The principle of hydraulic stretching, how to use the hydraulic tensioner

How the hydraulic tensioner works:

The working principle of the hydraulic tensioner is to use the hydraulic cylinder to directly apply external force to the bolt, so that the bolt to be applied is elongated within its elastic deformation range, and the bolt is slightly deformed, so that the nut is easy to loosen.

The hydraulic tensioner is installed at the position of the central axis of the bolt and is used to stretch the bolt axially to achieve the amount of stretch required by the bolt, and it is this stretch of the bolt that determines the preload required for bolt tightening. When the bolt is stretched, the nut will be separated from the contact surface of the equipment, and there is an opening at the lower end of the hydraulic tensioner for the operator to manually turn the nut, usually the rotation of the nut is achieved by a metal lever to toggle a dial ring outside the hexagon nut (or directly toggle the round nut). When the hydraulic tensioner is removed, the nut and the contact surface are tightly attached, thus locking the axial deformation of the bolt, i.e. locking the remaining bolt load in the nut.

The load applied to the bolt is proportional to the hydraulic pressure in the cylinder, and this design retains the payload very precisely. Since the load is applied directly to the bolt and all forces are applied to the bolt elongation, the space required for load generation can be minimized.

To put it simply, if the syringe is filled with high-pressure water from the end of the needle, the handle can be pushed out of the inside little by little.

Hydraulic stretching uses high-pressure oil to enter the piston cavity and then push the plunger to move.

Steps for proper use of hydraulic bolt tensioners:

1. Screw the round nut into the bolt and insert the toggle hole with the toggle handle until it is firm.

2. Put the hydraulic tensioner support seat into it and cover the round nut.

3. Screw the hydraulic tensioner into the bolt, and tighten the stretching head with a toggle handle to the coordination of each part without gap.

4. After installation, insert the quick joint of the high-pressure oil pipe connected with the ultra-high pressure oil pump into the quick joint on the hydraulic tensioner.

1) Operate the ultra-high pressure oil pump, input high-pressure oil to the hydraulic tensioner cylinder, the piston starts to work, and the hydraulic tensioner enters the working state, at this time, pay attention to the working pressure of the ultra-high pressure oil pump and the stretching length of the hydraulic tensioner, and be sure to control it within the set range.

2) When the working pressure and stretching length of the hydraulic tensioner reach the rated value, the ultra-high pressure oil pump should stop working immediately, insert the toggle handle into the toggle hole of the round nut, and toggle the round nut in the clockwise direction to firmly put it in place.

3) In use, if the process requires to increase the elongation length and need to continue to stretch, after the round nut is fastened in place, the ultra-high pressure oil pump should be depressurized according to the operating procedure, and then the toggle handle is inserted into the piston toggle hole of the hydraulic tensioner, and the toggle handle resets the piston. After that, the above method is followed until the process requirements are met. After the hydraulic tensioner is completed, the ultra-high pressure pump is first depressurized, and then disassembled, and there are two ways to disassemble, which can be selected according to the working environment

1) Toggle the stretching head with the toggle handle, first drain the hydraulic oil in the cylinder to the ultra-high pressure oil pump oil storage, reset the piston, and then disconnect the quick connector connected with the high-pressure oil pipe, unscrew the bolt out of the hydraulic tensioner, take out the supporting seat, and end the whole stretching process.

2) Disconnect the quick connector connected to the high-pressure oil pipe, first unscrew the bolt of the hydraulic tensioner, take out the support seat, loosen the screws on the end face of the piston with an Allen wrench, and then clamp the tensioner straight in the middle of the vice, slowly tighten the screw, and discharge the hydraulic oil stored in the cylinder until the piston is all reset.

Introduction to hydraulic bolt tensioners.

The hydraulic bolt tensioner is referred to as the hydraulic tensioner, and its power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, which refers to the oil pump in the hydraulic system, and provides power to the hydraulic bolt tensioner to realize the conversion of fluid hydraulic pump to mechanical energy.

Hydraulic bolt tensioner is applicable to electric power, shipbuilding industry, metallurgy, coal mining, petrochemical, heavy machinery and other fields.

Advantages of hydraulic bolt tensioner.

1. Generally, mineral oil is used as the working medium, and the relative moving surface can be lubricated by itself, and the service life is long.

2. Light weight, small size, small motion inertia and fast response speed.

3. Various components of hydraulic transmission can be arranged conveniently and flexibly according to needs.

4. Overload protection can be realized automatically.

5. The operation control is convenient, and multiple bolts can be tightened at the same time. Save labor costs.

6. It is easy to realize linear motion.

7. It is easy to realize the automation of the machine, when the electro-hydraulic joint control is adopted, not only can a higher degree of automatic control process be realized, but also remote control can be realized.

8. It can be used as a device for applying axial force to hydraulic interference connection for top pressure installation.

The working pressure of the four hydraulic tensioners is 150MPa.

1. The ordinary type is suitable for the stretching of single-specification bolts, with light weight and high precision. Small size and compact structure;

2. The interchangeable type of stretching head has strong versatility, and can be applied to the stretching of multiple specifications of bolts by replacing the stretching head;

3. Single-stage reset piston automatic reset design, suitable for frequent use;

4. Double return type double cylinder design, suitable for working conditions with narrow space.

Hydraulic bolt tensioner maintenance.

1. Operate in strict accordance with the methods and procedures required by the manual, and do not arbitrarily increase the working pressure and bolt stretching length input of the hydraulic tensioner, so as not to damage the sealing ring and related matching parts.

2. After the end of the work, it should be wiped clean and kept properly, especially the oil inlet interface should not seep into the ash (after the construction is completed, the quick connector part should be covered with a dust cap) to prevent damage to the cylinder and piston after entering the oil cylinder.

3. When replacing the O-ring and other accessories, pay attention to the anastomosis to ensure the sealing effect.

The oil pump is the power source of the four-column double-action tensile hydraulic engine oil finger pressure system, relying on the force of the oil pump to make the hydraulic oil enter the cylinder and piston through the combustion pipeline, and pass through the seal, so that the hydraulic oil can not leak. After that, through the check valve, the hydraulic oil is circulated in the oil tank, so that the cylinder and the piston circulate to realize the conversion between energy to complete the circulation of various actions.

Search: Recommended working principle of hydraulic tensioner: Wharton liquid section Wu hydraulic bolt tensioner, providing various types of hydraulic bolt tensioner, bolt hydraulic tensioner, hydraulic tensioner and other hydraulic bolt tensioners.

Hydraulic tensioner is the world's most advanced bolt pretensioning and disassembly tool, hydraulic bolt tensioner is widely used in the pretensioning of large-diameter bolts with simple operation, easy to use, high safety and so on. Practice has proved that the hydraulic tensioner has little damage to the equipment, the connection components are evenly stressed, and the reliability of the bolt connection is high. Hydraulic bolt tensioner is referred to as hydraulic tensioner, which has the function of bolt tightening and disassembly.

It can be widely used in metallurgical mining, petrochemical industry, shipbuilding industry, power system, rolling stock, heavy machinery and other industries. With the help of the hydraulic power provided by the ultra-high pressure pump, the bolt is stretched in its elastic deformation zone by using the allowable elastic amplitude of the material to achieve the purpose of tightening or removing the bolt. In addition, it can be used as a device for applying axial force to hydraulic interference joints, and it can be installed under top pressure.

Especially in the working environment with serious pollution or limited space area, the use of hydraulic stretching device is difficult to replace by any other tool, and is an ideal process equipment for the assembly of large and medium-sized mechanical products and equipment maintenance. The construction work efficiency has been greatly improved.

1. It can eliminate torsional load;

2. It has high precision;

3. Greatly increase the quality and safety performance of bolt joints;

4. It will not damage the flange and other components;

5. There is no need to consider the influence of friction coefficient;

6. Make the real synchronous stretching possible;

7. Suitable for bolts of different diameters;

8. It is easy to disassemble;

9. Strong versatility;

10. Time-saving and labor-saving;

11. Automatic operation has been realized.

There are four types of hydraulic tensioners: ordinary general-purpose type, stretching head interchange type, unipolar reset type and bipolar reset type.

The working pressure of the four hydraulic tensioners is 150MPa. The ordinary type is suitable for the stretching of single-gauge bolts, with light weight and high precision. Small size and compact structure; The interchangeable type of stretching head is highly versatile, and can be applied to the stretching of multiple specifications of bolts by replacing the stretching head; Single-stage return piston automatic reset design, suitable for frequent use; The double-pole return type double cylinder design is suitable for working conditions where space is limited.