Neumaier R. Hermetic Pumps: the latest innovations and industrial applications of sealles pumps

Houston: Gulf Publishing Company, 1997. - 617 p.
The development of hermetic pumps is inseparably linked to the design of the canned motor. This development is in turn closely associated with the names of the founder of "Hermetic" GmbH, in Freiburg-Gundelfingen, Hermann Krimer (1902 to 1993) and his staff. The present state of development of hermetic centrifugal pumps and rotary displacement pumps and the widespread use they have achieved is due mainly to them.
The development of the canned motor and permanent magnet coupling also influenced centrifugal pumps and rotary displacement pumps, leading to important new developments in design. In particular, experience with hermetic pumps showed the close relationship and need for harmonization between machinery construction and the construction of electric motors. It is not unusual today to find pump manufacturers with their own highly modern electric machine construction facilities producing all components for canned motor pumps.
In this publication, the author not only presents the development of the features, design characteristics and variety of types of hermetic pumps, but also deals with specific and application-oriented problems of centrifugal pumps and rotary displacement pumps in a simple but comprehensive and graphical manner, which will be valued by every specialist. The author does not restrict himself merely to an illustration of principles but also provides an ample number of examples of designs and applications which enables the details to be understood. This gives this book a welcome distinction from many other specialist works.
This book is not a textbook in the usual sense and makes no claim to be, but should really be seen as a treatise on hermetic pumps. It is to be warmly commended both to students at technical universities and at specialized institutions of higher learning, particularly those students specializing in design as well as engineers working in the field of design, project planning and operation.Centrifugal Pumps - Basic PrinciplesForewordIntroduction
Centrifugal pumps
Euler's Equation (from the velocities)
Euler's equation (according to the moment of momentum principles)
The H (Q) curve
The influence of a finite number of blades on the total head H and further hydraulic losses
System-head curve
Change in the rate of flow Q for a change in static head H, with the hydrodynamic component remaining constant at the system head curve
Two centrifugal pumps operating in parallel with the same curve, separate suction pipes and a common pressure pipe. The length of the suction pipes should be short compared with that of the pressure pipe
Two centrifugal pumps in parallel operation with an unequal characteristic curve, separate suction pipes and a common pressure pipe
Centrifugal pumps with a common suction and common pressure pipe
Centrifugal pumps with an unstable constant speed characteristic curve and short pipe line
Control of centrifugal pumps
Throttling control
Variable speed control
Efficiency during rotation speed control
Energy saving by variable speed control
Frequency converter for matching the delivery parameters
Matching the service data at impellers
Correcting the impeller output where the head
Matching the impeller output where the head is too low
Influence of viscosity on the characteristic curves
Efficiency and specific speed
Suction capacity - net positive suction head (NPSHA) and cavitation
The NPSH value for centrifugal pumps
Net positive suction head available (NPSHA)
Required NPSHR
Cavilation-free operation of centrifugal pumps
Development of the NPSHR curve
The influence of the physical properties of the fluid and temperature on the NPSHR
Change of NPSHR when impeller diameter is matched to the existing H(Q) values
Start of cavitation and cavitation pattern in the absolute and relative flow patterns
The behaviour of the NPSHR of centrifugal pumps when pumping near boiling fluids (liquid gas pumping)
Inducers, their purposes and operating characteristics
Purposes
Improvement of the NPSHR by use of an inducer
lnducers used for two-phase mixtures
Use of induce» to counteract liquid-gas cavitation
Increase in NPSHR values in the partial load range due to heating-up of the fluid on the inlet side; effect of рге-rotation and recircutation
Dependency on the physical fluid property and temperatures particularly for canned motor pumps and magnetically-coupled pumps
Influence of wearing ring clearance
Influence of motor power loss
Suction specific speed
Cavitation and materials
Measures for the avoidance of cavitation
Examples from conventional pump constructionHermetic centrifugal pumps - Basic PrinciplesHermetic centrifugal pumps, machines of the new generation
Hermetic torque transfer by the canned motor pump/permanent magnet central coupling
The three phase canned motor
Operating characteristics of the canned motor
Design of the canned motor
The use of canned motors in hazardous locations. Explosion protection according to European Standard "EN"
Level monitoring
Temperature monitoring
Test rig for canned motors
Heat loss and its dissipation
Pumping liquid near to boiling point
Heat balance of a canned motor pump
Temperature rise of the main delivery flow Q_ges
Temperature rise of motor partial flow Q_T
Friction losses at the rotor
Radial forces thrust at the rotor
Radial force Fr for volute casing pumps
Balance-reduction of radial force F_r
Bearings and radial thrust relief
Hydraulic carrying force F_L
Axial thrust at the impeller and its balancing devices
Hydraulic balancing using valve control at the impeller of single stage pumps
Thrust balance due to valve control at the rotor of multistage pumps
Operating range of canned motor centrifugal pumps
Q_min limitation
Q_min limitation due to NPSHR
Q_min limitation due to motor cooling/lubrication flow
Maximum discharge flow Q_max
Efficiency by limitation of Q_min - Q_max
Noise emissions from canned motor pumps
Examples of hermetic centrifugal pumps with a canned motor drive
Single-stage canned motor pumps
Multi-stage canned motor pumps
Multi-stage canned motor pumps of tandem design
Multi-stage design and axial thrust balance
Improved NPSHR characteristic in pumps of tandem design
Hermetic centrifugal pumps in can design for highly toxic fluids
Canned motor pumps in nuclear auxiliary system
Canned motor pumps used at high temperatures
Externally-cooled canned motor centrifugal pumps
Canned motor pumps with self-cooled motors
Canned motors with at-rest heating
Canned motor pumps in the low temperature and liquid gas range
Guidance of partial flow
NPSHR and NPSHA for liquid gas plants
Pumping suspensions
Vertically-mounted, immersion-type canned motor pumps
Canned motor pumps in high pressure systems
Typical uses of hermetic centrifugal pumps in high pressure applications
Canned motor pumps for supercritical gases
Pumping two-phase mixtures
Canned motor pumps as the main circulating pumps in the primary circuit of ships nuclear reactors
Canned motor pumps in the foodstuffs industry and bioengineering
Self-priming centrifugal pumps with a canned motor drive
Side channel pumps
Self-priming centrifugal pumps using the side channel principle with a
horizontal-type canned motor drive
Vertical side channel pumps with canned motor drive
Self-priming canned motor pumps with an impeller cell flushing system
Vacuum tanks for self-priming operation of canned motor pumps
Special measures to protect the canned motor when pumping contaminated liquids using self-priming by means of vacuum system
Regenerative pumps with a canned motor drive
Delivery characteristics
Constructional description
New regenerative pump developments by means of a radial centrifugal fluid entry into the impeller
Particular characteristics to be noted when operating canned motor centrifugal pumps
Characteristic curves which limit the normal working range
Measures for compliance with the Q_max - Q_min limitation
Design of orifice plates for setting Q_min and Q_max
Parallel operation of canned motor pumps
Safety and monitoring devices on canned motor pumps
Specified and recommended monitoring devices
Simplification of the installation of the power and control connections to the motor
Availability of canned motor pumps
Are canned motor pumps economical?
The permanent-type magnet coupling
Construction of a permanent magnet coupling
Magnet materials
Efficiency of magnetic couplings
Starting-torque characteristics of magnetic couplings
Selection criteria for magnetic couplings
Starting conditions
Influence of temperature on the magnets
Magnitude of power and losses of magnetic couplings
Power losses in magnetic couplings with high viscosity fluids
Operating principle and examples of construction of permanent magnet coupling pumps
Standard chemical pumps to DIN 24256 / ISO 2858
Single-stage magnetic coupling centrifugal pumps of monobloc construction
Multi-stage magnetic coupling centrifugal pumps
Multi-stage monoblock coupling centrifugal pumps
Magnetic coupling centrifugal pumps for heat transfer
Monobloc centrifugal pumps with magnetic coupling, for liquids at high temperature
Self-priming centrifugal pumps of magnetic coupling construction
The side channel principle
The imneller cell flushing nrinrinle
Regenerative pumps with a magnetic coupling
Magnetic coupling centrifugal pumps made of plastic
Vertical magnetic coupling centrifugal pumps
Hypernate magnetic coupling centrifugal pumps
Shaftless magnetic coupling centrifugal pumps
Venting
Axial hydraulic balance and balancing flow Q_T
Initial calculation for thrust forces and balancing flow
Multi-stage design
Safety and monitoring systems on magnetic coupling pumps
Dry-run protection
Partial flow temperature monitoring
Monitoring the can temperature
Roller bearing monitoring
Double wall security system (DWS)
Additional losses due to the DWS system
Transport of molten materials using the double wall system
Canned motor or magnetic coupling
Safety
Explosion protection
Maintainability
Temperature of the fluid
High pressure applications
Efficiency
Starting behaviour
Installation and space requirements
Noise level
Cost comparisonHermetic stirrers and isolating devicesRotary displacement pumps - Basic PrinciplesRotary displacement pumps

Rotary piston pumps
History
Rotary piston pumps of new design, operating principle and design of the displacers
Operating principle
Design of the displacers
Rotary piston pumps with rotating hub
Single vane design with rotating hub
Double vane design
Multi-vane (gear vane) design
Rotary piston pumps with fixed hub
Single vane design
Double vane design
Displacer shapes according to delivery characteristics
The characteristic curve
Delivery flow Q
Pumping head H or delivery pressure p
Power P
Piston clearances
Vane profiles and delivery flow fluctuations
Speed
Control
Suction characteristics, NPSHR and cavitation
Cavitation erosion due to suction and gap cavitation
Vapor gas cavitation
Avoidance of cavitation without changing the static suction head, the pipeline area and backpressure
Types of rotary piston pumps
Bearings
Pumps with bearings on both sides for the low pressure ranges
Pumps with single-side (overhung) bearing for the medium pressure ranges
Pumps with single-side bearing for high pressure
Pumps with single-side bearing for high system pressure
Pumps with single-side bearing with plastic rotors
Pumps of monobloc construction for the foodstuffs industry
Materials used in rotary piston pumps
Rotary piston pumps for fluids with abrasive ingredients
Low speed ranges
Large gap widths
Wear-resistant materials
Shalt sealing
Example of application of rotary piston pumps.
Gear pumps
Operating principle
Toothing
Irregularity
Delivery flow Q
The total head H or delivery pressure p
Power P
Materials used in gear pumps
Shaft seals
Gear pump design types
Gear pumps with spur-toothed wheels
Gear pumps with internal toothing
Sliding-vane screw pumps
Delivery principle of the sliding-vane screw pump
Geometry of the delivery chamber and kinetics of the vane value
Capacity and total head
Design of the sliding-vane screw pump
Technical aspects of operation
Screw pumps
Single screw design
Two-screw design
Two-screw pump with an external bearing system
Two-screw pump with internal bearing system
Three-screw pump with internal bearing system
Suction capacity and cavitation
Suction cavitation
Gap cavitation NPSHR_sp
Progressive cavity pumps (single-screw pumps)
Functional description of pump
Power input of pump
Suction capacity, NPSHR values
Dry-running protection
Progressive cavity pumps with inducing screw
Submersible type progressive cavity pumps
Sliding-vane pump
Reduction of the bending load on the vanes
Material of sliding-vane pumps
Sliding-vane pumps with positively-controlled vanes
Construction and operation of sliding-vane pumps with positive control
Vane pump with fixed vanes
Liquid ring vacuum pumps/compressors
Working principle
Determining the volume flow rate of a single chamber liquid ring vacuum pump
Shaft power Р_is
Liquid compressant
Fresh liquid operation
Combined liquid operation
Recirculating fluid operation using a closed circuit
Gas jet pump as an inlet pump for the liquid ring pumpHermetic rotary displacement pumpsHermetic rotary displacement pumps
The permanent magnet coupling for leak-free power transmission
Examples of designs of leak-free rotary displacement pumps
Gear pumps
Hermetic gear pumps of high pressure design
Progressive cavity pumps
Progressive cavity pumps with a magnetic clutch
Progressive cavity pumps with a canned motor drive
Sliding vane screw pumps
Screw pumps
Screw pumps with a magnetic coupling
Screw pumps with a canned motor drive
Sliding vane pumps with magnetic coupling and canned motor drive
Rotary piston pumps with a magnetic coupling
Liquid ring vacuum pumps/compressors
Liquid ring vacuum pumps/compressors with magnetic coupling
Liquid ring vacuum pumps/compressors with a canned motor drive
Peristaltic pumps
Noise emissions from rotary displacement pumps
Concluding remarks on the subject of hermetic rotary displacement pumps