Cryogenic For Efficient Handling of Liquified Gases
Ten years after the development of the Multi-Stage Liquid Chlorine Pump, Lawrence
began building Cryogenic Multi-Stage Pumps. These Cryogenic Pumps are used for handling
liquids such as oxygen and nitrogen, at temperatures as low as -320°F. The top
suction design of our pump has become a standard in the industry for handling fluids
which are near or at boiling point.
Since most cryogenic pumps operate close to the boiling point of liquid, the best
design solution is to use a vertical, top suction unit to prevent vapor binding.
Design considerations for our cryogenic pumps include special metallurgical
considerations due to low temperatures and flammability of liquified gases such as
liquid oxygen, thermal expansion and contraction and material behavior at cryogenic
temperatures, and extremely low NPSH.
Examples of Cryogenic Fluids
Liquid
Boiling Pt. (°F)
Sp Gr
Liquid
Boiling Pt. (°F)
Sp Gr
Oxygen
-298
1.14
Nitrogen
-320
.808
CO2
-109
1.18
Argon
-302
1.62
Methane
-259
.717
Propane
-45
.585
Helium
-452
0.124
Neon
-411
1.25
Capabilities Single-Stage: Flows to 4000 GPM (1819 m3/hr) Heads to 700 ft (213 m) Temperatures from -200° F to 700° F (-93° C to 371° C) Pressures to 300 PSIG (20.6 Bars)
Capabilities Multi-Stage: Flows to 4000 GPM (1819 m3/hr) Heads to 700 ft (213 m) Temperatures from -200° F to 700° F (-93° C to 371° C) Pressures to 300 PSIG (20.6 Bars)
Design Features
All designs and configurations position the inlet side of the pump above the
discharge. This top suction design prevents vapor binding while providing
rapid venting and continuous priming.
All impellers, whether single stage or multi-stage designs, are
supported by precision sleeve bearings which are positioned above and below every
impeller stage. This bearing configuration maintains the close tolerances
required for efficient pumping of cryogenic liquids.
The impeller may be either of the semi-open or enclosed design (seen right).
For oxygen it is recommended that the impeller be provided in a non-sparking
material such as bronze. The impeller is mounted to the shaft using a concentric bore
key drive. To allow close running clearances (to maximize pump hydraulic efficiency and
minimize the possibility of an impeller rub) the impeller is mounted
between upper and lower sleeve bearings.
Both single and multi-stage cryogenic pumps can be designed to incorporate an
inducer for low NPSH applications. Inducers are engineered to provide
optimum performance at the pump's operating speed.
Sensitive thermocouples are used to detect and monitor the liquid level in
the pump column. This safety feature ensures that the labyrinth seals
operate in vapor phase. Icing at the support plate is eliminated.
Easily replaceable cartridge assemblies are mounted in the bearing frame
above the top mounting plate. This configuration provides greater support
for the pump shaft and eliminates the reliance of the drive motor's bearings.
Shaft sealing is provided by a precision labyrinth seal which operates at the
suction pressure of the pump. This labyrinth seal eliminates the
requriement for costly and failure-prone high pressure gas seals.
Product Applications
Oxygen
Nitrogen
Argon
Methane
Neon
Other liquified gases