Rotameter

What is a rotameter?

A rotameter also known as a flow meter is the basic piece of equipment, commonly used across various industries. It helps to measure different types of agents - both liquids and gases. Rotameters are particularly important devices for heating systems. They are used in underfloor heating, as well as radiator heating manifolds.

How does a rotameter work?

The principle of operation of a rotameter is strictly connected to its construction. Its main element is a tapered tube, so called measuring (flow) tube. It’s filled with an agent. In case of central and heating systems - it’s water. Another important element of a rotameter is a float, placed inside of the tube. Thanks to it, one can easily read the value of the force that impacts the element.

How to read values shown by a rotameter?

Rotameters installed by heating systems manifolds have a clear scale drawn on the flow tube. The float inside floats up or down to a certain level. Thanks to this one can read the volumetric flow rate - it’s the value indicated on the scale. Keep in mind that to show accurate values, a rotameter has to be properly installed, and its elements - the tube and the float have to be functional.

Rotameters - available types

A flowmeter is used in various industries. Depending on the intended use, one can find various models available on the market. It’s common to classify the devices by the types made of plastic, glass and metal. A particular material is a key feature for the parameters of the system using the rotameter.

Which rotameters should you choose?

Before picking a rotameter, one should pay attention to several aspects. First of all, consider the pressure and temperature - in other words, the conditions under which the device is going to operate. The basic principle states that:

• Glass rotameters can work in places the temperature is not higher than 80°C, and the maximum pressure is 20 bar.
• Plastic rotameters operate well in temperatures up to 110°C and pressure up to 30 bar.
• Metal rotameters are the most durable and can be used anywhere the pressure rises up to 40 bar and the temperature reaches even up to 300°C.

The mentioned pressure and temperature are not the only factors that should be taken into consideration when buying a rotameter. It’s also advised to specify the range of the measuring scale. Other key elements are the dimensions of the device, as well as the connection size. Thus, a rotameter is a piece of equipment that should be fitted individually to all the aforementioned aspects. It’s a crucial point that is going to impact the device’s proper operation.

Water flow meter installation

Before starting the installation process, it’s highly suggested to carefully check whether the rotameter is not broken. To do this, control the condition of the flow tube, and then check if the float moves around as it should. If everything is fine - you can begin the installation.

Choose the spot at which the rotameter is going to be installed - it should be an area that is free from vibrations. They might disturb the device’s operation. The flow through the tube should be from the bottom to top. Install the rotameter in a vertical position. It’s important, as even a small tilt might result in incorrect values.

A good move - if possible - is installing a stop valve, in front of and behind the rotameter. What’s their purpose? In case the flowmeter breaks down, one can easily replace it without cutting the flow in the whole system.

Each device typically comes with a manual - it’s suggested to read it before using the rotameter.

How to maintain and clean a rotameter?

Regular maintenance of a flow meter might influence the clarity of the values indicated on the flow tube. The cleaning process is not very complicated and it can be performed by using water with diluted detergent. If it has not been done for a very long time, one might have to dismantle the element.

In addition to cleaning, one should also control the technical condition of the device. The basic check-up involves controlling the leak tightness of the connections. The tube and float also need to be checked. If you notice any signs of leakage or malfunction - consider replacing the equipment.

How much does a rotameter cost?

The price of equipment like a rotameter mostly depends on a particular model. The most popular devices used in floor heating are not very expensive. What’s more, when the advantages of a rotameter are considered, it’s not a big investment at all.