Keeping water and damage at bay

Edited by Mary C. Gannon, senior associate editor

The presence of water in any hydraulic system can be damaging, but in concrete pumps, free water can lead to oxidation, corrosion, cavity damage, and in the end, reduced service life. That’s why Weber Betonpumpen GmbH — a provider of concrete logistics for concrete pumps and stationary and mobile concrete mixing systems — uses oil dewatering systems to keep their operation reliable, fast, and efficient.

Hydraulically powered concrete pumps equipped with 20- to 60-m arms are capable of pouring ready-mix concrete even in hard-to-reach places. Depending on the size of the machine, their hydraulic capabilities require tank capacities ranging from 350 to 1000 l. Their permanent use in rough conditions often means dirt and larger quantities of water may ingressed into the hydraulic system.

Water causes contamination
If the oil reaches its saturation limit, it can lead to the presence of free water, which is visible when oil appears cloudy and milky. The higher the water content, the milkier the oil will appear. Free water will result in rapid oxidation of the oil and, thus, reduce its service life. In addition, acids may form and cause corrosion on the surfaces of different components. Free water can lead to the formation of vapor bubbles and, eventually, damage from cavitation.

Argo-Hytos’s COPS oil purification system removes water from concrete pumps, thus reducing corrosion, damage from cavitatiion, and extending equipment life.

Component failure will ultimately result in a standstill of the concrete pump. In the past, massive damage to seals on concrete pumps occurred, in particular, at temperatures at or around the freezing point. The damaged seals would then lead to pump damage of several thousand Euros yearly.

Dewatering for damage control
To reduce these costs, Weber Betonpumpen started looking for ways to remove water from hydraulic oils quickly and directly at the concrete pump. The only system that met its needs was the COPS (Compact Oil Purification System) by Argo-Hytos, which made it possible to dewater concrete pumps far below the saturation limits within hours. Compared to other systems, the COPS weighs half as much and is smaller. Its compact design makes it easy to transport from one machine to another.

The COPS is connected to the hydraulic tank like a mobile filtration unit using suction and return hoses. Wet oil is drawn into the reactor via a vacuum pump and heated. The combination of vacuum and heat draw out water, and the condensed water is collected in a separate tank and drained through a solenoid valve.

Filters and sensors keep it dry
A 5 μm fine filter is installed downstream from the drying process to ensure that the oil will be dry and filtered when it flows back into the hydraulic tank.

A LubCos H2O+ moisture sensor from Argo-Hytos monitors the dewatering process. The end of the drying process is indicated on a display and by two signal lights.

Thanks to its compact and lightweight design, the COPS system can be pushed directly against the concrete pump. Oil contained in the concrete pumps can be dried and filtered within 4 to 8 hr, depending on its volume.

The COPS is now used almost daily to dry and filter hydraulic oils from concrete pumps. It has helped avoid and reduce costs and proved to be an investment that will ensure that concrete can be delivered to hard-to-reach places quickly, reliably, and efficiently.

For more information, visit www.argo-hytos.com or call (419) 353-6070.

Moisture sensor stops damage One of the main rules of any hydraulic system is to keep water out. In small amounts it can cause corrosion and accelerate aging of the oil. In larger amounts, it can contaminate entire production areas with oil. In addition to the costs associated with the damage, the system must be cleaned and then filled with new oil. These costs can be minimized or prevented with advance warning. The LubCos H2O from Argo-Hytos specifically measures the water content of the oil and communicates the measured values via a 4-20 mA analog interface so that they can be read by a control system. Additionally, the sensor can be interfaced through an RS232 interface. The sensor measures relative humidity. In contrast to Karl-Fisher laboratory measurements, the LubCos H2O measures the degree of saturation with water from 0-100% at any time and regardless of the type of oil. A 0% reading means that the oil is absolutely dry, and no water is dissolved. A 100% reading means the oil is completely saturated with water. Additional water will be present as free water. This means users can tell at a glance what the saturation level is of their fluid and can initiate appropriate counter-measures when there is an increase in moisture.

Particle monitor ensures oil purity Oil purity is essential for reliable operation of valves and pumps. High concentrations of particles can cause components to malfunction or become damaged. An increase in particle concentration can also indicate that there is a damaged component or an increased dirt entry. Monitoring oil purity online makes it possible to detect changes in particle concentration immediately and take action. That is why monitoring of oil purity is increasingly performed online. For more than five years, Argo-Hytos has offered its online particle monitor OPCom, which it recently updated. Now, the OPCom II comes standard with a CAN-BUS, serial port, and a 4-20 mA output. It is also equipped with two additional digital interfaces, an alarm output, and an input for starting and stopping the measurement externally. These interfaces and features allow the OPCom II to be integrated effortlessly into control systems, such as those installed in test stands or machine controllers. Measurements can be time-controlled or based on machine or testing cycles. It measures 4, 6, 14, 21 ∝m particle sizes and operates in temperatures from –20° to 85°C. It is rated for operating pressures (dynamic) to 420 bar and meets ISO 4406:99 and SAE AS 4059E cleanliness standards. Interfaces include RS232, CANopen, analog 4-20 mA, digital input for starting and stopping measurements, and digital alarm output.