ARQUIMEDES SCREW PUMP METALLIC PROTOTYPE (ALUMINIUM + STAINLESS STEEL)

Thanks to the assurance obtained during the previous tests we decided to complete the prototype with a machined aluminum body.

Once the new parts were made we could simulate working conditions, actual adjustmen between parts and ready a more robust prototype than the previous one whose body was completely made of sintered powders of nylon.

The test bench confirmed the first tests results and helped us to know better the limits of each one of the pieces designed by our engineers and the possible points of improvement.

Here we show you a video of one of the tests carried out:

STAINLESS STEEL SCREW (II)

After quite a few attempts and difficult adjustment and setting of various machine tools and control devices we were able to manufacture the stainless steel screw, AISI-316.

This is the first and foremost part of the definitive bomb. Together with the sealing disk they represent the core of the mechanism that allows fluid pumping. In the image we show you the screw and the sealing disk "geared" in both its final version and its sintered nylon version, the latter a little unwell after hours of testing.

Watch the video:

In successive posts we will show you how we make the pump body in metallic material and the centrifugal separator that will allow us to separate water from hydrocarbons before pumping.

STAINLESS STEEL SCREW (I)

Once we've verified the design of the screw, we're starting its production in stainless steel.

Due to its geometry and its perfect fitting with the sealing disc it's the most complicated part of the pump.

Nevertheless we're confident of achieving the goal!.

FIRST PROTOTYPE OF OUR PUMP - TEST

Despite the inherent imprecision of the manufacturing technology we were able to operate our pump prototype which was completely made using Selective Laser Sintering of nylon powder.

See the video here:

CONSTRUCTION OF THE FIRST PROTOTYPE OF THE PUMP

Once the idea was developed, to build a skimmer equipped with a Archimedes screw pump but able to separate part of the recovered water, we start manufacturing of the prototype.

Although our final aim is to manufacture a robust pump capable of working with any type of fluid, and being stainless steel the material that responds to such requirements, we decided to make a first prototype using the technique of selective laser sintering of nylon powder.

In this way we built the first pump with a very fragile material, so that if it passed the test we would have guarantees of adjustment and operation to proceed with the very superior investment represented by the metallic prototype.

The technology used responded very well to expectations and not only. We got a prototype that geometrically validated our design but it was also a functional prototype with which we could verify the hydraulic behavour of the pump.

LET'S START!

Analyzing performance and design of the available pumps we are inclined to use screw pumps in our aim to reduce water content in the skimmer.

Its geometry and the way in which power transmission takes place makes us think that they are the most suitable to work together with a centrifugal separator.

Now is the time to take action: We will create a prototype that will allow us to verify the results of our theoretical study.

The challenge in front of us is huge. We have the need to design and manufacture three devices in one: a weir skimmer, an Archimedes screw pump and a centrifugal separator.

Since we have a long experience in skimmers manufacture we will leave it for the last moment, so we will concentrate at first on the design and manufacture of the pump as it represents the core of this new equipment for Oil Spill Response. We will call it:

OWSKIMMER

RECOVERED OIL PUMPING

In order to find a solution to the problem of the huge amount of water recovered together with the spilled hydrocarbons we need to know how these are pumped from the skimmers, because their knowledge will help us to find the best way to integrate the industrial separation methods presented in the previous post.

Once recovered the spilled oil using the different types of existing skimmer we need to pump it to the temporary storage tanks.

Sometimes the skimmer's workplace and the location of the operator advise the use of a suction pump or on the contrary a delivery pump.

When access to the spill zone is complicated it may be more interesting to use lightweight skimmers by working with a self-priming pump located in the proximity but on the ground or on the deck of the response vessel. This configuration has an important limitation, the pump maximum suction head. A self-priming pump will never be able to suck from a height greater than 9.8 meters, a height that is reduced as the viscosity of the product to be pumped increases.

To avoid this handicap skimmers can be equipped with transfer pumps. In this way the limitation of height becomes a minor problem. A logistical problem arises; however, to move and raise these skimmers it is necessary to use cranes.

Among the first type of pumps, the most used are lobes pumps, peristaltic pumps and membrane pumps. All are self-priming positive displacement pumps capable of working with high viscosities fluids even in the presence of solids. The differences between them focus on the necessary maintenance, diameter of solids, ability to work dry and price. In any case, they are bulky and heavy pumps, characteristics that hinder, but not prevent, their use as a transfer pump in skimmers.

Usually skimmers equipped with pumps use the following types:

• Lobe pumps: their weight does not make them the best solution
• Open impeller axial centrifugal pumps: emulsify the water-hydrocarbon mixture and work especially poorly with viscous hydrocarbons.
• Sealing disc Archimedes Screw Pumps: the most widely used and best-performing pumps to be uses with water-hydrocarbon mixtures and viscous hydrocarbons.