Stainless steel tubing for hydraulic control panels and power units

The value of a hydraulic control panel in the field is measured by how quickly it can be read and how easily it can be worked on when something fails. Haphazardly routed tubing, valves that block each other and gauges with no clear indication of which line they belong to all add to maintenance time. Our goal in panel and power unit tubing is a layout that is leak-tight, orderly and understandable to the service team at first glance.

Scope and boundaries

This service covers the stainless steel mechanical and hydraulic connection side of the panel and power unit. Hydraulic circuit design and the electrical and automation side are the responsibility of the system designer; we work from the hydraulic schematic and layout plan provided.

• Panel tubing with stainless steel tube and instrumentation fittings
• Pressure gauge, pressure switch and transmitter connections; test point (measuring port) connections
• Isolation and needle valves, ball valve and check valve groups
• Bulkhead fittings for penetrations through the panel wall
• SAE flange, adapter and hose connections at power unit outlets

How is it done?

Schematic and layout

The diameter, pressure and connection standard of each line are taken from the hydraulic schematic. Valves and gauges that the operator uses frequently are placed on the front face, while components that need only occasional attention go at the back. Lines are run parallel and at right angles wherever possible, and crossovers are kept to a minimum.

Pressure gauges and test points

Pressure gauges are connected with a needle valve or gauge valve in front of them, so the gauge can be isolated and replaced without shutting down the system. Test points are capped and positioned where they can be reached easily with the measuring instrument's hose. The connection thread of gauges and transmitters (BSP or NPT) is confirmed from the instrument itself; threads of the same size but different standards are never forced together.

Valve groups

Valves are positioned with the flow arrow, handle swing area and service access in mind. A ball valve whose handle hits a neighboring component when open, or a check valve installed in the wrong direction, are common panel mistakes that are only noticed at commissioning.

Tubing and support

Tube is cut square and clean and deburred; twin-ferrule fittings are tightened with the correct number of wrench turns. Lines are supported with clamps, and bends and routing are planned so that vibration and thermal expansion do not load the connections.

Bulkhead penetrations

Bulkhead fittings are used on lines that pass through the panel wall. Because the connection is fixed to the panel body, loads from the external hose or tube are not transferred to the internal tubing, and the external line can be replaced without opening up the panel.

Labeling

Lines, valves and gauges are labeled to match the numbers on the schematic. The labels let the maintenance team in the field read the schematic directly on the panel.

Common connection mistakes on panels

• Connecting a pressure gauge directly to the line without an isolation valve
• Forcing BSP and NPT threads of the same size together
• Tubes pulled into place under tension, with fittings loosening from vibration
• Test points left where the measuring hose cannot reach them
• Closing the wrong valve during a failure because the lines are unlabeled

Quality control

• Conformity of connection standards with the schematic and instrument ports
• Visual check of fitting make-up and connections
• Pressure and leak-tightness verification depending on the application
• Check of valve flow direction, handle clearance and labels
• Closing of open ports with protective caps before shipping

Applications by sector

Control panels and power units for deck equipment on offshore installations and drillships; crane, steering and hatch cover hydraulic control panels on ships and in shipyards; compact power units in the defense industry; hydraulic test benches in aviation; instrumentation panels in chemical plants; pump control skids in fire suppression systems; power unit piping in rolling mills.

Lead time

Standard fittings, valves and connection components are typically ready to ship within 1-3 business days, depending on stock availability. Project-specific work such as panel tubing is scheduled within an average of 10-20 business days after technical approval of the hydraulic schematic and layout. If no schematic is available yet, a preliminary assessment can be made from photos of the existing panel and a list of lines.