Hydraulics

it maintains a constant speed under varing load

The hydraulic lift was invented by Leon Edoux.

The principal is called Pascal's Principle.

Pascal's principle states that a pressure applied to an enclosed fluid is transmitted everywhere in the fluid. Hence, if a pressure is applied to one side of an enclosed fluid, all the other walls containing the fluid feel the same pressure. The pressure is transmitted without being diminished.

Fluid generally refers to either a liquid or a gas. If a pressure is applied to a compressible gas, Pascal's principle still applies, but the volume of the gas will change. For Pascal's principle to be useful to hydraulics, the fluid should be an incompressible liquid, which will transmit the applied pressure without changing its volume.

No, because it is not compund substance

hydraulics uses the principle of hydrostatic pressure to work

A pump that has more than one impeller. improve more pressure

Hydraulics are typically measured in pounds per square inch, which is a measurement of pressure, or force exerted with respect to area. To calculate the force used, multiply the pressure measurement by the area measurement in inches. This will give you the force in pounds, then convert that to tons.

mechanical and hydraulic are two different power transmission medium.

in mechanical brakes solid links or levers are used to achieve the required braking.

in hydraulic brakes there are no links, here the braking is achieved by the hydraulic fluid, the hydraulic system in which the force applied at the brake pedal is multiplied several times to achieve the requied braking.

presure of water from which it is posible other wise by michanism

it is due to to the pressure and suction of water

Hydraulic Mean Radius = Cross sectional area of conduit divided by the inside (wetted) perimeter.

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The most commonly used hydraulic fluids are oils, so yes they are flammable. However, most any fluid COULD be used as a hydraulic fluid depending on the system design requirements. So it really depends on exactly what type of fluid is being used whether it is flammable or not.

Water is a "hydraulic fluid" and is not flammable.

Under NFPA standards, petroleum-based hydraulic fluids are not "flammable" if their flash point is above 100o F (37.8o C); they would be "combustible". NFPA 1 (2009): 3.3.153.2 Definition of Flammable Liquid

1. hydraulic system are self lubricated
2. they don't produce much noise when compared to pneumatic system

I believe that servo is motorized and solenoid is magnetically activated.

1.Transmit power

2.Lubricate moving parts

3.Seal clearances between mating parts

4.Dissipate heat

Because liquids cannot be easily compressed into a smaller space.

Difficult question to answer without context. Key thing to understand is a pneumatic system uses a compressor, whereas a hydraulic system uses a pump.

Hydraulic fluid is essentially incompressible, whereas compressed air will fill any volume.

Ask yourself: What is my pneumatic/hydraulic system supposed to do?

How fast should it react and what horsepower is available to drive my compressor/pump? What force do I need at my actuator/motor or whatever the system is expected to power?

Generally, I think pneumatic systems can react more quickly but power density is lower, so if the load is very high a hydraulic system might be better.

A typical shop pneumatic system might only operate at 50psi, whereas a hydraulic system can operate at 3000psi.

Finally, it's also worth thinking about system safety: if a pneumatic component fails, there will be an explosive decompression, but if a hydraulic component fails, it will leak but will not explode because hydraulic fluid does not store energy, it only transmits it.

The main thing that happens when there is water in diesel fuel is that it will burn poorly or maybe not even at all. It will also sink to the bottom of the fuel tank.

Many principles are used in hydraulic systems the basic being the Pascal's law

pump selection requires many factors like the flow rate requirements, speed , pressure,cost ,maintenance, performance,reliability. step1: find out what type of actuator your are going to use depending on the type of loading .cylinder type actuator or a rotary type actuator like a hydraulic motor.

step2: find out the flow rate requirements depending upon the distance through which the load is to be moved in a specified time limit.

step3: find out the pressure requirements depending upon the magnitude of the load and the size of the actuator.now along with the flow rate you can find the power requirement of the pump and select the prime mover do drive the pump.

step4:find out the speed of the pump and along with flow rate calculations determine the pump size.

step5: gear ,vane and piston are the types of pump available for the fluid power applications.there are many subtypes available for these pumps.

gear pump= 500-3000 psi,1200-2500 rpm,efficiency 80-90 ,flow capacity 1-200 gpm

vane pump=1000-2000 psi,speed 1200-1800 rpm, efficiency 80-95, flow capacity 1-80gpm

piston pump=2000-12000 psi, speed 1200-3000 rpm, efficiency 85-98,flow capacity 1-200 gpm.

apart from these determine the power losses etc.,

The short answer: Cost effectiveness.

The long answer: Employing water as a hydraulic fluid is entirely possible for many applications, but produces several additional challenges which will dramatically and likely prohibitively raise the price of the apparatus. For most applications, the higher costs will represent an unmarketable product.

The issues include:

Viscosity: Water has a much lower viscosity and higher specific gravity than hydraulic oil. This results in at least 3 other issues. First, the piston and cylinder materials (usually steel) will erode much quicker due to the resulting higher velocity and more turbulent flow. Second, the use of special valves will be required to prevent the mechanical shock caused by abrupt fluid flow stoppage inherent to water. Third, the lower viscosity also means it will be more difficult to prevent leaks, requiring more stringently machined parts with much finer tolerances.

Bacteria: A closed water system can provide a breeding ground for all kinds of microorganisms. This can result in clogged lines, filters and a potentially unsafe/unhealthy condition in the event of a leak.

Corrosion: Oxygen in the water as well as sulfurous by-products from bacteria can potentially corrode component materials.

Temperature Range: Water freezes at 32 degrees Fahrenheit. If freezing occurs, and due to the non-compressible nature of ice, it will almost certainly damage or destroy hydraulic parts. Anti-freeze agents will need to be utilized at the cost of the inherent environmental and toxicity concerns of such substances.

Lubricity: Water's comparatively low lubricity will lead to increased contact friction and resulting wear of components.

All of these issues can be addressed and overcome, with the disadvantage of dramatically higher cost vs. hydraulic oil.

Lets liken this to a garden hose, a hose in the normally open position has water flowing through it until it is closed by turning the spigot off, normally closed is the reverse. Oddly enough when it comes to an electronic relay the opposite is true, whereas the switch is in the open (normally open) position therefore having no current passing through it until a switch to close the circuit and allow current to flow. Normally closed has current flowing at all times until the switch interrupts it stopping the flow of electricity.

A positive displacement pump ( gear, vane or piston pump) is driven by a prime mover (Electrical Motor or Engine) it sucs fluid from reservior and delivers oil to system. During loading a resistance to flow creates the pressure which is utilised to do the work through cylinder for linear motion or through hydraulic motor for rotary motion, Direction of flow is changed with help of direction control valve & system pressure is regulated by pressure control valve & flow is regulated by flow control valve

by using a non-compressible fluid, it acts like a solid push-rod.