Presentation for a physics lesson "Plumbing. Piston liquid pump." The topic of the lesson is “Plumbing. Hydraulic Press". Piston liquid pump hydraulic machine presentation

Objective of the lesson: To develop knowledge about the water supply system and operation hydraulic devices; To develop knowledge about the water supply system and the operation of hydraulic devices; device and principle of operation of a hydraulic press; device and principle of operation of a hydraulic press; what determines the gain in strength; what determines the gain in strength; know the hydraulic press formula. know the hydraulic press formula.

How does atmospheric pressure change with increasing altitude above the Earth? How does atmospheric pressure change with increasing altitude above the Earth? Why does a balloon filled with hydrogen increase in volume as it rises above the Earth? Why does a balloon filled with hydrogen increase in volume as it rises above the Earth?

Water supply Diagram of the water supply system With the help of pump 2, water flows into a large tank of water located in water tower 1. From this tower, pipes are laid along city streets at a depth of approximately 2.5 m, from which special branches ending with taps go to each individual house .

Piston liquid pump Water is supplied to the water tower tank by pumps. These are usually electrically driven centrifugal pumps. Here we will look at the operating principle of another pump, the so-called piston liquid pump, shown in Figure 126. Water is supplied to the water tower tank by pumps. These are usually electrically driven centrifugal pumps. Here we will look at the operating principle of another pump, the so-called piston liquid pump, shown in Figure 126.

Design The design of the hydraulic press of the hydraulic press is based on the law. based on law. Pascal Pascal Two communicating Two communicating vessels are filled with a homogeneous liquid and closed by two pistons, the areas of which are S 1 and S 2 (S 2 > S 1). According to Pascal's law, we have equality of pressure in both cylinders: p 1 = p 2 vessels are filled with a homogeneous liquid and closed by two pistons, the areas of which are S 1 and S 2 (S 2 > S 1). According to Pascal's law, we have equality of pressure in both cylinders: p 1 =p 2 S 1). According to Pascal's law, we have equality of pressure in both cylinders: p 1 = p 2 vessels are filled with a homogeneous liquid and closed by two pistons, the areas of which are S 1 and S 2 (S 2 > S 1). According to Pascal's law, we have equality of pressure in both cylinders: p 1 =p 2">

When a hydraulic press operates, a gain in force is created equal to the ratio of the area of ​​the larger piston. When a hydraulic press operates, a gain in force is created equal to the ratio of the area of ​​the larger piston to the area of ​​the smaller one. to a smaller area. F2F2 F1F1 S2S2 S1S1

1. What force must be applied to a smaller piston with an area of ​​0.1 m 2 in order to lift a body weighing 500 N located on a piston with an area of ​​5 m 2? 2. What force must be applied to the smaller piston with an area of ​​2. What force must be applied to the smaller piston with an area of ​​0.1 m2 to lift a body weighing 200 kg located on a piston with an area of ​​10 m2? 0.1 m2 to lift a body weighing 200 kg located on a piston with an area of ​​10 m2?

What force must be applied to a smaller piston with an area of ​​0.1 m 2 in order to lift a body weighing 500 N located on a piston with an area of ​​5 m 2? Given S 1 =0.1m 2 F 1 =500H S 2 =5m 2 F2=?F2=?F2=?F2=? Solution F2=F2= F 1 · S 2 S 1 F2=F2= 500 N · 5 m 2 0.1m 2 = N Answer: N F1F1 F2F2 S1S1 S2S2 =

What force must be applied to a smaller piston with an area of ​​0.1 m2 to lift a body weighing 200 kg located on a piston with an area of ​​10 m2? Given S 1 =0.1m 2 m 2 =20 kg S 2 =10m 2 F1=?F1=?F1=?F1=? Solution F1=F1= F 2 · S 1 S 2 F1=F1= 1960 N · 0.1 m 2 10m 2 = 19.6 N Answer: 19.6 N F = m · g F 2 =200 kg · 9, 8 N/kg=1960N F1F1 F2F2 S1S1 S2S2 =

Homework: - ξ 44, 45, 4, s Make a working model of a hydraulic press (two syringes of different volumes, a straw for a cocktail)

Water pipes. Piston liquid pump.

Physics lesson in 7th grade

Lesson Objectives

• Repeat the topic: atmospheric pressure, Torricelli's experiment, measurement atmospheric pressure
• Get acquainted with the design and purpose of a piston liquid pump and hydraulic press.
• Learn to solve problems on a topic.
• Promote mastery of techniques scientific research: analysis and synthesis.

Repetition…

• Why doesn't the Earth lose its air envelope?
• Why don't the molecules of the gases that make up the atmosphere all fall to its surface?
• Express the pressure of 1 mmHg in Pa. Art. What is the structure of a mercury barometer? Where are they used?
• Tell us about the structure of liquid and metal pressure gauges. What are they used for?

Solve the problem

• When taking a deep breath, about 4 dm 3 of air enters the lungs of an adult. Determine the mass and weight of this air.

• Answer: m=5, 16 g; Р=0.0516Н=51.6 mN.

Solve the problem

• High or low atmospheric pressure today if the mercury level in the Torricelli barometer is high

Solve the problem

• Is it true that on one surface of a notebook sheet whose dimensions are 16x20 cm atmospheric air presses with a force of more than 3 kN?

• Answer: yes, with a force of about 3.3 kN.

Solve the problem

• Is 1.5 kg of mercury sufficient to construct a Torricelli barometer from a tube with internal diameter 8 mm?

• Answer: yes, enough.

Solve the problem

• The flask was partially evacuated and the pressure in it became 100 mmHg. Art. The flask was closed with a stopper with a diameter of 3 cm and turned upside down. What mass of weight must be suspended from the cork to pull it out? (For simplicity, the friction of the stopper on the neck of the flask can be neglected)
• Answer: more than 6.2 kg

It's like running water

Does it supply water to our house?

Why tap water

Doesn't it always leak?

And on the fifth floor

There has been no water for a long time.

Water supply

• Water supply– a set of measures to provide water to various consumers: the population, industrial enterprises etc. Complex engineering structures and devices that supply water (including obtaining water from natural sources, purifying it, transporting it and supplying it to consumers) is called a water supply system.

• Why are water taps in houses not made higher than the water level in the water tower tank?
• Is there the same pressure in the water taps on different floors? What does it depend on?

Piston Liquid Pump

• Water is supplied to the water tower tank by pumps. These are usually electrically driven centrifugal pumps. We will look at the operating principle of another pump - the so-called piston liquid pump

Diagram of a piston liquid pump

Main parts:

 piston equipped with valve 1;

 cylinder with valve 2;

 pipe 3 (water is pumped through it, for example, into the tank of a water tower);

 pipe 4 (through it, water enters the pump and fills the cylinder).

Answer the questions

• Can a syringe be considered a pump?

Answer: no. The pump has a valve system that the syringe does not have. The movement of liquid in the pump always goes in one direction, in the syringe it goes in one direction, then in the opposite direction. The action of a syringe is similar to that of a pipette.

Answer the questions

• Where are the valves located and how are they arranged that allow air to be pumped into the bicycle inner tube?

• Answer: one valve is the leather piston cuff itself, the other is the nipple in the chamber.

What is the difference?

• A suction water (or air) pump requires less force to operate than a discharge pump. Why?
• Answer: when the suction pump located at the top of the well operates, the water rises due to the force of atmospheric pressure; at the pressure pump, the water is lifted by the force of human muscles

Technology is unthinkable without them,

Although they require a lot of skill.

They are used everywhere -

In pressing, stamping, forging...

(A. Kamenovsky)

Definition

• is a machine for processing materials by pressure, driven by a compressed liquid

A bit of poetry...

The ancients had a stone and a club

And our car runs on liquid.

She has two cylinders with a piston,

Each piston does its own thing.

Little ones we pressed on the liquid,

On the big one the same pressure was reported,

Well, since there is a lot more S,

That is a big advantage in strength.

Make up questions based on this text of the poem

• Are the cylinders and pistons the same? What is the difference?
• What does it mean: each piston does its own thing?
• On what law is the operation of a hydraulic press based?

• The fluid in the cylinders will be in equilibrium only when The force acting on the larger piston is as many times greater than the force acting on the smaller piston as the area of ​​the larger piston is greater than the area of ​​the smaller piston.

• The ratio characterizes the gain in power obtained in a given machine. According to the formula obtained, the gain in strength is determined by the ratio of areas.

• Therefore, the larger the piston area ratio, the greater the gain in power.

Solve the problem

• The area of ​​the small piston is S 1 = 5 cm 2, and the area of ​​the larger piston is S 2 = 500 cm 2. determine the gain in strength.

• That's right, it will be 100 times! Marvelous!

Application of hydraulic press

• For the first time, hydraulic presses began to be used in practice in late XVIII – early XIX century. Modern technology is already unthinkable without them. They are used in metalworking for forging ingots, sheet stamping, extruding pipes and profiles, pressing powder materials.
• Using hydraulic presses, plywood, cardboard and artificial diamonds are produced.

• Will the pressure produced by a hydraulic press change if the water is replaced with a heavier liquid - glycerin?
• Answer: no

• Will there be a difference in the operation of a hydraulic press on Earth and on the Moon?

• Answer: there will be no difference

• Even several people will not be able to lift a truck by grabbing its wheels. Why does one driver manage to lift the car a little while filling hand pump wheel balloon with air?
• Answer: the pump together with the cylinder forms a pneumatic machine, which gives a certain gain in strength.

• From a bathtub that is standing on the floor and does not have a drain hole in the bottom, you need to empty the water without turning the bathtub itself over. Is it possible to drain water from a bathtub using a siphon?
• Answer: water will pour out of the bath as long as the water level in it is higher than the level of liquid in the vessel into which the water is poured.

Reflection

• 1.What new did you learn? 2. What did you learn? 3. What difficulties did you encounter?

Lesson summary

• You can solve riddles forever.
• The universe is infinite.
• Thanks to all of us for the lesson,
• And the main thing is that it will be used for future use!
• I really enjoy working with you!

Homework

• §44, 45 teach
• Individual tasks for everyone on cards.

Piston pumps Piston pumps include reciprocating pumps whose working bodies
made in the form of pistons. Very
a common type of piston
pumps are plunger type pumps,
used in internal combustion engines.
Piston pumps are classified:
- By the number of pistons: 1-, 2-, 3-piston and multi-piston;
- On the organization of absorption processes and
injection – single- or double-acting;
- According to the kinematics of the drive mechanism: drive
pumps with crank mechanism,
direct-acting, manually driven.

Rotary pumps

Gear pumps

Screw pumps

“Hydraulic mechanisms” - Piston liquid pump. Hydraulic presses. Water pipes. Diagram of a 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.

“Substance pressure” - 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

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

Working volume axially 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.