During the Graduate Marine Engineer interview, you may be asked questions regarding your technical knowledge, including topics like pressure gauges. Let's dive into the types and working of pressure gauges to help you prepare.
Pressure gauges are essential instruments used to measure the pressure of fluids or gases in various systems. They provide valuable information for maintaining safe and efficient operations on ships and other marine vessels.
There are a few different types of pressure gauges commonly used in marine engineering:
Bourdon Tube Pressure Gauge: This is the most widely used type of pressure gauge. It consists of a curved, elastic tube (usually made of metal) that changes shape when pressure is applied. The tube is connected to a pointer mechanism, which indicates the pressure on a scale. Bourdon tube gauges can measure both low and high pressures accurately.
Diaphragm Pressure Gauge: Diaphragm gauges use a flexible diaphragm that deforms under pressure. This deformation is transmitted to a pointer or digital display to provide a pressure reading. Diaphragm gauges are suitable for measuring low to moderate pressures and are often used for sensitive applications.
Differential Pressure Gauge: This type of gauge is used to measure the pressure difference between two points in a system. It consists of two pressure inputs connected to a mechanism that calculates and displays the differential pressure. Differential pressure gauges are commonly used in systems with filters, pumps, or flow restrictions.
The working principle of pressure gauges involves the conversion of pressure into mechanical movement or electrical signals. In the case of a Bourdon tube pressure gauge, when pressure is applied to the tube, it tends to straighten. This causes the mechanism connected to the tube to move, resulting in the rotation of a pointer on a scale. The scale is calibrated to provide an accurate pressure reading.
Diaphragm pressure gauges work similarly, but instead of a curved tube, a flexible diaphragm is used. The diaphragm deforms under pressure, which is then translated into movement of the pointer or digital display.
Pressure gauges should be regularly calibrated and maintained to ensure their accuracy. Marine engineers must have a good understanding of pressure gauges, including their types, working principles, and appropriate applications, to effectively monitor and control pressure in marine systems.
