Reed switches and Reed sensors in Spirometers

A Lung function test or Pulmonary Function test, PFT for short, is a system to evaluate the respiration system of a patient. It uses a Spirometer to check how much air a person’s lungs can hold, how quickly he or she can move air in and out of the lungs, or how well the lungs add oxygen to the blood and remove carbon dioxide from the blood. The result of these tests help rule out lung diseases such as Bronchitis or Asthma.

A PFT equipment consists of a Spirometer, and generates a graph called a Spirogram. This shows a graphical plot of the flow of air going in and coming out of the lungs. The patient is given a tube, and told to take air into the lungs fully, and exhale by blowing into the tube for as long as possible. This volume and speed of air intake is then translated to lung function. The results of the graph are left to the interpretation of the Doctor after taking into account the body type, age and gender of the patient.

Reed Switches help measure the volume of intake and the time. The Spirometer’s spindle consists of multi-pole magnet and an reed switch which counts the number of pulses or rotations taken by the spindle. The pulses generated are used by the PFT’s controller to generate the graph and assess the patients lung capacity and functionality.

Application Classification

Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.

Pulse Counting Type

Pulse counting type application When an application requires the volume of a fluid, or a distance, or the RPM of a machine tool Continue reading -> Nov 7, 2020

Recommended Products

The Reed Switches and Sensors used in such applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.

UM-0018-M Ultra Miniature Reed Switch

This highly sensitive, Form A type, UM-0018-M Ultra Miniature Reed Switches are designed for switching high speed signal loads with an Continue reading -> Nov 8, 2022

UM-0018-H Ultra Miniature Reed Switch

These highly sensitive, Ultra Miniature Form A reed switches are designed for low power, high speed switching applications and Continue reading -> Nov 8, 2022

MS-212 Ultra-miniature Cylindrical Sensor

MS-212 Magnet Sensor Drawing starFeatures10W Contact Rating. Normally Open contact. Two sensitivity bands. Sputtered Ruthenium Continue reading -> Oct 30, 2020