Man operating CNC drilling and boring machine in workshop.

WIKA’s GLS-1000 incorporates the best of both worlds: the simple design and operating principle of the mechanical float switch, but with modern digital switching technology. For even more functionality, it can come with a temperature sensor. This innovative yet economical solution is ideal for measuring level and temperature in a hydraulic power pack’s fluid tank. 

Float switchesare the go-to devices for measuring liquid levels across multiple industries. They consist of just a few components –guide tube, float, some switches – which make them the most economical way to monitor limit levels. Commonly found in hydraulic power packs, compressors, and cooling systems, float switches make sure that a process receives the right amount of media; if the fluid goes above or below a predetermined level within a tank, the switch automatically shuts off to prevent overflow or dry running.

The Elegance of Float Switches

The float switch working principle is as simple as it is effective. A float with a built-in magnet moves up or down a guide tube alongside the liquid level of a vessel. At defined measuring points, the magnet triggers a hermetically sealed reed contact that has a normally open (N/O), normally closed (N/C), or changeover function. Since the float’s magnetic field – and not the physical float itself – is responsible for activating the mechanical switch, the entire operation is contact-free and, therefore, potential-free.

The float switch is also a highly versatile level instrument. It works effectively in oil, water, diesel, refrigerants, and even foamy liquids. To ensure the instrument is optimized for a particular medium’s density, operating temperature, and other characteristics, the float can come in a variety of shapes, sizes, and materials. 

Digital Float Switch: The Same Simplicity but with More Functionality

Hydraulic power pack diagram

Design principle and application description of a hydraulic power pack (HPP)

The float switch has entered the 21st century. The digital float switch retains all the positives of the conventional version and adds even more versatility, namely the capability to process digital signals. 

Instead of the classic reed contacts found in a conventional float switch, the digital version has a semiconductor sensor. The magnetic field of the float’s magnet activates this sensor, resulting in a measurable resistance change. The electronics of the switch detects and processes this resistance change to generate an electrical switching signal. 

The digital signal via the PNP/NPN switching output provides an unlimited number of switching cycles. Since there are no mechanical contacts, as is the case with conventional float switches, the semiconductor sensor does not suffer from wear and tear.

Digital Float Switch in a Hydraulic Power Pack

Hydraulic power packs(HPPs) are standalone units that provide the necessary power to run presses, lifts, tools, and industrial machines of all types. For safety and efficiency, operators need to ensure that the fluid level, temperature, and pressure are all within prescribed operating limits. For an HPP oil tank, the key measurements are level and temperature.

 digital float switch can monitor a tank’s limit levels in real time to avoid the damaging effects of having too much or too little fluid. The semiconductor sensor supplies an extremely reliable switching function over its long lifetime. With the addition of an RTD, digital float switches have the ability to monitor both level and temperature.

WIKA’s Digital Float Switch: A Hardworking Sensor for Both Level and Temperature

The GLS Digital Float Switch

Model GLS-1000 float switch with digital switching technology

With its PNP/NPN switching output signal, long service life, and excellent resistance to shock and vibration, WIKA’s GLS-1000digital float switch is a versatile, durable, and cost-effective solution for monitoring limit levels in HPP oil tanks and other vessels. 

The process connections, guide tube, and case are all stainless steel for a long service life. The cylindrical or spherical floats are made of 316Ti (a stainless steel alloy) or Buna/NBR (nitrile rubber), and come in a range of diameters, heights, operating pressures, and medium temperatures. The GLS-1000 can feature up to four switching points that are either PNP or NPN. And since it has the same design and geometry as mechanical float switches, users can easily swap out their classic float switch with this digital model.

For extra convenience, the GLS-1000 can be outfitted with a temperature sensor in the form of a 2-wire Pt100 or Pt1000 resistance thermometer. Since an HPP oil tank requires both level and temperature monitoring, this two-in-one option saves space, installation time, and money.  

The semiconductor float switch’s advanced electronics also open the door for future functionalities – internal diagnostic capabilities, sensor parameterizing options, operational status display – that are currently available only in more expensive level measuring technologies such as guided microwave, ultrasound, or vibration limit switches. Customers who make the switch today are poised to integrate digital level measurement into the automated manufacturing processes of tomorrow.

As with all float switches, this device is not designed for use in liquids with large or coarse particles, nor should the liquid be highly viscous, highly abrasive, or have a tendency to crystallize. All these conditions impede the free movement of the float within its chamber.

Since the company’s founding in 1946, WIKA has been at the forefront of technological advancements. At the same time, we understand the importance of the bottom line and pride ourselves on designing and recommending cost-effective solutions for our customers. Contact us with your questions and comments about our line of level monitoring solutions, including whether it’s time to swap out your classic reed-contact float switch for a digital model.

Leave a Reply