Flow switches are quite useful and perform a wide variety of functions. Some are for measurements of flow, for instance, while others work in a protective fashion, shutting down a pump or valve when a certain threshold is met. In today’s article we are going to discuss the insertion flow switch and go a little into flow switches in general so that you have a better idea of how they function and what kinds of applications that the various types are suited for. Let’s take a closer look at flow switches and how they work.
What are flow switches?
Flow switches are, simply put, devices which can monitor flow (and sometimes other variables) and can send signals to other devices. This can be utilized to shut a system down, for instance, if a safety threshold has been violated, or it could simply supply metrics so that the flow in a particular system might be managed. Flow switches measure the flow of steam, gas, or liquids and what differentiates them from flow meters is that a switch will generally have a valve body, a switching unit, and a sensing device. Think of them as flow meters with extended functionality.
What are the types of Flow switches?
Flow switches are generally categorized within 4 types. The types are as follows:
- Velocity – Velocity switches are designed to measure the speed of flow, generally in cubic feet per minute.
- Volumetric – Volumetric switches are designed to measure the flow of gas or liquid, measuring in volume per increment of time.
- Liquid – Designed for lubricants, water, chemicals, and slumes, Liquid flow switches are quite indispensible to many industry applications.
- Gas – Gas switches are used for such things as steam or air and are most commonly used with HVAC systems for measurement and protection of the units.
Insertion flow switch types
Now that we have categorized the basic types, let’s talk a little about some of the most common insertion flow switch types that you will encounter:
- Paddle – Paddle flow switches (or vane sensors) generally employ an electrical contact for a specific flow rate target. These have many applications, such as air conditioning, damper control, checking boiler air flow, or general protection of pumps and motors against low or no flow scenarios.
- Piezo – Piezo flow switches, like the paddle variety, use electrical sensors in order to effectively monitor flow conditions in pipes. Applications for Piezo flow switches include food processing, oiling systems, distributors, and rotary drum flow measurements.
- Shuttle/Piston – Shuttle (or piston) flow switches employ an electrical output and target a specific flow rate that can be measured with many mediums, such as water, gas, oil, and air. Applications of these switches include low flow detection in cooling pipelines, lubrication systems, and oil flow measurements.
- Thermal – Thermal switches are concerned with utilizing heat to measure flow and accomplish this typically with dual sensors and electrical contact outputs. Excellent for leak detection, these units are typically employed in water heaters, liquid transfer, and chillers.
Let’s take a look at a few examples of flow switches that are commonly used in Industry today.
Series V8 Flotect Vane Operated Flow Switch
Our first example is a Paddle/Vane model called the Series V8 from Dwyer. This switch is leak proof and chemical resistant, fitting a 1 to 6 inch pipe and it is ideal for preventing impacts to production by
“This switch is leak proof and chemical resistant”
protecting unattended equipment. This unit has an operation pressure range scaling up to 10 bar (150 PSIG) and is rated for temperatures up to 100 degrees Celsius/212 degrees Fahrenheit. Applications for this switch include heating and refrigeration, air conditioning, water treatment, cooling lines, food processing, chemical processing, machinery, and machine tools. If you would like to learn more about the flow switch then feel free to click the link below:
Series P1 Brass Flow Switch
These brass piston-type flow switches are optimal for detecting excessive or insufficient flow patterns, with .10 – 1.5 preset actuation pointsfor the measurement of liquid flow. Ideal applications for the Series P1 include Hydraulic systems fluid management, Semiconductor coolant flow, and Industrial cleaning equipment flow monitoring. If you would like to learn more about the Series P1 flow switch then feel free to click the link below:
Series TDFS2 Thermal Dispersion Flow Switch
Our third entry is the Series TDFS2 Thermal dispersion flow switch. This flow switch is designed to track whether the flow rate is above or below the level which you have defined. It utilizes LED lights in order to provide a quick visual of this data and comes with both NO and NC NPN outputs. Applications for the Series TDFS2 include Chillers, Liquid transfer systems, water heaters, and Boiler flow measurements. For more information please feel free to click the link below:
Series BFM Bulk Flow Monitor
Our last entry is the Series BFM Bulk Flow monitor and this Piezo – style flow monitor comes with a lot of bells and whistles. Designed for monitoring low or no flow scenarios in chutes or pipes, the dentral processing unit is capable of monitoring virtually anything that is travelling through the pipes and it is excellent for detecting materials or their absence in Pneumatic Conveyance systems. Two LED indicators (green for flow, red for no flow) help to give you the flow status at a glance and these easy to install units need no maintenance once they are in place. The Series BFM is also good for a large number of applications, such as:
- Drag converyors
- Air and water systems
- Food processing
- Chemical processing
- Oil spray/lubrication systems
- Rotary drums
- Discharge chutes
- Gravity feed and slurry systems
For more information on the Series BFM please feel free to click the link below:
Today we’ve discussed the function and types of flow switches in an effort to clear up a little of the mystery and to explain what they can do for you. If you are managing a building or large industry endeavor be sure to consider adding flow switches to your current infrastructure. You’ll be glad that you did!