Chemical dosing and metering

This information is for you to use as a guide to understanding what you actually need for your dosing or metering application. The same principle can be used for selecting any item of mechanical plant such as pumps or valves but in this instance we will apply it to dosing pumps

The first advice is that we should ignore the pumps themselves, at least for the time being, we must focus on what we may call the scale of complexity. This principle uses a simple numerical scale numbered 1 to 10 to determine what your application actually requires

So at the lower end of the scale (No1)we can use a simple manual hand operated pump used to fill a container by eye, for example the mechanic at your local garage filling a canister to refill the oil in your car engine, it will be low flow, low pressure and visually controlled

At the higher end of the scale (No10) we have a high specification dosing or metering pump with full ATEX approval (for use in a hazardous area) maybe API design, exotic materials, instrumentation contacts for status signalling, fault indication, whatever you can imagine “all the bells and whistles”

We can now put some substance to our scale based upon what you may want

1)      Transfer various fluids into a container

a.        Manually operated hand pump
                                                                                                                                               

2)      Transfer fluid  using an manually operated motor driven pump

a.       Electrically driven pump with manual control
                                                                                                                                                      

3)      Transfer fluid automatically using a motor driven pump

a.       Electrically driven pump with automatic control
                                                                                

4)      Transfer fluid at various rates automatically and manually adjust flow rate

a.       Electrically driven, automatic control, variable speed /adjustable stroke
                                                                               

5)      Transfer fluid from a reservoir of fluid (IBC or similar) by sucking it into the pump, manually adjustable flow rate                               

a.        Electrically driven pump, automatic control, variable speed or adjustable stroke capable of suction lift                                                                                                                                  

6)      Transfer fluid from a reservoir, suction lift, variable flow, automatic operation and programmable for different applications

a.       Electrically driven pump, automatic control, variable speed or stroke, suction lift and programmable

7)      Transfer fluid from a reservoir, suction lift, variable flow, programmable but I also need to signal the pump and or process status and indicate any faults

a.       Electrically driven pump, automatic control, variable speed, suction lift, programmable with status indication and fault signalling
                                                                                                                                                                                                                      

8)      Transfer fluid from a reservoir, suction lift, variable flow, programmable, status and fault indication but I am also pumping aggressive or toxic chemicals

a.       Electrically driven pump, automatic control, variable speed, suction lift, programmable status indication fault signalling and exotic materials
                                                                                                                                                                     

9)      Transfer fluids, suction lift, variable flow, programmable, status and fault indication, for aggressive chemicals, at high flow and or high pressure,

a.       Electrically driven pump, automatic control, variable speed, suction lift, programmable with status indication fault signalling, exotic materials and high flow / high pressure                                                                                                                                                                                                                                                                               

10)   Transfer fluids, suction lift, variable flow, fully programmable, status and fault signalling, for aggressive chemicals at high pressure / high flow in a hazardous area such as a petrochemical works and I need repeatability of process

a.       Electrically driven pump, automatic control, variable speed, suction lift, programmable with status indication fault signalling, exotic materials and high flow / high pressure for hazardous area application and or API design specification

You can use different terms for your applications, what we are trying to establish is that it is vital to understand that there is no reason to even ask for quotation for equipment in the 9 or 10 scale of complexity if your application actually only needs something in the 3 or 4 region, conversely do not expect a simple diaphragm dosing pump to be capable of products designed for the 8, 9, 10 categories, it will fail  “horses for courses”

Our experience dictates that applications for items in the 9 or 10 regions are less frequent than those in the 3 or 4 region, obviously the relevant costs will be higher for the more complex pumps.

What you must remember is that if you are dosing a toxic chemical into a process stream and you must monitor and adjust the system to achieve specific results and in the case of metering, accurately repeat the process “start thinking 8, 9 or 10” accept the fact that it will be more expensive initially but long term you will have safe reliable system with low whole life costs

Cheshire Pump Company can provide pumps for all of your dosing and metering applications from simple fluid transfer to fully programmable ATEX approved equipment designed to API specifications