Water Hydraulics
General Information about Water Hydraulics
Water Hydraulics has come so far that we can offer components that make water hydraulic systems comparable to conventional hydraulic systems. In our programme we have directional valves, proportional pressure control valves, flow dividers, pilot operated check valves, relief valves, pressure regulating valves, variable pumps and many other functions that combined enables us to offer a system suitable for most tasks.
Water has no lubricating properties. That challenge is overcome by choosing the right materials; plastic and stainless steel. In all of our components where two surfaces are touching one is plastic and the other stainless steel. Because there is no need to handle oil residue between moving parts, water hydraulic components have a higher volumetric efficiency (less internal leakage). A clear example is our directional valve.
Our water hydraulic systems operate on clean water with no additives except for antifreeze.
Pros:
The environmental factor is an obvious one. Oils are an environmental hazard but water, even with antifreeze, is not. Water hydraulic systems can operate in environments with a high fire risk that cannot adopt conventional oil systems. Reduced fire and toxicity risk may also lead to lower insurance premiums. The incompressibility of water also offers excellent controllability with rapid response. Another pro is that you do not need a return line if you have a good water supply.
Limitations:
Today we run our water hydraulic systems up to 160 bar without issue. With the right amount of cleaning, a water hydraulic system has the same service life as a conventional system. If the systems are used at above 160 bar the service life is reduced considerably.
Water Hydraulic Pumps
| Type | Displacement cm 3 Max | Displacement cm 3 Min | Max RPM unboosted | Max RPM boosted* | Max Input Power (kW) | Max Water Flow (l/min) | Max Cont. Pressure (bar) | Weight (kg) | Max Temperature (°C)** | Min Temperature (°C)*** |
|---|---|---|---|---|---|---|---|---|---|---|
| P1 | 1,5 | 0,8 | 2000 | ---- | 0,55 | 2,4 | 100 | 1,5 | 90 | 2 |
| P3 | 4 | 3 | 1800 | 2000 | 1,75 | 6 | 160 | 1,9 | 90 | 2 |
| P6 | 6 | 3.3 | 1800 | 2000 | 3,8 | 12 | 160 | 2,2 | 50 | 2 |
| P15 | 19 | 8 | 1800 | 2000 | 11 | 37,2 | 160 | 8 | 50 | 2 |
| P30 | 35 | 20 | 1800 | 2000 | 19.5 | 66 | 160 | 10 | 50 | 2 |
| P60 | 70,3 | 35 | 1800 | 2000 | 42 | 146 | 160 | 19 | 50 | 2 |
| P180 | 225 | 104 | 1800 | 2000 | 114 | 430 | 160 | 82 | 50 | 2 |
*Higher RPM is possible with higher supply pressure, contact us for more information.
**Higher temperatures are possible, contact us for more information.
***Lower temperatures are possible, contact us for more information.
These axial piston pumps are completely oil free and can be run on tap or ocean water. No lubrication needed. The pistons are manufactured slightly oversized to compensate for wear that happens during the first hour of the pump operating. Please note that the water has no lubricating properties and that the small amount of leakage that happen is for cooling purposes to protect the plastic materials.
Glucose: When ordering pumps intended to use a glucose solution it is required that you specify this when ordering. This is because we need to slightly adjust the diameter of the pistons to compensate for wear.
Suction Line:
There are two main versions of the pumps, one that has the purpose of “sucking” the fluid and one that has the inlet pressurized. Pumps intended for a pressurized inlet can be used both directions and has a drain line that must be connected to a tank. The pumps that are intended to do the suction themselves have no drain line. The suction line is made a size bigger compared to a corresponding oil hydraulic system.
Motor Pump Units:
A standard range of bell housing and couplings are available for operating with the IEC electrical motor. Please note that the pumps are not capable of operating with induced axial or radial loads on the output shaft.
Temperature:
The units will generate full performance from 2°C to 50°C. For temperatures below 2°C antifreeze has to be added, for example propylene glycol (E1520). The amount differs case to case. Operation above 50°C is possible; contact us for advice and more information.
Filtration:
All incoming water to the pumps must be pre-filtered to a nominal rating of 25µm with a filter element rating of ß10 = 75 or better. Return line filtration is advisable on closed loop systems.
Directional Valves for Water Hydraulics
These directional valves are intended for tap or salt water and they are all a type of slide valve but with the upside of having less leakage compared to a conventional hydraulic valve. The water flow is controlled with a plate that is moved with the actuator (electric, air or hand). When the plate is in position it’s pressurised and seals the other channels. The power needed to start movement is significant but once it has been put in motion it is very easy to continue moving it. That is why the directional valves in electronical designs are provided with a circuit board that limits the power of the magnet to the holding force.
Glycose:
The directional valves function excellent with glycose solutions. When using a high concentration of glycose the fluid gains lubricating properties and to compensate the holding force needs to be increased. Contact us for more information.
Options:
The valves are available in 4/3, 4/2 and 3/2 for different slide configurations
The valves are available for pipe and subplate assembly, not available for NG6 assembly
Actuation:
-Electromagnet, different voltages
-Air pilot
-Mechanical pilot, hand, foot etc.
Temperature:
The units will generate full performance from 2°C to 50°C. For temperatures below 2°C antifreeze has to be added, for example propylene glycol (E1520). The amount differs case to case. Operation above 50°C is possible; contact us for advice and more information.
Proportional Pressure Control Valves for Water Hydraulics
These proportional pressure control valves are intended for tap or salt water and they are all a type of slide valve but with the upside of having less leakage compared to a conventional hydraulic valve. The water flow is controlled with a plate that is moved with an electromagnet.
Directional Valves:
There are two available options for directional valves, 4/3(A and B to T) and 4/2(cross – parallel). Available for pipe or block assembly.
Pressure Reducing Valves:
Pressure reducing valves are available for pipe or sub plate assembly for pressures up to 160 bar.
Glycose:
The directional valves function excellent with glycose solutions. When using a high concentration of glycose the fluid gains lubricating properties, to compensate the holding force needs to be greater. Contact us for more information.
Temperature:
The units will generate full performance from 2°C to 50°C. For temperatures below 2°C antifreeze has to be added, for example propylene glycol (E1520). The amount differs case to case. Operation above 50°C is possible; contact us for advice and more information.
Cylinders for water hydraulics
The cylinders are only available in the durable 316 stainless steel model. It’s a tie bar design and is available in the sizes D32 to D100. Different attachment options are available such as stroke, double acting, male threaded rod end and front flange mounted.
A tie model has no welds that are prone to corrosion as time passes. That is why these cylinders are not only durable, they are also very easy to service when for example a spare part needs to be installed.