In this article we will illustrate the features and performance of vertical pumps for sludge treatments.

There are two types of centrifugal pumps that can be used in many industrial sectors for their efficiency, versatility and ability to withstand pressures and flows:

• vertical;

• horizontal.

Their main difference is the shape and the position of their shaft. Horizontal centrifugal ones have a horizontally positioned shaft, whether it is between bearings or suspended.

Instead, as we can guess, vertical-line centrifugal pumps for slurry treatments have a vertically positioned shaft.

By choosing a vertical pump you can benefit from several advantages:

• the footprint is less than in a horizontal pump;
• it allows you to work on a small area;
• the NPSH (Net Positive Suction Head) can be varied and adapted to a wide range of applications;
• it is suitable for the treatment of liquids with high pressures and high temperatures, as well as sludge, even highly abrasive and / or acidic ones.

The main applications of vertical pumps for slurry treatments have to deal with:

• power plants;
• washing of mining materials, quarries and aggregates;
• coal, sewage and sludge transfer;
• mines;
• wood pulp and paper;
• chemical industry.

These applications require vertical pumps to sometimes work even in extreme conditions, by handling acidic, abrasive or highly abrasive fluids and / or sludge.

Vertical pumps for highly abrasive and / or acidic sludge

As the name suggests, vertical pumps for highly abrasive and / or acidic sludge treat and move waste fluids with a high solids content. In fact, slurry is a unique mixture composed of a fluid – usually water – and some type of powdered solid.

Since the handled material is heavy and it can also contain corrosive or volatile substances, vertical sludge pumps must have a very powerful mechanism.

Experts divide the sludge into two categories:

• sedimented: sludge characterized by coarse particles that generate an unstable mixture;
• not sedimented: sludges made up of fine particles not very wearing.

In any case, the selection of the most appropriate pump to handle the sludge must take into account the flow rate and the power required by the pumping. Furthermore, the presence of abrasive or acidic particles puts the pump under particular stress, due to erosion caused by physical friction or chemical reaction.

The PEMO Pumps range has 20 basic models, which can be adapted in horizontal, vertical, submerged and multistage versions and which generate more than three thousand customizable configurations.

All shafts, bases and bearings are oversized to increase the mechanical life of our pumps. The overall dimensions are compact and have an industrial quality design.

The impellers are open and can be made of rubber or metal. The latter are usually made in Hardalloy PEMO (750-800 HB) or in AISI or Hastelloy C and they can also be made in other metals or alloys, on request.

The bodies are mainly built in cast iron and in two separable parts. Some models are already available in Hardalloy PEMO and on request they can be made in stainless steel, Hastelloy or other metals.

Vertical pumps for sludge treatment are grouped into three series:

• JOLLY: designed for applications with highly abrasive and / or acidic fluids and muds;
• MEC: designed for use in tanks or wells and to be moved easily;
• AUS: also suitable for dry operation.

Jolly series pumps

The Jolly series vertical pumps for abrasive sludge are designed for fixed installation or they are suitable for barges. They have a heavy mounting plate with bolt holes and lifting eye bolts and they are particularly strong. They can be designed according to the specific needs of the customer.

They work with flow rates from 5 to 1500 m3 / h at a maximum pressure of 7 bar.

The maximum length of Jolly pumps under the plate can reach 4-5 meters. The submerged parts and the internal parts of the casings and the impeller are rubber or hard alloy (700 ÷ 800 HB) coated.

The shafts of Jolly pumps are supported above the base plate by two or three bearings and are designed according to the immersion length and the head of the system.

It reduces vibrations and simplifies maintenance of Jolly pump bottom. It is enough to change the guide bush and the sleeve that have been worn by the abrasive materials. Substitution frequency depends on the total operating head of the pump and the size of the abrasive particles.

MEC series pumps

The MEC series pumps are also designed for applications with highly abrasive and / or acidic fluids and sludges and they are substantially similar to the Jolly ones.

However, unlike the latter they are not mounted on cantilever brackets. In fact, they are kept in a vertical position inside tanks or wells thanks to suspension devices (wire ropes, chains or other) that are hooked to the lifting eye bolt of the sturdy metal structure which is located on their top. Their configuration allows you to easily move them from one location to another.

The lengths below the plates are standard and do not exceed 2 meters.

The pumps of the MEC series also operate with flow rates from 5 to 1500 m3 / h at a maximum pressure of 7 bar.

AUS series pumps

From a mechanical point of view, the AUS series vertical pumps for abrasive sludges are similar to those of the JOLLY and MEC ones. In fact, AUS also works with flow rates from 5 to 1500 m3 / h and a maximum pressure of 7 bar. The maximum length of the pump under the base is 1.5 meters.

The particular arrangement of the casing-impeller assembly distinguishes this series. This also makes it possible to run dry.

This feature combined with simple maintenance (greasing the bearings is practically the only care required) ensures that the AUS slurry pumps are able to operate even in really extreme conditions.