Piston liquid pump physics lesson presentation. Piston liquid pump. Hydraulic machine formula

Types of hydraulic pumps Based on the nature of the force action, and therefore the type of working chamber, dynamic and volumetric pumps are distinguished. In a dynamic pump, the force on the liquid is carried out in a flow chamber, constantly communicating with the inlet and outlet of the pump. In a positive displacement pump, the force on the liquid occurs in the working chamber, which periodically changes its volume and alternately communicates with the inlet and outlet of the pump. Dynamic pumps include: 1) vane: a) centrifugal; b) axial; 2) electromagnetic; 3) friction pumps: a) vortex; b) screw; c) disk; d) jet, etc. Volumetric pumps include: 1) reciprocating: a) piston and plunger; b) diaphragm; 2) winged; 3) rotary: a) rotary-rotational; b) rotary-translational. A unit consisting of a pump (or several pumps) and a driving motor connected to each other is called a pump unit.

External gear pumps - very wide range of drive shaft rotation speeds - wide range of operating pressures up to 30 MPa, volume up to 16.6 l/s - very wide range of viscosities of the working fluid - high level noise - average service life - low price

Blade hydraulic pumps Fig Vane (vane) pump series MG-16: 1 blade; 2 holes; 3 stator; 4 shaft; 5 cuff; 6 ball bearings; 7 drainage hole; 8 cavities under the blades; 9 rubber ring) 10 drain hole; 11 drain cavity; 12 annular projection; 13 cover); 14 spring; 15 spool; 16 rear disc; 17 box; 18 cavity; 19 hole for fluid supply with high pressure; 20 hole in the rear disk 21 rotor; 22 front disc; 23 ring channel; 24 supply hole; 25 housing - average range of drive shaft rotation speeds - average range of operating pressures up to 10 MPa, flow rate up to 4 l/s - average range of viscosities of the working fluid - low noise level - very long service life - average price

Radial piston hydraulic pump Diagram of a radial piston pump: 1 - rotor; 2 - piston; 3 - drum (stator); 4 - axle; 5 - suction cavity; 6 - discharge cavity - medium range of drive shaft rotation speeds - wide range of operating pressures up to 50 MPa, flow rate up to 15 l/s - medium range of viscosities of the working fluid - low noise level - very long service life

Axial piston hydraulic pumps inclined 1 - in the drive shaft; 2, 3 ball bearings; 4 rotary washer; 5 connecting rods 6 piston; 7 rotor; 8 spherical distributor; 9 cover; 10 central spike; 11 housing - wide range of drive shaft rotation speeds - very wide range of operating pressures up to 40 MPa, flow rate up to 15 l/s - very wide range of viscosities of the working fluid - high noise level - long service life - high price

Hydraulic distributors When operating hydraulic systems, it becomes necessary to change the direction of the flow of working fluid in its individual sections in order to change the direction of movement of the actuators of the machine, it is necessary to ensure the desired sequence putting these mechanisms into operation, unloading the pump and hydraulic system from pressure, etc.

Gear pump– a rotary pump with working units in the form of gears (gears), ensuring geometric closure of the working chambers and transmitting torque.

Gear pumps are used in hydraulic drives as independent low-pressure power sources or as auxiliary pumps for feeding hydraulic systems.

The gear pump consists of a housing, a drive gear and a driven gear, a shaft, an axis, and two side covers. The gears are in mesh and have the same modules and number of teeth.

The housing is the stator, the drive gear is the rotor, and the driven gear is the displacer. The working chambers are formed by the working surfaces of the housing, two side covers and gear teeth. The housing has a suction and discharge cavity.

Gear pumps

The operating principle of a gear pump is as follows. In the pump, the suction cavity is located on the side where the gear teeth disengage. When the gear teeth disengage, the volume of the cavity increases and a vacuum is created in the cavity. The process of absorption of the working fluid occurs. After this, each of the gears moves the working fluid located in the tooth cavities in opposite annular directions from the suction cavity to the discharge cavity. A pumping process occurs in which opposing volumes of liquid are first connected in the injection cavity, and then the liquid is forced out of the injection cavity to the pump outlet by the teeth of the gears that engage.

Gear pumps

The working volume of a gear pump is determined by the formula:

where m is the module of the teeth; z – number of gear teeth; b – width of the gear ring.

Gear pumps are unregulated, since the parameters that determine the pump displacement are constant.

Gear pumps are also used as hydraulic motors.

Advantages gear pumps– simplicity of the device, reliability in operation, compactness and low cost.

Disadvantages of gear pumps are pulsation of fluid flow, sensitivity to overheating, low volumetric efficiency at high temperatures, significant noise.

Axial piston pumps

Axial- piston pump is a rotary pump in which the working chambers are formed by the working surfaces of the cylinders and pistons, and the axes of the pistons are parallel (axial) to the axis of the cylinder block or make an angle of no more than 45º with it.

Axial piston pumps are widely used in hydraulic transmissions of self-propelled agricultural and road construction vehicles.

Axial piston pumps, depending on the location of the rotor, are divided into pumps with an inclined disk (the axes of the drive link and rotor rotation coincide) and pumps with an inclined block (the axes of the drive link and rotor rotation are located at an angle).

Axial piston pumps

Slant disc pumps have the most simple circuits. The pistons are connected to the inclined disc by a point contact or connecting rod. The cylinder block with pistons is driven into rotation by the shaft.

To supply and drain working fluid to the working chambers, two arc-shaped windows are made in the end distribution disk - suction and discharge. To ensure the movement of the pistons during suction, forced driving of the pistons through the connecting rod is used, and for pistons with point contact, coil springs are used.

The operating principle of the pump is as follows. When the pump shaft rotates, torque is transmitted to the cylinder block. At the same time, due to the presence of the angle of inclination of the disk, the pistons perform a complex movement - they rotate together with the cylinder block and at the same time perform a reciprocating movement in the cylinders of the block, during which the working processes of suction and discharge occur.

Axial piston pumps

When the shaft rotates clockwise, the working chambers located to the right of vertical axis distribution disc are connected to the suction port.

The translational movement of the pistons in these chambers occurs in the direction from the distribution disc. At the same time, the volumes of the chambers increase, and the liquid fills them under the influence of a pressure difference. This is how the absorption process occurs.

The working chambers, located to the right of the vertical axis of the distribution disk, are connected to the discharge window. In this case, the pistons move towards the distribution disk and displace liquid from the working chambers.

Axial piston pumps

The working volume of an axial piston pump with an inclined disk is determined by the formula:

q0 = Sпhz = πd²/4 zDtgβ ,

where Sp – piston area; h – maximum piston stroke (h = Dtgβ); z – number of pistons; dп – piston diameter; D – diameter of the circle where the cylinder axes are located in the block; β is the angle of inclination of the disk.

The working volume of the pump depends on the angle of inclination of the disk.

You can change the working volume by changing the angle of the disk. The greater the angle of inclination β, the greater the pump displacement. The maximum permissible angle of inclination of the disk usually does not exceed 25º.

Axial piston pumps

Regulation of the flow of an axial piston pump is achieved by changing the angle of inclination of the disk.

Axial piston pumps are reversible: when they are supplied with oil under pressure from another pump, they become hydraulic motors of rotational motion.

The advantages of axial piston pumps are stability of parameters during long-term operation with variable external conditions; high volumetric and mechanical efficiency; sufficient durability.

Disadvantages of axial piston pumps – high price; high sensitivity to vibrations; increased requirements for the fineness of filtration of the working fluid.

Hydraulic cylinders

Hydraulic cylinders – volumetric hydraulic motor with limited reciprocating movement of the output link.

Depending on the design of the working chamber, hydraulic cylinders are divided into piston, plunger, telescopic, membrane and bellows.

Piston cylinders are most widely used in volumetric hydraulic drives due to their simple design and high reliability. The working chamber of a piston hydraulic cylinder is formed by the working surfaces of the housing and the piston with the rod. The housing contains a piston rigidly connected to the rod.

Hydraulic cylinders

The cylinder has two cavities - piston and rod. The piston cavity is a part of the working chamber limited by the working surfaces of the housing and the piston. The rod cavity is a part of the working chamber limited by the working surfaces of the body, piston and rod.

The operating principle of a piston hydraulic cylinder is as follows. When the piston cavity is connected to the pressure line, the piston with the rod moves to the right under the influence of the pressure force of the working fluid. At the same time, the working fluid is displaced from the rod cavity. When the working fluid is supplied to the rod cavity, the piston with the rod moves in the opposite direction under the influence of pressure.

"Hydraulic mechanisms"- Piston liquid pump. Hydraulic presses. Water pipes. Scheme hydraulic press. A device that allows you to get a big gain in strength. Hydraulic Press. Problem solving. Hydraulic brakes. What force must be applied to the smaller piston. Hydraulic lifts and jacks. The purpose of the lesson.

“Physics problems on pressure”- Other units of pressure. Experience. Answers to tests. Measuring instruments. Tests. Experience: IS IT POSSIBLE TO STAND ON LIGHT BULB? This design can even withstand an adult. Ways to reduce and increase. Pressure solids. A similar experiment can be carried out with one light bulb placed in the middle!

"Gas pressure"- What does gas pressure depend on? Why does the gas press? Gases and liquids. Boiled egg. Gas pressure on the walls of the vessel. Round holes. The ball increases its volume. Pressure. Metal cube. Gas pressure. Formula for calculating pressure. Piston.

"Pressure of matter"- Complete the task. The gas pressure will increase. Gas pressure. Cause of gas pressure. What is pressure? Abstract. Solve quality problems. Cards with formulas. The secret of treasures. Experimental task. What new things have you learned? Air pressure. Take a practice test.

"Volume hydraulic machines"- Change in fluid energy. Volumetric hydraulic machines. Number of pistons. Overtaking mechanism details. Shaft rotation speed. Main indicators and characteristics of OGM. Face distributors. Plate OGM. OGM working chambers. Brief information about volumetric hydraulic machines. Application of OGM. Working chambers. Power ratio.

“Solving Pressure Problems”- Air front. Why is air pressure different at the top of a mountain and at its base? The tip of the spike has a very small cross-sectional area. Continuous thermal motion of molecules and gravity. We climbed the mountain, it became difficult for us to breathe. Pipes for supplying water to great heights are made of durable material.

There are 30 presentations in total

Municipal autonomous educational institution

"Lyceum No. 7" Berdsk

Pressure gauges Piston Liquid Pump Hydraulic Press

7th grade

Physics teacher I.V.Toropchina

Pressure gauges

To measure more or less

atmospheric pressure use pressure gauges

(from Greek "manos" - loose, "metreo" - I measure).

There are pressure gauges liquid and metal .

Liquid pressure gauge

The liquid pressure gauge consists of a double-bend glass tube,

into which some liquid is poured. With flexible

tubes, one of the pressure gauge elbows is connected to a round flat

a box covered with rubber film.

Liquid pressure gauge

The operation of the pressure gauge is based on comparing the pressure in a closed

knee with external pressure in the open knee. The deeper

immerse the box in liquid, the larger it becomes

the difference in the heights of the liquid columns in the pressure gauge elbows, and thus

more pressure is produced by the liquid.

Metal pressure gauge

Using a metal pressure gauge

measure blood pressure compressed air and other gases.

1.A metal tube bent into an arc

2. Arrow

3.Zubchatka

4. Crane

5. Lever

Metal pressure gauge device

The end of the tube communicates with tap 4 with the vessel in which the pressure is measured.

As the pressure increases, the tube

unbends. Movement closed

its end using lever 5 and

teeth 3 are transmitted to the arrow

2, moving near the instrument scale.

When the pressure decreases, the tube

(due to its elasticity)

returns to previous position, A

arrow - to zero division

scales.

Application of pressure gauges

Pressure gauges are used in all cases where

need to know, control and regulate

pressure. Most often, pressure gauges are used in

thermal power engineering, chemical, petrochemical

enterprises, food industry enterprises.

Pressure gauge for measurement blood pressure called: tonometer

Piston Liquid Pump

The action of piston liquid pumps is based

on the fact that under the influence of atmospheric pressure

the water in the tube rises behind the piston .

Piston liquid pump design

1 – piston 2 – 2 – valves

Pump operating principle

When the piston moves up water, under the influence of atmospheric pressure, enters the pipe, lifts the lower valve and moves behind the piston. When the piston moves down The water under the piston presses on the bottom valve and it closes.

Pump operating principle

At the same time, under water pressure, the valve inside opens

piston, and water passes into the space above the piston. At

subsequent upward movement of the piston, the

the water above it, which is poured into the barrel. Behind the piston

a new portion of water rises, which upon subsequent lowering of the piston

will be above him, etc.

How does an air chamber piston pump work?

1-piston

2-suction valve

3-discharge valve

4-air chamber

5-handle

Mechanisms that operate using some kind of liquid are called hydraulic (Greek “hydro” - water, liquid).

Main part hydraulic machine There are two cylinders of different diameters, equipped with pistons and connected by a tube.
The space under the pistons and the tube are filled with liquid (usually mineral oil).
The heights of the liquid columns in both cylinders are the same as long as no forces act on the pistons.

Hydraulic machine formula

Let us denote the forces acting on the pistons - F 1 And F 2 , piston areas - S 1 And S 2 .

Then the pressure under the small piston is: p 1 = F 1 S 1 , and under the big one: p 2 = F 2 S 2 .
According to Pascal's law, pressure is transmitted equally in all directions by a fluid, therefore p 1 = p 2 Substituting the corresponding values, we get