Level and Pressure Sensors, Gauges, Switches


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Cates offers the full line of APG products.

Ultrasonic Level Sensors

APG offers a line of sensors with accuracy of 0.25% of detected range.

Because the speed of sound is constant, under fixed atmospheric conditions, the time from the sound burst to the return is measured and translated into a distance. The sensor’s microprocessor calculates the distance and converts it to a level indication, volume measurement, or a rate of flow. It also compensates for temperature, and filters the signal. 

Common uses for ultrasonic level sensors are level, volume, and flow monitoring. Other uses include presence or absence detection, and object dimensioning. 

Continuous Float Level Transmitters

APG offers magnorestrictive level measurement sensors. Continuous flow level transmitters can be used in a very wide variety of liquids. Applications that require a heavy duty sensor with a simple setup and long lifespan are an ideal fit for APG float transmitters.

Submersible Pressure Transducers

Submersible pressure transducers work just like other pressure transducers, except they’re inside a water-tight housing, and they read in feet or inches of liquid (adjusted to specific gravity) rather than PSI.

Sumbersible pressure transducers are incredibly versatile and inexpensive. They can measure the level of just about any liquid within their temperature range. Because of this, they’re often used in waste liquids where the exact chemical makeup is ill defined. They’re also becoming popular for battery powered applications because of their low current draw.

Float Switches

Float switches work much like a standard light switch, they open and close contacts to control whether or not signal current can pass through. They are either Normally Closed, meaning current is flowing, or Normally Open, meaning current is not flowing. The “Normal” state is when the float switch is down, resting on its cable or float stop.

Point level sensors in general are great for controlling pumps and alarms when a liquid level must be maintained within a certain window of acceptance. A great example is pump control. If tanks get too full, there are two risks, overflow, and if filled from the bottom, pump failure. If a tank gets too low, you risk pump failure as well. Float switches are a great method for turning pumps on and off.  

Level Switches

APG offers pneumatic, paddle wheel, and vibrating level switches. Each has its own merits for specific applications.

Controllers & Displays

APG controllers and displays are designed for flexibility and simplicity. They work very well for remote standalone applications where control systems are unavailable, or as a convenient display as part of a larger system.

Digital Pressure Gauges

Digital pressure gauges use pressure transducers to provide a reliable, high accuracy reading on an attached digital display. Unlike analog (dial) pressure gauges, digital gauges are built for reliability in demanding conditions.

APG digital pressure gauges are inherently durable. They’re built to withstand the tough stuff, like vibration, over pressure, water hammer, etc.

Pressure Transducers

APG pressure transmitters, also known as pressure transducers, use piezoresistive technology to accurately measure pressure.

There are a few different methods of mounting the sensing element to the pressure transmitter diaphragm. Each has its own set of pros and cons. For example, some perform better in low pressure environments, others in high pressure. We’ll use the best method according to the configuration of your sensor. 

APG pressure transmitters are used throughout the industry, in both process and storage environments. The PT-L families are built for industrial applications in pressure ranges up to 10,000 psi, and are suitable for both liquids and gasses. They are designed to provide accurate measurements and a long life expectancy at a low cost. 

Hammer Union Pressure Transducers

Like all APG pressure transmitters, the hammer union pressure transducer uses piezoresistive principles to monitor pressure on a diaphragm. The real difference is how it is constructed to handle the shock, vibration, weather, and rough handling that prevails on a drilling or production rig.

Hammer union pressure transducers are an important tool on an oil and gas rig. They provide critical measurements during drilling and production operations, such as the following:

  • Acidizing
  • Measurement While Drilling
  • on Chocke Manifolds
  • Extraction
  • Fracturing and Cementing
  • on Mud Pumps
  • New Well Development
  • Nitrogen Injection
  • on Service and Cement Trucks
  • on Standpipes
  • Stimulation
  • and Wellhead Measurement

Tank Cloud M2M Remote Tank Level Monitoring

Tank Cloud is perfected for a single remote tank, or an entire tank farm. APG has it convered, no matter what the situation.

APG Tank Cloud master level sensors connect directly to the Internet for single tank applications. They also use Modbus to connect up to 10 slave sensors for tank farm applications.

The sensors can be programmed remotely — so once the sensors are on the tanks, powered up, and connected you can walk away and do the rest from your office.


Cates Control Solutions
14221 Gulfstream Park
Webster, Texas 77598


(713) 944-0101 PHONE
(800) 882-1881 PHONE


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