Checklist for Hydraulic System Care and Maintenance

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Hydraulic systems have a variety of applications ranging from small-scale industries to large-scale industries. Recently, hydraulics has applications in automobiles, agriculture, mining, marine, aerospace, etc. So, utmost care is required to maintain these hydraulic systems and to avoid accidents. Proper maintenance of the hydraulic system and hydraulic fuel is necessary to minimize the premature breakdown of the system and to maximize uptime. So, in this article, we are discussing the checklist for hydraulic system maintenance and care.

Hydraulic Fluid Care

Hydraulic fluids such as oils play a vital role in the working of the hydraulic system. They act as the lifeblood of hydraulics. These fluids not only transfer pressure and energy but also provide lubrication and cooling to the system. The following four points are necessary to control the efficiency of hydraulic fluids used.

1. Control the Temperature of Fluids:

Temperature increases as a result of the continuous flow of liquid through the system. In conventional hydraulic systems, due to excessive temperature, varnish and sludge deposits are formed as a result of oil oxidization. Similarly, pump cavitation occurs as a result of too low temperature. However, in modern hydraulic systems that use servo-hydraulic valves, nitrogen fixation occurs as a result of extreme temperature. Use a hydraulic oil cooler or a large size reservoir to solve the issue of over-temperature

2. Keep the Hydraulic System Clean:

Eliminate the presence of contaminants such as dirt, water, cutting fluids, and metal particles from the hydraulic fluids. These foreign particles enter into the system through the reservoir cover, leaks in the suction lines, breather fill openings, etc. To protect the system from contaminants, always clean the area around dipsticks, and fill plugs and hydraulic filters before removing them for maintenance or checking.

3. Keep the Hydraulic Fluid Clean:

Storing hydraulic fluids unused for a long time will create deposits in the tank. So, always use good storage and handling practices to prevent contamination of fluids.

4. Keep an Oil Analysis Program:

According to OEM’s specification, hydraulic fluids need to maintain the required oil cleanliness level through the proper filtration methods. But the oil filtration interval can be changed depending on the working environment.

Hydraulic System Maintenance

A basic hydraulic system includes components like pumps, fluids, valves, pressure regulators, actuators, etc. All the analysis work carried out on hydraulic fluids will become effortless when the system itself fails. So, the top 10 hydraulic system management checklist is included below.

1. Check Fluid Levels:

Fluid levels need to be monitored a regular intervals. Add filtered oil if required and use the same oil brand and viscosity grade as directed by the manufacturer.

2. Inspect breather caps, breather filters and fill screens:

Breather caps and filters are used to prevent contaminants from entering into the system. So, don’t punch holes on these screens.

3. Check filter indicators and/or pressure differential gauges:

Replace the components that show any negative indications.

4. Inspect all Pipes, Pipe joints, and hoses for leaks and frays:

Excessive leakage of hydraulic fluids will cause environmental and safety hazards, high oil consumption, and overheating. So, diagnose such leakages from the beginning itself.

5. Use built-in thermometers or hand-held infrared detectors to check system temperature:

If the temperature rises above 140ºF check the check fluid quantity, relief valve settings, reservoir, and cooler operations

6. Inspect the reservoir for signs of aeration:

Aeration occurs when the air trapped in the hydraulic fluid circulates through the system. This results in pump aeration, low fluid levels, air leaks in the suction line, low fluid temperature, etc.

7. Inspect the pump for signs of cavitation:

Cavitation is the process of forming bubbles in hydraulic fluids. This will damage the working of pumps.

8. Inspect the sample of hydraulic fluid:

Check the color and odor of fluids to verify the level of contamination. Better use a Patch test Kit or a Laser Particle Counter and maintain the periodic oil analysis report.

9. Use an infrared thermometer to scan electrically controlled servo valves:

The temperature above 150ºF indicates that the valve is sticking.

10. Scan the electric drive motor:

Use an infrared thermometer to measure housing hot spots and rotor-bearing temperatures.

5 Tips - Checklist When Buying The Right Hydraulic Valve

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Each and every hydraulic machine requires and uses hydraulic valves for varying purposes. Some machinery requires few simple valves for execution, whereas, others require dozens of complex valves. They are available in a variety of sizes according to the international standards. So, the valves are selected depending on their applications. In this article, we provide you with 5 tips that you want to remember when you buy a hydraulic valve.

          A hydraulic valve acts as an important component in the hydraulic machinery that affects the performance and efficiency of the system. These hydraulic valves are used in hydraulic systems to direct the flow of fluids and to switch at a certain pressure. The direction of the flow of liquid is determined using the position of the spool. The spool can be controlled mechanically or electrically and it is located inside the cylinder bore. These valves must be capable of withstanding 3000 PSI or more fluid pressure, so, they are built using steel or iron. The major role of hydraulic valves is to sustain a balanced state of power dynamics in various mechanical systems.

          Hydraulic valves can be classified according to their functions, working type, inner sealing, controlling, and installation mounting. Mounting in pipelines, with threaded connections such as cartridge valves, sub-plate mounting or flange mounting is the different installation mounting available. Commonly, there are 3 types of hydraulic valves, direction control valve (direct the flow of fluid, halt or initiate the flow), pressure control valve (maintain the pressure level), and flow control valve (monitor and regulate the rate of flow).

Below provided are the 5 best tips for you to buy hydraulic valves:

1. Know and understand the function of a hydraulic valve:

Hydraulic valves are used to control the pressure and flow of hydraulic fluids within the system and can function hydraulically, pneumatically, manually, electrically or mechanically. They play an important role in controlling the function and safety of the equipment. So, a good knowledge of hydraulic valves is vital for buying.

2. Have an understanding of the components:

A hydraulic valve comprises a bonnet, seat, and disc (to prevent leakages). So, if you have enough knowledge about these components, then, it will be beneficial for you to purchase the best in the market.

3. Be specific about what you are looking for:

Various types of hydraulic valves are available in the market. But, if you purchase one, always choose the type that fits your system as per the technical specifications and nomenclature. Otherwise, it will cause a malfunction of the system.

4. Always pick the right size:

Different manufacturers produce hydraulic valves. But, if you purchase one, don't rely on the manufacturer’s valve flow rating (other than OEM). So, the smartest way to pick the right size is to opt for the Original Equipment Manufacturer. This will improve the overall performance of the system.

5. Choose three-position directional valves (four-way):

In this hydraulic valve, there will be one way for the pump, one for the reservoir or tank, and two for the inlet to the actuator. And it has 3 positions: one normal, one crossway, and one straight way.  This arrangement of valves will provide better efficiency.

How Does A Hydrostatic Pump Work?

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Hydrostatic pumps serve a valuable role in hydraulic systems not only for their primary function of fluid conveyance but also for their versatility in generating a seamless and adaptable fluid transmission. These pumps, classified as variable displacement pumps, excel in diverse applications and offer an efficient solution.

          Hydrostatic pumps are engineered to facilitate fluid movement within hydraulic systems offering a fluid transmission mechanism characterized by continuous variability, which sets them apart from hydrodynamic pumps that possess fixed (negative) displacement characteristics. These positive displacement pumps operate by employing seals or valves to generate a pumping action, utilizing components such as pistons, screws, gears, lobes, diaphragms, or vanes, depending on the specific pump design.

HOW DO DIRECTIONAL CONTROL VALVES WORK?

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 DCVs play a crucial role in hydraulic circuits by enabling bi-directional motion for hydraulic actuators and offering advantages to any device equipped with a motor. Their versatility lies in their ability to be precisely controlled to assume different positions, making them suitable for a wide range of functions.

          Directional control valves serve the purpose of maintaining fluid in a standby state, effectively halting its flow within the system until it is required to initiate and execute its designated task. While these valves offer significant advantages, the intricacies of their mechanical components can occasionally give rise to complications, including potential contamination issues.

          To circumvent problems or failures associated with Directional Control Valves (DCVs), the most effective approach is to prevent contamination within the system. Ensuring that the oil remains clean, maintains a suitable temperature, and stays free from moisture intrusion (thus averting water contamination) will serve as a robust preventive measure against the majority of DCV failures. This, in turn, will enhance the durability of DCVs within the hydraulic system.

What is the purpose of having a hydraulic oil cooler?

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 Hydraulic machinery plays a crucial role in various industries, enabling precise control and safe operation of industrial equipment, thereby ensuring seamless production processes. Nonetheless, these systems are susceptible to temperature fluctuations, which can lead to malfunctions or total breakdowns. One effective solution to safeguard your equipment from overheating and sustain its peak performance is the utilization of hydraulic oil coolers.

Understanding Oil Coolers:

An oil cooler serves as a heat exchanger designed to cool hydraulic fluid, serving as a safeguard against overheating and extending the operational lifespan of your hydraulic machinery.

How It Operates:

The oil cooler functions by extracting heat from the hydraulic oil system. This process involves circulating cooling fluid through the unit's matrix, permitting it to undergo a heat exchange process, subsequently lowering its temperature before reintroducing it into the hydraulic tank.

          The prevailing oil cooler type primarily employs either air or water as its cooling medium. However, some manufacturers have adopted hybrid designs that incorporate both mediums to enhance efficiency and effectiveness.

Principle of Operation for Hydraulic Excavators

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The hydraulic system within a hydraulic excavator is an extraordinary feat of engineering, akin to the machine's nervous system. It sends signals to coordinate various components of the arm enabling the excavator to perform tasks such as digging, lifting, and transporting substantial loads of soil, rocks, and other materials.At the core of this hydraulic system lies the hydraulic pump, which is driven by the engine. The pump generates the essential hydraulic pressure required for the operation of the hydraulic cylinders. Without this hydraulic pressure, the excavator's arm would remain immobile.

        Now, let's delve into how this hydraulic pressure translates into actual movement. This is where the hydraulic cylinders come into play, acting as the equivalent of the biceps and triceps in our analogy. They provide the force needed to move the arm in various directions. When hydraulic fluid is pumped into the cylinder, it exerts pressure on the piston, causing the rod to move. The rod's movement, in turn, powers the machine's arms, booms, and buckets. The hydraulic system relies on control valves, akin to the brain of the machine. These valves regulate the flow of hydraulic fluid to different parts of the arm. They enable the operator to exercise precise control over the excavator's movements, almost as if they were controlling it with their thoughts.