State-of-the-Art Vapour Pressure Measurement System 

The Model P-780 RVP/VL20 Analyser, from Orb Instruments (USA) is the result of combining the latest, state-of-the-art technology with over 20 years of industry experience - an unsurpassed, high-quality Vapour Pressure measurement system that produces the process control signal required to perform today’s optimised and cost-efficient petroleum blending operation.

Using a simply constructed, yet rugged measurement chamber and sample delivery method, operational 

cost savings have been realised without complicating the analytical system. The P-780 demonstrates 

the optimisation of the fluidics paths by employing components and materials that allow for a rapid 

measurement cycle without limiting accuracy, repeatability or reliability.

The P-780’s RVP measurement cycle is based on the ASTM Methods D-5191, D-4953 and D-5482 and correlates to D-6377 by using a digitally controlled syringe sample handling system, micro-volume solenoid valves and an angled measurement chamber equipped with a high-resolution pressure sensor and magnetic stirrer. 

To further enhance the precision and usefulness of the Model P-780 RVP/VL20 Analyser, an optional validation/grab sample system can be added. This will allow the end user to either introduce a reference solution or an unknown sample for immediate analysis. This feature provides a simple system verification or a quick analysis of a non-automated sample stream. The optional dual-stream sampling system offers an economic way of automatically monitoring two sample streams with a minimal loss of measurement response time.

Other features include: RVP correlates AStM D5191 evacuated cell method Vl20 correlates to AStM 5188 evacuated cell method, Both correlate to AStM 323, Reports multiple AStM method correlations, Remote select RVP or Vl20, Operating range RVP 0-35 psi Vl20 25°C to 65°C, Rapid analysis cycle of 6 minutes or less, Superior repeatability RVP less than 0.05 psi Vl20 less than 1°F (0.5°C), Increased reliability with operating uptime greater than 99%, elevated sample temperatures up to 75°C, Validation & stream switching and Remote diagnostics over IP.