---
title: Specifying Your Air Operated Diaphragm Pump
description: "Specifying Your Air Operated Diaphragm Pump\nAN AIR OPERATED DOUBLE DIAPHRAGM PUMP IS A VERY VERSATILE AND FORGIVING PUMP WHEN IT COMES TO WHAT IT CAN ACHIEVE."
---

[Unibloc Blog](https://blog.unibloctech.com)

# [Specifying Your Air Operated Diaphragm Pump](https://blog.unibloctech.com/specifying-your-air-operated-diaphragm-pump)

 Written by [Leighton Jones](https://blog.unibloctech.com/author/leighton-jones) | Feb 9, 2021, 5:41:00 PM

### Specifying Your Air Operated Diaphragm Pump

#### AN [AIR OPERATED DOUBLE DIAPHRAGM PUMP](https://unibloctech.com/brand/flotronic-one-nut-pumps/) IS A VERY VERSATILE AND FORGIVING PUMP WHEN IT COMES TO WHAT IT CAN ACHIEVE.

One pump can cover a multitude of applications; however there are some guidelines that can help with getting the right pump first time.

 

#### WHAT DO YOU NEED TO KNOW:

 

1. Name of the liquid that is going to be pumped.
2. Flow Rate required
3. Viscosity at pumping temperature
4. Specific Gravity
5. Any particulates in the liquid – what size – abrasive or not.
6. Maximum / Minimum Temperature of the Liquid being pumped, or any cleaning agent used to clean the pump.
7. Where is the liquid in relation to the pump – above or below the Inlet of the pump, how far from the pump.
8. Where are you moving the liquid to – above or below the pump, how far away from the pump.
9. Diameter of any existing or proposed suction / delivery pipework
10. Any certification requirements

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#### NAME OF THE LIQUID THAT IS GOING TO BE PUMPED:

 

- Use Chemical Compatibility Charts to select a suitable material for pump Body & Manifolds (Wetted Parts)
- Use Chemical Compatibility Charts to select Diaphragm Materials of construction, normally PTFE faced, though solid Nitrile or EPDM is also available. 
    - Wetted O Rings in Manifolds, etc will normally follow the material on the face of the Diaphragm.

#### FLOW RATE REQUIRED:

 

- Use the company Flow charts to select a suitable pump model in our range.
- Avoid selecting a pump at the top of its range, especially on a 24/7 application – aim to use a pump at between 25% and 75% of its performance.
- **[Flow Charts Available Here](https://www.flotronicpumps.com/uploads/documents/Flow%20Curves%20-%20All.pdf)**.

#### VISCOSITY AT PUMPING TEMPERATURE:

 

- Flow curves are calculated on water with viscosity of 1Cps.
- Higher Viscosity will affect the pump performance – check friction losses in any pipework before specifying a pump.
- Best option can be to over size the pump and aim to run it slowly.
- Also recommended to position the pump as close as possible to the source of the liquid and keep any pipework as straight as possible, with a minimum diameter same as the pump inlet.

#### SPECIFIC GRAVITY:

 

- Flow rates are calculated on water with an SG of 1
- Higher SG’s can affect pump performance especially if there is a Suction Lift required.

#### ANY PARTICULATES IN THE LIQUID – WHAT SIZE – ABRASIVE OR NOT:

 

- Check ball / manifold clearances are large enough to let any particles through the pump.
- If the liquid is abrasive, consider upgrading the pump with hardened parts to resist the abrasion.

<https://info.unibloctech.com/on-demand-webinar-how-to-use-aodd-pump-technology-to-improve-processing>

#### MAXIMUM / MINIMUM TEMPERATURE OF THE LIQUID BEING PUMPED, OR ANY CLEANING AGENT USED TO CLEAN THE PUMP

 

- Select Pump material to resist the max temperature – for example Stainless Steel / PTFE pumps are rated to 135°C, while Polypropylene is limited to 80°C.
- Select Diaphragms to resist Max Temperature – standard 100°C – High Temperature 135°C

#### WHERE IS THE LIQUID IN RELATION TO THE PUMP – ABOVE OR BELOW THE INLET OF THE PUMP, HOW FAR FROM THE PUMP.

 

- If the liquid is below the pump, you have a Suction Lift – Our AODD Pumps normally have a dry suction lift of 3.6 meters and a wet lift of 8.2 meters.
- If the liquid is in tanks above the pump – consider using reinforced diaphragms if the liquid is more than 5 meters above the pump.

#### WHERE ARE YOU MOVING THE LIQUID TO – ABOVE OR BELOW THE PUMP, HOW FAR AWAY FROM THE PUMP

 

- Diaphragm pumps work on a 1:1 ratio so the pump can achieve a liquid head the same as the air pressure given to the pump – 2 Bar Air Pressure will give a 20 meter head.
- Work out the friction losses in your pipework against the required flow rate to calculate the delivery head required.

#### DIAMETER OF ANY EXISTING OR PROPOSED SUCTION / DELIVERY PIPEWORK

 

- Inlet and outlet on the pump should be the same size as any pipework where possible.
- Avoid having an inlet connection on the pump larger than the diameter of the suction pipework.

#### ANY CERTIFICATION REQUIREMENTS.

 

Flotronic have pumps with all of the certifications below in their range.

- Sanitary Certification -  3A 
- FDA - **[(EC) 1935/2004](https://www.flotronicpumps.com/uploads/documents/COC%20-%20Food%20Safe%20(EC%201935-2004%20(10-2011)%20%26%202023-2006)%20March%201st.pdf)**
- **[ATEX certification for Explosive areas](https://www.flotronicpumps.com/atex/)**

 

### Appropriate **Pumps**

[**710 Series Stainless Steel Pump**](https://unibloctech.com/product/flotronic-710-series-stainless-steel-pump/)

<https://unibloctech.com/product/flotronic-710-series-stainless-steel-pump/>

[**Barrel Unloading System**](https://unibloctech.com/product/flotronic-barrel-unloading-system/)

 

 

[**Slimline Pump**](https://unibloctech.com/product/flotronic-slimline-pump/)

 

 

### Related Videos

##### [Flotronic One Nut Pump - Diaphragm Change](https://unibloctech.com/video_library/changing-a-diaphragm-on-the-one-nut-flotronic-air-operated-double-diaphragm-pump/)

##### [One Nut Animation](https://unibloctech.com/video_library/how-the-flotronic-unique-air-operated-double-diaphragm-pump-works/)

 

 

 

[View full post](https://blog.unibloctech.com/specifying-your-air-operated-diaphragm-pump)

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