The key difference between manometer and piezometer is that manometer is used to measure the gas pressure, whereas a piezometer is used to measure the liquid pressure.
Manometer and piezometer are two pressure-measuring devices that have applications in many occasions and experiments.
What is a Manometer?
A manometer is a device used to measure fluid pressure. Depending on different criteria, manometers can be categorized into different types of devices as follows:
- U-tube manometer
- Enlarged-Leg manometer
- Well-type manometer
- Inclined-Tube manometer
Among them, the U-tube manometer is the simplest device. It has a U-shaped tube or column that is filled with a reference liquid such as mercury. This displays the pressure level. Upon exposure of the column to the atmosphere, liquid levels in the limb tend to be equal, and it also indicates atmospheric pressure. Moreover, if we connect one of the columns to the pressure vessel, a difference in the level of the liquid in the limbs can be observed. This can signify the pressure of the liquid in the vessel.
An enlarged-leg manometer has a float that can be observed in the enlarged leg that we can use to note or indicate the value. There are two legs in this system. They can be changed to change the measurement span.
A well-type manometer has a large well in one of the legs. There is another leg that features a simple tube. There is a large change in the height of the tube upon a minute change in the displacement of the levels of the liquid in the well.
An inclined-tube manometer has a slant shape, and it has a -degree angle of the measuring leg. This device has a sensitivity that is improved with the inclination. Usually, this type of device is used in measuring small differences in pressure.
What is a Piezometer?
Piezometer is a device that is useful in measuring underground water pressure. This device can convert the water pressure into a frequency signal through a diaphragm and a tensioned steel wire. This wire can vibrate at its natural frequency when a change in pressure happens on the diaphragm. After that, the vibration of the wire that is located close to the magnetic coil can generate a frequency signal that can transmit the signal to the readout device.
There is a nest of piezometers that can be important in indicating the pressure; a greater pressure can lead to a greater elevation of the top of the water that can be found inside the piezometer.
In the context of groundwater measurements, the first piezometers used were open wells or standpipes that are installed into an aquifer. Moreover, this type of device that is in a durable casing can be buried and pushed into the ground for the measurement of the groundwater pressure at a desired point of installation.
What is the Difference Between Manometer and Piezometer?
The manometer and piezometer are two types of devices that are useful in measuring pressure. The key difference between manometer and piezometer is that the manometer is used to measure the gas pressure, whereas the piezometer is used to measure the liquid pressure.
Below is a summary of the difference between manometer and piezometer in tabular form for side-by-side comparison.
Summary – Manometer vs Piezometer
Manometers and piezometers are two useful pressure-measuring devices. The key difference between manometer and piezometer is that manometer is used to measure the gas pressure, whereas a piezometer is used to measure the liquid pressure.
1. “MAXIMATOR-High-Pressure-Manometer-01a” By CEphoto, Uwe Aranas or alternatively © CEphoto, Uwe Aranas (CC BY-SA 3.0) via Commons Wikimedia
2. “Zone de l’union6476” By Lamiot – Own work (CC BY-SA 3.0) via Commons Wikimedia