The document discusses the operational sequence of filter presses and the advantages of using hose pumps for various applications, highlighting their leak-free design and gentle pumping action. It mentions challenges faced in specific applications, such as back pressure management and abrasive materials, and cites examples of successful pump implementations in industries like ceramics and brewing. The summary emphasizes the importance of careful gearbox specification and the potential for ongoing sales in filter press applications.

1. Filter Press Applications
Paul Nelsen
Managing Director

2. Typical Filter Press Operational Sequence
•Initially, the filter press is empty and the pump
delivers high volumes at low discharge pressure
As the press gradually fills then a back pressure builds
up in the discharge line. This is normally monitored by
a pressure switch on the filter press and as the back
pressure increases, the speed of the pump is reduced
to reduce the amount of product being fed to the press
•When the filter press’s pressure reaches it’s maximum
pressure then the pump stops and the rotor shoes act
as a valve maintaining this pressure
•The pressure will reduce as the material is filtered and
at a pre-defined pressure the pump will restart and
product will flow into the filter again

3. Typical Discharge Pressure – Pump Speed
Characteristic
Discharge Pressure - Pump Speed Profile
for Filter Press Applications
16
14
12
10
8
6
4
2
0
0 5 10 15 20 25 30 35 40
Pump Speed in RPM
Discharge Pressure in Bar

4. Key Reasons to Use a Hose Pump
• Leak-free design – no spillages costs
• Can pump abrasive products
• Gentle pumping action – low shear rate and
minimal product damage
• Rotor shoe seals the discharge line and can be
used to maintain pressure to the filter
• Pump has a linear Speed - Flow characteristic

5. Application Issues
• Shim the pump to withstand the maximum
pressure at low speed – this introduces and
element of over-shimming when the pump is
running at high speed
• Fit a pulsation damper or air dome to reduce
pulsation and act as a product accumulator
• The filter press’s back pressure can be sufficient to
drive the pump backwards – gearboxes fitted with
drive brakes are recommended. This also
eliminates product slip

6. Pumping Ceramic Slurry to a Filter Press
•CEMA in Romania manufacture a
range of clay products including
bathroom tiles
•A VF80 pumps the clay slurry to
a filter press at up to 15 bar
•Previously, the customer used
AOD pumps which suffered
severe wear due to the abrasive
properties of a clay slurry with a
high solid content
•Note the air dome installed
vertically

7. Kieselguhr Filter Press
•Yeast in it’s many forms is a
challenging product for a
pump – it is abrasive and is
shear sensitive
Blue Verderflex pumps are
supplied to Seit Schenk in
Waldstetten, Germany as
part of their diatomaceous
earth or Kieselguhr filter
press systems for Breweries

8. •The Verderflex Pumps
replaced Screw fed
Centrifugal pumps because
of excessive wear and
damage to the yeast
An additional benefit is an
EHEDG compliant design

9. Complete Kieselguhr System

10. Filter Presses for Vineyards
In this instance, Centrifugal
pumps were replaced because
of spillage costs
The OEM customer uses pumps
fitted with DIN 11851 Hygienic
Port Flanges and specially
modified filler tubes with an
additional 180° U bend

11. Chemical Industry
Lakerij Verschure in
Belgium have a VF50
feeding Aluminium Oxide to
a filter press
In this application, the back
pressure and gearbox
combination resulted in the
pump running reversing
while maintaining 15 bar –
fitting a drive brake onto
the gear motor eliminated
this problem

12. VF125 on a Filter Press Application
•A VF125 has been supplied to Ciba Chemicals in
France to feed chemical waste into a filter press
Reflecting the size of the pump, the large In-Line
Pulsation Damper can be seen on the left hand side

13. Summary
• Successful filter press applications require
consideration when specifying the gearbox
and should be supplied with pulsation
dampers
• They represent a significant business
opportunity as multiple ongoing pump
sales can be achieved

14. For more information,
please visit our website
or call 1-855-535-4213
www.verder-us.com