All about the characteristics of ball valves. Device, manufacturers and specifications according to GOST ball valves Designation of flanged ball valves

What is DN, Du and PN? Plumbers and engineers need to know these parameters!

DN - The standard designating the conditional internal diameter.

PN - Standard designating nominal pressure.

What is Du?

Doo- formed from two words: Diameter and Conditional. DN = DN. Do is the same as DN. It's just that DN is more of an international standard. Du - Russian-language representation of DN. Now it is categorically necessary to abandon such a name Du.

What is DN?

DN- Standardized diameter representation. GOST 28338-89 and GOST R 52720

Nominal diameter DN(Nominal diameter; Nominal bore; Nominal size; Nominal diameter; Nominal bore): Parameter used for piping systems as a characteristic of the connected parts of the valve.

Note - The nominal diameter is approximately equal to the internal diameter of the connected pipeline, expressed in millimeters and corresponding to the nearest value from a series of numbers taken in the prescribed manner.

What is DN usually measured in?

Under the terms of the standard, it seems that it does not have a strict binding to a unit of measure (it is written in the documents). But it refers to the size of the diameter. And diameter is measured by length. And because the unit of length can be different. For example, inch, foot, meter, etc. For Russian documents, we simply measure in mm by default. Although the documents say that it is still measured in mm. GOST 28338-89. But it does not have a unit of measure:

How does it not have, if it has? Can you write in the comments how to understand this phrase?

It seems to have reached ... DN (serial number of diameter expressed in millimeters). That is, it does not have a unit of measurement, but, as it were, contains constant values ​​(digital discrete values ​​of the type: 15,20,25,32...). But it cannot be designated, for example, as DN 24. Because the number 24 is not in GOST 28338-89. There are strict values ​​in order like: 15,20,25,32 ... And only they need to be chosen for designation.

DN is measured by the nominal diameter in mm (millimeter = 0.001 m). And if you see DN15 in Russian documents, then this will indicate an inner diameter of about 15 mm.

Conditional pass- indicates that this is the inner diameter of the pipe, expressed in millimeters - conditionally. The term "Conventional" means that the diameter value is not accurate. Conventionally, we accept that it is approximately equal to some values ​​of the standard.

Under the conditional passage (nominal size) is understood the parameter used for pipeline systems as a characteristic of the connected parts, for example, pipeline connections, fittings and fittings. The nominal diameter (nominal size) is approximately equal to the inner diameter of the pipeline to be connected, expressed in millimeters.

According to the standard from: GOST 28338-89 it is customary to choose those numbers that have been agreed upon. And you should not invent your own numbers with commas. For example, DN 14.9 would be a designation error.

Nominal diameter approximately equal to the internal diameter of the connected pipeline, expressed in millimeters and corresponding to the nearest value from a series of numbers taken in the prescribed manner.

Here are the numbers:

For example, if the real inner diameter is 13 mm, then we write as: DN 12. If the inner diameter is 14 mm. then we take the value DN 15. That is, we select the number closest in value from the list of the standard: GOST 28338-89.

If both the diameter and the wall thickness of the pipe should be indicated in the projects, then it should be indicated as follows: f20x2.2 where the outer diameter is 20 mm. And the inner diameter is equal to the difference in wall thickness. In this case, the inner diameter is 15.6 mm. GOST 21.206–2012

Alas, we have to obey someone else's standards

Any imported materials from abroad were most often developed using a different length dimension: Inch

Therefore, most often the sizes are focused on the inch. Usually, a quotation mark is written for the place of the word inch.

1 inch = 25.4 mm. Which is the same 1” = 25.4mm.

Dimension table. Usually, a quotation mark is written for the place of the word inch.

1/2" = 25.4 / 2 = 12.7. But in reality, this 1/2" dimension is equal to a 15 mm passage. More precisely, maybe 14.9mm. for steel pipe. In general, the dimensions may differ by a few mm. Therefore, in such cases, for accurate calculations, you need to find out the inner diameter of a particular model separately.

For example, size 3/4” = 25.4 x 3/4 = 19 mm. But we write in the documents “conditionally” DN20 - approximately the inner diameter is 20mm.

Here are the actual sizes that most often correspond in the Russian translation.

The table shows the inside diameter in mm.

Nominal pressure PN: More details in GOST 26349 and GOST R 52720.

Has a unit of measurement: kgf/cm2. The designation kgf means kg x s (kilogram times s). c=1. c characterizes, as it were, the coefficient of force. That is, by multiplying a kilogram (mass) by a force, we convert mass into force. This is such an amendment for meticulous physicists. If you designate kg / cm2, in principle, you will also not be mistaken if you believe that we perceive mass as a force. Also, such a unit as kg / cm2 is erroneous in that pressure is formed from two units (force and area). Mass is another parameter. Because the mass only on the surface of the earth creates the force that presses on the earth (gravitational force). The value of c=1 on the surface of the earth. And if you fly away to another planet, then the gravitational force will be different, and the mass will create a different force. And on another planet, the coefficient c=1 will be equal to another value. For example, c=0.5 will create half the pressure.

What is PN for?

The PN value is needed in order to indicate to the device the pressure limit that must not be exceeded for the normal operation of the device for which this value is set. That is, when designing, the designer must know in advance what maximum pressure the device is designed for.

For example, if the device was given a value of PN15, this means that the device is designed for operation with a pressure not exceeding 15 kgf / cm2. Which is approximately equal to 15 bar.

1 kgf/cm2 = 0.98 bar. Roughly speaking, the value of PN is approximately equal to the Bar or the atmosphere.

For example, if the device was given a value of PN10, then it is designed for a pressure not exceeding 10 bar.

Definition of PN according to the standard

The highest excess working pressure at a working medium temperature of 293 K (20 °C), at which a given service life (resource) of valve body parts having certain dimensions, justified by strength calculation with selected materials and their strength characteristics at a temperature of 293 K (20 °C).

Russian norms: GOST 26349-84, GOST 356-80, GOST R 54432-2011

European Norms: DIN EN 1092-1-2008

American norms: ANSI/ASME B16.5-2009, ANSI/ASME B16.47-2006

GOST 28343-89
(ISO 7121-86)

Group G18

INTERSTATE STANDARD

FLANGED STEEL BALL VALVES

Technical requirements

Flanged steel ball valves. technical requirements

ISS 23.060.20
OKP 37 0000

Introduction date 1992-01-01

INFORMATION DATA

1. INTRODUCED by the Intersectoral State Association "Energomash"

2. Decree of the USSR State Committee for Standards dated 22.11.89 N 3423 put into effect the state standard of the USSR GOST 28343-89, which is used as the international standard ISO 7121-86, from 01.01.92

3. Period of inspection - 1995, frequency of inspection - 5 years

4. INTRODUCED FOR THE FIRST TIME

5. RE-ISSUE

1 AREA OF USE

1 AREA OF USE

This standard applies to ball steel flanged valves for nominal pressure from 1 to 10 MPa (from 10 to 100 kgf/cm) and nominal bore from 10 to 500 mm, intended for new design.

2. LINKS

Reference documents are given in Appendix 1.

3. DEFINITIONS

This International Standard uses the definitions given in ISO 6708 and ISO 7268 and the following definitions:

3.1. Construction length - the distance between two planes perpendicular to the axis of the body and located at the ends of the body.

3.2. Antistatic design - a design that provides continuous electrical conductivity between the body, ball and stem of the valve.

3.3. Pull-out Stem - Designed to prevent the stem from being pulled out of the body in the event of a packing change without relieving system pressure.

3.4. Effective diameter - the specified minimum diameter of the flow section of the valve in the fully open position of the valve.

4. MODELS

Cranes have "full" or "reduced" bores (see Fig. 1) and face-to-face dimensions in accordance with the requirements of ISO 5752.

Damn.1. Models

Models

Note. In some types of fittings produced in large series for nominal pressure 10 and small series for nominal pressure 16 and 20, the ball (plug) (when fully or partially closed) can protrude beyond the edges of the flange surfaces.

5. CONDITIONAL PASS

Conditional passage () is selected from the range: 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 150, 200, 250, 300, 350, 400, 450, 500.

6. SERIES OF NOMINAL PRESSURES

Conditional pressure is selected from the range: 10, 16, 20, 25, 40, 50, 100.

7. RELATIONSHIP OF PRESSURES AND TEMPERATURES

The allowable pressure/temperature ratios for housings given in the relevant tables of ISO 7005-1 are not limited by seal material. The limits of these ratios are set by the valve manufacturer and are indicated when marking (see clause 12.3).

8. CONSTRUCTION

Typical designs of ball valves with the optimal location of the taps are shown in Fig. 2.

Damn.2. Typical designs of ball valves with optimal branch location

Typical designs of ball valves with optimal branch location

ball type

1 - possible location of the outlet; 2 - the ends of the trunnion can be pinned,
coupling or both

Type of shell

The structural elements of the crane are shown in Fig.3.

Damn.3. Terminology

Terminology

1 - connecting flange; 2 - diameter of the passage opening of the housing; 3 - body neck;
4 - neck flange; 5 - effective diameter; 6 - body; 7 - construction length

8.1. Frame

8.1.1. General provisions. The body can be one-piece or split. In a split housing, the design strength of the connection point must correspond to the strength of the connecting flange of the housing.

By agreement with the customer, special measures may be provided to protect the body cavity from overpressure.

8.1.2. Casing wall thickness (see drawing 4)

Damn.4. Wall thickness

Wall thickness

8.1.2.1. The minimum wall thickness during manufacture () is indicated in Table 1, except for the cases according to paragraphs 8.1.2.2 and 8.1.2.3.

Table 1

Housing wall thickness

It is allowed to increase the thickness of metal walls if it is necessary to take into account, for example, assembly stresses, efforts to close the valve, non-annular cutouts and stress concentrates.

8.1.2.2. The minimum wall thickness (clause 8.1.2.1) is at the hull neck at a distance from the outer surface of the hull and is measured from the inside surfaces, where is the inside diameter as defined in 8.1.3.4.

Outside the distance, the throat section at an annular section with an internal diameter must have a thickness of at least , this value can be determined by interpolation of the value corresponding to the value equal to at nominal pressure.

If , then the minimum thickness of the neck wall will be greater than the base one, and this thickness should be on the entire section of the neck with a diameter

8.1.2.3. In some areas, wall thicknesses less than the minimum value are allowed, subject to the following restrictions:

a) a section with a thickness less than the minimum value may be located inside a circle whose diameter does not exceed ,

where is the inner diameter according to Table 2;

- the minimum thickness of the body wall according to Table 1;

b) the measured value must not be less than ;

c) the distance between the circles must not be less than .

8.1.3. Case dimensions

8.1.3.1. The overall length shall comply with the requirements of ISO 5752.

8.1.3.2. The body connection flanges shall comply with the requirements of ISO 7005-1.

Note. If the design of the housing does not allow drilling through holes in the flange, then threaded holes are provided.

8.1.3.3. The connecting flanges are cast or stamped together with the body or with the branch pipes of the split body, and can also be joined by welding, and for valve bodies with nominal bore >50 mm, the flanges are butt welded. Then heat treatment is carried out, which is necessary to ensure the possibility of using the material in the entire range of operating temperatures.

8.1.3.4. For bodies without lining, the diameters of the through holes must comply with Table 2.

table 2

Inlet Inner Diameter

8.1.3.5. The minimum through hole in full bore valves and in valves with a narrowed passage must be round in shape, and its diameter must correspond to the values ​​\u200b\u200bspecified in Table 3.

Table 3

Effective diameter

8.1.3.6. The design of the valve body with a nominal bore of 50 mm should provide for the possibility of making, if necessary, a drainage hole (see drawing 2a). The threads in the holes shall comply with the requirements of ISO 7-1 and Table 4.

Table 4

Drain outlets

8.2. Ball

The holes of the ball must have a round shape and diameters indicated in Table 3. Other form is agreed with the customer.

8.3. Stem with "pull-out" protection

The design of the valve must exclude the "tearing" of the stem from the body in the presence of pressure in the system in case of replacement of the stuffing box seal, since the fasteners of the seal themselves do not secure the stem.

8.4. saddle rings

The seat rings or seat assembly shall be designed to be replaceable, except for one-piece welded bodies.

8.5. fasteners

All bolted connections shall have coarse metric (see ISO 261) or inch (see ISO 263) threads.

8.6. Requirements for antistatic performance

Where necessary, valves must be provided with a device to provide continuous electrical conduction between stem and body in 50 mm valves or between ball and body in larger valves. This device must meet the following requirements:

a) located in a place protected from ingress of foreign particles and corrosion under the influence of external conditions;

b) when testing devices for electrical conductivity, carried out on assembled dry products after hydrostatic tests, an energy source not exceeding 12 V DC should be used, while the discharge should occur with a resistance of not more than 10 ohms. Tests are carried out at least 5 times;

c) the design should provide for the removal of antistatic only by artificial means.

9. CONTROL

9.1. The design of the crane provides for the possibility of controlling the crane with a handle or a key.

9.2. Manual valves should be closed by turning the handle or wrench clockwise or counterclockwise.

Note. The faucet must be closed in a clockwise direction, unless there are special instructions to the contrary. In this case, the customer must specify the exact execution in accordance with Appendix 2.

9.3. The handle shall be marked to indicate the "open" and "closed" positions.

9.4. The installation of the handle or key must ensure that they can be easily removed and replaced.

Note. In the manufacture of valves with a wrench, the latter should be installed parallel to the passage channel in the plug, unless there is a special instruction from the customer.

9.5. Cranes should be provided with a ball bore direction indicator. If the wrench (handle) is the only direction indicator, then the assembly design should be as accurate as possible.

9.6. Travel stops must be provided for both the fully open and closed positions of the valve.

10. MATERIALS

10.1. Frame

The materials specified in ISO 7005-1 are used for the manufacture of the body, nozzles, covers. The drain plug must be made of the same material as the housing. Do not use cast iron plugs.

10.2. Ball, stem and seat ring cage

Materials are chosen by the manufacturer, unless there are special instructions from the customer (see Appendix 2).

10.3. saddle rings

The material of the rings is chosen by the manufacturer, unless there are special instructions from the customer (see Appendix 2).

10.4. Stem seals, packings, body seals, gaskets use materials that must be suitable for use at the maximum temperature indicated on the rating plate.

10.5. plate

The rating plate should be made of corrosion-resistant material. It must be attached with corrosion-resistant elements or welded.

11. TESTING

11.1. Each valve is pressure tested in accordance with ISO 5208.

11.2. When tested for tightness, the leakage rate in a valve with gaskets made of elastomeric or polymeric materials must comply with class 3 according to ISO 5208.

12. MARKING

12.1. Each faucet should be marked in accordance with ISO 5209, except as noted below.

12.2. Marking should be applied directly to the housing or a plate securely attached to the housing. The plate on which the marking is applied must be individual and different from the name plate (see clause 12.3).

The body marking must contain the following indications:

a) conditional passage (with the corresponding numerical value) indicating the effective diameter for valves with a narrow passage, for example 80/57;

b) conditional pressure (with the corresponding numerical value);

c) body material designation (see ISO 7005-1);

d) heat designation (if required by the customer or relevant regulatory and technical documents);

e) manufacturer's name or trademark;

f) an arrow indicating the direction of the flow of the medium (for valves with only one-way flow of the medium);

g) connecting flanges having gasket grooves, marked with an o-ring (eg R25 - see ISO 70051-1). Marking should be applied to the end face of both flanges.

12.3. The housing or nameplate marking must contain the following information:

a) pressure or temperature limitation set by the manufacturer depending on the material or design of the shut-off elements (pressure drop in the ball at a temperature of 20 °C, if it is less than the pressure drop of the body).

The maximum allowable temperature and corresponding pressure should also be indicated;

b) the number of this standard;

c) an indication of antistatic performance, if any (see clause 8.6).

Note. At the choice of the manufacturer or at the request of the customer, other additional information may be indicated, if they do not contradict those specified in this standard.

12.4. For valves with nominal bore<50 мм маркировку наносят на фирменную табличку, где указаны следующие сведения:

a) conditional passage (and the corresponding numerical value);

b) conditional pressure (and the corresponding numerical value);

c) material designation;

d) manufacturer's name or trademark.

13. PREPARING FOR SHIPMENT

13.1. After testing, each crane must be dried and prepared for shipment.

13.2. Faucet covers must be made in accordance with the following requirements.

13.2.1. External surfaces not subject to lubrication shall be suitably protected, except for austenitic steel parts.

13.2.2. Machined working and threaded surfaces must have an easily removable rust-resistant coating, except for parts made of austenitic steels.

13.3. During transportation, the ball must be in the fully open position, unless prohibited by design.

13.4. Through holes and flange surfaces must be closed with wooden, plastic or metal plugs.

13.5. Cranes are allowed to be transported without packaging, securely fixed on the base (pallet) or packed in boxes.

APPENDIX 1 (mandatory). REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

ANNEX 1
Mandatory

APPENDIX 2 (informative). ORDERING DATA

APPENDIX 2
Reference

Electronic text of the document
prepared by CJSC "Kodeks" and checked against:
official publication
Hydraulic and pneumatic systems.
Valves: Sat. standards. -
M.: Standartinform, 2005

After deciding on editing in heating or water supply systems, connecting water or heat metering devices, it is impossible to do without the use of shut-off valves. As it is desirable to use ball or plug valves. Before choosing the type of valves, it is necessary to understand what requirements it must meet. That is, it will be necessary to determine such parameters as the size of ball valves, the material and type of valve connection.

Specifications

The dimensions of the ball valve consist of thread parameters, dimensions.

One of the key characteristics of a ball valve can be called the internal (through) diameter. Other parameters include operating pressure and temperature. Of course, these parameters are determined by the material from which the cranes are made. An important role is also played by which company produced these products.

As an example, you can study the most commonly used ball valves in everyday life. Namely, when arranging engineering parts in an apartment building or a private house. Practice shows that when arranging such systems, cranes with different geometric parameters are used.

In particular, when arranging engineering systems, ball valves with passage diameters of ½ inch are used. In addition to those indicated, taps with a diameter of 1.1 ¼ 1 ½ inches are used. For example, when creating engineering networks in a country house, it is enough to use fittings with a diameter of half an inch. For the heating system, the best option would be to use fittings of three quarters of an inch. If the system is built on the basis of the natural movement of the coolant, then it makes sense to increase the diameter of the pipes and valves used to two inches.

But, of course, when choosing pipes and valves, it is necessary to be guided by the results of the calculations, which should be part of the project. Most manufacturers put markings on the surface of the faucet body, in which the installer will always see what are the dimensions of the faucets required for network installation.

The marking, as a rule, looks like this DN (nominal diameter) 15, it means that the tap has an internal (through) diameter of 15 mm, or about one second of an inch. The second digit under the designation Pn indicates the working pressure for which this shutoff valve is designed.

Documentation regarding ball valve dimensions

GOST 21345-2005 defines the ratio of the nominal diameters of ball valves and the pressure at which the operation of this type of product is permissible. So, for example, valves with DN20 can be installed in a network with a nominal pressure of the working medium of 17 MPa. It should be noted that there is a division into through passage and partially through passage cranes.

Historically, all sizes of diameters, internal and external, the nominal parameters of the thread are measured in inches. That is, in the system of measures that is adopted in some countries. To convert inches to familiar millimeters, you can use the following ratio - one inch is equal to 25.4 millimeters. But you need to understand that this is a very conditional ratio and when placing an order, the dimensions for ball valves are in inches and not in millimeters.

In the same document there is a reference to GOST 28338-89, which defines the dimensions of the diameters that are used in the design and manufacture of shut-off and other valves. In fact, these two and several more regulatory documents are the main ones for designers of heat and water networks for multi-apartment and private houses.

By the way, the calculation of the nominal diameter of the pipeline is determined at the design stage of the network, based on the heat load, the required parameters of temperature, pressure and the flow rate of the working medium. The calculated diameter of the pipeline is the reference point from which the brand of valves is selected.

The dimensional characteristics of a ball valve include the type of thread and its location. Both external and internal threads are used in taps. Valves with a thread applied to the outer surface are called a nut-nut, if the thread is applied to the inner surface, then such products are called a fitting - fitting.

Construction length and height

Another dimension that is directly related to the valves is the construction length. The definition of this term is as follows: this dimension shows the length of the pipeline section that will be replaced by shutoff valves. That is, this is the distance from one end of the crane to the other. Construction height is the distance from the lowest point of the crane to the highest. In other words, these are the overall dimensions.

These dimensions must be taken into account by the designer when designing the pipeline system. In addition, he must install a ball valve with dimensions that provide free access to it for maintenance and repair. In addition, it is necessary to provide access to fasteners for assembly and dismantling.

The size of the construction length is determined by GOST 3326-86. So, for example, a crane, DN 20, designed to work in a pipeline system with a pressure of Pn 4MPa, has a construction length of 150 millimeters.

By the way, the construction length is measured only in millimeters, in contrast to the diameters of the through holes and thread ratings.

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Ball valves in the modern world are used everywhere. For example, for installation and connection of water pipes, installation and connection of a boiler, installation of radiators or a heating system as a whole, or connection of water and gas meters, etc. Such products are very popular, but due to the wealth of varieties and sizes, choose the right ball valve happens to be difficult. Therefore, every owner of the house should have at least a rough idea about these products.

Device description

Why is the valve called "ball"? The answer is simple - there is a metal sphere inside the device. When turning the valve it allows or blocks the passage of water or gas through the pipes. Such a locking device is especially popular in private houses or apartments.

Depending on the manufacturer, as well as on the purpose of use, the dimensions of ball valves may vary, so this must be taken into account when purchasing. But nevertheless, if we compare the dimensions of modern products with those that were produced 10 years ago, then the current ones will be much more compact, more reliable and more functional than their predecessors.

Each device has the following details:

• Frame. In it and is a metal sphere, which prevents or facilitates the passage of gas or water.
• The twisted part. Thanks to it, if necessary, you can disassemble the ball valve.
• The working part, that is, a metal ball.
• Seals. In order for a metal sphere to fit snugly, various materials are required that contribute to this.
• Actuating stem - reduces effort when turning the valve.
• The control lever is the valve itself.

The safety margin of the products is designed for strong fluid flows that will constantly pass through the ball valve. Therefore, such devices can be fearlessly placed even in the most "water-pressurized" places.

Characteristics and dimensions

As mentioned above, it is recommended that you familiarize yourself with the dimensions of the locking devices before buying. For example, the classification of ball valves for water is based on the diameter of the passage inside the product. In addition, the devices differ in the type of threaded coating and operating pressure indicator.

Knowing the size of the internal passage of the ball valve purpose and frequency of use can be determined locking mechanism. So, mechanisms with a size of 1, 1.25 or 1.5 inches indicate infrequent use and are not designed for constant loads. Otherwise, the device will fail.

In everyday life, products with a diameter of 0.5 (about 12.5 mm) or 0.75 inches are used. The first option is great for water supply, and the second for heating systems with a circular pump. If the circulation is based on the natural working environment, pipes with a diameter of 40-50 mm will be required. Otherwise, you can get by with narrower products.

Of course, there are other models with an even larger diameter, but they are installed purely in production or at special facilities. In everyday life, products with a diameter of 0.5 to 1.5 inches are quite enough.

Marking

On closer examination of the ball valve, you can find some symbols on it. These signs carry a lot of useful information like tags on clothes. The ability to decipher this data will allow you to understand whether this device is right for you.

Marking is regulated by GOST R 52760. The document says that the manufacturer is obliged to indicate on a prominent part of the product or on a separate plate the information necessary for the buyer. As a rule, the following data is indicated on ball valves:

• DN - directly, the diameter of the internal passage.
• PN - maximum pressure value. As a rule, it is indicated in atmospheres.
• Design and operating pressure values.
• The material from which the body of the ball valve is made.
• One or more arrows indicating the direction of flow.
• The minimum and maximum temperatures at which the device can operate.
• Manufacturing date.

The best materials and manufacturers

The metal or alloy from which the ball valve is made plays a significant role in its use. Poor quality material can break the device in the shortest possible time. As a result, a broken product will cost the financial cost of replacing it.

Ball valves are usually made of brass or nickel-plated brass. These materials have proven themselves for a long time. However, it is not recommended to purchase products, the material for which was silumin. Cranes made of silumin may crack or literally fall apart during installation, especially if they were made by an unscrupulous manufacturer.

ValTec is the undisputed leader in the ball valve market. It has long established itself as a quality and reliable manufacturer of sanitary ware. Therefore, first of all, it is worth focusing on the products of this company.

If there are no models from ValTec, you can purchase devices from Bugatti. She also is of excellent quality, but is present in the plumbing market less than its competitor. Domestic producers also want to take the lead. For example, the Bologovsky Valve Plant, which, after "stagnation", is trying to make up for lost time due to low prices and high-quality products.

The high demand for ball valves has had a significant impact on the variety of products, the level of competition and the quality of products. But, despite the rich choice, it should be remembered that for each purpose there is a crane of a certain size. Therefore, when buying, you must be guided by this principle.

Purchasing a product of the wrong diameter can cost you nerves, time, and possibly money. Therefore, choosing a model for heating, you should not aim at sizes of 1-2 inches. Otherwise - a return request, extra running around and again searching for a suitable product.

Today, ball valves are used in various pipeline systems. They are indispensable helpers when you need to urgently shut off the pipeline chain. The product is useful for plumbing work and allows not only to redirect the flow of water, gas, but also to block the required area. To buy a really desired type of such a device, you need to know its technical characteristics.

Peculiarities

Externally, the ball valve device is not difficult. This valve is similar to two circular discs with a cylindrical mount and a tap. The part has a fixed body, as well as a rotating part (ball). Classification is carried out according to two criteria, such as:

• type of working medium - for liquid, gas, steam;
• mounting method.

Typically, such a valve is attached to the flanges, due to which the connection is reliable. The ball flange valve is easy to use and versatile. For this reason, he successfully replaced the valves. In addition, flanged valves, according to the type of fastening, are coupling, welded and choke. They are used in the installation of pipelines and gas pipelines, oil media lines, oil pipelines, cooling systems and compressed air lines. In addition, such devices are indispensable in agriculture, food, chemical industry and shipbuilding.

Due to the strong interflange connection, they ensure the tightness of the fasteners with the main pipe. Their distinguishing feature is the ease of dismantling if necessary. The size of the products is different, which allows the use of these devices in different pipelines.

The central component of such a product is a ball-shutter. Inside it usually has a hole in the form of a circle or square. The shutter itself is fixed inside the body through a certain combination of fasteners and gaskets. It has a connection with a lever, thereby controlling the flow of the working medium of the pipeline system. The valve has two positions: open and closed.

Specifications

The designs of these devices comply with GOST standards. The standards clearly spell out all the technical characteristics of such devices. The tightness is usually type A. The diameter range of the valves varies from 15 to 1400 mm. The conditional passage of devices is different. In the lines of well-known brands, you can see products with a nominal or conditional diameter, for example, DN equal to 40, 50, 65, 80, 100, 150 mm.

The most popular among buyers is the variety of 50 mm and more. With a small diameter value, the ball is called floating (DN 25, 32). When this figure exceeds 50 mm, the ball is sealed on the supports. The average weight of the product is about 13 kg. PN is the nominal (maximum) pressure of the working medium at which the valve can operate. Usually it ranges from 1.6 to 4 MPa. The construction length of such products can be 102, 254, 356, 533, 850, 914 mm, while a slight deviation in length up to 2–8 mm is allowed.

The degree of passage of the working medium determines the type of crane. It may be incomplete if it passes up to 50% of the total volume.

Classic or standard options skip about 70-80% of the working environment. Full bore analogues provide the transmission of substances up to 90%. The products are suitable for vertical and horizontal line laying.

Usually, manufacturers indicate a marking on a tap with designations of its type, type, nominal bore, pressure and standard. Example: the crane is marked KSh. F. 500-2500 GOST 28908-91. In this case, the marking means the following:

• KSh - ball valve;
• F - flanged;
• conditional passage 500 mm;
• pressure 2500 MPa;
• parameters GOST 28908-91.

Knowing the marking will allow you to accurately buy a device for specific needs. The disadvantages of ball flanged valves are the large weight and the length of the handles that is far from always appropriate in the manual type of models.

In addition, buyers note that not all products meet the requirements stated in GOST, which is reflected in the low quality of individual products. This is due to the presence on the shelves of counterfeit goods made of low-quality metal. This causes poor performance and a short service life. In addition, compared to other analogues, flanged ball valves are more expensive.

There are also limitations: they cannot be used in pipelines, the fluid flow of which contains impurities of solid particles. This leads to abrasion of the chassis, and then to the formation of leaks.

It is undesirable to use such devices in pipelines with silty liquid. The accumulation of sediment will quickly lead to breakdown of the valve and failure of its operation.

Kinds

Depending on the different value of the diameter of the products, the ball flanged valves are different. They have a different body, which can be two- and three-piece. However, the hull design can be not only collapsible. All-welded cranes occupy the majority of the market. Collapsible counterparts are distinguished by the fact that worn parts in them can be updated. This allows you to extend the service life of products up to several years.

Disassembly of such products is simple and does not take much time. The material of manufacture of all varieties is stainless steel. It is resistant to corrosion, while the ball valve in the products of foreign companies can be hollow inside. The class of the drive used in the device is also different. The gearbox can be manual or electric, requiring auxiliary supports. In addition, the drive can be pneumatic.

According to the material of manufacture today, such products can be not only steel. On the shelves of shops you can bathe products from materials such as:

• cast iron;
• bronze;
• brass.

The best types of products are steel versions of stainless steel devices with a locking mechanism that regulates the flow of the working medium up to 80%.

Manufacturers

In the modern market for such products, a lot of ball flanged valves are offered to the attention of buyers. According to the consumer's assessment, the shut-off valves of the following companies can be called worthy of attention:

• Broen;
• Naval;
• Danfoss Jeep F.

These valve options are able to completely shut off the substance that enters through the pipeline. For example, Naval brand products have an all-welded hull. The product is lightweight and easy to use. Due to the high density, he is not afraid of pressure drops. Thanks to the removable handle, it is possible to change its position by 180 degrees.

The connection of other options can be flanged, welded or threaded. These products are chosen due to the fact that they significantly reduce hydraulic losses. Devices withstand temperatures up to 250 degrees. Their installation is carried out taking into account counter flanges with certain parameters of diameters, fasteners and gaskets. Connecting dimensions are subject to GOST 12815.

Sometimes you can hear the term "ball valve under the valve." This means that the construction lengths of the crane itself and the valve match. You need to know the explanation in order to choose the right product when buying. Thus, the length of valves KSh F DN 50, 80 and 100 corresponds to the lengths of gate valves made of steel 30s41nzh ZKL-2, 31s31nzh ZKL-Z, 31s38nzh, 30s41p, ZKS, ZVK and the lengths of gate valves made of cast iron 30ch6br, 31ch6br, 31ch7bk, 31ch17br, 31h 16br, 31h12nzh , 31ch11nzh and ZKVSH, characterized by the same diameters. Usually the length is according to the European DIN standard.