PuK - Process Technology & Components 2024

Pumps and Systems
Progressing cavity pumps
ment as would be fitted in the vast
majority of applications. The main deciding
factor for using a flexible rod
would be that the lubrication required
for joints is eliminated. The benefit
would be that there would be no contamination
of the slurries by the lubricant
when using lubricated joints, in
the event of a joint seal failure.
nation of the anode and cathode slurries.
This would lead to a reduction of
final product quality.
Therefore, a flexible shaft is the
obvious choice, however there is a
disadvantage to using a standard
flexible shaft. The traditional flexible
shaft is manufactured from metals,
often titanium or duplex stainless
steel. Due to the limited flexibility of
Coupling rod is manufactured
additively
such a construction, the flexible shaft
needs to be longer than would otherwise
be the case with a coupling rod
For hygienic applications, a coupling featuring a joint system.
rod system is available with open When considering automated
joints using a stainless-steel rod and
pins. For battery applications, such
a system is not suitable due to the
abrasive nature of the slurries and
the danger of metal particle contami-
cleaning, the increased volume within
the pump housing due to its increased
length would lead to increased
product wastage. Ideally
therefore, a concept was needed to
Fig. 2: The progressing cavity pump is designed for complex battery applications.
reduce the length of the pump housing
as much as possible whilst providing
sufficient coupling rod flexibility
to ensure reliable pump operation.
New production techniques opened
possibilities to resolve this conundrum
without incurring the significant
tooling costs associated with injection
moulding. By using additive
manufacturing, it was possible to rapidly
prototype potential designs and
subsequently manufacture the final
production components.
To develop a shorter coupling rod
that would reduce the pump housing
length, be able to withstand the
mechanical loads and to fulfil the demands
of automated cleaning presented
a challenge. Using the latest
CFD programs, a coupling rod design
was eventually finalised and incorporated
into the final battery pump
configuration. Using experience from
food applications where cleaning in
place to hygienic levels is the standard,
a tangential inlet connection was
incorporated to improve the cleanability
of the pump by providing optimised
flow conditions within the
housing.
Pump stator is also manufactured
additively
Fig. 3+4: Elastomer stators and additively manufactured stators are compatible with a separable
stator system.
To successfully cover the demands
of battery slurry applications, a new
concept would be required also for
the pump stator. Normally, progressing
cavity pumps are fitted with a stator
manufactured from an elastomeric
material. However, due to the
chemical aggressivity of some of the
fluids used in battery production, especially
the NMP for cathode slurries,
an alternative stator material would
need to be used.
In such applications it was usual
to use a stator manufactured from
PTFE. The manufacture of PTFE stators
is a mechanical process where
the stators are produced on a lathe,
the inside profile being turned to size.
However, given the success of manufacturing
the flexible rod using additive
manufacturing, it was decided
to try and produce stators using the
same process.
After extensive testing a new design
was born offering increased ac-
28 PROCESS TECHNOLOGY & COMPONENTS 2024