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Engineers often use metal domes in electronic applications. However, a lesser-known use case for metal domes is as a pressure switch. As a result, metal domes are an overlooked solution for air or water pressure switches. Still, metal domes can be a cost-effective and easy-to-use alternative for engineers designing such devices.
What is a Pressure Switch? And, How to Incorporate Metal Domes
A pressure switch, also known as a differential pressure switch, is an electro-mechanical device that can recognize a difference in pressure between two points. These devices create an electrical connection when it reaches a certain threshold, most typically by air or water. The switch makes an electrical contact on either rise or fall from a certain preset level.
The most common type uses a pre-adjusted spring to sense the volume difference. Then, you can use it to make a contact change for an increase or decrease in pressure.
Alternatively, you can use a tactile metal dome to sense the desired force of a pressure application. When the micro-switch is triggered, the dome’s pretension directly correlates to the air or water pressure actuating the switch, making an electric contact. When the pressure drops, the metal dome resets to its original state.
Types of Switch Contact
Pressure switches usually have two different types of contact: normally open or normally closed. You can use both to make a contact change based on an increase or decrease in pressure.
When using a metal dome as normally open, the dome is mounted and curved away from the PCB contact pad. It will remain open until enough pressure can close it. Physical force from air or water applied to the top of the dome pushes the dome down until it encounters the PCB and closes the switch.
Snaptron custom designs and manufactures a variety of round metal domes that reliably and accurately work for these kinds of devices, specifically with limited space. Round domes, custom-designed to go bi-stable, meaning the state of a dome exhibits two stable conditions, can be used as normally open pressure switches. However, they can also function as normally closed pressure switches depending on your needs.
A Custom Solution From REA Technologies Pressure Switch Solution
REA Technologies partnered with Snaptron to research a novel design for a normally closed differential pressure switch. This version requires only two components, a stainless-steel dome soldered to a circular PCB board. Mount the dome curved toward and in contact with the PCB for this unique configuration. Design the small round dome with a flange so you can fully solder it down to support and seal the switch assembly. REA Technologies can also make it incorporate gold-to-gold contacts.
The switch operates when air or water pressure pushes the dome away from the PCB’s contact pad, opening the circuit. It maintains electrical contact until the applied pressure becomes strong enough to break the connection. Once the pressure decreases, the metal dome resets to its normally closed state.
The REA Technologies option is reliable and capable of hundreds of thousands of cycles. Therefore, it would be a desirable choice for remotely monitoring pressure containers and pipelines. Additionally, it has a very small, accurate pressure threshold. As a result, you can use various switch applications across many different industries such as aerospace, defense, marine, automotive, or energy.
Engineers can use metal domes not only in electronic user interface applications but also as reliable, unique pressure switches. In addition, they are cost-effective and easy to implement into designs. Choose a normally open or normally closed version—metal domes provide an innovative, consistent pressure switch solution when space is limited and accuracy is critical.
Contact a Snaptron sales representative today to learn more about our pressure switch solutions.
