Spring safety valves. Safety Valve Safety Spring Valves
Safety Spring Valve (PPC)- view pipe fittingsdesigned to automatically protect equipment and pipelines from excess of pressure over a predetermined value by resetting an excess of the working medium and providing discontinuation of the discharge at the closing pressure and restoring the operating pressure.
Basic assembly units and valve parts:
1 - body, 2 - saddle, 3 - spool, 4 - cover, 5 - rod, 6 - nut, 7 - hairpin, 8 - spring, 9 -Sillone (installed in bellows valves), 10 - locking screw, 11 - adjustable Sleeve, 12 Operating sleeve, 13 - partition, 14 - Adjusting screw, 15 - Cap, 16 - threaded flange.
Principle of operation.At a normal operating pressure, the compressed spring force is pressed to the saddle (the passage for resetting the working medium is closed). When the pressure is raised above the established value, the oppositely directional force begins to operate, which compresses the spring, and the spool rises, opening the passage for resetting the working medium. After reducing the pressure in front of the valve to the closing pressure, the springs under the action of the spring is pressed again to the saddle, stopping the reset of the medium.
Setting position - vertical, cap up.
Tightness of the shutter- Class "in" GOST R 54808. At the request of the customer, it is possible to manufacture with other classes of tightness.
Possible valve execution:
- A hermetic cap having a node forced opening, and without such a node.
- Balancing bellows.
- Thermal protective partition.
- "Open" lid.
- A locking element that impede the triggering of the valve.
Accession to the pipeline:
- flange;
- under the lens (flange according to GOST 9399);
- fizher
- assay.
Sylphon valves.
The bellows is a mechanism compensating for the reservation effect on the outlet of the valve. The bellofone is designed to protect the valve spring from the harmful effects of the aggressive working medium in conditions of elevated or reduced temperatures. The bellows valves are made from steel stamps 12x18n9tl and 12x18n12mztl and are designed for worm media with a temperature of minus 60 ° C and below. The designation of the bellows valves: KPP4C, PPPS.
The execution of sealing surfaces and the connecting dimensions of the flanges of the valve - according to GOST 12815-80, row 2, construction lengths - according to GOST 16587-71.
Valves DN 25 Pn 100 kgf / cm2 can be made with fitting ends for accession to the pipeline according to GOST 2822-78, as well as with flange compound According to GOST 12815-80, row 2.
Safety valves with nominal pressure PN 250 kgf / cm2 and Pn 320 kgf / cm2, as well as other models are designed to protect equipment from unacceptable pressure excess by automatically reset the excess of the working medium. Used on equipment with liquid and gaseous working environments that do not cause corrosion of cabinet parts more than 0.1 mm.
Safety valves with stamped consuming body can be manufactured with an individual construction length (L and L1), height (H) and connecting dimensions Flanges, which makes it possible to use them as substitutes for imported reinforcement without changing the already mounted equipment and pipelines.
Calculation of the bandwidth of valves - according to GOST 12.2.085-2002.
Pressure pressure, pH- the greatest overpressure At the entrance to the safety valve, in which the shutter is closed and the specified gate tightness is ensured.
Pressure start opening, RN.O.(Pressure of the start of the start; installation pressure) - overpressure at the inlet in the safety valve, in which the force seeking to open the valve is balanced by the efforts holding the locking element on the saddle. With a pressure start of the opening, the specified tightness in the valve gate is disturbed and the lifting element begins.
Pressure full discovery, RP.O.- excessive pressure at the entrance to the safety valve, in which the proof of the reinforcement is performed and the maximum is achieved bandwidth.
Closing pressure, RZ(Pressure Pointing) - overpressure at the inlet in the safety valve, in which, after resetting the working medium, planting a locking element on the saddle with the provision of a given shutter tightness is occurred. Pressure closing valves, RZ - at least 0.8 pH.
Backpressure- overpressure at the outlet of the reinforcement (in particular, from the safety valve).
The backpressure is the sum of static pressure in the exhaust system (in the case of closed system) and pressure arising from its resistance when working media.
Mandatory minimum order information.
When ordering valves, you must fill in the questionnaire (Appendix B):
- product type, designation, type designation (on the table of figures);
- nominal diameter of the inlet nozzle, DN, mm;
- nominal pressure, pn, kgf / cm2;
- pressure pressure (pH, kgf / cm2) or spring number (when specifying only the spring number, the valve is configured to a minimum value from the range of the specified spring);
- case material;
- the presence in the design of the valve node of the manual undermining;
- the presence in the design of the valve of the bellows.
An example of a designation when ordering a safety spring valve:
An example of the designation when ordering a valve of safety spring DN 50 pn 16 kgf / cm2 made of steel 12x18H9Tl with a manual undermining node, pressing pressure - pH \u003d 16 kgf / cm2, KPP4R model on TU 3742-005-64164940-2013:
Valve Safety KPP4R 50-16 DN 50 PN 16 kgf / cm2, pH \u003d 16 kgf / cm2, 17 nnzh17nzh. When placing an order, the need to configure the valves with response details (response flanges, gaskets, studs, nuts, nuts, for valves DN 25 PN 100 - nipple with cape nuts and gaskets).
Check valve is an element of a pipeline system, which provides for the movement of the working medium in only one direction. Its use is required for autonomous pumping stations and other equipment that can fail when the fluid flow moves in the opposite direction.
Reverse spring valve is one of the varieties of locking elements. It refers to the category of fittings direct action And it works automatically on the energy of the working medium, which warns the output of the equipment in order when the power supply is disabled and other faults.
Constructive features
The spring valve constructively consists of three elements:
- The housing is usually made of brass and equipped with elements for fastening to the pipeline (coupling, thread). The housing is also made of steel, cast iron and polypropylene. The selection of the material is determined by the parameters of the working medium, the diameter of the pipeline.
- The working element representing the movable spool includes two plates with a special hermetic gasket between them and the rod.
- The executive body representing the spring located between the plates of the working element and the saddle. Provides automatic overlap of fluid current when a pressure decreases or a change in its direction. The minimum pressure of the working medium depends on the spring rigidity, at which the valve automatically opens.
Benefits check valves Spring:
- the possibility of mounting in any position;
- simplicity of design;
- universality.
At the same time, the valve is sensitive to pollution in water, which lead to wear of sealing plates, so it is desirable to install a filter before it. It is also recommended to mount the valve in easily accessible places to simplify it. maintenance and replacement.
It is desirable to install the valve in a vertical position so that the blocking force of the spring coincides with the action of gravity. For right mounting It is necessary to navigate the arrow applied to the valve body, which shows the transmitted direction of the current of the working medium.
Scope of application
Reverse Spring Valves are widely used in systems. autonomous water supply, Outdoor networks of apartment buildings. They are installed on the suction lines of pumps, in front of capacitive water heaters, boilers, water meters and other equipment.
The company "Nemen" sells safety valves designed to work in various environments. We offer, which can be installed vertically on the pipeline area or boiler aggregates.
Appointment of safety reinforcement
The safety valve is a form of fittings that is designed to automatically protect pipelines and equipment from exceeding pressure over a certain, predetermined value by resetting overweight working media. The valve also provides a discharge stop when restoring normal operating pressure. Safety valve is a direct valve fittings directly from the energy of the working medium.
Principle of operation of the safety valve
When the safety valve is in a closed state, the power pressure of the reinforcement is affected by the power pressure in the pipeline, which seeks to open the valve, as well as preventing the discovery force from the deposit. In the event of an occurrence in the system of perturbations provoking the increase in pressure of the medium over the worker, the prulchery force of the spool to the saddle decreases. When its value is zero, there is an equilibrium of active forces from the valve and the pressure of the medium simultaneously affecting the valve. If the pressure in the system continues to increase, the locking body opens and reset the excess medium through the valve. Reducing the volume of the medium leads to normalization of pressure in the system and disappearing of perturbing effects. When the pressure level falls below the maximum permissible, the locking body returns to its original position under the influence of force from the depositter.
Safety spring valves
In such safety valves, the springs compression force is used as counteraction of the pressure of the working medium. Due to the installation of various springs, the same safety spring valve can be used for several limits setting the maximum allowable pressure. IN spring valves There is no seal in the rod. If the valve is installed in systems with an aggressive working medium, the spring is isolated using the glands, an elastic membrane or a bellows. The bellows seal is used in cases when the leakage of the working medium from the pipeline is unacceptable.
All vessels operating under high pressure must be equipped with safety devices from pressure enhancement. This uses:
lever-cargo PCs;
safety devices with destroying membranes us;
Level-cargo PCs are not allowed to use on mobile vessels.
Circuit diagrams of the main types of PC are shown in Figures 6.1 and 6.2. Cargo on the lever-car valves (see fig. 6.1,6) it must be securely fixed in the specified position on the lever after the valve targeting. The design of the spring PC (see Fig. 6.1, c) must exclude the possibility of tightening the spring over the established value and provide for the device for
Fig. 6.1. Basic schemes of the main types safety valves:
checking the function of valve valve in working condition by compulsory opening it during operation. The device of the spring prevention valve is shown in Fig. 6.3. The number of PCs, their size and bandwidth should be calculated so that in Fig. 6.2. The discontinuous safety membrane did not exceed more than 0.05 MPa for vessels with a pressure of up to 0.3 MPa,
15% - for vessels with a pressure of 0.3 to 6.0 MPa, by 10% - for vessels with a pressure of more than 6.0 MPa. When working PCs are allowed to excess pressure in the vessel by no more than 25%, provided that this is an excess of the project and reflected in the vessel passport.
PC bandwidth is determined according to GOST 12.2.085.
When determining the size of the flow sections and the number of safety valves, the calculation of the bandwidth of the valve on G (in kg / h) is important. It is performed according to the method described in the SSBT. For water vapor, the value is calculated by the formula:
G \u003d 10B 1 B 2 α 1 F (P 1 +0.1)
Fig. 6.3. Spring device
safety valve:
1 - body; 2 - spool; 3 - spring;
4 - reducing pipeline;
5 - protected vessel
where bI - coefficient, taking into account the physicochemical properties of water vapor when operating parameters in front of the safety valve; can be determined by expression (6-7); varies from 0.35 to 0.65; The coefficient that takes into account the ratio of pressures before and behind the safety valve depends on the adiabatic indicator k. and indicator β, with β<β кр =(2-(k+1)) k/(k-1) коэффициент B 2 = 1, показатель β вычисляют по фор муле (6.8); коэффициент B 2 varies from 0.62 to 1.00; α 1 is the races coefficient, indicated in the passports of safety valves, for the modern designs of low lifting valves α 1 \u003d 0.06-0.07, high-lines - α 1 \u003d 0.16-0.17, F.- passenger area of \u200b\u200bthe valve, mm 2; R 1 - maximum overpressure in front of the valve, MPa;B 1 \u003d 0.503 (2 / (k + 1) k / (k-1) * 
where V.\ - specific volume of steam in front of the valve when parameters P 1 and T. 1, ) m 3 / kg - the temperature of the medium in front of the valve at a pressure P L ° C.
(6.7)β \u003d (p 2 + 0.1) / (P 1 +0.1), (6.8)
where P.2 - Maximum overpressure for the valve, MPa.
Adiabstract index k. depends on the temperature of the water vapor. At a pair of 100 ° C k. = 1.324, at 200 "with k. = 1.310, at 300 ° C k.= 1.304, at 400 "with k.= 1,301, at 500 ° Ck.= 1,296.
The total bandwidth of all installed safety valves should be at least the maximum possible emergency inflow of the medium to the protected vessel or apparatus.
Safety membranes (see Figures 6.2 and 6.4) are specially weakened devices with precisely calculated pressure destruction threshold. They are simple in design and at the same time provide high reliability of equipment protection. The membranes fully seal the dumping hole of the protected vessel (before the trigger), cheap and easy to manufacture. Their disadvantages include the need to replace after each triggering, the impossibility of accurately determining the pressure of the membrane, which causes to increase the safety stereos of the protected equipment.
Membrane safety devices can be installed instead of lever-cargo and spring safety valves, if these valves under a specific environment can be used as a result of their inertia or others with the Chin. They are also installed before the PC in cases where the PC cannot reliably operate due to the features of the effect of the working medium in the vessel (corrosion, crystallization, harnessing, sample). Membranes are installed even in parallel with the PC to increase the throughput of the pressure reset systems. Membranes are installed even in parallel with the PC to increase the throughput of the pressure reset systems. Membranes can be discontinuous (see Fig. 6.2) broken, broken down (Fig. 6.4), cutting, leaching. The thickness of the discontinuous membrane A (in mm) is calculated by the formula:
Pd./ (8σ. bP K. t. ) ((1+ (Δ / 100)) / (1 + ((Δ / 100) -1)) 1/2
where D. - working diameter; R-the pushing pressure of the membrane, σ BP - the strength of the material of the membrane (nickel, copper, aluminum, etc.) during tension; TO 1 - temperature coefficient variable from 0.5 to 1.8; δ is the relative elongation of the membrane material at break,%.
For tear-up membranes by the value determining the pressure pressure,
is diameter D. H. (see Fig. 6.4), which is calculated as
D H \u003d D (1 + p / σ BP) 1/2
It is not allowed to install any locking reinforcement between the vessel and the safety device, as well as behind it. In addition, safety devices must be placed in places that are convenient for their maintenance.
Safety devices. Safety devices (valves) should automatically prevent pressure from increasing the pressure on the output of the working medium into the atmosphere or the recycling system. Installing at least two safety devices is required.
On steam boilers, only pulsed safety valves should be installed on the steam boilers.
The diameter of the passage (conditional), installed on the boilers, arms,; Cargo and spring valves should be at least 20 mm. Admission to reduce this passage to 15 mm for boilers steam-capacity up to 0.2 t / h and pressure up to 0.8 MPa when installing two valves.
The total bandwidth of the safety devices installed on steam boilers should be at least rated boiler performance. The calculation of the bandwidth of limit devices of steam and water boilers should be performed at 14570 "Valves Safety steam and water boilers. Technical requirements".
Safety device installation locations are defined. In particular, in hot water boilers, they are installed on weekends or drums.
The technique and frequency of regulation of safety new (PCs) on boilers is indicated in the installation instructions and exemplary valves should protect the vessels from exceeding pressure in them more than 10% of the calculated (allowed).
Short response:All vessels operating under high pressure must be equipped with safety devices from pressure enhancement. This uses:
spring safety valves (PCs);
lever-cargo PCs;
pulse safety devices consisting of a main PC and a direct-action control pulse valve;
safety devices with destructive membranes;
other safety devices whose application is agreed with Gosgortkhnadzor of Russia.
Valve Safety spring flange 17c28nzh is one of the main types that is used to protect pipeline equipment. The valve safety spring 17c28nzh is designed to protect equipment and pipelines, from unacceptable pressure in the system. Ensuring safe pressure values, carried out by automatic reset of excess working media into a specially installed, reducing pipeline or into the atmosphere, and when restoring the operating pressure, the safety valve 17c28nzh stops the discharge of the working medium.
The valve safety spring 17c28nzh is mounted with equipment and with a flange connection. The valve safety spring 17c28nzh flange has a service life for more than 11 years, and the manufacturer gives it a guarantee of 18 months from the date of commissioning of the valve. Safety valve 17c28nzh is notometric in relation to the external environment.
Material of the main parts from which the safety spring valve 17c28nzh with a flange compound is produced:
- Case, cover - steel 25l
- Disk, saddle - steel 20x13
- Stock - steel 20x13 / steel 40
- Gasket - ad1m
- Spring - 50hf.
Safety spring valve device 17c28nzh
1 .Cap
2 . Regulating screw
3 . Spring
4 . Cap
5 . Stock
6 . Hand undermining knot
7 . Knot of spool
8 . Saddle
9 . Housing
Overall and connecting sizes of the safety valve 17c28nzh
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DN, mm. |
Dimensions, mm. |
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Specifications of safety valve 17c28nzh
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Name |
Value |
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Diameter nominal, dn, mm |
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Hole diameter in DC saddle, mm |
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Permissible leaks in the gate, see 3 / min |
5-for 1-water |
10-for air 2-water |
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Section area of \u200b\u200bFC, mm 2, not less |
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Pressure nominal at the entrance of the PN, MPa (kgf / cm 2) |
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Pressure nominal at the output of the RN, MPa (kgf / cm 2) |
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Pressure full opening RP.O. 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 |
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Pressure closure PZ. |
not less than 0.8 pH |
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Limits of pressure settings, pH MPa (kgf / cm 2), 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) |
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Environmental temperature, |
from minus 40 to 40 |
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The temperature of the work environment, |
from minus 40 to 450 |
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Working environment |
Water, par |
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Curvage coefficient? |
0.8 for gaseous; 0.5 for liquid media |
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The connecting dimensions and size of the sealing surfaces of the case |
according to GOST 12815-80, AP.1 series 2 |
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Mass without flanges (kg) |
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