Spring safety valve device. Safety valve. Basic valve assemblies and parts

The NEMEN company sells safety valves designed to operate in various environments. We offer, which can be installed vertically on a pipeline section or boiler units.

Purpose of safety valves

Safety valve- a type of fittings that is designed to automatically protect pipelines and equipment from pressure exceeding a certain predetermined level established value, by dumping excess mass of the working medium. The valve also ensures that venting stops when normal operating pressure is restored. A safety valve is a fitting direct action, operating directly from the energy of the working environment.

Working principle of safety valve

When the safety valve is in the closed state, the sensitive element of the valve is affected by the force from the operating pressure in the pipeline, which tends to open the valve, as well as the force from the set point preventing the opening. If disturbances occur in the system, causing an increase in the medium pressure above the working pressure, the force of pressing the spool against the seat decreases. When its value is zero, there is a balance of active forces from the set pointer and the pressure of the medium, simultaneously acting on the valve. If the pressure in the system continues to increase, the shut-off valve opens and the excess medium is discharged through the valve. Reducing the volume of the medium leads to normalization of pressure in the system and the disappearance of disturbing influences. When the pressure level drops below the maximum permissible level, the shut-off element returns to its original position under the influence of force from the setpoint.

Safety spring valves

In such safety valves, spring compression force is used to counteract the pressure of the working medium on the spool. By installing different springs, the same safety spring valve Can be used for multiple maximum allowable pressure settings. Spring valves do not have a stem seal. If the fittings are installed in systems with an aggressive working environment, the spring is isolated using stuffing box devices, an elastic membrane or a bellows. Bellows seals are used in cases where leakage of the working medium from the pipeline is unacceptable.

A check valve is an element of a pipeline system that allows for the movement of the working medium in only one direction. Its use is mandatory for autonomous pumping stations and other equipment that may fail when the fluid flow moves in the opposite direction.

A spring check valve is one of the types of shut-off elements. It belongs to the category of direct-acting valves and is activated automatically by the energy of the working environment, which prevents equipment failure in the event of a power outage or other malfunctions.

Design features

The spring valve is structurally composed of three elements:

A body usually made of brass and equipped with elements for fastening to the pipeline (coupling, thread). The body is also made of steel, cast iron and polypropylene. The choice of material is determined by the parameters of the working environment and the diameter of the pipeline.
The working element, which represents a movable spool, includes two plates with a special sealed gasket between them and a rod.
An actuator representing a spring located between the work element plates and the seat. Provides automatic shutoff of fluid flow when pressure decreases or changes its direction. The minimum pressure of the working medium at which the valve automatically opens depends on the stiffness of the spring.

Advantages of spring check valves:

Possibility of installation in any position;
simplicity of design;
versatility.

At the same time, the valve is sensitive to contaminants in the water, which lead to wear of the sealing plates, so it is advisable to install a filter in front of it. It is also recommended that the valve be mounted in an easily accessible location to facilitate maintenance and replacement.

It is advisable to install the valve in vertical position so that the blocking force of the spring coincides with the action of gravity. For correct installation it is necessary to focus on the arrow marked on the valve body, which shows the direction of flow of the working medium through.

Scope of application

Spring check valves are widely used in systems autonomous water supply, intra-house networks apartment buildings. They are installed on the suction lines of pumps, in front of capacitive water heaters, boilers, water meters and other equipment.

The flanged spring safety valve 17s28nzh is one of the main types that is used to protect pipeline equipment. The spring safety valve 17s28nzh is designed to protect equipment and pipelines from unacceptable excess pressure in the system. Ensuring safe pressure values is carried out by automatically discharging excess working fluid into a specially installed outlet pipeline or into the atmosphere, and when the operating pressure is restored, safety valve 17s28nzh stops discharging the working medium.

The spring safety valve 17s28nzh is mounted with the equipment and using a flange connection. The flanged spring safety valve 17s28nzh has a service life of more than 11 years, and the manufacturer provides a guarantee for it for 18 months from the date the valve is put into operation. Safety valve 17s28nzh is not sealed in relation to the external environment.

Material of the main parts from which the 17s28nzh safety spring valve with flange connection is made:

Housing, cover - Steel 25L
Disc, seat - Steel 20Х13
Rod - Steel 20Х13/Steel 40
Gasket - AD1M
Spring - 50HFA

Safety spring valve device 17s28nzh

1 .Cap

2 . Adjustment screw

3 . Spring

4 . Lid

5 . Stock

6 . Manual detonation unit

7 . Spool assembly

8 . Saddle

9 . Frame

Dimensions and connecting dimensions safety valve 17s28nzh

DN, mm

Dimensions, mm

Technical characteristics of safety valve 17s28nzh

Name	Meaning
Nominal diameter, DN, mm
Seat hole diameter dc, mm
Allowable leakage in the valve, cm 3 /min	5-for air 1-for water		10-for air 2-for water
Seat cross-sectional area Fс, mm 2, not less
Nominal inlet pressure РN, MPa (kgf/cm2)
Nominal outlet pressure РN, MPa (kgf/cm2)
Full opening pressure Рп.о. MPa (kgf/cm 2), no more	For gaseous media: pH+0.05 (0.5) for pH<0,3 МПа; 1,15 Рн для Рн>0.3 MPa For liquid media: pH+0.05 (0.5) for pH<0,2 МПа; 1,25 Рн для Рн>0.2 MPa
Closing pressure Рз	not less than 0.8 pH
Spring setting pressure limits, pH MPa (kgf/cm2), not less	0,05-0,15 (0,5-1,5); 0,15-0,35 (1,5-3,5); 0,35-0,7 (3,5-7,0); 0,7-1,0 (7-10); 1,0-1,6 (10-16)
Temperature environment, РС		from minus 40 to 40

Working environment temperature, °С		from minus 40 to 450

Characteristics of the working environment	Water, steam
Flow rate?	0.8 for gaseous; 0.5 for liquid media
Connecting dimensions and dimensions of housing sealing surfaces	according to GOST 12815-80 version 1 row 2
Weight without flanges (kg)

Each node of the pipeline system plays an important role in ensuring its performance. For example, a spring safety valve is pipeline fittings necessary to protect against destruction when excess pressure appears in the pipeline. This is possible by releasing the environment from the system.

Another spring valve ensures that the discharge of the medium stops when operating pressure will be within normal limits.

Features and principle of operation

Safety valve spring type– direct-acting fittings that operate from the environment. Where in the system can it appear? overpressure? As a rule, the reason lies in external and internal factors:

incorrectly assembled thermomechanical circuit;
heat transfer from sources;
equipment is not functioning properly.

The spring-loaded safety clutch valve is installed wherever there is a risk of excessive maximum pressure. As a rule, these are household or industrial storage vessels operating under pressure.

The great popularity of this fitting is due to simple design, easy settings, product range. After all, such variety and possibilities allow you to choose optimal model for specific conditions.

The safety throttle is installed vertically. The design of a spring flanged safety valve involves the use of a butterfly valve as a locking element, which, when locked, is placed between the seats.

The downforce is set using a special device and a spring for the safety valves.

When the pressure is very high, the specified clamping force is not enough to contain the media, so the excess is removed until the pressure is equalized to the operating level.

The passport for the spring safety valve allows you to learn about the design of the product. The main components are the setter and the shut-off element. The latter consists of a saddle and a bolt.

Using the adjuster, it is adjusted so that the spool is properly pressed against the seat to prevent the passage of medium. The adjustment is made using a screw.

The valve closing pressure is usually taken to be 10 percent lower than the operating pressure.

Product classification

Let's look at what types of safety products exist.

According to the nature of the elevation of the closing organ:

two-position action;
proportional action.

According to the height of the organ:

full lift;
mid-lift;
low-lift.

By type of load on the spool:

cargo;
magnetic spring;
lever-spring;
spring-.

Based on the operating principle:

direct – traditional safety products;
indirect action – pulse devices.

One of the modifications widely used in industry is the angular safety spring choke.

Another classification principle is based on nominal diameter. For example, if a DN15 spring check valve is used, this means that the nominal diameter is 15 mm, and a DN50 spring clutch check valve is 50 mm.

Product characteristics

Capacity calculation is carried out according to GOST 12.2.085. The devices can be used in petroleum, chemical, gaseous and liquid environments. Tightness is determined according to GOST 9789-75.

The closing pressure of the valve is more than 0.8 pH, where pH is the setting pressure, and is the highest at the inlet to the valve, at which it remains in the closed state, while maintaining proper tightness.

Springs for them are most often made of 50HFA steel. Spring check valve type 402 is made of cast iron.

To check the serviceability of the device in working condition, the spring safety valve SPPK has a solution for manual opening, purge, therefore, products without SPPK do not have the ability to manually open.

The dimensions of the sealing surfaces of the flanges are determined according to GOST 12815-80.

As an example of one of the modifications of the device, we will give a 17s28nzh fuse, corresponding to TU3742-017-00218118-2002.

The device has the following characteristics:

working pressure – 1.6 MPa;
working environment – non-aggressive, gas, steam, water;
case material – steel;
sealing material – stainless steel;
connection – flange;
temperature - from minus 40 to plus 250 degrees;
weight and length depend on the nominal diameter.

Nuances of choice

To choose the optimal product, you need to take into account the requirements that apply to them:

timely and trouble-free installation of a safety valve at a specified increase in the level of operating pressure in the system;
V open position the necessary throughput must be provided;
timely closing of the valve with the required level of tightness;
ensuring stable operation.

Cost is of no small importance when choosing. For example, let’s look at how much you can buy a 17s28nzh spring safety valve: the price for a return clutch spring throttle starts from $300.

Of course, a lot depends on the manufacturer. Thus, a similar Danfoss spring check valve will cost more – from $400.

Features of the product (video)

Installation nuances

Before installing the spring safety valve, follow these simple steps:

check the labeling;
inspect the body for external damage;
remove the protective cap;
there should be no foreign objects inside;
It should be remembered that during installation the components of the product will heat up.

The installation process is carried out in accordance with current safety rules and regulatory and technical standards. The choice of location, design and number of valves, as well as the direction of discharge of the medium, is determined by the project.

The location must be selected so that there is easy access for maintenance and repair. Installation is carried out in a vertical position in top point vessel. The installation can also be carried out near a vessel or pipeline, but there should not be a shut-off device between the products.

The size of the fitting cannot be less than the diameter of the valve inlet pipe.

A check spring poppet valve with a large number of discs can provoke an increase in their resistance, which can change the pressure difference in the upper and bottom parts of the product. Therefore, it should be installed in the latter area.

Self-installation of such devices is a complex procedure that requires experience and certain skills. Therefore, it is necessary to turn to professionals.

Problems and repairs

Leakage of the medium through the valve occurs when the pressure is lower than the set pressure.

delay of foreign objects on the sealing elements - it is necessary to purge the throttle;
damage to the sealing elements - grooving or grinding is performed, followed by a leak test; if the depth of damage is more than 0.1 mm, mechanical treatment must be performed;
spring deformation - it is replaced;
misalignment of elements due to heavy load - the load is removed, the flow and inlet lines are checked, it is necessary to re-tighten the studs;
reduced opening pressure - adjustment, deformation of the spring - it is being replaced;
poor-quality assembly after repair - eliminate all assembly defects.

Repair of safety spring chokes must be left to professionals. The cost of the procedure will cost from $50.

A mandatory element of equipping autonomous water supply systems in dachas and country houses is a check valve. That's exactly what technical device, which may have different design, ensures the movement of liquid through the pipeline in the required direction. Check valves installed in an autonomous water supply system reliably protect it from the consequences of emergency situations. Referring to direct-acting valves, check valves operate automatically using the energy of the working medium transported through the pipeline system.

Purpose and principle of operation

The main function that a water check valve performs is that it protects the water supply system from critical flow parameters of the liquid transported through the pipeline. Most common cause critical situations is to stop pumping unit, which can lead to a number of negative phenomena - draining water from the pipeline back into the well, spinning the pump impeller in the opposite direction and, accordingly, breakdown.

The installation of a check valve on the water allows you to protect the water supply system from the listed negative phenomena. In addition, the water check valve prevents the consequences caused by water hammer. The use of check valves in pipeline systems makes their operation more efficient and also ensures correct functioning pumping equipment with which such systems are equipped.

The principle of operation of the check valve is quite simple and is as follows.

The flow of water entering such a device under a certain pressure acts on the locking element and presses the spring, with the help of which this element is kept closed.
After the spring is compressed and the shut-off element is opened, water begins to move freely through the check valve in the required direction.
If the pressure level of the working fluid flow in the pipeline drops or water begins to move in the wrong direction, the spring mechanism of the valve returns the shut-off element to the closed state.

By acting in this way, the check valve prevents the formation of unwanted backflow in the piping system.

When choosing a valve model installed on a water supply system, it is important to know regulatory requirements, which manufacturers of pumping equipment require for such devices. Technical parameters, according to which a check valve for water is selected in accordance with these requirements, are:

working, test and nominal closing pressure;
diameter of the landing part;
conditional capacity;
tightness class.

Information about how technical requirements The check valve for water must correspond, as a rule, contained in the documentation for the pumping equipment.

For equipping water supply systems household use They use spring-type check valves, the nominal diameter is in the range of 15–50 mm. Despite their compact dimensions, such devices demonstrate high throughput, ensure reliable operation of the pipeline, low level noise and vibration in the pipeline system on which they are installed.

Another positive factor of using check valves in a water supply system is that they help reduce the pressure created by the water pump by 0.25–0.5 Atm. In this regard, a check valve for water allows you to reduce the load both on individual elements of pipeline equipment and on the entire water supply system as a whole.

Design features

One of the most common materials used to make the body of water return valves is brass. Choice of this material is not accidental: this alloy demonstrates exceptionally high resistance to chemically aggressive substances that may be present in water transported through a pipeline in a dissolved or suspended state. Such substances, in particular, include mineral salts, sulfur, oxygen, manganese, iron compounds, etc. The outer surface of the valves, which during their operation is also exposed to negative factors, is often protected with a special coating applied by the galvanic method.

The check valve device requires the presence of a spool, for the manufacture of which brass or durable plastic can also be used. The sealing gasket present in the check valve design can be rubber or silicone. For the manufacture of important element The locking mechanism - spring - is usually made of stainless steel.

So, if we talk about structural elements spring check valve, then this device comprises:

composite type housings, the elements of which are connected to each other by means of threads;
a locking mechanism, the design of which includes two movable spool plates mounted on a special rod and a sealing gasket;
a spring installed between the spool plates and the seat at the outlet of the through hole.

The principle of operation of a spring check valve is also quite simple.

The flow of water entering the check valve under the required pressure acts on the spool and depresses the spring.
When the spring is compressed, the spool moves along the rod, opening the passage hole and allowing the fluid flow to move freely through the device.
When the pressure of the water flow in the pipeline on which the check valve is installed drops, or in cases when such a flow begins to move in the wrong direction, the spring returns the spool to its seat, closing the throughput hole of the device.

Thus, the operation scheme of the check valve is quite simple, but nevertheless ensures high reliability of such devices and the efficiency of their use in pipeline systems.

Main types

Having understood how the check valve installed in plumbing system, you should also understand how to choose it correctly. On the modern market there are different kinds check valve devices, the design, material of manufacture and operation scheme of which can vary significantly.

Sleeve type spring check valve

The body of this type of valve consists of two cylindrical elements connected to each other using threads. The locking mechanism includes a plastic rod, upper and lower spool plates. The position of the elements of the locking mechanism in the closed state, as well as their opening at the moment when the pressure of the water flow reaches the required level, is ensured by a spring. Between themselves constituent elements the housings are connected using a sealing gasket.

Spring loaded check valve with brass spool and spherical spool chamber

The distinctive features of this type of shutter are easy to see even in the photo. The brass body of such a valve in its middle part, where the spool chamber is located, has a spherical shape. Such design feature allows you to increase the volume of the spool chamber and, accordingly, the throughput of the check valve. The locking mechanism of this type of water valve, which is based on a brass spool, works on the same principle as in any other type of valve device.

Combined spring type check valve with drain and air vent

Many of those who decide to independently install a pipeline system often have a question about why they need a check valve equipped with drainage and air vent systems. The use of check valves of this type (especially for equipping pipelines through which hot working fluids are transported) makes it possible to simplify the process of installation and maintenance of such systems, increase their reliability, reduce the total hydraulic pressure, and reduce the number of installation connections.

On the body of this type of valve, which can be seen even in the photo, there are two pipes, one of which is used for installing an air vent, and the second serves as a drainage element. The branch pipe for the air vent, on the inner surface of which is threaded, is located on the device body above the spool chamber (its receiving part). Such a pipe is needed to bleed air from the pipeline system, for which a Mayevsky valve is additionally used. The purpose of the pipe, which is located on the opposite side of the body - at the outlet of the valve, is to drain the liquid that has accumulated after the valve device from the system.

If you install a horizontal check valve, its air outlet pipe can be used to mount a pressure gauge. If you place a combined check valve on a pipeline vertically, then its drainage pipe can be used to drain water accumulated after such a device, and the air vent pipe can be used to remove it from the part of the pipeline that is located before the check valve. air jams. That is why, when deciding how to install a check valve combined type, you should clearly understand what functions such a shutter should perform.

Spring valves with polypropylene body

Check valves, the body of which is made of polypropylene, even if you look at the photos of such devices, look very similar to oblique bends. These types of check valves, for installation of which the polyfusion welding method is used, are installed on pipelines also made of polypropylene. An additional oblique outlet in the design of valves of this type is necessary to accommodate the elements of the locking mechanism, which makes it easier Maintenance such a device. Thereby constructive solution It is not difficult to carry out maintenance and repair of a check valve of this type - it is enough to remove the elements of the locking mechanism from its additional outlet without violating the integrity of the device body and the tightness of its installation in the pipeline system.

Other types of check valves

In pipeline systems designed to transport water, other types of check valves can be installed.

The check valve is equipped with a special shut-off element - a spring-loaded petal. The big disadvantage of valves of this type is that when they operate, significant shock loads are created. This has a negative impact on technical condition the valve itself, and can also cause water hammer in the pipeline system.
Double-leaf type check valve devices are compact in size and light in weight.
A lift coupling check valve includes a spool as a shut-off element that moves freely along a vertical axis. The operation of the locking mechanism can be based on the gravitational principle, when the spool returns to the closed state under the influence of its own weight. A spring can also be used for this purpose. If you decide to install a gravity check valve on the pipeline, keep in mind that such a device can only be installed on vertical sections of the system. Meanwhile, the gravity valve is characterized by a simple design, while demonstrating high reliability during operation.
There are check valves whose closing element is a spring-loaded metal ball. The surface of such a ball can be additionally covered with a layer of rubber.

Deciding which check valve is best and whether an expensive valve is needed in the pipeline system is more complex design, you should first get to know technical characteristics such a device and compare them with the operating parameters of the pipeline system. The main purpose of the check valve, as mentioned above, is to pass water through the pipeline in the desired direction and prevent the liquid flow from moving in reverse side. In this regard, you should choose a check valve for water based on the pressure under which the water flow moves in the pipeline. Naturally, it is necessary to take into account the diameter of the pipes on which such a valve should be installed.

When installing the pipeline, you should also keep in mind that you can install a check valve different ways. On pipes of significant diameter, flanged and check valves are installed. wafer type, and on small-diameter pipes - coupling valve devices. Welding method installation of check valves is used mainly for installation on polypropylene and metal-plastic pipes.

If you choose the right check valve and the method of its installation, such a device will not only last long time, but will also ensure the correct operation of the entire pipeline system.

How to install correctly

Having understood the question of why a check valve is needed and its role in the pipeline system, you should also study the rules for installing it on an already operating or newly created pipeline. Such devices are mounted on various elements of pipeline systems:

on pipelines of autonomous and centralized water supply;
on suction lines served by deep and surface pumps;
in front of boilers, cylinders and water flow meters.

If you are interested in check valves that can be installed in both vertical and horizontal positions, choose spring models rather than gravity ones. You can find out in which direction the water flow should move through the valve by looking at the special arrow marked on the body of the device. When installing coupling-type check valves, be sure to use FUM tape for good sealing. Moreover, we should not forget that check valves require regular maintenance, so they must be installed in accessible places in the pipeline.

When installing a check valve on the suction line submersible pump care should be taken to ensure that a coarse filter is installed in front of such a device, which will prevent it from getting into inner part devices for mechanical impurities contained in underground water. A perforated or mesh cage can also be used as such a filter, into which a check valve installed at the inlet end of the suction line of a submersible pump is placed.

When installing a check valve on an already operating pipeline, you must first disconnect the system from the water supply and only then install the shutter device.

How to make your own check valve

The simple design of the check valve allows you to make it yourself if necessary.

To solve this problem you will need following materials and tools:

tee with internal thread, which will serve as a body;
a coupling with a thread on the outer surface - the seat of a homemade check valve;
rigid spring made of steel wire;
a steel ball, the diameter of which should be slightly smaller than the diameter of the hole in the tee;
a steel threaded plug that will serve as a stop for the spring;
a standard set of plumbing tools and FUM sealing tape.

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