Consists of esters or specially selected hydrocarbon fractions. They were developed for vapor-diffusion pump fluids:
- High purity, very low pressure, very stable
- Pressures lower than 10-7 torr obtainable
- No need for cold trap
- Good pumping speed
- No corrosive deposits or vapors
Physical Properties of Apiezon Oils
| |
Type B |
| Vapor Pressure,vtorr @20°C |
10-6 |
| Boiling Point,°C @ 1 torr |
220 |
| Flash Point (open cup)°F |
470 |
| Pour Point(ASTM) °F |
15 |
| Density, g/ml @ 20°C |
0.872 |
| @ 40°C |
0.859 |
| Viscosity, kinematic,cS @ 20°C |
142 |
| @ 50°C |
49.3 |
| @ 100°C |
7.0 |
| Coefficient of Expansion per °C over 20-30°C (ASTM) |
0.00073 |
| Thermal Conductivity Btu/in |
0.91 |
Invoil Oil B
Good for small or large vapor diffusion pumps. Good pumping speed and high backing pressure. If a cold trap is used, oil B can obtain a higher vacuum than oil C does.