It is very important to choose the right valve type when buying diaphragm valves. This article will introduce common diaphragm valve types. It will explain how they work, how they are operated, and what they are used for. This article will help you to choose the right valve before you buy it.
Diaphragm Valve Types by Body Design
Weir Type Diaphragm Valve
The Weir-type diaphragm valve has a special structure with a weir inside. When the valve is closed, the diaphragm sticks to the weir to create a seal. The short stroke of the diaphragm can keep the seal in place when it is in use.
Weir-type diaphragm valves are suitable for corrosive media and frequent opening and closing applications. They are used a lot in industrial systems, like chemical and water treatment.
Weir-type diaphragm valves last a long time, are easy to look after, and are cheap. This type of valve is well-established, has been used in many situations, and is reliable for most standard industrial settings.
Straight-Through Diaphragm Valve
Straight-through diaphragm valves are mainly used in situations where the risk of clogging is high. The valve body has a straight flow channel without a weir structure. It allows the medium to pass smoothly through the valve and reduces stagnation and build-up within it.
Straight-through diaphragm valves are often used when dealing with slurries, sludge, and materials with solid particles. In these conditions, it’s often more important to reduce the risk of clogging than to control the flow precisely, so the straight-through design is better.
Straight-through diaphragm valves have three main advantages. They can handle more liquid at once, are less likely to get blocked, and make the system more stable. However, it should be noted that because the diaphragm is subjected to greater deformation and stress throughout its entire stroke, it usually has a shorter lifespan than the Weir-type diaphragm valve.
Diaphragm Valve Types by Actuation Method
Manual Diaphragm Valves
Manual diaphragm valves are good for systems that are simple and don’t have a lot of moving parts. If you’re using small equipment, auxiliary pipelines, or applications that don’t need to be adjusted often, you can meet the basic usage requirements by using them manually.
The advantages of manual diaphragm valves are that they are cheaper, simpler to make, and easier to install and maintain. If you don’t have much money and don’t need a high level of control, this type of valve is a good choice.
Pneumatic Diaphragm Valves
Pneumatic diaphragm valves are often used in process systems that are always running. In these types of operating conditions, valves need to respond to control signals stably and quickly, and pneumatic drive is more likely to meet the system’s operational requirements.
When buying valves, it’s important to look at how quickly they respond and what their usual state is (normally open or normally closed). This helps to make sure that the system works safely in unusual situations, like when there’s a gas outage. Pneumatic diaphragm valves usually need to be used with a control system. In some cases, a positioner is also used to improve control accuracy.
Electric / Hydraulic Diaphragm Valves
You should use electric or hydraulic diaphragm valves when you need precise control or when there is no air supply on site. These valves can replace pneumatic actuators, which makes them a reliable option for valve control. They are usually only used when pneumatic diaphragm valves are not suitable, because they are quite expensive and need special computer equipment.
Diaphragm Valve Types by Application Requirement
Industrial Process Diaphragm Valves
Industrial process diaphragm valves are often used in places like chemical processing and water treatment, where they need to work reliably for a long time. When choosing a valve, the most important things to consider are how well it can resist rust, how reliable it is, and how much it costs to maintain. This helps to make sure that the system can be used safely and without any problems.
Hygienic Diaphragm Valves
Sanitary diaphragm valves are used mostly in the food, pharmaceutical, and bioengineering industries. In these industries, how easy it is to clean and if it follows the relevant rules or not directly affect how safe the production is and the quality of the product.
Normal industrial diaphragm valves often create cleaning dead zones, so there may be some contamination. So, when buying sanitary diaphragm valves, you need to think about how well they clean, if they can be cleaned using CIP/SIP, and how the surface is finished. This will make sure that the valves meet the industry’s hygiene and safety requirements.
How to Choose the Right Diaphragm Valve？
You can work out which diaphragm valve is right for you by answering a few simple questions.
Is The Fluid Solid or Liquid?
If the liquid has solid particles, sludge, or is likely to scale, you can choose a Straight-Through diaphragm valve to reduce the risk of it getting blocked. If you are dealing with clean media, you can choose a Weir-type diaphragm valve.
Do You Need to Automate The Process?
Pneumatic diaphragm valves are often used for systems that need to be controlled from a distance or are used a lot. For applications with a lower operating frequency where manual operation is enough, manual diaphragm valves are usually good enough.
Are There Any Rules about Compliance or Hygiene?
If you need to use it in the food, pharmaceutical, or bioengineering industries, you should choose a Hygienic diaphragm valve. It is not recommended to use a general industrial diaphragm valve.
Do You Care More about Lifespan or Flow Capacity?
If you want a valve that will last a long time and work well, Weir-type diaphragm valves are the best choice. If you want a valve that can handle a lot of water and won’t get clogged, Straight-Through diaphragm valves are a good option.
By answering the questions above, you can quickly identify several suitable diaphragm valve types, which will reduce the risk of choosing the wrong ones and make buying them easier.
FAQ
If You Select The Wrong Type of Diaphragm Valve, Will Replacing The Diaphragm Later Solve The Problem?
Usually not. The way the diaphragm valve is built affects how the liquid flows through it and puts pressure on the diaphragm. If the type of diaphragm is not right for the conditions it’s used in, replacing the diaphragm cannot solve the problems of blockage or lifespan.
Are There Big Price Differences between Weir-type and Straight-through Diaphragm Valves?
The two models are usually pretty similar in terms of price, drive method, and specs. The differences are how often they need to be cleaned, how often the diaphragm needs to be replaced, and how much they cost to run over time.
Are Pneumatic Diaphragm Valves Suitable for Automation Systems?
It may not be suitable. Pneumatic diaphragm valves are used a lot in automation systems, but it’s still necessary to check that their response speed and failure state (normally open or normally closed) meet the system’s requirements. If these conditions don’t match, it will affect how the system normally works.
Can Sanitary Diaphragm Valves Be Used in General Industrial Applications?
Yes, but they will cost more. Sanitary diaphragm valves are made to a higher standard and cost more. If the application doesn’t have any sanitary requirements, a standard industrial diaphragm valve is usually a better choice.
Once You Know The Type of Diaphragm Valve, What Should You Do Next?
Once you have figured out what kind of diaphragm valve you need, the next steps are usually:
The materials used for the diaphragm and valve body
The size and pressure rating
How to install it and what interface is required
Final Thoughts
In selecting diaphragm valves, the type of valve is more important than the size and material. You can only consider the size and material in practice when the types actually match.
Target Hydraulics is a company that knows a lot about industrial fluid control solutions. They have lots of experience with diaphragm valves and have a professional technical team. If you are unsure which type of diaphragm valve is best for your needs, please contact us. Just tell us what your media is, how it’s used, and what you need it for, and we’ll suggest the best valve for the job. This way, you won’t have any surprises, and your system will be more reliable in the long run.
