Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63H—MARINE PROPULSION OR STEERING
  • B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
  • B63H25/06—Steering by rudders
  • B63H25/08—Steering gear
  • B63H25/12—Steering gear with fluid transmission
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
  • F15B21/04—Special measures taken in connection with the properties of the fluid
  • F15B21/044—Removal or measurement of undissolved gas, e.g. de-aeration, venting or bleeding

Definitions

• the present invention relates to a device for purging marine hydraulic steering systems of the type containing a hydraulic pump actuated by the boat steering-wheel and having first and second fluid inlet/outlet ports, a hydraulic piston cylinder device with first and second chambers on either side of the piston and first and second hydraulic conduits between the inlet/outlet ports of the pump and corresponding inlet/outlet ports of the respective chambers, said device comprising a valve unit which can be coupled into the respective connection between the inlet/outlet port of the respective chamber and the inlet/outlet port of the pump, via which valve unit the air in the fluid can be released.
• Hydraulic steering arrangement for boats are usually purged in the same manner as brake systems in automobiles for example, by opening purging nipples on the hydraulic cylinders and pressurizing the cylinder. In systems with air in the fluid, the air passes through the nipple first mostly air and some of fluid and finally fluid alone, whereafter the nipples close.
• Such purging methods which usually require two people (one ••pumping" and one opening and closing the purging nipple) present special problems for marine steering arrangements.
• marine steering arrangements of this type have the hydraulic cylinder mounted near the boat rudder shaft, which is in general mounted behind the engine or in any case near the rear portion of the engine, the job of collecting oil purged with the air will be difficult.
• U S Re 33043 discloses a device which eliminate the above mentioned problems.
• the known device comprises a system of non-return valves, a throttle valve and a collecting container, which is integrated into one unit. Via quick-couplings in the conduits between the steering wheel pump and the hydraulic cylinder it can be coupled as a shunt over the cylinder.
• the device makes it possible for one person to perform purging by merely turning the steering wheel. The pressure difference thereby produced is used in the valve system to purge liquid with air into the receptacle. After purging has been completed, the device can be disconnected whereupon automatic valves close the branch connections in the conduits between the pump and the cylinder.
• the device described solves without a doubt the problems associated with conventional purging, but is on the other hand expensive and complicated and therefore not suitable to be permanently installed in simpler types of hydraulic steering systems.
• the known device is primarily suited for use in connection with service, i.e. when filling and purging the hydraulic systems.
• the purpose of the present invention is to provide a purging device of the type described by way of introduction which, at the same time as it eliminates the problem of fluid spillage during purging, is so inexpensive and uncomplicated that it can be permanently installed in the hydraulic system.
• valve unit has manually operated purging valve means, by means of which the respective chamber can be coupled to a third conduit which opens into an inlet of a fluid receptacle.
• the third conduit is at least partially transparent and leads to the pump of the hydraulic system .
• the purging device according to the invention is uncomplicated and can be manufactured at substantially lower cost than the known device described above.
• Purging can be performed simply by one person and the risk of fluid spillage is entirely eliminated.
• the purging is performed by first opening a purging valve and thereafter turning the steering wheel in that direction which will reduce the volume in the associated chamber.
• the open valve is closed and the other valve is opened, whereafter the steering wheel is turned in the opposite direction until fluid without air bubbles again can be observed in the third conduit.
• Figure 1 shows a schematic sideview of a marine hydraulic steering system with a purging device
• Figure 2 is a longitudinal section through a valve unit in the purging device.
• 1 generally designates a hydraulic pump, on the pump shaft of which a steering wheel 2 is mounted.
• the pump 1 has two inlet/outlet ports 3, 4 for connection to a hydraulic steering circuit and an inlet 5 for filling hydraulic fluid into the steering circuit.
• the pump 1 is previously known in its entirety and therefore need not be described in more detail here.
• the pump is connected via hydraulic conduits 6 and 7 and a valve unit (generally designated 8) to a hydraulic piston cylinder device with a piston rod 10, intended to be connected to a steering arm on a rudder shaft (not shown) .
• a piston 11 divides the interior of the cylinder into two chambers 12, 13 with individual inlet/outlet ports 14 and 15 respectively, which communicate with the valve unit 8 via a connecting conduit 16 and a pipe stub 17 respectively, which is screwed into a threaded portion of the inlet/outlet port 14 and also serves as an anchoring element for mounting the valve unit on the hydraulic cylinder 9.
• Figure 2 shows a longitudinal section through a valve unit 8.
• the unit comprises a valve housing 20 containing a first straight through channel 21, to which the conduit 6 and the pipe stub 11 are connected and a second angle through channel 22, to which the conduit 7 and the connecting conduit 16 are connected.
• First and second passages 23 and 24 respectively join the channels 21 and 22 respectively with a third channel 25, which is not a through-channel, and through which a third hydraulic conduit 26 ( Figure 1) , preferably of transparent material at least in its upper portion, communicates with the filling port 5 of the pump.
• the passages 23, 24 respectively open into threaded bores
• FIG. 27 shows the valve unit 8 with the purging screw screwed out somewhat, so that a constricted communication is established between the channel 22 and the channel 25.
• the ports 14, 15 from the chambers 12, 13 are located on the upper side of the cylinder 9 and the pump 1 is located at a level above the cylinder to assure that when there is air in the system, as little fluid as possible will be pumped out during the initial purging.
• the chamber 12 is purged in a corresponding manner by screwing out the purging screw 31 after the screw 32 has been completely screwed in to seal the passage 24, whereafter the steering wheel is turned so that fluid is supplied to the chamber 13 via the conduit 7.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Analytical Chemistry (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Ocean & Marine Engineering (AREA)
• Fluid-Pressure Circuits (AREA)
• Details Of Reciprocating Pumps (AREA)
• Power Steering Mechanism (AREA)

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Cited By (1)

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• 1991
  • 1991-05-28 SE SE9101616A patent/SE468473B/sv not_active IP Right Cessation
• 1992
  • 1992-05-26 WO PCT/SE1992/000354 patent/WO1992021559A1/en active Application Filing
  • 1992-05-26 US US08/146,031 patent/US5503098A/en not_active Expired - Fee Related

Patent Citations (1)

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