs a lower foundation area and offers simple drop-in maintenance in tight, confined spaces.

For project engineers, the practical differences from a horizontal pump are footprint, alignment and seal access. There is no coupling to align and no baseplate beyond the motor support and drain pan, which cuts civil work and installation hours. Seal access is from above, and the cartridge seal slides out with the rotor, so seal changes do not need heavy handling equipment beyond a light hoist.

Selection and ordering checklist for the PVML

• Normal, minimum and maximum flow with differential head and specific gravity.
• Suction conditions and NPSH available.
• Liquid, temperature and solids content; diffuser tuning to the best efficiency point.
• Casing pressure and flange class (Class 300 standard).
• Seal arrangement, API 682 category and flush plan.
• Motor frame (IEC or NEMA P-base), power, speed and frequency.
• Material class and testing requirements.
• Space limits and the lifting height for pulling the rotor.

Installation, commissioning and maintenance

A vertical in-line pump is supported by its piping and a motor support head, so check pipe supports and nozzle loads. Because the motor shaft carries the impeller, motor bearing condition directly affects pump reliability and the motor must be specified for the pump thrust. The standard drain rim and drain-pan base options keep leaks off the floor. Maintenance is simplified by the cartridge seal and the removable assembly, which lifts out without disturbing the casing and piping. Keep a spare impeller, diffuser and seal on site for critical services.

Typical applications of the PVML in Oman and the GCC

The brochure lists petroleum refining, production and distribution on and offshore, petrochemical and heavy-duty chemical processing, gas industry services, water and general industry. In Oman and the GCC the PVML is relevant for offshore platforms and compact process modules where deck area is expensive, for refinery services such as reflux and product circulation, and for gas processing booster duties where low NPSH and fine control of minimum flow matter.

Information to send with your PVML RFQ

• Liquid, temperature, specific gravity and vapour pressure.
• Flow range, head and suction pressure or NPSH available.
• Flange class, materials and API 610 class.
• Seal plan and instrumentation.
• Motor details or the preferred motor supplier.
• Delivery site and inspection plan.

Documents and quotation

The Flowserve PVML brochure PS-10-28 is attached on this page. Send your duty data and we will confirm availability and lead time. Seven Star LLC is an independent supplier and does not claim any official status with the manufacturer.