Service

The situation

• A customer from the automotive industry operates a press transfer line, in which 13 axial piston pumps of the type 900 CV 3.000 provide the required power. This hydraulic system allows the production of needed body parts. In the course of the reorganisation and restructuring of the press line. the customer decided to have all existing hydraulic pumps and the associated spare hydraulic pumps inspected and if necessary, have them repaired.

The task

• Delivery of hydraulic pumps in early December, inspection and repair period max. 6 weeks, that means: Delivery date not later than mid-January.

The problem definition

• The specific problem was that all hydraulic pumps had to be partly dismantled, to detect major damage, and then remounted for an advanced check so that any fault occurring during this time would have affected the subsequent redelivery or repair and would have affected the timely delivery and the return date.

The solution

The team-oriented processing of dismantling, damage assessment, procurement of new parts, regeneration of old parts, assembly and testing led to common success. Delivery of the last, the thirteenth hydraulic component on 12 January of the year.

The situation

• A customer from the steel industry operates a 2-leg continuous slab casting machine, which was put into operation in 1979. This system enables the casting of slabs of dimensions up to 1,800 mm to 2,600 mm in width and 215 mm thick. The monthly production amounts to an average of 230,000 tonnes. The centre point of the system is the ladle turret, which can handle a ladle with a total weight of 560 tonnes (about 400 tonnes of liquid steel weight).

The problem definition

• The special problem with this, is that with any disturbance, such as a pipe burst, malfunctioning valve etc., no tilting of the ladle may occur. This means that the tracking of all four hydraulic cylinders must be ensured to the lower end position, to meet the safety requirements and the needs of the production. It therefore had to precisely meet criteria, such as the synchronous accuracy of < 1 % as well as modifications in the sealing system (reduction of leakage oil portion to the piston rods).

The task

• After some nine years of usage the four synchronising cylinders were made available for the first time within the framework of preventive maintenance and repair.

The solution

• The repair presumed therefore that all four hydraulic cylinders have absolutely the same diameter ratios and thus exhibit identical surface ratios and thus fulfilled the condition V1 = V2. In practice, all dimensions had therefore to be adapted to the processing measure of the hydraulic cylinder, which had the highest damage level.

Ocean capable freighter

• Oil rigs must be built, supplied and serviced. For this special ocean capable freighters are needed. They can easily hold 1,600 tonnes load. However, the difficulty is not the loading and unloading at the port, where the freighter can safely be moored at the wharf, but on the high seas, in the immediate vicinity of the oil platforms. To maintain a constant position via GPS, with centimetre accuracy, so called bow thrusters are used. Bow thrusters are propellers that are fitted across the ship at the bow.

A4VSO1000 on the 1,000-Horsepower engine

• In our case, this bow thruster failed. The ship was no longer able to accept cargo on the high seas. The hydraulic pump, powered by a 1,000 HP hydraulic motor, was defective. Nothing was possible.
  
  Back at the port, the A4VSO1000 hydraulic pump was removed and sent by airfreight to Hydraulic Service Rhein-Ruhr GmbH in Oberhausen. The hydraulic specialists repaired this pump in record time.
  
  The pump was returned to Mexico by airfreight. Not only the hydraulic pump, but also two hydraulic experts from HSRR. Once there, the pump was reinstalled in the port by our professionals from Oberhausen.
  
  Test run - and the missed voyage could be resumed.

Conclusion

• Of course, this operation was very costly. The shipowners calculated the possible omissions and came to the conclusion:

Repair needs assurance