Edwards EXT250 Turbomolecular Pump Modules: B736-01-000 / 4022.436.8226 / TAB22Q-5/PURF3-R / 2L81-050097-52

Technical Dossier

Product Details And Specifications

Edwards EXT250 Series: Comprehensive Module Range and Technical Overview

The Edwards EXT250 turbomolecular pump is a high-vacuum pumping unit deployed across global heavy industry sectors including semiconductor fabrication, analytical instrumentation, nuclear research facilities, chemical processing plants, and oil refinery vacuum systems. With a pumping speed of approximately 230–250 L/s for nitrogen and an ultimate pressure below 1×10⁻⁸ mbar, the EXT250 occupies the mid-range segment of Edwards' turbomolecular product line. It is engineered for continuous-duty operation in both clean and moderately contaminated process environments. The EXT250 platform is compatible with Edwards' EXC series controllers and integrates with standard RS-232 and analog I/O interfaces for process automation. Its compact flange-mount design (ISO-K 100 inlet) makes it a standard replacement unit in legacy vacuum systems where footprint constraints are critical. Installed base spans facilities in Europe, North America, and Asia-Pacific, with documented deployments in mass spectrometry, electron microscopy, thin-film deposition, and particle accelerator beamline systems.

The Evolution of EXT250 Architecture

The EXT250 was introduced as part of Edwards' second-generation turbomolecular pump platform, succeeding the EXT70 and EXT150 series. Early production units (pre-2000) used ceramic ball bearings throughout the rotor assembly, requiring periodic lubrication maintenance intervals of 20,000–30,000 operating hours. Mid-generation revisions introduced hybrid ceramic/steel bearing configurations and improved rotor blade geometry, increasing pumping efficiency by approximately 12% while reducing acoustic noise output. Later variants incorporated active magnetic bearing (AMB) options for vibration-sensitive applications such as electron beam lithography and scanning transmission electron microscopy (STEM). The EXT250 controller interface evolved from proprietary analog signal protocols to RS-232 serial communication, and subsequently to RS-485 multi-drop configurations compatible with SCADA and DCS integration. Units manufactured after 2005 carry CE and RoHS compliance markings. The EXT250 series entered end-of-active-production status; Edwards' current equivalent platforms are the nEXT240 and nEXT300 series, which offer backward-compatible flange dimensions but require updated controller firmware. For facilities maintaining legacy EXT250 installations, long-term spare parts availability and refurbishment support remain the primary procurement strategy.

EXT250 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified components and assemblies within the Edwards EXT250 turbomolecular pump ecosystem. Each entry is classified by functional category.

Complete Pump Assemblies

B736-01-000: EXT250 complete turbomolecular pump unit, ISO-K 100 inlet flange, standard bearing configuration, 24 VDC supply.
B736-00-000: EXT250 base pump assembly without controller interface board, for OEM integration.
4022.436.8226: EXT250 pump assembly variant, European market part number cross-reference, equivalent to B736-01-000.
2L81-050097-52: EXT250 rotor/stator sub-assembly, factory-balanced, for pump rebuild and refurbishment programs.
TAB22Q-5/PURF3-R: EXT250 pump with integrated purge port and foreline adapter, configured for reactive gas service.

Rotor & Bearing Assemblies

B736-10-000: EXT250 rotor assembly, full replacement, dynamically balanced to ISO 1940 G1.0 grade.
B736-11-000: EXT250 hybrid ceramic bearing set, upper and lower, for mid-life refurbishment.
B736-12-000: EXT250 steel ball bearing set, legacy configuration, pre-2002 production units.
B736-13-000: EXT250 bearing retainer and preload spring kit, complete set.

Controller & Electronics Modules

EXC100E: Dedicated turbomolecular pump controller for EXT250, RS-232 interface, 100–240 VAC input, panel-mount format.
EXC120: Upgraded controller variant with RS-485 and analog 0–10 V speed setpoint input, compatible with EXT250.
EXC300: Multi-pump controller platform, supports up to 3× EXT250 units via serial daisy-chain, rack-mount format.
B736-20-000: EXT250 internal PCB controller board, embedded variant for OEM pump configurations.

Seals, Gaskets & Service Parts

B736-30-000: EXT250 O-ring and seal kit, Viton compound, full pump service set.
B736-31-000: EXT250 inlet screen and particle trap assembly, stainless steel, ISO-K 100.
B736-32-000: EXT250 foreline adapter, NW25 to ISO-K 100, for backing pump connection.
B736-33-000: EXT250 vent valve assembly, normally-closed, 24 VDC actuated, for controlled pump-down sequencing.

Sourcing Hard-to-Find & Obsolete EXT250 Parts

The EXT250 series has transitioned to end-of-active-manufacture status within Edwards' current product portfolio. OEM spare parts availability through authorized distribution channels is limited to existing warehouse stock. DriveKNMS maintains a dedicated inventory program for EXT250 components sourced through certified secondary market channels, including decommissioned equipment recovery, factory-refurbished exchange units, and cross-compatible new-old-stock (NOS) components. All sourced units are subject to incoming inspection against Edwards' published dimensional and performance specifications. For facilities operating EXT250 pumps within long-lifecycle systems — including nuclear instrumentation, synchrotron beamlines, and continuous-process chemical plants — DriveKNMS provides lifecycle extension support including rotor exchange programs, bearing replacement services, and controller board repair. Procurement inquiries for obsolete part numbers, including regional cross-references such as 4022.436.8226, are processed within one business day. Emergency same-day quotation is available for critical process downtime situations.

Quality Control for the EXT250 Range

Each EXT250 unit processed through DriveKNMS undergoes a structured inspection and functional verification protocol specific to turbomolecular pump architecture. Incoming units are visually inspected for rotor blade damage, bearing wear indicators, and housing integrity. Rotor assemblies are spin-tested on a dedicated balancing rig to verify residual imbalance within ISO 1940 G1.0 tolerance. Bearing sets are assessed for radial play and axial preload using calibrated gauge tooling. Controller boards are bench-tested for correct ramp-up sequencing, over-speed protection response, and serial communication protocol compliance. Pump bodies are leak-checked at the inlet flange and foreline port using a helium mass spectrometer leak detector to a sensitivity of 1×10⁻⁹ mbar·L/s. Units that complete full functional verification are issued a DriveKNMS inspection certificate documenting test parameters, measured values, and technician identification. Refurbished exchange units carry a 90-day operational warranty covering bearing and rotor assembly performance.