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 Technical Notes

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.