# FLUID FLOW IN HYDRAULIC SYSTEMS

Parameters and Principles Affecting Fluid Flow in Hydraulic Systems

– Weight – Density – Specific weight

– Pressure – Fluid Column Height – Force

– Pressure such as fluid column height

– Visibility

Block Module (B)

Energy Conservation

The Bernoulli equation

The continuity equation

A quiet, bubbly stream

Hydraulic cylinder speed control

1- Speed ​​control with input current control

2- Speed ​​control with output current control

3. Speed ​​control by sending part of the flow to the tank

Operators

Operators are used in the hydraulic system to convert fluid pressure to mechanical power. The amount of power generated depends on the flow rate and pressure drop on the operator and its overall efficiency. The greatest advantage of the hydraulic system over mechanical systems is the flexibility of the power components (hoses and pipes) and the direct conversion of fluid power into linear and rotational motions.

Hydraulic actuators are divided into three basic types:

—A – Linear Operators (Cylinders)

(B) continuous rotating rotary actuators (hydraulic motors)

-C – Rotary operators with limited spin domain (quasi-rotary)

Hydraulic linear actuators

– Used in hydraulic cylinders to apply linear force and move the load or hold it in the desired position. The following factors are relevant to the choice of hydraulic cylinders.

—Cylinder application

– Interior Building

– Force required

– Working day

—The number of cycles per unit of time

– Installation method

– Acceleration and deceleration force

The bow of the piston rod

– In a hydraulic cylinder, the piston rod, like a column, is subjected to pressure. Therefore, the rod must be of sufficient diameter to prevent buckling. Euler theory is used to calculate the proper diameter of piston rod in relation to buckling. In applying this theory, it is necessary to consider the length of the piston rod and its connection to the load. Cylinder manufacturers provide the necessary guidance in their catalogs by specifying the diameter of the piston rod per pressure course (for compressive forces).

Max cylinder speeds

– The maximum speed of the piston rod is limited by the following two factors:

1. The flow rate into and out of the cylinder

2- Cylinder resistance to impact loads caused by piston stop

Working temperature

– The maximum working temperature of the elastomeric seals should not exceed 80 ° C in order to prevent rapid damage to the elastomeric seals. Occasionally, it is necessary to install a heat shield to prevent outside heat from penetrating into the cylinder. Using the metal piston rings, the permitted operating temperature range can be increased instead of the elastomeric seals. The breakdown of mineral oils begins at temperatures above 50 degrees Celsius. This problem also exists at low temperatures.
Oil storage tank

– Proper design of the reservoir is one of the factors contributing to increasing the efficiency and service life of hydraulic system components. A tank is a place where sludge, water, and metal particles are deposited and allowed to air bubbles to escape from the surface by escaping to the surface. Therefore, the reservoir is not only the storage space for hydraulic fluid, but also the main site for supplying the required conditions.

– The suction line filter of the pump should be well below the oil level and within 1 to 2 inches above the oil level.

– To prevent oil from foaming, the main return line should be installed below the oil level (twice the return line above the tank floor) and in an area in front of the pump suction line.

– Leakage lines have a pressure of zero and must be separated from the main return line and drained above the oil level. As a result, insoluble air is removed from the oil, preventing airflow in critical lines.

Atmospheric lines containing large amounts of air should be discharged above the oil level, above the oil level, and within the slope of 5 to 10 degrees.

– Respiratory duct installed on the surface of the tank equipped with a filter.

– The oil feed tube is equipped with a filter.

—A glass speculator

– Outlet at the lowest point.

– Painting the interior wall

—Wave waves

—Hydraulic fluids

Mineral oils have been available since the beginning of the 20th century, but the use of additives to improve the chemical and physical properties of hydraulic oils began in the 1940s. These oils are highly flammable and may present a serious risk when used at high temperatures.

Hydraulic fluid properties

– Relative density or specific gravity (about 0.9)

—Lazette

—A visceral person

—Visual Specifications – Pressure

– Cutting stability

—Foam flooring

– Falling point

– Compressibility

– Thermal expansion

– Lubrication

Types of Hydraulic Fluids

– Mineral oil

– Milk solubility in water

– Milk solubility in oil

-Glycol water fluids

– Ester phosphate

Pipes and fittings

Types of guides

1. Steel rigid pipes

Semi-rigid pipes

3. Plastic pipes

4.4 Flexible hoses

Filters and filters

– The worst enemy is the advanced and precise hydraulic components of contaminated fluid.

Factors affecting infection are:

1. Contamination during the manufacture, maintenance and assembly of components by metal particle, pipe thread chips, pipe cap particles, sealing materials, welding particles, and intra-particle masses.

2. Creating contamination during operation of the device due to the entry of water into the hydraulic tank, gas production in the tank, mass in the pipes, used abrasive particles, abrasive metal particles, oil oxidation.

3.3 Pollution from outside the hydraulic system.

The filters

– A filter is used to separate coarser particles than the filter and provides less resistance to the flow of current. Inside the building, metal plates with holes up to a maximum of 0.0059 inches (about 150 microns) were used.

Filters

Filter is a device that is capable of separating insoluble micronutrients in the fluid. Studies have shown that particles as small as 1 micron can have a deleterious effect on the hydraulic system.

– Filters can be installed on the pump outlet line with many types available on the return line to the tank.

– Use 25- to 35-micron filters in the return line. It is essential to use 10 micron types in highly sensitive systems that use servo valves.

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