Case study: Double Diaphragm Pumps in Chemical Application

A chemical manufacturer/supplier was transitioning to a new facility and looking to reduce their reliance on compressed air. They had purchased a facility that would be completely renovated into a new manufacutring plant giving them the opportunity to evaluate all kinds of pumping options and technologies for installation into the new facility. They had previously employed various pump technologies from centrifugal and gear pumps to air-operated double diaphragm (AODD) pumps - each having its own benefits and drawbacks.

Why avoid centrifugal pumps?

While centrifugal pumps are electric driven and more efficient than AODDs, users lose out on many operational benefits provided with the simple yet reliable double diaphragm pump technology. Centrifugal pumps do not handle solids well and cannot deadhead or be run dry.  They also shear fluids and can foam or froth depending on the chemical – some of the key advantages offered by double diaphragm pump technology. 

Many of the chemicals used can have some level of solids or particulates suspended in the material which can be difficult for a centrifugal pump to handle effectively.  Centrifugal pumps also impart more shear on the liquid chemicals and can aerate and froth or foam up the fluid more than a diaphragm pump depending on the chemical being pumped. 

Why not gear pumps?

Like centrifugal pumps, gear pumps are electric driven, so they check the box for lack of compressed air.  They still come with many of the challenges that centrifugal pumps come with.  Rotary pumps impart more shear, and they all have a mechanical seal that can cause issues with leaking and wear.  They are also more difficult and costly to maintain and repair for the maintenance crew that must keep the plant functioning. 

Are diaphragm pumps the ultimate choice?

Evaluating all their options, they determined that diaphragm pumps were the most robust and least troublesome solution for chemical transfer within the facility.  Double diaphragm pumps can handle any material they needed to run through it. The pumps can self-prime and run dry as needed and are easily maintained.  They decided to bring over numerous 2-inch Graco AODD pumps from their old facility and purchased some additional air pumps, but the company still did not want to rely solely on pneumatic pump technology due to the massive air consumption and compressor install that would be required. AODD pumps were selected for applications in which the pump isn’t running that often since they’re durable, safe, and easy to wash down if chemicals are spilled on them. 

"There were even times the compressors would turn on when the pumps weren't even running, just because there were enough leaks adding up that the employees couldn't find or see that would fire the compressors"

- Plant Manager

QUANTM EODD: The Solution that Bridged the Gap

2-inch QUANTM electric-operated double diaphragm (EODD) pumps were selected and installed at the updated plant location. The company selected applications with longer run times where they would feel the full benefit of going electric. This allowed them to avoid purchasing and maintaining an additional compressed air system.

QUANTM pumps provide the same operational benefits as an AODD pump – they don’t require relief valves, check valves, or return lines and can be run dry and stalled when needed.  They can handle all the materials being transferred within the facility without worrying about shear or mechanical seal and part life.  By using direct electric power, the pumps are up to 80% more energy efficient than the pneumatic counterparts. This allowed the facility to minimize the size and number of compressors that were installed in the new plant location which reduces overall operating costs and install costs, driving a sizeable cost savings for the user.

By eliminating the need for compressed air, QUANTM pumps remove the air exhaust and the muffler as well, meaning the pumps will not freeze, addressing another common issue with AODD Pumps.  With no muffler, QUANTM is also a completely sealed system, so chemicals could not leak into the plant through the muffler exhaust in the event of a diaphragm failure.  This, along with the noise reduction of electric pumps, creates a cleaner and safer environment for workers and reduces the chance the plant will have a reportable loss of containment instance with a pump.

Chemical Blending Facility Applications

Pneumatic Pump Applications

Air-operated double diaphragm (AODD) pumps were selected for several transfer applications in the new facility. This technology was selected for these applications because it can withstand the dirty environments and hold up to the variety of chemicals pumped. They were mainly placed in applications that have shorter run times, helping to minimize the company’s reliance on compressed air.  

1. Loading and unloading from trucks
   The customer uses either pressurized gas or an AODD pump to load and unload tanks for transfer. This process is the same whether they are loading/unloading at their facility or at their customer site.  The preference is to load and unload from the bottom of the tanker to prevent foaming, but the safer method is to fill from the top which presents challenges. 
   
   
2. Raw Material from drums & totes to mixers
   Several AODD pumps are used as a mobile solution to unload material from the smaller containers into mixers in smaller volumes. Pneumatic pumps were selected for this application due to their versatility to move around the facility and ability to handle the various chemicals as well as being easy to wash between chemicals.
   
   
3. Wastewater Treatment
   All pumps in selected for wastewater applications in this facility are pneumatic – while the mixer runs all the time, the pumps are not continuous operation between tanks which limits the amount of compressed air required and did not justify installing an electric QUANTM pump.
   1. Like all chemical companies, they capture any run off from the process into a general holding area and need a pump with good suction to evacuate the sump water into the large mixing tanks. 2-inch double diaphragm pumps were selected for the water treatment process because there are usually solids.
   2. Chemicals are added into the mixing tanks to help clean the water before it is run through the filter press. AODD pumps are used for each step of the transfer process from tanks through the filter press and back to the next tank for another quality test until the water is up to city standards.
   3. An AODD pump is also used to pass water through the filter press. The pump is connected to a controller that will increase pressure up to 100 psi at which point they will take apart the filter press and remove sludge from the filter.

QUANTM Electric Pump Applications

QUANTM electric-operated double diaphragm (EODD) pumps were chosen in applications with longer run times where the company would feel the full benefit of going electric. This allowed them to minimize their air compressor capacity and avoid purchasing additional compressed air systems for the new location. 

1. Raw material from tanks to mixers
   QUANTM EODD pumps are installed to transport raw material from large, bulk holding tanks to the mix tanks where the final chemical blend is created. Some of the lines are over 500 feet with minimal pitch to help with flow and pressure on the pump. QUANTM pumps were selected for this application because operational hours here are higher than when pulling from a small tote.
   
   
2. Final product from blenders/mixers to trucks and containers
   QUANTM Pumps also sit under the blending tanks to evacuate final product and send it to fill the truck or container that will deliver it to their customer. Similar to the raw material tanks, these are fixed mounted pumps that will transfer thousands of gallons of material over per batch and will run at much higher capacities than the small tote transfer pumps.  For this reason, it was deemed that QUANTM electric pumps made the most sense.  With QUANTM pumps being a sealed system, it also is a safer option for under tank mount applications due to the lack of muffler exhaust that could spill chemical when a diaphragm fails.

The transition to a new facility provided the chemical manufacturer with the opportunity to optimize their pump technology. By carefully evaluating the drawbacks of centrifugal and gear pumps, they recognized the superior performance and operational benefits of double diaphragm pumps. The integration of QUANTM EODD pumps further enhanced by efficiency, safety and cost-effectiveness reduces the need for compressed air and minimizes environmental risks. This strategic decision not only improved their operational capabilities but also created a cleaner, safer and more sustainable manufacturing environment.