Hydraulics

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.

cvt

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.

Barber chairs are often raised and lowered using gas or hydraulic struts. These struts work by using strong springs or pressurized gas. Some of these devices can be recharged, or have replaceable seals, but others are disposable items that are replaced as a unit.

IS : 2062 - Specification of Steel for General Structural Purposes

CHEMICAL COMPOSITION

Grade C% Max. Mn% Max. S% Max. P% Max. Si% Max. C.E.% Max.

A 0.23 1.50 0.050 0.050 0.40 0.42

B 0.22 1.50 0.045 0.045 0.40 0.41

C 0.20 1.50 0.040 0.040 0.40 0.39

MECHANICAL PROPORTIES

Grade UTS(MPa) Min. Y.S.(MPa) Min. El.% Min. 5.65 Sqrt(So)

Bend

Test

A 410 250 240 230 23 3T

B 410 250 240 230 23 2T & 3T *

C 410 250 240 230 23 2T

* 2T - <= 25mm

* 3T - > 25mm

Static Hook Load:

The static hook load is the maximum weight in static conditions (not tripping) that the derrick/mast and the substructure can withstand.

For instance in a stuck pipe situation, if a derrick is able to pull up to 1,000 Klb before failure, then its SHL will be 1,000 Klb (not considering safety margins). This value has nothing to do with the power of the rig, which is determined by the power of the drawwork.

To calculate the static load that the derrick/mast and the substructure will withstand, it is needed to find the heaviest load in AIR, and it can be either casing or drilling string, in most cases it will be the casing string, unless small holes are being drilled.

SHL = (HAS + TB + MO) * 1.25

SHL…Static Hook Load (lb)

HAS…Heaviest String in Air (lb)

TB…Traveling Block (lb)

MO…Margin of Overpull (lb)

The flow of oil in an hydraulic system can be compaired to any water system; in both systems you will find the tank (place where the liquid is store), the conduits or channels through which the liquid will travel (pipes), the pump (to impulse the liquid through long distances or to de a job such as filling a cylinder (piston) or pushing hot or cold water through an air conditioning system in a building, filters (to ensure purity of the liquid), and finally you may have temperature controls. The oil characteristics of a hydraulic system are such that permits the oil to perform amazing work such as keeping a building structure level (this is the case at the outshore airport of Tokyo, which keeps sinking into the see bed and by means of hydraulic systems they turn the support of the structure hydraulic jacks as needed to keep the whole airport level.

The brakes in any car is another example of a hydraulic system where the flow of oil impulse by the brake pedal and or the ABS pump will force the pads of the brakes grab the wheel discs hindering the wheels from turning.

The power steering in any car is another example of oil flowing trough pipes to help the driver turn the car around.

1. car fuel pump 2. excavator 3. human heart

travel jack hydraulic type with 50 metric tonnes capacity - specification