Vandens pagrindo

Vandeniu skiedžiama hidraulinė alyva

Molylub Hydrofluid THS  yra specialios cheminės formuluotės, pilnai sintetinės bazinės alyvos pagrindo bechloris spaudimo perdavimo alyvos koncentratas. Turi puikias antikorozines savybes ir lengvai perneša deformacines apkrovas. 

Vandeniu skiedžiamos didelės talpos pramoninės hidraulinės sistemoms, aukštų temperatūrų aplinkoje dirbanti hidraulika, eliminuojanti užsidegimo pavojų. Patvirtinta :

Dieffenbacher

Siempelkamp ContiRoll

 

Spalva

 

 

 

 

 

 

< 1,5

 

DIN ISO 2049

 

 

Tankis

 

prie 15 °C

 

kg/m³

 

1110

 

DIN 51 757

 

pH vertė (3% skysčio)

 

 

 

 

 

9,2

 

DIN 51 369

Špyžiaus drožlių testas

1 : 20

korozijos pakopa

0

DIN 51 360 - 2 dalis

 

Refraktometro reikšmė

 

 

 

 

 

1,5

 

 

Darbinės koncentracijos

%

 

5 - 10

 

 

Vandens Hidraulika:  Privalumai ir Trūkumai

Vandens pagrindo hidraulinės sistemos

tradiciškai buvo naudojami kalnakasybos programų ir karšto metalo srityse plieno gamykloms. Akivaizdus privalumas vandens sistemų šiose pramonės šakose yra jų atsparumas ugniai. Vandens pagrindo hidraulinės sistemos taip pat turi ne taip akivaizdžiai matomų ekonomiškumo pranašumų lyginant su alyviniu skysčiu.  

Water Hydraulics:  Benefits and Limitations

Water hydraulics combines the high power density of hydraulics with the clean operation of pneumatics. But water's inherent physical properties present design challenges.

Water-based hydraulic systems traditionally have been used in longwall mining applications and in hot-metal areas of steel mills. The obvious advantage of water systems in these industries is their fire resistance. Water-based hydraulic systems also have not-so-obvious cost advantages over oil based fluid. First, non-toxic, biodegradable synthetic additives cost much less per-gallon than oil based fluids do. One gallon of concentrate can make 20 gal of a solution containing 95% water and 5% additive.

Water-based hydraulic systems traditionally have been used in longwall mining applications and in hot-metal areas of steel mills. The obvious advantage of water systems in these industries is their fire resistance. Water-based hydraulic systems also have not-so-obvious cost advantages over oil based fluid. First, non-toxic, biodegradable synthetic additives cost much less per-gallon than oil based fluids do. One gallon of concentrate can make 20 gal of a solution containing 95% water and 5% additive..

Sealing the system

Two more perceived problems with water hydraulic systems are bacterial infestation and difficulty in maintain proper concentrations. Sealing the system from atmosphere can hold bacterial growth in check. Addition of an anti-bacterial agent to the fluid can have a lasting effect on preventing bacterial buildup if air is excluded from the system. Sealing the system from the atmosphere also keeps out most airborne contaminants — a common cause of component failure.

A sealed reservoir eliminates another problem suffered by many hydraulic systems: water ingression. Dissolved suspended water contaminates hydraulic oil. The only detriment water ingression has in a water-based system, though, is that is alters the concentration of additive. Water ingression is still undesirable, but its occurrence is far less detrimental in a water-based system than in one using oil.

This addresses another misconception about water-based systems: water-based systems must be closely monitored to ensure that the additive concentration stays within tolerance. That is because water evaporates from the reservoir more readily than the additive does. Consequently, water evaporation causes the additive concentration to increase. When new fluid is added to a system, samples of the existing fluid must be taken to determine the concentration of additive in solution. These results then reveal the ratio of additive to fluid that must be added so that fluid concentration is correct.

With a system that sealed from the atmosphere, the evaporation problem is virtually eliminated. Fluid that escapes by leakage is a solution containing water and additive. Therefore, the quantity of fluid in the system changes, but concentration does not. System fluid is replenished simply by adding a pre-mixed solution of water and additive to the reservoir.

Special considerations

the high power-to-weight ratio of water hydraulics, coupled with its cleanliness, prove ideal for this rib-cutting saw in a meat processing plant. because the hydraulic motor is so small and lightweight, the saw is easy to maneuver, which maximizes ergonomics and productivity. a saw powered by pneumatics would be larger and heavier, and  one powered by an electromechanical drive would be too bulky and heavy to be practical.

The high power-to-weight ratio of water hydraulics, coupled with its cleanliness, prove ideal for this rib-cutting saw in a meat processing plant. Because the hydraulic motor is so small and lightweight, the saw is easy to maneuver, which maximizes ergonomics and productivity. A saw powered by pneumatics would be larger and heavier, and one powered by an electromechanical drive would be too bulky and heavy to be practical.

Water-based hydraulic systems can be more prone to pump cavitation if they are not properly designed. Generous porting and other passageways should be provided to keep fluid velocities less than 20 ft/sec — preferably, below 15 ft/sec in pressure lines. Velocity in suction lines, in general, should not exceed 2 to 3 ft/sec. Velocities in return lines should be held less than 5 to10 ft/sec. Higher return velocities can promote foaming when fluid re-enters the reservoir. Components should also be carefully sized because rapid changes in fluid pressure and velocity can cause dissolved air to precipitate from solution and cause damage similar to that produced by cavitation.

An important consideration for water-based systems is that major components should be designed specifically for use with water fluid, rather than modified from versions originally intended for oil service. An oil valve retrofitted for water service may work, but its compromise in performance will be obvious when compared to a valve designed for water service.

Tubing, hose, and fittings usually can be identical to those for oil systems. Pumps, valves, and actuators for water service, however, exhibit some significant differences from components for oil systems. Pump gears, for example, should be made of super-hard alloys to resist wear. A pump's gear face should be wider than that of an oil pump because water's low viscosity requires a larger area to form an adequate lubricant film. Cylinders used in water systems should have bronze-clad pistons to minimize wear between pistons and cylinder walls. Spring- or O-ring-energized seals should be used to minimized leakage across the piston.