Fluid Switch Blog

How to Choose a Level Sensor

level sensor

We speak frequently about the various applications where level sensing is used and how to best provide accurate measurements. But for this post though, we’ll be going back to basics to overview some of the most important things to consider when you are choosing a level sensor. After all, this decision will be the measure that keeps your machines and operations running smoothly and safely.

Step 1: Determine the Substance & What Must Be Measured

This is perhaps one of the most important factors in choosing a level sensor. Different liquids characteristics must be considered to make an accurate measurement. For example, highly viscous liquids like oils and grease can change the sensor requirements.

Other factors that affect monitoring a liquid level is factoring in if there could be build up in the tanks if it will be sticky or corrosive, and even the specific gravity of the liquid (the ratio of the object’s density to that of water).

In addition to the liquid being measured, you must also consider the tank that’s holding the material as its part of the larger picture.

For example, if there are limits to how the sensor is mounted to it, if the temperature inside must remain a certain degree or if there are pressure requirement or vibrating conditions that could possibly alter the accurate measurement, you’ll need to consider these factors in advance.

Determine if switching or continuous level monitoring is required for the application prior to making a selection. Also, submersible sensors placed inside a tank or those that are mounting externally are options you’ll need to choose from.

Step 2: Consider Conditional Factors

Outside of the most basic elements detailed above, you’ll need to also consider conditional factors that could change your options for level monitoring.

Can the contents inside the tank make contact with the sensor at all? Will it affect performance over time if so? Level sensor options will change based on these details.

  • Pressure sensors provide accurate measure using the measure of the bottom and open space within a tank.
  • Float switches work by measuring the level of a liquid based on its ability to float on the surface. They can be mounted vertically or horizontally and mounted on the inside or outside of a tank.
  • Ultrasonic level sensors use waves and echoes to measure a substances level and service.

Gathering as much information as possible will arm you with key information to make the best decision for level sensors.

Have questions? Need Answers? Speak to the professionals at SMD Fluid Controls. We can make recommendations, build custom solutions that work for you and help you feel confident you’re making the right choice for your application.


Multilevel Sensors for Chemical Processing

Custom Multilevel Sensors

Chemical processing plants are under stringent demands for quality and accuracy. These facilities also operate under unique environments where caustic fluids are present. One small inconsistency can easily result in a bad batch or even dangerous outcomes. To improve the measure of liquids at these facilities, level sensors are required that can be customized to fit different tanks and to be chemically resistant.

Choosing the right level sensor can improve quality and maximize output while also providing key real-time data on the liquids in vessels.

Here are some options to consider when it comes to multilevel sensors for chemical processing.

Direction & Location of Switches

One of the key considerations when choosing the correct level sensor for chemical processing is where and how it will be mounted. Both Horizontal and Vertical sensors mounted on top, bottom and tank level, can be made from a variety of materials depending on the chemicals used.

The FM10 & FM20 multilevel float switches are ideal for many chemical environments because they resist corrosion and can be used in restrictive spaces as well as handle high pressures and temperatures being used in many chemical applications.

Customized multilevel float switches can be used when you need precise monitoring of liquid levels in a tank while also saving space.

Early Planning Help

If your application will require a customized level sensor or float switch, but you’re unsure exactly what’s needed, the engineers at SMD Fluid Controls will work with you to design a fully customized multilevel fluid switch that does what you need it to, precisely and unique to your needs. Configure and customize switches and sensors work with up to six fluid levels.

Speak with an expert today!

Customized Sensors: Get the Fit You Need

Fluid sensors and level switches are used in a number of applications across industries to provide leak detection, overflow alarms, low-level warnings and even overfill shutoffs. In many of these cases, they are detrimental to operations and livelihood.

These sensors can be mounted on vessels in a number of different ways – top, side and back mounted, for example, depending on a number of factors. When used, they provide an accurate measure of the contents inside. Applications like agricultural machines, fuel delivery systems, chemical processing and so many others all make use of the sensors to operate safely and efficiently each day.

customized sensor

Sometimes though, basic won’t cut it. Standard sensors are great for so many reasons, yes. They help get the job done, offer protections and necessary advanced warnings -but what happens when you have a harsh environment, above normal heat requirements or serious dangers present?

At Fluidswitch we offer OEM customized versions of standard sensors so they can do what you need them to for your application.

Here are just some of the reasons why customizing sensors may be necessary:

  •           Safety Concerns

Depending on operating conditions and your specific application, you may require extra safety outside of the usual. In rugged applications or where discrete wiring and jackets on cables for volatile environments is necessary you may need a custom-designed sensor.  Our team will work with you to make sure your demands are met.

  •        Temperature Demands

For some applications, maintaining a certain temperature as well as liquid level in the vessel is critical. Think about bottling consumer beverages or chemical processing plants where accurate temperature maintenance will make or break an outcome. Fluidswitch can integrate both of these capabilities into a single unit to help you save space and resources while achieving the correct outcomes.

  •     Unique Batch Requirements

Another reason you may be wondering about customization for level sensors and float switches can relate to how large or small a job is. If you’ve taken on a load that’s not typical for your usual production numbers and you don’t want to over order unnecessary resources, no matter the quantity, SMD Fluid Controls will work with you no matter the quantity – large and small and get you the parts you need.

Have questions? Ask us about customizing parts to fit your needs!

Contact us today to schedule a consultation!


Better Water Management: Level Monitoring and Pump Controls

water management tank

Water is an essential element that’s used in a multitude of ways each day. Proper management is important for safety measures as well as conservation efforts. For this reason, there are a number of wastewater treatment options and monitoring systems that can be used.

In water towers for example, where water reserves are stored for droughts and power outages, maintaining proper water levels and pressure is critical. Then there are wastewater facilities, where there’s also an urgent need to monitor tank levels and have alarms that sound before an overflow situation occurs.

In addition to overflow dangers, there are issues like building up of matter on the walls of a vessel, sludge in the tanks and pressure loss that can all negatively impact water management.

Pump controls and level sensors added to these applications are a solution for accurately monitoring and helping to ensure water remains safely stored and separated.

SMD Fluid Controls offers pump level control options so you can regulate fluid levels and configure your tank system as needed. Using a pump or valve with a Double Pole Double Throw (DPDT) relay as well as float level switches combined with your product, we can help tanks to automatically pump up or down and keep your application running as needed.

Contact SMD to configure your application!

Oil & Water Might Not Mix but Here’s How to Measure Their Liquid Levels Anyway

oil water mix

Oil and water don’t mix. It’s not only a common analogy used to describe two things that are very different from one another, it’s also something that’s visually obvious if you’ve ever poured the two liquids into the same vessel. The oil will always float to the top because of density and the molecules in each substance. In other words, their specific gravity values are different.

When it comes to monitoring liquid levels in a tank this might seem like an issue but with the right level sensor, it’s no problem at all. Here’s why.

First, let’s look at a more practical scenario of this occurrence:

In a tank that collects runoff at a worksite, for example, both water and oil will be present. A pump is used to remove excess but must do so by taking each substance out one at a time.

Oil, since it floats to the top, can be removed first and then recycled. The level sensor should indicate when all the oil’s been removed and turn off before water is accidentally pumped into the new oil reserve.

SMD Fluid Switch fs20

SMD answers to the call for needs like this and more with its FS20-2090.

The FS20 model float switches are intended to be used as an oil/water interface switch that will sink in oil and float on water. Made from 316 stainless steel and custom-designed for high-pressure applications, the models have a specific gravity of .70 with 150°C max temperature and a max PSIG of 750.

If you’re in the market for a specific density sensor to work with your application, let the experts at SMD Fluid Switch help. We can provide full size, miniature, specialty and customized vertical float switches perfect for the job whatever your industry and whatever your needs.

Contact us today!

Perfecting Moisture Control with Liquid Level Sensors


For people living in New England this summer, humidity has become a regular weather occurrence. In addition to threats for tropical storms, the conditions make the skin feel sticky and even make it difficult to breathe.

To assist with keeping rooms at reasonable temperatures and conditions, dehumidifiers offer a solution. These machines work to remove moisture in the air and prevent mold, dust, and allergens as well as reduce energy consumption. To do so, they pull moisture into the dehumidifier and process it through coils that are cooled with a refrigerant. The result is cooler, drier air.

Recognizing how much moisture has been removed and when the machine should and should not be running requires accurate measure.

By adding a liquid level switch to your dehumidifier you can provide customers with a more reliable and efficient machine as well as more comfortable living conditions.

Other parts of the country are also battling record hot temps but they are experiencing the opposite and instead dry air wreaking havoc on comfort levels. Humidifiers can be used to add just the right amount of moisture back into the air. As A/Cs are in overdrive cooling spaces, these machines need to accurately release moisture levels in the air. With a level sensor placed inside the machine, you don’t have to worry about the humidifier running constantly or erroneously turning on once water has run out and causing breakage.

SMD Fluid Controls manufactures and supplies a wide variety of fluid switches, float switches, temperature gauges, and liquid level sensors. Looking for a standard off-the-shelf product or custom sensors designed to meet your specific needs? We can make sensors to measure anything!


Level Sensors: How They Work & What They Do

liquid level sensors

How do you measure the level of liquid in a contained space that’s flowing freely and in some cases too hot or dangerous to come in contact with? The answer is –  Level Sensors.

Using a magnet and reed, the most basic sensors can monitor liquid levels through the activation of switches that activate alarm about too much or too little liquid present in the container.

But don’t let their simplicity fool you. Level sensors aren’t just loved because of their cost sensibility, they are also vital to operations in industries across the globe. They don’t just measure the presence of a medium in a container, but also the absence. These low-level warnings and can even detect leaks before dangerous situations occur. This accuracy and dependability keeps businesses successful and the public safe.

Liquid measurement and monitoring is so important in fact, that new devices and technologies continue to incorporate the sensors in them as a way to deliver important data to and from advanced machines.

Depending on the type of process materials being measured, different sensor types can be used.

Two options for how to handle materials are typically chosen from – contact or non-contact measurement. This is based on various factors from the density to the temperature of the material being measured and whether or not there are sanitary requirements. As the name indicates, a contact measurement method would be the sensor located inside the vessel itself and able to come in contact with the material being measured without putting the project at risk. A non-contact method would include a sensor mounted to the outside of the tank.

Here is a break down on the different types of sensors offered by SMD Fluid Controls.

Contact Sensors:

Float Switches – These are the most commonly used devices for level measurement and utilize magnetic floats and reed relays to measure liquid medium.


FL50 – Chemical Resistant Plastic Ultrasonic Point Level Sensor


Contacting UltrasonicThese options are great for point level measurement of liquid and work by measuring the timing and speed of sound waves.

Optical SwitchesThese sensors have built-in electronics and work with no moving parts. They can perform point level sensing and pressure sensing up to 2500 psi.

optical sensor

OS950 – Miniature Plastic Optical Level Sensor

Submersible Tank Level Sensor – These are a versatile option that can gauge tank levels by the hydrostatic pressure and offer stable and continuous measurement from depths up to 211 meters.

submersible sensor

FT60 – Downhole Submersible Level Sensors

Non-Contact Sensors:

Ultrasonic Radar – This option uses radio waves to measure levels and is best for highly viscous or difficult liquid media that must be measured in real-time. Our ultrasonic sensors are made from 316 stainless steel and have a temperature maximum of 90°C with pressures up to 5,000 PSI in custom configurations.

Load CellsThis non-contact method of measurement is typically used outside of a tank to measure its contents by weight and may be suitable when non-contact with materials being measured is required.

Ready to order? Have questions?

Whether you need a prefabricated float switch or a custom designed liquid level sensor, we can help! Our full OEM services are available whatever your industry and whatever your needs! Contact us today!

Level Sensing in Healthcare: Improving Bioreactor Vessel Conditions


In the medical field, laboratories are filled with research and development teams testing and improving pharmaceutical drugs and other life-saving innovations. A key piece of equipment in this is a bioreactor vessel which is used to create a biologically active environment where chemical processes, as well as live organisms, can be tested and studied.

In order to work properly, the bioreactor vessel’s internal environment must remain at accurate temperatures, nutrient concentrations and maintain any pressurization or gases for fermentation or oxygen.

Level sensors incorporated into the bioreactor vessels helps manage these needs.

Level sensing is critical in medical environments and biotechnology especially inside a bioreactor vessel where the process of agitating broth, consisting of cell culture and raw materials, and allowing it to settle happens. Once the broth subsides, fermentation begins and this emits carbon dioxide as a result of cell growth.

The Problem

While the vessel consists of filters responsible for the gas exchange and protection from outside contaminants, a foaming resulting from fermentation creates a unique problem in the vessel. If the foam level reaches the filters, it then disrupts the gas exchange and can even damage the filter itself.  Once this occurs, staff must use a pricey de-foaming agent to lower the foaming level in the vessel so its use is economically unsound.

Capacitive Level Sensors

At FluidSwitch we can help with this issue by installing a capacitive level sensor, also known as RF admittance. This will only diffuse the de-foaming agent when the level sensor detects foam.

The Capacitive level sensor works by, “processing capacitance with reference to the dielectric constant of the material being measured and the voltage being used to complete the circuit. These measurements are used to determine vessel levels. Higher levels of dielectric material result in greater capacitance, meaning the former can be easily gauged with the latter.”

Utilizing this sensor would decrease the cost of the defoaming agent as well decrease the loss of expensive culture in the vessel due to damaged filters.

Spend less time trying to keep the bioreactor vessels contents safe and more time focused on developing new important innovations.

Get in touch with Fluid Switch today!

Better Irrigation Management with Ultrasonic Liquid Level Sensing

irrigation on farm

It’s no secret that today’s farmers and the agricultural industry as a whole are faced with many challenges when it comes to providing high quality and consistent food for consumption.

One of the largest risks is food waste and the discarding of less than perfect crop yields for selling in stores. These deformed fruits and vegetables and those with abrasions are adding up 20 billion pounds of produce that are being left out.

The USDA has found that “30 million acres of cropland, 4.2 trillion gallons of irrigation water, 1.8 billion pounds of nitrogen fertilizer, and 780 million pounds of pesticides went into producing food that was thrown away.”

Controlling the delivery of water to crops is important for sustaining profitable yields of food production and has been around for ages.

For this blog, we’ll look at a key way to turn things around and it starts crop-level with the resources being used to monitor and deliver vital water to these plants. Referred to as, “precision agriculture” farms can maintain precise water allocation as a tool for curbing food waste.

This is done through the use of ultrasonic liquid level sensors.

Today, automated irrigation distribution systems are becoming a popular choice over traditional methods because they remove the intensive human labor required to open and close gates and they provide much greater accuracy when it comes to water level measurement.

As an effective method, irrigation staff is no longer needed to manually raise gates to release water. Not only reducing intensive labor demands and saving water but also removing the factor of human error from the equation.

Utilizing ultrasonic liquid level sensing, sensor-driven channel gates that distribute precise volumes of water based on requested parameters are possible.

There’s more.

The sensors are also collecting important data that can be shared with farmers to provide exact details on how much water was delivered and help define future orders. Reducing waste of precious water resources especially during a drought, and even protecting crops from rot and damage due to overwater.

SMD Fluid Controls offers a variety of ultrasonic liquid level sensors and transmitters for continuous, non-contact tank level measurement. Our industrial ultrasonic sensors operate using the most state of the art working principles and are available in a variety of materials and prices.

Get in touch to learn more about how we can help with your application’s specific requirements.

Surviving a Heatwave: Float Switches Make Generator Power Reliable

heat wave sun

As a heatwave makes its way through many U.S. states and record temperatures are predicted, it’s important to remember the chances this weather has to also create dangerous conditions at work and at home. Everything from tropical storms, lightning, and power outages are possible.

In some cases, power outages can be truly detrimental. Consider the hospitals where lives depend on electricity to keep people alive or construction sites and factories where power is critical to maintaining operations and productivity.

The chances of an outage during extreme heatwaves are attributed to increased electricity consumption and high-temperatures as well as storm damage.

Luckily, generators exist to ensure power can be maintained at these critical sites. Even these, however, require fuel and ongoing maintenance to operate properly.

Enter float switches.

Keeping generators working reliably and without hiccups requires a steady supply of fuel. Float switches can monitor fuel levels to prevent overflow and to ensure the equipment never becomes low, leading to shut off.

In the case of either condition becoming an issue, the float switch can also be used to send an alarm and alert users of the changed conditions before it becomes a spill or breakage.

Whether you need a prefabricated float switch or a custom designed liquid level sensor, SMD Fluid Controls can help. Get in touch today!

Understanding which generator is necessary for your needs is important to guide you to the float switch application best suited to monitor and maintain that power source. Once you’ve selected the appropriate equipment, monitoring standards can be set.

SMD Fluid Controls offers a wide variety of industrial float switches and liquid level sensors as well as custom multilevel fluid switches, combination level and temperature sensors, ultrasonic liquid level sensors, and optical level sensors for a diverse range of uses.