For effective oil separation, the pump that feeds an oil separator must be suitable to pump the mixture without emulsifying the oil. Suparator® systems are supplied with three types of pumps; electric driven diaphragm pumps, progressing cavity pumps or double diaphragm pumps. Every pump is supplied with the proper controls.
A special pump is the EM type pump. It is an electric driven, single-diaphragm pump. The diaphragm, made from an elastomer, covers the pump chamber and is forced up and down by means of an excenter, driven by an electric motor-reductor combination. Check valves in the inlet and outlet allow the fluid to move in one direction only.
Due to the large inlet and outlet ports and clearance between diaphragm and pump housing, debris and particles can easily pass through the pump without causing any damage. It makes the pump ideal for media which, in addition to oil, contain a lot of other pollution. It reduces maintenance to replacing the diaphragm 3 to 4 times a year, an inexpensive component which is easily replaced, keeping maintenance cost very low. The heavy, bronze, pump housing is very durable, making the pump suitable for use in virtually any environment.
The pump is not suitable for applications that require a high differential pressure. The maximum allowable suction height is less than 1 meter and the discharge height (pressure) should not be more than 5 meter (0,5 bar). The pump is self-sealing in the counter-flow direction only which means it can not be used in situation where the liquid level on the suction side is considerably higher than the level on the discharge side, unless special measures are taken.
The ES type pump is a progressing cavity pump; it uses a 'screw' type rotor, turning in a specially formed, rubber, stator. The smooth pumping action makes it very suitable to pump oil/water mixtures without causing any emulsification.
This type of pump has excellent suction and discharged characteristic which makes it very suitable in many applications. A lift of 3 meters or even more is not a problem and long distances can easily be bridged.The pump-action is slightly pulsating but this is of no concern in the applications in which it is used.
Due to the intensive contact between the stainless steel rotor and rubber stator, it is susceptible to abrasive matter and debris in the fluid. Therefore it is recommended to use a strainer (not a filter) in the suction side of the pump to remove chips, fines and other coarse matter. A magnet, placed inside the strainer, may be of great value in reducing the wear of the pump rotor and stator.
Pumps are an important component in any Suparator® installation. Although the use of pumps is common throughout industry, for oil/water separation, selecting the correct pump is critical and not as easy as it might seem.
Centrifugal pumps, used in 90% of the pump applications, are not suitable because the pumping mechanism creates high shear forces which break up oil into very fine drops. Centrifugal pumps turn oil/water mixtures into emulsions that are difficult to split.
Positive displacement pumps are a much better solution. This range of pumps includes hose pumps, double diaphragm pumps, progressing cavity pumps, impeller pumps, gear pumps and many more. However, not all types of positive displacement pumps are suitable. Issues like shear forces, exercised on the fluid, fluid viscosity and compatibility with temperature, chemicals and other process parameters come into play.
Suparator® systems are supplied with carefully selected and configured pumps to guarantee optimal performance in all applications. Three different types are used: electric driven diaphragm pumps, progressing cavity pumps and air driven double diaphragm pumps.
Although not the preferred solution, there are a number of advantages in using this type of pumps. Since the pump is air driven it is intrinsically explosion proof. Pump parts are available in an extensive range of materials so chemical compatibility will be less of a problem. The pump is capable of passing abrasive fluids without too much problem. The draw back is that the pumping action may emulsify the oil.
A simple and reliable pump; easy to maintain and very suitable for the application if configured in the correct way.
Suction and discharge characteristics are not impressive but in many applications there is no need for this.
A very rugged and reliable pump type with excellent performance characteristics in both suction and discharge. This makes it possible to place the pump at a considerable distance from, or considerably higher(!) than, the tank or bath it pumps from. Low revolution rates warrant a smooth pumping action and ideal forwarding of the oil/water mixture.
Reliability is a primary issue, particularly since oil/water separation systems tend to get little to no attention. Suparator® systems and installations are configured for unattended operation; 24 hours/day, 7 days/week. This is only possible if the proper controls are fitted. Pump control systems supplied with Suparator® installations are matched to the selected pump and specific process conditions and requirements and can include: