The Engineer's Guide to Combined Level & Temperature Sensors
Why Monitoring Both Level and Temperature Matters in Hydraulic Systems
Maintaining the correct oil level and temperature in hydraulic systems is critical for safe and efficient performance. Ignoring either parameter risks equipment failure and costly downtime. Modern industrial operations cannot afford the luxury of reactive maintenance approaches when it comes to hydraulic system management.
In real-world hydraulic systems, even a short deviation from recommended oil temperature or level can accelerate oxidation, damage seals, and reduce overall efficiency. The interconnected nature of these parameters means that problems in one area quickly cascade into system-wide issues. Continuous monitoring allows maintenance teams to take preventive measures before costly breakdowns occur, transforming maintenance from a reactive to a proactive discipline.
The consequences of inadequate monitoring are both immediate and long-term:
- If oil overheats, it can lose viscosity, oxidize, and break down. This leads to reduced lubrication, cavitation, and damage to seals and pumps. Overheated hydraulic fluid becomes a chain reaction of problems, where decreased lubrication properties cause increased friction, which generates even more heat, creating a destructive cycle that can destroy expensive components within hours.
- If oil runs too low, pumps may run dry, resulting in immediate mechanical wear and potential system shutdowns. Low oil levels also lead to air entrainment, which causes erratic system behavior, increased noise levels, and accelerated component wear throughout the entire hydraulic circuit.
A hydraulic level sensor paired with temperature monitoring prevents these failures by ensuring systems stay within safe operating ranges. This dual-parameter approach provides engineers with comprehensive visibility into system health, enabling data-driven maintenance decisions that extend equipment life and optimize performance. With a high-temperature level sensor and an integrated temperature-sensing switch, engineers gain precise insight into fluid conditions and avoid catastrophic outcomes.
Industries such as mining, construction, and heavy manufacturing depend on uninterrupted hydraulic performance. In these high-demand environments, where downtime can cost thousands of dollars per hour, a hydraulic level sensor combined with a high-temperature level sensor is not simply a monitoring tool—it becomes a critical safeguard. The harsh operating conditions in these industries, including exposure to dust, vibration, extreme temperatures, and corrosive substances, make reliable monitoring even more essential. When integrated with a temperature-sensing switch, the system can automatically trigger alarms or shutdowns, protecting workers, equipment, and production schedules.
How Combined Sensors Work
A combined level and temperature sensor integrates two measurement functions into one unit, representing a significant advancement in hydraulic system monitoring technology. The engineering behind these devices combines proven measurement principles with modern materials and manufacturing techniques to create robust, reliable monitoring solutions.
The float mechanism detects the liquid level while a built-in probe or switch monitors the temperature. Together, they provide comprehensive monitoring in a compact device. This integration eliminates the complexity and potential reliability issues associated with managing multiple separate sensors, cables, and connection points.
In industrial environments, this integrated design reduces wiring complexity and minimizes potential failure points. The consolidation of monitoring functions into a single device also simplifies system diagnostics and troubleshooting, as technicians only need to focus on one component rather than coordinating between multiple sensors. The use of durable materials such as stainless steel or brass ensures that the sensor can withstand vibration, sudden pressure changes, and fluid contaminants without performance loss.
The core components work in harmony to provide accurate, real-time monitoring:
- Float mechanism: Senses rising or falling fluid levels through a precisely engineered buoyancy system that responds to even minor level changes, providing early warning of potential problems.
- Temperature element: Activates when fluids exceed a set limit, utilizing thermostatic principles that have been refined through decades of industrial application and proven reliable in the most demanding environments.
Compared to using two separate sensors, a combined solution offers significant operational advantages:
- Space savings in compact reservoirs are particularly important in mobile equipment and tight installation environments where every cubic inch matters.
- Fewer wiring points and simpler installation, reducing both initial installation time and ongoing maintenance requirements.
- Improved reliability by reducing potential failure points, following the engineering principle that fewer components typically mean higher overall system reliability.
Engineers can use a temperature-sensing switch to trigger alarms or automatic shutdowns if overheating occurs. This combination ensures hydraulic systems remain both cooled and sufficiently filled, which is essential for maintaining uptime. The automated response capability removes human error from the equation and provides protection even during unmanned operation periods.
In critical applications, the temperature sensing switch is often connected to PLC or SCADA systems, enabling real-time alerts for remote operators. This digital integration provides an extra layer of protection in mining, chemical plants, or power generation facilities. The ability to integrate with existing control systems means that hydraulic monitoring becomes part of a comprehensive facility management approach, where all systems work together to optimize performance and prevent failures.
Key Selection Criteria
Choosing the right industrial temperature sensor with integrated level monitoring requires evaluating both environmental and system factors. The selection process should consider not only current operating conditions but also potential future changes in system requirements or operating environments.
Materials
Material selection represents one of the most critical decisions in sensor specification, directly impacting both performance and longevity:
| Brass | Cost-effective and suitable for mild conditions, brass offers good corrosion resistance in many hydraulic fluids and provides excellent machinability for custom configurations when needed. |
| Stainless Steel | Resistant to corrosion, chemicals, and high heat. Ideal for aggressive environments and food-grade systems. Stainless steel construction also provides superior resistance to vibration and mechanical stress, making it the preferred choice for mobile equipment and high-vibration applications. |
Mounting Options
Proper mounting configuration ensures optimal sensor performance and longevity:
Vertical stem for top-entry installations, providing direct access to the fluid while maintaining easy serviceability and calibration access.
Horizontal mounting for side-entry applications, ideal for situations where top access is limited or where specific level detection points are required.
NPT threaded fittings for secure connections in pressurized tanks, ensuring leak-proof installation and providing standardized connection points that simplify replacement and maintenance procedures.
Pressure & Temperature Ratings
System compatibility requires careful attention to operating parameters:
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Confirm the sensor's maximum operating pressure matches the hydraulic system, including consideration of pressure spikes and transient conditions that may exceed normal operating pressure
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Select a high temperature level sensor when working with hot hydraulic oils or fluids above standard operating ranges, ensuring that the sensor maintains accuracy and reliability even under extreme thermal conditions.
Electrical Outputs
Output selection should align with system control requirements and future expansion plans:
Switch output
Simple on/off signaling when thresholds are reached, ideal for basic alarm systems and straightforward control applications.
Continuous output
Real-time monitoring for integration with digital control systems, providing detailed data for trend analysis and predictive maintenance programs.
By carefully evaluating these criteria, engineers ensure the chosen hydraulic level sensor will operate reliably and deliver accurate data across the system's life cycle. This thorough selection process represents an investment in long-term system reliability and performance optimization.
Applications and Use Cases
Combined sensors are used wherever hydraulic reliability is essential, spanning diverse industries and applications that demand uncompromising performance and reliability.
Heavy-Duty Hydraulic Reservoirs
The Series 20 is a heavy-duty sensor for high-temperature fluids, designed for large industrial systems. It withstands continuous operation and ensures reservoirs remain within safe parameters. These applications typically involve large-capacity reservoirs serving multiple hydraulic circuits, where sensor failure could impact entire production lines or critical infrastructure systems.
OEM Compact Equipment
Series 40 and 43 miniature sensors are ideal for smaller mobile equipment. They combine space efficiency with durability, supporting OEMs that require integrated monitoring in tight designs. Mobile equipment presents unique challenges, including vibration, space constraints, and varied operating conditions, making these compact sensors essential for reliable operation.
High-Temperature Fluids and Harsh Environments
When hydraulic systems operate near furnaces, in foundries, or in extreme climates, a float switch with an integrated temperature sensor for hydraulic oil provides accurate measurements despite thermal stress. These environments test the limits of sensor technology, requiring robust construction and proven reliability under extreme conditions. Engineers seeking guidance on how to monitor hydraulic tank level and temperature in these conditions rely on stainless steel options for maximum protection.
These applications highlight the versatility of ACT Sensors' solutions across industries, from heavy industry to precision OEM systems. Each application presents unique challenges that require specific sensor configurations and performance characteristics.
Spotlight: ACT Sensors Series 20, 40, and 43
ACT Sensors provides tailored solutions for different hydraulic system requirements, with each series designed to excel in specific applications and operating environments.
- Series 20: A robust hydraulic level sensor with integrated temperature monitoring, built for heavy-duty applications. Its stainless-steel construction makes it suitable for harsh, corrosive, or high-temperature environments. The Series 20 represents the pinnacle of industrial sensor technology, designed for applications where failure is not an option.
- Series 40: A compact, lightweight sensor designed for OEMs. Ideal for areas with limited space but requiring reliable monitoring. Despite its small size, the Series 40 maintains the accuracy and reliability expected in industrial applications.
- Series 43: Similar to Series 40 but enhanced for slightly higher pressures and durability, offering flexibility in design options. This series bridges the gap between compact design and heavy-duty performance, providing versatility for diverse applications.
Each model combines level and temperature sensing in one device, reducing the need for multiple components. Engineers benefit from simplified installation, reduced maintenance, and confidence in ACT Sensors' quality and reputation for reliability.
Installation and Maintenance Best Practices
Proper installation ensures the reliable performance of the combined sensors throughout their operational life, while proper maintenance practices maximize return on investment and prevent unexpected failures.
Mounting Guidelines
Correct mounting procedures are essential for optimal sensor performance:
- For vertical entry, secure the sensor with appropriate brackets or NPT threads, ensuring proper alignment and support to prevent stress on the sensor body.
- For horizontal installations, ensure the float moves freely without obstruction, maintaining clear movement paths and avoiding interference from tank internals or fluid turbulence.
- Always confirm the mounting orientation matches the manufacturer's recommendations, as improper orientation can affect both accuracy and sensor life.
Preventive Maintenance
Regular maintenance ensures continued accuracy and extends sensor life:
- Inspect floats for debris or buildup during routine maintenance cycles, cleaning as necessary to maintain proper operation and prevent false readings.
- Verify calibration of the temperature sensing switch to maintain accuracy, using appropriate test equipment and following manufacturer procedures.
- Check seals and connectors regularly for leaks or wear, replacing components before failure occurs to prevent system contamination or sensor damage.
Replacement Intervals and Spare Parts
While sensors are designed for long service life, regular inspections determine when replacement is necessary. Keeping spare ACT Sensors on hand ensures minimal downtime in critical operations, supporting maintenance planning and emergency response procedures.
Cost Benefits and ROI of Integrated Sensors
Using a combined level and temperature sensor reduces both short- and long-term costs while providing measurable returns on investment through improved system reliability and reduced maintenance requirements.
- Reduced downtime: Early detection of overheating or low oil prevents major failures, translating directly to improved production efficiency and reduced emergency repair costs.
- Simplified procurement: One component instead of two means fewer part numbers and simplified inventory management, reducing procurement overhead and storage requirements.
- Long-term lifecycle savings: Fewer components to install and maintain, less wiring, and lower replacement costs over time create compelling economic advantages that improve with system age.
These advantages deliver a strong return on investment, making ACT Sensors' solutions a smart choice for hydraulic systems where reliability and cost-effectiveness are equally important.
FAQs About Combined Level & Temperature Sensors
Why is it crucial to monitor both level and temperature in a hydraulic system?
Without accurate monitoring, overheating leads to oil breakdown, and low oil causes pump damage. Together, these risks can shut down entire systems and create safety hazards for personnel and equipment.
Can a single sensor accurately measure both parameters?
Yes. ACT's combined level and temperature sensor integrates both functions into one device, providing reliable and precise measurements that meet or exceed the accuracy of separate sensors.
What is the maximum operating temperature for a heavy-duty level sensor like the Series 20?
The Series 20 functions as a high-temperature level sensor, designed to withstand elevated oil temperatures in industrial reservoirs while maintaining accuracy and reliability.
How does a combined level and temperature switch improve equipment safety?
It reduces failure points and provides automatic alarms or shutdowns through the temperature sensing switch, protecting both equipment and operators while minimizing the potential for human error.
Are miniature sensors (Series 40/43) suitable for high-pressure environments?
Yes, the Series 40 and 43 are designed for compact applications and engineered to handle pressures found in small OEM systems without compromising accuracy or reliability.
What is the difference between a temperature switch and a continuous temperature output?
Temperature switch: Provides on/off signaling when a threshold is reached, ideal for alarm and shutdown applications.
Continuous output: Delivers real-time monitoring for advanced control systems, enabling trend analysis and predictive maintenance.
How do you select the right material (Brass vs Stainless Steel)?
Brass: Adequate for mild fluids and non-corrosive environments where cost considerations are important.
Stainless steel: Recommended for harsh environments, corrosive fluids, or high temperatures where maximum durability is required.
Can ACT Sensors provide custom wiring and connectors for OEM integration?
Yes, ACT Sensors offers customization for connectors, wiring, and integration needs, supporting OEMs with specific design requirements and helping optimize system integration.
What are the advantages of a combined sensor over two separate units?
- Saves space in compact equipment, particularly important in mobile applications.
- Simplifies installation with fewer wiring points, reducing installation time and complexity.
- Reduces potential failure points, improving overall system reliability.
- Lowers overall procurement and maintenance costs through consolidated inventory and maintenance procedures.
How do I install a sensor with NPT threads in a hydraulic reservoir?
Thread the sensor securely into the port, use appropriate sealing tape or compound, and ensure proper torque without overtightening. Always check for leaks during initial testing and follow manufacturer specifications for installation procedures.
Conclusion
Monitoring both fluid level and temperature is essential for hydraulic system safety and efficiency in today's demanding industrial environments. A hydraulic level sensor with integrated temperature monitoring provides engineers with dependable data to prevent breakdowns and extend equipment life while optimizing system performance and reducing operating costs.
ACT Sensors' Series 20, 40, and 43 models offer solutions for heavy-duty, compact, and specialized applications. Each combines reliability, precision, and long service life in one device, backed by proven performance in diverse industrial applications worldwide.
Explore ACT Sensors' range of industrial temperature sensor solutions. Contact our team today to find the right product for your application and keep your systems running at peak performance. Our technical experts are available
to help you select the optimal sensor configuration for your specific requirements and operating conditions.