The PR+ range of reversing pumps from Hydraulic Projects come in a range of five precision gear pumps suitable for 12 or 24 volt systems.
Each pump is fitted with check valves as standard and can be used with balanced or unablanced cylinders. The gear form has been designed to give minimum noise with smoothness of operation and maximum performance up to 55 bar.
The pumps can also be used for other applications on sailing or powerboard such window and door openers and swim platforms.
The PR+ range of pumps is also available with relief valves which provide independent control of the maximum pressure available at each service port. Relief valves can be fitted to either 1 or both services. They are used in many applications worldwide including sports car suspension lifters, door and hatch openers and snow blowers.
They are available with the same 0.6, 1.0, 1.5, 2.0 and 2.5 litre per minute flows as the standard PR+ range. Pilot check valves are also fitted as standard and, they can be used with both balanced and unbalanced cylinders. They have an advanced protective coating designed especially for the salt laden atmosphere of the marine environment.
Reversing type gear pumps driven by 12 or 24 volt DC permanent magnet motors. Incorporated in the design are pilot operated check valves that prevent the pump being back driven by the manual steering system or rudder load. The motors have an IP67 rating and can be removed from the pump without allowing air into the hydraulic system or fluid to escape. They can be used with both balanced and unbalanced cylinders. The pumps incorporate a fluid reservoir plus an unloading solenoid to allow the steering cylinder to ‘float’ when not in autopilot mode.
When used in conjunction with a cylinder of your choice it forms a linear actuator to enable secondary steering via an autopilot.
It is important to select the correct size of pump as it directly influences the ability of the Autopilot to steer the vessel. If the pump is too large, the vessel may over steer and will use more power; if it is is too small then the Autopilot may struggle to maintain a course.
“Hard Over Time” is the time that the pump takes to drive the rudder from port to starboard. An Autopilot Drive will need to give a nominal “Hard over time” of 10 to 12 seconds unless otherwise specified by the Autopilot manufacturer. The type of vessel to be steered must be considered as the “Hard over time” may be faster on lightweight planing craft / modern yachts and slower on displacement power boats/ long keel yachts.
To use the table in our product pictures, you will need to know the volume of your steering cylinder, then simply select the "Hard over time" that you require. Follow the column down until you approximately match your cylinder volume and then select the pump on that row. If your cylinder has a smaller volume then it will have a faster “Hard Over Time”, but if it is larger, it will have a slower “ Hard Over Time”.
