Mechanical diaphragm pumps vs Hydraulic diaphragm pumps

[ADAG]

Hello,
I need to select a metering pump for an Aluminum Sulfate Solution (20%) in a Potable Water Treatment Plant.
Capacity: 100 gph, 24-hour full load service.

What are the issues to consider when choosing between an Hydraulic and a Mechanical diaphragm pump? Advantages and disadvantages of each?


Any help will be greatly appreciated.

Regards,

Armando

 

[BigJay]

ADAG

Here is a starter for 10.

Your dose rate may well be the key issue. Is the 100 gph related to the solution or the chemical mass flow? Either way, a finger in the air guess says that your volume flow rate is going to be in the order of 0.1 to 1 lph. At this low flow rate, motor driven or solenoid pumps are the cheapest and most practical option. You should select a duty standby system with flow monitoring or similar controlling the changeover. The pumps will cost a few hundred pounds (uk), the pipe work and controls will have a similar cost.

Hope that this helps.

 

[BigJay]

Further to last post.

I assumed that by gph you meant gramms per hour.
Did you actually mean gallons per hour?

 

[ADAG]

Thanks Jay, I actually meant gallons (of solution) per hour and this is pretty much a constant figure. Probably that is too much for a solenoid pump?

Best Regards,

 

[BigJay]

Gallons per hour being the case then I agree, solenoids are out of the window. However, I would still advise a duty standby system on whatever you use, as both pump types you have mentioned are vulnerable to the occaisional failure.
I have used Alldoss and Prominent pumps in similar conditions and both makes are satisfactory.

Regards

 

[bimr]

The standard pump for your application is a mechanical diaphragm pump by manufacturer's such as Bran + Luebbe or Milton Royal.

A quality mechanical diaphragm pump probably has a lifetime of 20 years and the operating folks love them. The electronic solenoid driven pumps are for light duty applications and for the most part, are throwaways and should be avoided unless you want to deal with a maintenance headache.

The hydraulic diaphragm pump is probably a little more heavy duty pump than the mechanical diaphragm pump and probably more heavy duty than what you need for your application. Generally, on potable water application, you are discharging to low pressure.


The website here gives a good comparison of the pumps:

http://www.cstechnology.com.au/MeteringPumps.html