Uses for Dosing Pumps

The Many Important Uses for Dosing Pumps

The need to accurately measure and dispense a fixed volume of fluid is quite common and is encountered in many types of human activity. An instance that many people have recently experienced is the use of a hypodermic syringe to draw the small but precise quantity of the COVID-19 vaccine with which they were subsequently injected. This principle is similar to that of dosing pumps. Although some may differ significantly in their operation, these devices all employ a means to measure and dispense uniform, pre-determined volumes of liquid as required.

Banks of automatic syringes of differing capacities are a common feature in many medical research facilities. There, their role is to speed things up by processing large batches of samples simultaneously, mixing measured volumes of biological fluids with the necessary quantities of liquid reagents. A similar need frequently occurs in many other industries. Rather than relying on manual measurements, dosing pumps are generally the method of choice when performing tasks on an industrial scale.

The Treatment Process

In practice, one will need to look no further than the water that issues from a household tap to experience the results of this crucial measuring technology. Water treatment plants source their raw supply from various sources and must subject it to several processes to render it potable. During some of those processes, it is necessary to add measured amounts of a liquid reactant essential for purification purposes. Typically, these additions are performed by dosing pumps.

There are several stages in the overall treatment process at which such chemical agents may be required. After straining off any larger detritus in the early stages, the untreated water is kept in sedimentation tanks. This allows any dense suspended solids to settle out, leaving a much clearer liquid for the filtration stage. However, often organic colloids present remain suspended. Adding a suitable volume of an appropriate chemical flocculant offers a means to overcome this problem, and this is a job for a dosing pump.

Later, during the treatment, it becomes necessary to adjust the pH of the partly-treated water. This is done mainly to improve the taste, and the pH should be somewhere between 6,5 and 8,5. To achieve this, precise quantities of an acid or alkali must be added. The required amount will be determined by the total water volume to be treated and its current pH level. From these figures, it is possible to calculate the quantity and nature of the neutralising agent required. This can then be added with the aid of dosing pumps.

Finally, the water is freed of microorganisms, often by using some form of ultra-fine filtration technology such as reverse osmosis. However, the story doesn’t end there. To ensure it remains free of germs and safe to drink during its journey through the city’s pipeline system between the plant and the consumers’ taps, it is usual to add a suitable disinfectant. Chlorine, either as a gas or a hypochlorite solution, is most often the choice, but ozone is also used in some plants. Either way, the necessary quantities of gas or liquid are likely to be introduced with dosing pumps.

Commercial Pump Uses

The food we eat, much like our water, is a commodity that, in today’s world, is often subjected to extensive processing. Even where this is not the case, one can hardly produce items such as cakes, biscuits, and ketchup on a commercial scale by measuring out the ingredients with spoons and teacups. Flavourings and colourants are commonly added, as are other foodstuffs such as fruit. It is generally more convenient to introduce these in the form of a liquid or puree. In either form, the quickest and most accurate way to add these and similar ingredients is to use a dosing pump.

As indicated earlier, one manner in which these devices can create and deliver a metered dose is by employing a plunger mechanism similar to that of a syringe. As the plunger is withdrawn, it draws liquid in through an intake valve. On compression, the metered dose is ejected via the output exit.

Other forms rely either on a diaphragm or peristaltic action for their operation. In the former, a diaphragm is displaced to draw in the metered-dose and relaxed to release it. In peristaltic dosing pumps, a flexible tube is compressed at intervals designed to isolate and subsequently expel fixed quantities of fluid.

Contact Prochem to learn more about the aptly-named Prominent range.

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