Valve ball description and installation instructions

Sphere introduction
1, the principle of spherical spinning
Comparison of sphere forming methods
(1) Casting method
This is a traditional processing method. It requires a complete set of equipment for smelting and pouring. It also requires a large workshop and more workers. It has large investment, many processes, complicated production processes, and environmental pollution. The technical level of the workers directly affects the quality of the products, and the problem of leakage of the capillary pores of the spheres cannot be completely solved. However, the blank processing margin is large and wasteful, and it is often found in the processing process that the casting defects are scrapped, so that the product cost is increased. The quality cannot be guaranteed. This method is not suitable for the factory.
(2) Forging method
This is another method used by many valve companies in China. It has two kinds of processing methods: one is to cut and heat into a spherical solid blank by round steel, and then mechanically process it. The second is to form a circular stainless steel plate on a large press to obtain a hollow semi-spherical blank, and then to weld the spherical blank to be mechanically processed. The material utilization rate is high, but a high power is required. Presses and furnaces, as well as argon-old welding equipment, are estimated to require 3 million yuan to generate productivity. This method is not suitable for the factory.
(3) Spinning method
Metal spinning method is an advanced small and no chip processing method. It belongs to a new branch of pressure processing. It combines the characteristics of forging, extrusion, rolling and rolling, and has high material utilization rate (up to 80-90%). ), saving a lot of processing time (1-5 minutes forming), the material strength can be doubled after spinning. Due to the small area contact between the rotating wheel and the workpiece during spinning, the metal material is in a two- or three-direction compressive stress state and is easily deformed. Under a small power, a high unit contact stress can be obtained (up to 25- 35Mpa), therefore, the equipment is light in weight, the total required power is small (less than 1/5-1/4 of the press), and has been recognized by the foreign valve industry as an energy-saving sphere processing scheme, and also applicable. For processing parts of other hollow rotors.
Spinning technology has been widely used and developed at high speed in foreign countries. The process and equipment are very mature and stable, and realize the automatic control of machine, electricity and liquid integration. At present, the spinning technology has also been greatly developed in China, and has entered the stage of promotion and practicality.

2. Technical conditions for spinning spherical blanks
According to the production needs of the factory and combined with the characteristics of spinning deformation, the following technical conditions are formulated:
(1) Spinning blank material and type: 1Gr18Nr9Tr, 2Gr13 steel pipe or steel plate;
(2) Spinning ball blank shape structure:

3. Spin forming scheme
The ball spinning is different due to the different types of blanks selected, and two solutions can be used for analysis:
3.1, steel tube shrinkage spinning method
The scheme is divided into three steps: the first step is to cut the steel pipe according to the size, and then rotate it with the spindle in the spindle chuck of the spinning machine tool, and the rotary wheel rotates the tube blank several times by means of the hydraulic copying device, so that The tape is gradually reduced to form a semi-spherical sphere; the second step is to cut the formed spherical portion and process the welding groove; and the third step is to weld the two hemispheres by argon welding to the desired hollow spherical blank. .
The advantages of the steel tube neck spinning method: no need for a mold, the forming process is relatively simple; the disadvantage is that a specific steel pipe is required, a weld seam is required, and the cost of the steel pipe is high.
3.2, steel plate rotation method
There are two ways for this scheme: the first method uses the top force of the flat plate hydraulic material to press the outer end surface of the spherical core mold, rotates with the main shaft, and uses a hydraulic profiling device to rotate several times. The pressure gradually shrinks and deforms the flat plate on the mandrel to obtain a hollow hemisphere, then cuts off the excess burrs and processes the welding groove, and then welds the two hemispheres to the desired hollow sphere blank by argon welding. .
The second method also uses a flat plate blank, except that after spinning into a hemisphere, it is also necessary to unscrew a semi-finished product in a cylindrical shape, and then install the semi-finished blank in the inner hemispherical core mold, using and diameter. The same tailstock ejector is pressed tightly, and the same spinning method as the necking of the steel tube is performed. The cylindrical section is gradually retracted (closed) to form another hemisphere, and the excess metal material of the closing mouth is attached to the ejector rod, and finally cut off. The excess is obtained to obtain a desired hollow hollow ball blank.
The advantages of this method of steel plate spinning method: the steel plate is convenient in source, the price is lower than the steel pipe, and the complete hollow structure sphere can be realized. Compared with the previous scheme of the steel tube neck spinning method, the disadvantage is that two core molds are needed, the spinning process is complicated, the structure and control of the spinning equipment are complicated, and the equipment cost is high, but from the aspects of economic benefit and product quality. Analysis, this program is still the best solution.

4, the selection of spinning machine
The spinning machine consists of three parts: machine, electricity and liquid. It is a relatively advanced medium-sized machine tool with advanced electromechanical and hydraulic integration. The principle of the machine tool. It consists of a main shaft gearbox and hydraulic ejector, tailstock, roller frame, bed and other parts.

In terms of hydraulic transmission, there is a hydraulic station and its hydraulic system that provides all power to the machine except the spindle. The horizontal direction of the rotary wheel is a spinning and contouring control device, including a contoured valve, a contour plate, an adjustment mechanism and a bracket.
In the electronic control, advanced computer automatic control is adopted to realize the automation of the spinning process.

What is the maximum operating pressure of the ball valve at the maximum and minimum temperatures?
The ball is the opening and closing part of the ball valve, also called the ball core and the ball. The ball rotates around the center line of the valve body to achieve the function of opening and closing the ball valve. It is cut with a plane and the cross section is a round face.
The cross section of the ball has the following properties:
1. The line connecting the center of the sphere and the center of the section is perpendicular to the section.
2. The distance d from the center of the sphere to the radius of the sphere R and the radius r of the section have the following relationship: r^2=R^2-d^2 The circle that the spherical surface is cut by the plane passing through the center of the sphere is called the big circle. A circle that is not cut through the cross section of the center of the sphere is called a small circle. On the sphere, the length of the shortest line between two points is the length of a bad arc between the two points through the big circle of these two points. We call this arc length the spherical distance of two points.
We know that the main features of the ball valve are its compact structure, easy operation and maintenance, suitable for general working media such as water, solvent, acid and natural gas, and also suitable for medium with harsh working conditions such as oxygen, hydrogen peroxide, methane and Ethylene and the like. The ball valve body may be integral or combined. The nominal pressure rating (PN) of the ball valve indicates the maximum working pressure of the valve at normal temperature. For example, PN4.0 indicates that the maximum working pressure at operating temperature of -290C to 380C is 40 Bar (4.0 MPa).
The ball valve nameplate shows the maximum operating pressure allowed for the ball valve at maximum and minimum operating temperatures.

What is the main reason for the high reliability of the ball valve?
1) The pair of sealing parts of the ball and the valve seat will not cause scratches, sharp wear and other failures, and will not get stuck during operation (in the absence of lubricant), so it can be reliably applied with corrosive media and low boiling point liquids. Medium
2) The built-in valve stem structure eliminates the hidden danger that the valve stem may fly out due to the loosening of the packing gland under the action of fluid pressure;
3) The ball valve with anti-static and refractory structure is suitable for pipelines conveying oil, natural gas and gas.

How to install the valve sphere is correct
Sphere Definition: A graph consisting of all points in space where the distance to the fixed point is less than or equal to the fixed length is called a sphere. A sphere is a solid figure of a continuous curved surface, and a geometry surrounded by a sphere is called a sphere. There is no absolute sphere in the world. Absolute spheres exist only in theory.
1. Remove the protective cover on both sides of the flange end and rinse it with the valve fully open.
2. Before installation, the whole machine test should be carried out according to the specified signal (electricity or gas) (to prevent the use of vibration due to transportation). After passing the test, it can be installed on the line (wiring according to the electric actuator circuit diagram).
3. Flush and remove any remaining impurities in the piping (which may damage the seat and ball) before preparing to connect to the pipeline.
4. During installation, do not use the actuator portion of the valve as a lifting point for lifting to avoid damage to the actuator and accessories.
5. This type of valve should be installed in the horizontal or vertical direction of the pipe.
6. The pipe near the installation point should not be drooped or subjected to external force. Pipes can be used.