Conical Union or Flat-Face Union? How to Choose the Right One?
When selecting industrial fittings, the question often arises: what is the difference between a conical union and a flat-face union? Both solutions are used to easily disconnect an installation, but their sealing methods are completely different. Choosing the right type has a direct impact on the tightness and reliability of the entire system.
What is a union?
A union is a threaded fitting that allows installation components to be quickly disconnected without the need to rotate the pipes. It is commonly used in water, heating, compressed air installations and in industry.
The two most common types are:
Conical Union – Metal-to-Metal Sealing
In a conical union, tightness is achieved by the perfect fit of two conical surfaces.
Advantages:
✔ no additional gasket,
✔ high durability,
✔ resistance to high temperatures,
✔ fewer consumable components.
This type of union is very often used in industrial installations where durability and connection reliability are important.
Flat-Face Union – Sealing with a Gasket
A flat-face union uses a flat gasket most commonly made of:
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rubber,
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PTFE,
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fibre,
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sealing materials intended for a specific medium.
When the nut is tightened, the gasket is compressed between two flat surfaces, ensuring tightness of the connection.
Advantages:
✔ easy gasket replacement,
✔ simple construction,
✔ possibility of selecting the gasket according to the medium and operating temperature.
How to Recognise the Difference?
The easiest way is to look at the sealing surface.
Conical union
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has a conical surface,
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does not have a flat gasket,
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seals through contact between two metal cones.
Flat-face union
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has a flat surface,
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uses an additional gasket,
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tightness depends on the condition of the gasket.
Which Union to Choose?
There is no universal solution.
The selection depends on:
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type of medium,
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operating temperature,
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pressure,
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installation requirements,
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method of subsequent servicing.
If you are not sure which union will be suitable, it is worth consulting the choice with people who work with industrial fittings on a daily basis.
Why Buy from POLBERIS?
At POLBERIS, we offer a wide selection of steel, stainless steel and galvanized unions for industrial and installation applications.
Why do customers choose us?
✔ wide selection of sizes and materials,
✔ products for industrial and high-pressure installations,
✔ fast shipping from stock,
✔ professional technical advice,
✔ thousands of products available from stock.
Our specialists will help you select the appropriate union for a specific application, helping you avoid costly mistakes and downtime.
Looking for the Right Union?
Check the POLBERIS offer and choose a solution suited to your installation. If you have questions about selecting conical or flat-face unions, contact us – we will be happy to help you choose the best solution for your application.