Innovations in Hydraulic Systems

Technological innovation encases the advancement of components, connections, procedures and techniques, all of which are relevant parts of a whole product. Hydraulic system innovations are important because they include improving the development and application of sensors and measurement systems for monitoring and diagnostics.

Figure 1. Light Gate Principle

System Facts
Many factors can reduce the service life of hydraulic components and systems. To prevent particle, water or gas contamination, an appropriate fluid cleanliness level must first be defined and then maintained. Once the minimum fluid cleanliness level required for acceptable component life in a system has been established, the next step is to monitor fluid cleanliness. This ensures the target cleanliness level is maintained on a continuous basis.

Knowing the contamination level of a hydraulic or lubricating system - specifically water, gas or solid contaminants - is valuable information for an operator. It enables further analysis of filter configuration efficiency, wear changes in systems, secondary contamination or simply maintaining the required fluid cleanliness. Timely and accurate information enables the operator to provide counteractive measures as necessary.

Contamination Awareness
As previously stated, contamination has myriad effects on hydraulic systems including accelerated oil aging, shortened fluid life, additive failure, corrosion, cavitation, abrasion, erosion and increased wear. Therefore, detecting and defining the precise level of contamination at any time is necessary for the functionality and efficiency of a system.

This involves taking fluid samples from the system at regular intervals and testing them, which can be done two different ways. The first way to test fluid cleanliness is to send the fluid sample to a laboratory for analysis. The second is to use a mobile electronic instrument designed for this purpose.

Figure 2. CCM 01

Contamination Monitoring Systems
Internormen contamination monitoring systems provide mobile and stationary fluid monitoring and particle counting. All diagnoses are made immediately and accurately according to effective standards. A range of products to measure particulate contamination is an essential part of a broad maintenance approach. Such systems are intended not only for in-line and off-line operation, but for online applications as well.

In-line
The measuring device is located inside the machine, and the measurements are conducted there as well.

Off-line
The measuring device is located outside of the machine, and is not connected to the machine itself.

Online
The measuring device is located outside of the machine, but is directly connected to the machine and to its control system.

All systems can be connected to external PCs to control operations and manage data using an MS-Excel-based data manager.

Particle Counters
The metal particle monitor (MPM 01) and contamination control monitor (CCM 01) are in-line monitoring systems for permanent and stationary operations. Internormen particle counters operate with different sensors. For example, the contamination control system (CCS 2, upcoming CCS 3) and the CCM 01 are equipped with a laser sensor that detects particles in a fluid based on the light gate principle (Figure 1). These particles are counted in different channels.

The CCM 01 particle counter with laser sensor measures fluid to determine contamination classes according to ISO 4406:99 and NAS 1638. It fulfills requirements for daily measurements and continuous monitoring and analysis of hydraulic systems and test stands.

Functions and Features
The set operates with hydraulic and gear fluids as well as synthetic esters. The CCM 01 was designed as a cost-effective in-line monitoring solution for stationary and permanent operations, and can be installed in new or existing systems. It consists of the particle flow rate sensor (PFS 01), a cable to connect the sensor (l = 5 m) and the CCM 01 display unit.

The CCM 01 set performs the following functions:

• Automatic particle counting and display of measuring results every 20 seconds, according to contamination classes ISO 4406 or NAS 1638

• Storage of 100 measured data in selectable storage intervals

• Transmission of current measuring results via RS 232 interface

• Four programmable contamination limit values with four potential free relay points

When exceeding the limit value, the appropriate relay point closes, allowing observation of control functions in the hydraulic and lubrication system.

The stored data can be transmitted onto an external PC using the RS 232 interface in a Windows Excel file. Evaluating and managing stored measurements can be performed in Excel tables and diagrams (data manager software must be installed on the PC).

The CCM 01 Set works in pressures up to 50 bar (725 psi), in temperatures from 0°C to 70°C (32°F to 158°F) and a viscosity range of 10 to 400 mm²/s (46 to 1854 SUS). The maximum acceptable volume flow is 50 l/min (13.3 gal/min).

Particle Flow Rate Sensor
The PFS 01 consists of two sensor elements; a laser sensor for particle counting and a thermal flow sensor for measuring the volume flow. The PFS 01 operates based on the off-line flow principle. Using a counter-balance valve, a partial flow of the oil is lead through the flow sensor and laser particle counting sensor. The sensor integrated in the PFS 01 operates on the light gate principle and it is calibrated with ISO MDT according to ISO 11171:2000.

Applications and Benefits
The CCM 01 set is utilized in contamination monitoring of devices for filter support, wind power plants, mobile and stationary hydraulic and lubricating systems, as well as different test stands for hydraulic components.

It provides benefits such as an immediate and precise diagnosis of a hydraulic system's condition, accurate determination of the optimal date for filter element changes and monitoring of filter performance with respect to the required standards. The CCM 01 can define the condition of new fluids when introducing them into a system, offering evidence for the influence of changed external conditions on the system's particulate level.

Innovative System Trends
During the last few years there has been a transition in hydraulics - from off-line measurement to online measurement in contamination monitoring. Manufacturers are currently focusing on developing devices for in-line measurements. Internormen offers in-line monitoring systems that include sensors and indicators for in-line measurements and classification of contamination classes according to ISO 4406 and NAS1638. This system also involves detection and counting of metal particles, devices for measuring and monitoring saturated water in oil, and laboratory particle counters.

Applying these measuring techniques provides continuous condition monitoring and diagnosis of hydraulic systems. It also enables wear surveillance and early recognition of damage, which is essential for large gears and lubrication systems.