In the field of instrumentation, pressure gauges are essential devices used to measure and monitor pressure in various industrial processes.

These gauges rely on different types of sensors and elements to accurately detect and display pressure readings.

In this article, we will delve into two commonly used pressure gauge sensors: C type sensors and spiral sensors.

We will explore their components, operation, material considerations for sensor stability, advantages of C type sensors, and compare them with spiral sensors.

Pressure Gauge Sensors and Elements

Pressure Gauge Sensors

Pressure gauge sensors are responsible for converting pressure into mechanical movement, which is then translated into readable values on the gauge dial.

Two widely employed sensor types are C type and spiral sensors, each with its own unique design and functionality.

Introduction to C Type Sensor

The C type sensor is a popular choice in pressure gauges due to its reliable and precise measurement capabilities.

It consists of several key components that work together to provide accurate pressure readings.

C Type sensor Introduction

Components of C Type Sensor

The C type sensor comprises a Bourdon tube, a link, a sector gear, a pinion gear, and a pointer.

The Bourdon tube, typically made of metallic materials like stainless steel or copper alloy, is a curved tube that tends to straighten under increasing pressure.

This straightening motion is transmitted through the link, sector gear, and pinion gear, resulting in the rotation of the pointer on the gauge dial.

Movement and Operation of C Type Sensor

As pressure is applied to the C type sensor, the Bourdon tube experiences a radial expansion, causing it to straighten.

This straightening movement converts the pressure into mechanical motion, which is then transferred to the sector gear and pinion gear.

The gears amplify the movement and rotate the pointer on the gauge dial, indicating the corresponding pressure value.

Material Considerations for Sensor Stability

To ensure sensor stability and accuracy, material selection is critical.

C type sensors are commonly constructed from stainless steel or copper alloy due to their excellent mechanical properties, resistance to corrosion, and stability over a wide range of pressures and temperatures.

The choice of material depends on the specific application requirements.

Advantages of C Type Sensor

These sensors offer several advantages that make them highly desirable for pressure measurement applications:

  1. High Accuracy: They provide precise and reliable pressure measurements, making them suitable for critical and demanding industrial processes.
  1. Wide Pressure Range: These sensors can handle a wide range of pressures, from low to high, ensuring versatility and adaptability across various applications.
  1. Durability: These sensors are known for their robust construction and resistance to environmental factors, ensuring long-term performance and reliability.

Introduction to Spiral Sensors

Spiral sensors are another type of pressure gauge sensor commonly found in instrumentation.

They offer distinct features and benefits compared to C type sensors.

Spiral Type sensor Introduction

Components and Operation of Spiral Sensors

Spiral sensors consist of a spiral-shaped sensing element, a connecting link, and a pointer-dial assembly.

The spiral-shaped element is designed to unwind or tighten under pressure changes, translating the pressure into rotational movement.

Pressure-Movement Relationship in Spiral Sensors

Spiral sensors exhibit a linear relationship between pressure and rotational movement.

As pressure increases, the spiral element unwinds, causing the pointer to rotate on the dial and
indicate the corresponding pressure value.

Description of Pointer and Dial in Spiral Sensors

The pointer-dial assembly in spiral sensors provides visual representation of pressure readings.

The pointer is connected to the spiral element, and its rotation corresponds to the pressure applied.

The dial is marked with calibrated units to facilitate accurate pressure interpretation.

Comparison: Spiral Sensors vs. C Type Sensors

While both spiral and C type sensors are widely used in pressure gauges, they differ in certain aspects:

  1. Design and Operation: C type sensors rely on the straightening motion of a Bourdon tube,
    while spiral sensors utilize the unwinding or tightening of a spiral-shaped element to measure pressure.
  1. Pressure-Response Characteristics: C type sensors exhibit non-linear pressure-response characteristics,
    while spiral sensors demonstrate a more linear relationship between pressure and rotational movement.
  1. Accuracy and Range: C type sensors offer high accuracy and are suitable for a wide pressure range,
    whereas spiral sensors may have limitations in terms of accuracy and range.


Pressure gauge sensors are vital components in the field of instrumentation, enabling precise measurement and monitoring of pressure in various industrial processes.

This article explored two commonly used sensors: C type and spiral sensors.

We examined their components, operation, material considerations, advantages of C type sensors, and compared them with spiral sensors.

By understanding the characteristics and functionalities of these sensors, professionals can make informed decisions when selecting pressure gauges for their specific applications.