Paul NelsenManaging Director

Filter Press Applications

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

Typical Discharge Pressure – Pump Speed Characteristic

Discharge Pressure - Pump Speed Profile for Filter Press Applications

0

2

4

6

8

10

12

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16

0 5 10 15 20 25 30 35 40

Pump Speed in RPM

Dis

ch

arg

e P

res

su

re in

Ba

r

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

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

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

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

•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

Complete Kieselguhr System

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

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

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

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

For more information, please visit our websiteor call 1-855-535-4213

www.verder-us.com