Flowserve Durco Mark 3 ISO Chemical Process Pump

Flowserve Durco Mark 3 ISO chemical process pump, decoded

The Flowserve Durco Mark 3 ISO is a metallic, mechanically sealed, back pull-out chemical process pump built to the ISO 2858 dimensional standard and the ISO 5199 design standard. It is a platform rather than a single model: one hydraulic and mechanical concept is offered with several casing options, four impeller styles and five frame or mounting configurations. Seven Star LLC supplies the Durco Mark 3 ISO range as an independent supplier in Muscat, serving plants in Oman and the GCC.

The name carries three pieces of information. Durco is the Flowserve chemical-pump brand, Mark 3 is the generation of the platform, and ISO tells you the casing, flange and baseplate dimensions follow the international standard rather than the ANSI one. That matters when a unit replaces an existing ISO pump, because nozzle positions and footprints can be kept.

Mark 3 ISO technical specifications

Ratings are the family maxima. Not every size, material and configuration reaches every limit at once, so the final selection must be confirmed against the pump curve and the pressure-temperature chart for the exact build.

How the Mark 3 ISO pump works

Liquid enters through the suction nozzle and is accelerated by the impeller. The reverse-vane semi-open impeller is the signature of the Mark 3 design: vanes on the back of the impeller push solids and fluid away from the seal area, which Flowserve presents as a way to keep efficiency without giving up reliability. The clearance between impeller and casing is set from outside with a micrometer-style adjustment, so wear can be taken up quickly without opening the pump.

The rotating assembly sits in a ductile-iron bearing housing with heavy-duty bearings and labyrinth seals. A back pull-out layout lets the whole rotating element be withdrawn while the casing stays piped, which shortens repair time on hazardous services.

Configurations of the Durco Mark 3 ISO family

The five casing options and four impeller options give a large combination space. A pump on an acid transfer duty will not look like one built for a fibrous slurry, even though both are called Mark 3 ISO.

Where the Mark 3 ISO fits in the plant

Typical roles are feed, transfer, circulation and loading of aggressive or toxic liquids where a sealed pump is acceptable. Flowserve lists chemicals and petrochemicals, oil and gas (upstream, midstream and downstream), power, water management, life sciences, mining, pulp and paper, and food and beverage as served industries. Sealless pumps of the Durco range are a separate product line and are not covered here.

The pump normally works with a single or dual mechanical seal and a seal support system chosen for the fluid. The SealSentry seal-chamber concept is listed by Flowserve as part of the platform to extend seal life. Related Flowserve seal and valve families are quoted separately when needed.

Selection and ordering checklist for Mark 3 ISO

• Fluid name, concentration, specific gravity, viscosity and solids content
• Rated and minimum flow, differential head, NPSH available
• Suction and discharge pressure, to confirm standard 16 bar or 25 bar casing
• Operating and maximum temperature, including cleaning or steam-out
• Casing and impeller materials based on corrosion and erosion
• Configuration: CK, N, H, P or R
• Seal arrangement, flush plan and any API-style support system
• Driver power, speed, frequency (50 Hz in Oman) and area classification such as ATEX zone

Installation, commissioning and maintenance of the Mark 3 ISO

Mount foot-mounted units on a rigid baseplate and align pump and driver with the coupling guard off. Check pipe strain before the final bolt-up: the multi-ribbed discharge flange is designed to tolerate pipe loads, but misalignment still shortens bearing and seal life. Prime the casing, vent the seal chamber and verify flush flow before the first start.

Routine work is bearing-oil checks, seal leakage observation, and resetting the impeller clearance from the external adjuster as the impeller wears. Flowserve publishes a maintenance checklist and maintenance-kit literature for the platform. Keep a spare rotating element, mechanical seal and bearing set for pumps on critical duties; the back pull-out layout makes element swaps quick.

Typical Mark 3 ISO applications in Oman and the GCC

In Oman and the wider Gulf, ISO chemical pumps appear in refineries and petrochemical complexes, fertiliser and chlor-alkali plants, desalination chemical dosing and cleaning skids, and industrial-zone process plants. Outdoor sites bring high ambient temperature, dust and humidity near the coast, so motor enclosure, paint system and bearing-housing protection should be specified with the climate in mind. Hot-service builds at the upper end of the temperature range need thermal-growth allowance in the piping design.

Information to send with an RFQ for Mark 3 ISO

• Duty point, fluid data and temperature range
• Preferred configuration code and nozzle sizes
• Required materials and seal arrangement
• Motor data and hazardous-area requirement
• Existing pump model if this is a replacement
• Quantity and delivery site

Documents and quotation

For the Durco Mark 3 ISO please send the application data above and we will confirm which Flowserve documents, such as the brochure, user instructions and maintenance checklist, can be provided.

Seven Star LLC is an independent supplier in Muscat and prepares quotations against the duty you supply. Send your request with the series name Mark 3 ISO and the configuration code.