RPVOT (RBOT) Oxidation test apparatus

Test method

The RPVOT (RBOT) procedure employs severe oxidation conditions to rapidly determine oxidation stability. Suitable for both new and in-service oils, the RPVOT (RBOT) method is applicable to many types of petroleum oils. The sample is oxidized in the presence of water and a copper catalyst in a stainless steel pressure vessel under an initial pressure of 90psi (620kPa). Pressure inside the vessel is recorded electronically or mechanically while the vessel is rotated at 100rpm at constant temperature, and the amount of time required for a specified drop in pressure is the oxidation stability of the sample. A variation of the RPVOT (RBOT) method is the Thin Film Oxidation Uptake Test (TFOUT) for gasoline automotive engine oils.

Features

• 2, 3 and 4-unit systems
  
• Oxidata® Pressure Measurement System
  
• Conforms to ASTM D2112, D2272 and IP 229 specifications for RPVOT (RBOT) testing
  
• Conforms to ASTM D4742 specifications for TFOUT testing

Description

Constant temperature bath rotates oxidation pressure vessels at 100rpm at an angle of 30° in accordance with ASTM specifications. Includes drive system and oil bath with electronic solid state temperature control. Meets ASTM requirements for heat transfer capability and temperature control precision. A convenient carriage arrangement allows the oxidation vessels to be inserted quickly and securely in the drive system. A strong magnet holds the vessel in place while locating pins in the carriage engage the base of the vessel. PTFE guides support the pressure vessel stem for added stability. If the vessel becomes obstructed for any reason, the magnetic carriage releases it to prevent damage. A chain and sprocket drive system powered by a heavy duty capacitor start motor rotates the vessel carriages at 100rpm. Drive shafts ride on PTFE fluorocarbon bearings which provide extended service and are compatible with silicone heat transfer fluids and other types of bath oils. The bath temperature is controlled within ASTM specified limits by an electronic solid state controller with °C/°F switchable digital setpoint and display. Over-temperature protection is provided by a built-in limit control that automatically interrupts power to the bath when the bath liquid temperature exceeds 16.7°C (30°F) above the temperature setting or 177°C (350°F). Power must then be manually restored by the operator after checking the cause of the problem. The pressure vessel carriage vanes circulate the bath oil during testing to ensure temperature uniformity, and an auxiliary stirrer can be operated between tests to prevent sludging of non-silicone bath oils. The bath interior is constructed of welded stainless steel and is fully insulated.

A hinged section of the bath cover provides easy access to the vessel carriages. Vapor barriers in the cover close around the vessel stems to contain vapors from the hot bath medium. A chemically-resistant polyurethane finish protects the bath exterior and control cabinet. The Oxidation Pressure Vessel consists of pressure vessel body, cap and stem with inlet needle valve in accordance with ASTM specifications. The vessel holds one borosilicate glass sample container between two PTFE discs. The closure ring tightens by hand to seal cap to pressure vessel body. The vessel connects to a pressure recorder or rotary transducer and rotates on magnetic carriage in RBOT bath. Withstands working pressure of 500psi (3450kPa) per ASTM specifications. A stainless steel construction ensures proper rate of heat transfer. The closure ring is constructed of chrome plated steel. Includes PTFE fluorocarbon wear disc and sample container cover disc. Includes Oxidata® Pressure Measurement Systems, which are electronic pressure measurement systems exclusively designed for RPVOT (RBOT), TFOUT and other ASTM oxidation test methods. Powerful Oxidata software for Windows environments. Monitors up to twelve pressure and four temperature channels. It can be installed to most manufacturers RPVOT(RBOT)/TFOUT test apparatus. Complete electronic measurement systems for plotting pressure versus time and temperature in RPVOT (RBOT) and TFOUT testing. Each system includes transducers, pressure vessel couplings, RTD probe assembly, multiplexer, data acquisition card, software, and mounting and connecting hardware. Systems are available in two, three and four pressure vessel configurations, and additional channels can be added for up to a total of twelve.