VAT Throttle Valves: 20446-UE24-ACQ1 VMUS-2 3870-04172 99F0065

Technical Dossier

Product Details And Specifications

VAT Series 20446 Throttle Valve: Comprehensive Module Range and Technical Overview

The VAT Series 20446 pendulum-type throttle valve is a precision pressure and flow control component deployed across the most demanding high-vacuum process environments globally — including semiconductor wafer fabrication (CVD, PVD, etch chambers), flat panel display manufacturing, solar cell deposition systems, and industrial coating lines. VAT Group AG, headquartered in Haag, Switzerland, holds a dominant position in the global vacuum valve market, with Series 20446 representing one of its most widely installed throttle valve platforms in 200mm and 300mm process tool architectures.

The specific configuration 20446-UE24-ACQ1 / VMUS-2 / 3870-04172 / 99F0065 identifies a fully actuated pendulum throttle valve with integrated position controller, designed for closed-loop pressure regulation in load-lock and process chamber applications. This part number encodes the valve body size, actuator type, controller variant, and seal material — all critical parameters for cross-referencing and replacement sourcing.

The Evolution of VAT Series 20446 Architecture

VAT's pendulum throttle valve architecture has evolved through several distinct generations since its commercial introduction in the 1990s. Early Series 20446 units used analog position feedback with discrete PID controllers and required external pressure transducer integration. Mid-generation variants introduced the VMUS (Valve Management Unit Series) integrated controller platform, consolidating pressure setpoint management, valve position feedback, and diagnostic I/O into a single compact unit mounted directly on the valve actuator.

The VMUS-2 controller generation — as present in this SKU — introduced RS-232/RS-485 serial communication, improved position resolution to sub-0.1° accuracy, and added configurable pressure control modes (pressure mode, position mode, and learn mode). Later VMUS-3 and VMUS-4 variants added DeviceNet and EtherCAT fieldbus compatibility, reflecting the industry shift toward digital process tool integration.

Compatibility considerations are significant: VMUS-2 controllers are not pin-compatible with VMUS-3/4 without wiring harness adaptation. Seal material codes (99F0065 = Viton/FKM O-ring set) must be matched to process chemistry — fluorine-based processes require FFKM (Kalrez/Perlast) alternatives. Valve body size (20446 = DN40 nominal bore) must match the conflat or ISO-K flange specification of the mating chamber port.

VAT Series 20446 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified configurations within the VAT Series 20446 pendulum throttle valve platform. Each entry reflects a distinct combination of actuator, controller, seal, and communication variant:

20446-UE24-ACQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-2 controller, Viton seals
20446-UE24-AHQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-2 controller, FFKM seals
20446-UE24-AAQ1: DN40 pendulum throttle valve, 24VDC actuator, analog position output only, no integrated controller
20446-KE24-ACQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-2, Viton, ISO-K flange variant
20446-UE24-ADQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-3 controller, DeviceNet interface
20446-UE24-AEQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-3 controller, RS-485 interface
20446-UF24-ACQ1: DN40 pendulum throttle valve, 24VDC actuator, VMUS-2, extended temperature range
20446-UE24-ACQ2: DN40 pendulum throttle valve, 24VDC actuator, VMUS-2, Viton, metric connector variant
20446-UE24-ACQ1-0001: DN40 pendulum throttle valve, VMUS-2, factory-configured for APC (Adaptive Pressure Control) mode
20446-UE48-ACQ1: DN40 pendulum throttle valve, 48VDC actuator variant, VMUS-2 controller
20446-UE24-ACQ1-0002: DN40 pendulum throttle valve, VMUS-2, configured for downstream pressure control
20446-QE24-ACQ1: DN63 bore pendulum throttle valve, 24VDC actuator, VMUS-2 controller
20446-QE24-AHQ1: DN63 bore pendulum throttle valve, 24VDC actuator, VMUS-2, FFKM seals
20446-RE24-ACQ1: DN100 bore pendulum throttle valve, 24VDC actuator, VMUS-2 controller
20446-RE24-AHQ1: DN100 bore pendulum throttle valve, 24VDC actuator, VMUS-2, FFKM seals
20446-SE24-ACQ1: DN160 bore pendulum throttle valve, 24VDC actuator, VMUS-2 controller
20446-UE24-ACQ1 VMUS-2 3870-04172 99F0065: Full assembly — DN40 valve body + VMUS-2 controller unit + seal kit 3870-04172 + O-ring set 99F0065

Sourcing Hard-to-Find & Obsolete VAT Series 20446 Parts

The VMUS-2 controller platform has been superseded by VMUS-3 and VMUS-4 in current VAT production. As a result, complete assemblies carrying the VMUS-2 designation — including 20446-UE24-ACQ1 VMUS-2 3870-04172 99F0065 — are no longer available through standard OEM distribution channels and must be sourced from specialist industrial spare parts suppliers.

DriveKNMS maintains a dedicated inventory program for end-of-life VAT throttle valve assemblies and sub-components, including: complete valve assemblies (tested), VMUS-2 controller boards (repaired and tested), actuator motor assemblies, seal kits (3870-04172 and equivalent), and position sensor modules. Our sourcing network covers decommissioned semiconductor fab equipment globally, enabling us to fulfill single-unit and bulk requirements for facilities operating legacy process tools where platform migration is not economically viable.

Quality Control for the VAT Series 20446 Range

VAT Series 20446 throttle valves present specific test challenges due to the integration of mechanical, pneumatic/electromechanical, and electronic subsystems within a single assembly. DriveKNMS applies the following verification protocol to all Series 20446 units prior to shipment:

Leak integrity test: Helium mass spectrometer leak test at <1×10⁻⁹ mbar·l/s across valve seat and body seals. Position controller calibration: VMUS-2 units are connected to a reference pressure transducer and cycled through full open/close range; position linearity and repeatability verified to ±0.2° across 0–90° travel. Actuator torque verification: Motor drive current and torque output measured at 0°, 45°, and 90° positions against VAT factory specification. Communication interface test: RS-232/RS-485 command/response protocol verified using VAT VMUS terminal software; all diagnostic registers read and logged. Seal condition inspection: O-ring seating surfaces inspected under 10× magnification; seal kits replaced as standard on all refurbished units. Final functional cycle test: 500-cycle endurance run in position mode with data logging of position error and settling time.