Category Archives: Seko Manual And Analogue Dosing Pumps

The History of Metering Pumps

An old petrol pump

An old petrol pump

The original metering pumps used a plunger mechanism, and came into use during the 1930s. They used a crank to drive the piston, and the flow rate of the pump could be changed by adjustment of the crank. Unfortunately, the piston had direct contact with the liquid being pumped, and so were subject to leaks, making the pumps inaccurate – especially when the fluids being pumped were corrosive or had a lot of suspended particles

This problem was solved 20 years later, with the introduction of hydraulic diaphragm pumps. In these pumps, the piston was separated from the fluid being pumped. A diaphram divided the pump into two chambers. The piston would drive hydraulic oil into and out of one chamber, which in turn would cause the diaphragm to flex. This flexing would displace water into and out of the other chamber. As the oil was clean and non-corrosive, the nature of the fluid being pumped would not affect the piston. The diaphragm was free from leaks and could be made of a corrosion-resistant material.

In the 1970s, solenoid technology was applied to metering pumps. The diaphragm was now flexed by the magnetization of a solenoid coil. This dropped the purchase cost of metering pumps significantly, due to a reduction in the number of moving parts, and also meant that maintenance was cheaper. Importantly, solenoid technology allowed metering pumps to accept electronic signals, moving the metering pump closer to the digital age.

At first these solenoid-driven pumps had a significant flaw – they could only be run at high speed. Therefore, they had reduced accuracy, could not be used to pump fluids that would be damaged by high-pressure pulses, and the diaphragm wore out faster than other designs. Over the years, motors have improved with new technology, from new kinds of motors, to digital flow meters and controllers, increasing their accuracy, regulating strokes with precision, and negating many of the flaws they once had.

Dosing pumps

Dosing generally applies to the feeding of chemicals or other liquid additives, in accurately measured small quantities, into a process fluid at intervals to give sufficient time for the chemical to react or show the results. Diaphragm dosing pumps or piston dosing pumps are commonly used. The use of peristaltic or tube dosing pumps is also preferred by some users.

A peristaltic pump is generally preferred by the laundry and catering industries due to the ease of operation and the relatively low cost. These are regarded as the cheapest type of dosing pump for high volume installations where the price of the pump is amortised into the price of the supplied fluid detergent, brightener, softener etc.  The peristaltic pump is ideal for measuring  the exact dosing for each wash or rinse cycle. Dosing pumps are in reality a metering pump and these terms are used to refer to the same type of pump unit. A dosing pump can be a high pressure pump, however there is a large user base where the dosing of additives is into either no pressure or very low pressure systems.

A reliable dosing pump supplier will offer all types of pumps to suit each application. Acids are commonly dosed into process fluid streams by pumps with the wet component in materials suitable for reliable and safe handling of the specific acids being. The wetted pump chamber is typically PVDF, Poly Propylene, Stainless steel or some other noble metal.  Valve seats are also in the same materials with Teflon (PTFE)  valve balls and diaphragms making up the most common materials when speaking about diaphragm or piston dosing pumps.

Chemical pumps are available in all types of materials and it is important to specify the acid or alkali or other additives  to be dosed.

Aquarium dosing pump

Dosing pumps are also necessary on saltwater aquarium systems if one wishes to automate the calcium and alkalinity dosing. The small SEKO PR1 peristaltic pump is a very popular choice and can be automated with reef timer systems available from saltwater aquarium equipment suppliers. Seko will welcome all enquiries for the aquarium dosing pump arrangement we are able to supply.

Industrial dosing pump

Pumps are not all the same regardless of what industry wisdom tries to preach. When one considers a chemical dosing pump application, the chemical pump one has in mind is not a dosing or metering pump. Dosing pumps are not common applications to most industrial fitters or engineers and do not generally form part of their experiences on a daily basis. Typically dosing pumps would be used in water treatment on chillers, heat exchangers, cooling towers and on the odd occasion in the actual process stream when specific chemicals or additives need to be injected into the system. Dosing pumps can also be used in lubrication applications for grease or oils. Many of these applications are out sourced from the suppliers of the chemicals, additives or lubricants.

Swimming pool dosing pumps

Large swimming pools are generally maintained from a pH and Chlorine point of view by installing chemical dosing pumps. The pumps are controlled by probes for Redox (chlorine values in the water) or Ph which are directly coupled to the suitable Seko dosing pump designed for that application. The pumps are similar to those used in Industrial applications. Generally two pumps one with alkaline dosing and one with acid dosing would be connected to a pH controller and as the demand for either acid or alkaline is registered, the relevant pump will activate. Redox is controlled in a similar manner with liquid chlorine being measured by the dosing pump at the correct dosage based on the redox reading. Seko has a specific range of dosing pumps for Redox and Ph which integrate the redox controller (probe connects directly into the pump) or pH.

The metering pump industry is extremely competitive with many users looking for the cheapest options based on the dosing volume in litres per hour and pressure in bar. Price however cannot be the only consideration and here Seko have poured huge resources in terms of research and development into developing a  high quality, economical and efficient, low cost of ownership dosing pump range. As far as economically priced dosing pumps is concerned, Seko have added the correct stock profiles for each country they service. This means that when a specific dosing pump is required, Seko generally have that item ex stock in the country where it is required. Seko dosing pumps are also supported by a dealer network of qualified and experienced people. 

Regardless of what one requires a dosing pump for, whether it be an aquarium dosing pump, a swimming pool application or industrial dosing pumps for some specific process additive, Seko generally has the right pump for your application. Dosing is a science which when coupled to the correct metering pump equipment, becomes an art. In terms of a high pressure pump for dosing, Seko is capable of supplying units which inject specific measured doses up to 20 bar.

The range of solenoid driven diaphragm dosing pumps, peristaltic metering pumps and electric motor TEFC electric motor piston and diaphragm dosing pump options ensure a comprehensive solution to most applications in the industry.

Seko international dosing pump manufacturer

Seko Kompact series of economical chemical dosing pumps constant and proportional dosing

Seko in South Africa are stocking the high quality, low cost, economical chemical dosing Kompact range in two variations. The AMS 200 is the standard constant dosing pump version and the AMC 200 is the proportional metering pump which is capable of being controlled by the pulse generated from a water flow meter.

Speak to one of our Seko dosing /metering pump specialists for more information.

Seko Tekno Evo AKS Dosing Pump

Seko Tekno Evo AKS range is the very basic model in this analogue solenoid chemical dosing pump range. The unit allows the operator to set the dosing rate which is continuous if set on the pump program interface alone. One is able to choose a full 0 to 100% range or the reduced 0 to 20% range. The unit can be coupled to a Seko controller for a more accurate and controlled proportional dosing system.

The PDF below provides all the technical data relating to the Seko Tekno Evo AKS range.

Please call 082 651 9841 for more assistance or email sales@gmpumpsa.com

Seko Tekno Evo APG Dosing Pump

Seko developed the APG range to be the economic model of a versatile range of metering equipment. This range of chemical dosing pumps is designed for constant and proportional dosing being capable of receiving pulse and 4 to 20 mA signal from pH or redox probes, controllers and flow meters. The very cost effective pricing makes this range a serious contender in the water treatment, steam and process markets.

The PDF below will provide full technical data including dimension and performance detail.

Please call +27 82 651 9841 for more information or email sales@gmpumpsa.com

Seko Tekno Evo AKL Dosing Pump

The Seko Tecno Evo AKL dosing or metering  pump range is the next step up from the base AKS models. This range has the added feature of being able to receive a level control cable which turns the pump off prior to the unit drawing in air. The effect is that the unit does not loose prime between chemical tank changes saving the operator valuable time.

While all the technical data is available on the attached PDF file below, please call +27 826519841 or email sales@gmpumpsa.com for more information or assistance.