outlet. In response to the difference in pressure, the liquid will travel up the column a distance that can Depending on the application, at PCE Instruments, in the category Manometers, you will find a large selection of built-in and handheld instruments. The principle behind a manometer gas or liquid pressure gauge is extremely simple. Hydrostatic equilibrium shows that the pressure when a liquid is at rest is equal at any point. For example, if both ends of the U-tube are left open to the atmosphere then the pressure on each side will be equal. As a consequence the level of the liquid on the left-hand side will be the same as the level of the liquid on the right-hand side – equilibrium. However, if one end of the U-tube is left open to the atmosphere and the other connected to an additional gas/liquid supply this will create different pressures. U-tube manometer working principle The traditional U-Tube device is the most common with one end of the partially liquid filled tube open to the atmosphere and the other connected to an outside source. By measuring the different heights of liquid on the left and the right hand side of the U-tube it is possible to calculate the pressure from the outside source in relation to atmospheric pressure.

The inverted U-tube design is used to measure low-pressure between two separate points to a relatively high level of accuracy. Liquid is introduced to the U-tube at either end with a volume of air separating the different liquids. The use of a tap allows air to be expelled from or admitted into the inverted U-tube device. Thereby adjusting the pressure difference and giving an accurate reading

On the 10th of July 2015, a crew member from the M.V. Hyundai Dangjin died when he fell from the ladder whilst reading the outboard draught marks. Manometers are proven tools for accurately determining the outboard draught marks and negate the need for climbing down the side of a ship to read the marks whilst the ship is alongside a wharf. Manometers add to the safe working practices of surveyors and seafarers and provide safety for the ship itself. Manometers work on typically having a U-shaped tube filled with either mercury or water. The reason that Will measurements be taken in multiple locations or just one? In other words, does the manometer need to be portable or stationary? fluid, freon etc. To use the APM digital manometers with these media, isolation must be provided in the form of a buffer, such as mineral oil or dry air.

The micro-design is a modified version of the basic U-tube except one side of the tube has a larger cross-section. The manometer definition of measuring pressure is still the same but due to the structure of the U-tube it is able to measure minute pressure differences. Digital gas manometers are used by heating and boiler engineers for a variety of purposes including monitoring gas pressure in piping systems. It is important to ensure a manometer used for gas pressure is ATEX approved as this certification ensures the instrument is suitable for use in potentially hazardous environments. Manometers for Water Pressure Simple U-shaped manometers are often no more complicated than this, with an engineer having to calculate the exact differential pressure between the sources. Most electrical manometers do most of the hard work

Product Specification

The following sections outline some of the different types of manometers in further detail: U-Tube Manometers A manometer measures pressure difference, either between a process and a fixed reference pressure (gauge or absolute manometers) or between two ports (differential manometers). How to Use a Manometer

U-tube manometers are one of the simplest varieties available. They are a type of analogue manometer commonly used as differential pressure measurement instruments with flow meters, often used when measuring pressure difference in pitot tubes, nozzles and orifices in airflow and ventilation systems. While these two devices are used to measure air pressure there are subtle differences. If we look at the original mercury barometers they were simply a glass tube filled with the mercury and part-vacuum. The height of the mercury column would rise and fall in tandem with differing atmospheric pressure. This was calibrated against a scale allowing the measurement of actual atmospheric pressure. The main point being that the tube was one column and both ends were closed. A liquid manometer in comparison to a mercury barometer, showing the difference in working principle Operating standards can fluctuate from one ship to the next, and ship list management is not an exception. I have worked with officers who have had no practical means of accurately measuring their ship’s list and have accepted a 20cm list as being upright when conducting a draught survey. Being able to manage and evaluate list accurately is paramount to safe loading practices and can assist greatly in the accuracy of draught survey calculations.U-tube manometers consist of relatively few parts and are usually one of the cheaper types of manometer, but the trade-off for this is that accuracy can be poor. As a result, a u-tube manometer should not be used to measure particularly small pressure differences and an alternative manometer should be used instead. Lastly, the viewing angle is key when working with u-tube manometers to ensure the reading is as accurate as possible. Micromanometers Before commencing work it is very important to make sure that your manometer is suitable for the task at Inclined manometers are typically used to measure liquids and gases where the pressure is very low. The angled design of the inclined manometer makes it particularly well-suited to this role, enabling accurate measurements to be taken. Despite this, digital manometers are often preferred nowadays due to their high levels of accuracy and ease of use. Digital Manometers The accuracy of manometers ensures that ships can be made upright after completion of loading. This is an important safety factor for ships loading to maximum sailing draughts, as a ship that is listing after completion of loading will end up exceeding the maximum sailing draught on either to port or starboard side. gas and air condition systems at close to atmospheric pressures. A correctly calibrated tester can also

Since so many different types of manometer are available, it is recommended to refer to the operating manual of your manometer to determine instructions for use. Advantages and Disadvantages of Manometers When using a manometer to measure water pressure, the model in use must be suitable for liquids to avoid potential damage to the instrument. Similarly, if the liquid contains chemicals or other potentially hazardous substances, you should be aware of the damage it could cause if an unsuitable manometer is used. Additionally, over-pressuring the manometer may cause subsequent readings to be incorrect due to internal diaphragm bending or rupturing, so it is essential to use the correct instrument with care. Manometers for Air PressureThe Anton APM series of instruments are suitable for use with most gaseous and liquid media (including water). They are NOT suitable for use with corrosive substances or cyclic hydrocarbons, e.g. motor oil, transmission A manometer allows the measurement of additional liquid/gas sources against atmospheric pressure or against other liquid/gas sources. There are various types which allow you to adjust the pressure on one side to give a more accurate reading. It is also the option to have closed/open ends and the U-tube design which differentiates these two pressure measurement devices. A differential U-tube is closed and both ends are filled with different liquid/gas at different pressures. This tends to be used where the pressure needs to be measured directly, not based on an outside pressure. Micromanometers are similar to other manometer types, but they are specifically designed to measure very small pressure differences. These instruments are highly sensitive and are well suited to taking accurate, precise readings of the smallest differences. Although they are primarily used for measuring differential pressure, micromanometers can also be used to test or balance systems and calculate velocity or volumetric flow rate. Inclined Manometers hand. There is a very wide range of different manometers that specialise in testing between different