Positive displacement piston pumps

The first geometry class we attended in school, we have been taught a basic concept: the shortest distance between point "A" and point "B" is a straight line. Very straight forward, without beating around the bush. This concept is even more important when applied to industrial operation in which workers manually move the semi-finished products from one workstation to another, or conveyor belts that convey the products to the next processing phase, manual or automatic forklifts that supply the processing stations with raw materials and store the finished products. All these are typical examples of displacement from point A to point B. What if we had to move a non-solid substance from "A" to "B"? If it were to take, for example, milk from the UHT processing line to bottling system? In this case we could not use forklifts, mechanical belts nor hands but we would need some sort of a pump.

One of the most important functions of a pump is to transfer energy from a power source to a fluid and create a flow to move it by means of a pressure. A pump transforms energy into motion and motion into flow. In industry, pumps play a very important role and there is a large variety of models and applications.

To better understand the world of pumps, it is important to quickly know about the two main categories of pumps:

1. Dynamic pumps: pumps belonging to this category create energy which is continuously added and increases the speed of the product which is converted into pressure or lift.
2. Volumetric piston pumps: for this category of pumps, energy is periodically added and directly increases the pressure or lift.

The volumetric pumps can be of three main types:

• Reciprocating: in which a piston or a diaphragm moves a certain amount of liquid with each stroke. The volumetric pumps FBF Italia are built with this operating typology.
• Rotatory: the transfer of the liquid from the suction to the discharge takes place by means of lobes, gears, vanes, screws or other mechanisms
• Mixed technology: eccentric and peristaltic cam, in which the pumped liquid is not in contact with the rotating elements.

Volumetric piston pumps have a large variety of applications than goes from beverages, to agricultural use for nutrient injection in irrigation systems, to spray dryers for the production of ground coffee, spices and powdered eggs.

Typically, a specific flow rate of a volumetric piston pump can be attained by varying the pistons’ speed or the length of the pistons’ stroke. The combination of piston speed and cylinder volume are directly impacting on the volumetric pump flow rate. In fact, these two elements - the speed of the pistons and their volume - directly determine the machine flow rate.

The piston pump can be utilized for a wide range of applications. The pump will provide a constant flow regardless of the discharge pressure. Consequently, the pump can act as a flow regulator for the entire system, protecting it from excessive pressure damages.

Let's see some of the most interesting products that can be processed by volumetric pumps: egg white, egg yolk, margarine, coffee and concentrated coffee, ingredients, tomato pulp, tomato paste, flavorings, milk, concentrated milk, dairy products, proteins milk, cream and milk, skim milk, hemoglobin, blood plasma, pig plasma, hydrolyzed gelatin, fruit juice, fruit concentrate, orange pulp, concentrated soy milk, coconut milk, liqueur based cream, puree fruit, dried garlic, maltodextrin, waste water.

These types of pumps are mechanically reliable and have an exceptionally long lifetime when properly maintained. The generous dimensions make them rather bulky but robust, they operate at a very low operating pressure which allows, even when working dry, to minimize the possibility of damage (but it is not recommended to do so!)

Among the large variety of pumps available in the industrial market, positive displacement piston pumps can meet most customer needs, in many different types of applications with very low management costs. These pumps are one of the best solutions when it comes to moving a product from one point to another in the processing system.

Do not hesitate to contact the closest FBF office to speak with a competent technician who can propose the best pumping solution for your process system.