IntroductionWe have some friends who may not know much about pressure relief valves, let alone pressure relief valve models. This is no big deal, because after all, we will rarely come into contact with the pressure relief valve alone. Some friends who specialize in this industry, or businessmen are more knowledgeable. In fact, there are many aspects of our lives where we need to come into contact with this device. We have all used a pressure cooker, or seen a heater and so on. These are our common things, and these things will have pressure relief valve device. So, what approach do we need to take when buying one? How to choose the pressure relief valve? With these questions, we start today's topic.
Pressure relief valve model introduction
We know that the main purpose of the pressure relief valve device is to prevent the various applications of the internal pressure indicators, under certain circumstances to rise above the permissible value of the situation. The fundamental purpose of this device is to ensure the safe operation of the corresponding equipment, this device is an automatic device. This device for high-pressure heater water measurement of a special device.
At present, the domestic manufacturers of the relevant production for indoor water supply system pressure relief month specifications include:
Nominal Diameter: DNS0-200mm.
Nominal Pressure: I.0MPa, I.6MPa, 2.5MPa.
Valve body material; copper, ductile iron, gray 1:3 cast iron
Generally, the choice of pressure relief valve, its caliber is allowed to be smaller than the system main line.... Orange to two grades. Such as the main pipeline for the DN125mm below, the pressure relief valve specifications should be small one gear; main pipeline for the DNIS0 ~ above,.... Pressure relief - cabinet specifications can be a small one or two. Of course, the choice of pressure relief valves equal to the caliber of the main pipeline is more safe and reliable. Pressure relief valve pressure level should be based on the working pressure of the fire water supply system to determine. If the system working pressure. Less than 1.0MPa, can choose the nominal pressure of I.O plus the pressure relief valve; system working pressure is greater than I.0MPa face less than I.6MPa, can choose the nominal pressure of I.6MPa pressure relief week; system working pressure is greater than I.6MPa. Nominal pressure should be selected for 2.5 plus Pal pressure relief valve. In other words, the pressure relief valve should be consistent with the valve pressure level on the fire pump outlet pipe.
Pressure relief valve working principle
The working principle of different pressure relief valve models is the same. Because the so-called pressure relief valve is a fully sealed form, so that when the valve valve to make the opening and closing action, you can completely use the connection of a pipeline, the internal media discharge. Generally is used to rotate the adjusting screw to adjust the spring compression, and then use the valve stem to the spring force to the valve. Once the internal medium force exceeds the spring, it will force the valve to lift up, thus discharging the excess medium immediately. In addition, when the medium pressure inside the equipment returns to a normal, the valve can be closed under the action of the spring itself.
Structural Classification of Pressure Relief Valves
The basic situation is the same for the structure of different pressure relief valve models. First of all, we say that the sealing of the pressure relief valve is entirely dependent on the compression of the spring to generate force, which allows the valve flap closely with the seat sealing surface contact, thus playing a sealing effect. The sealing surface of the valve flap and valve seat is made of iron-based cemented carbide surfacing.
The surface of the valve stem is nitrided, which has good resistance to scuffing and corrosion. The crank small shaft and handle constitute the manual mechanism. Power plant operation should be regularly rotated the mechanism, check the situation. Positioning plug is adjusted in the pressure relief valve guide sleeve, screwed into the positioning sleeve side hole to prevent the positioning sleeve rotation.
Pressure relief valve structure has two main categories: spring-loaded and lever-loaded. Spring-loaded is that the valve flap and seat sealing by the force of the spring. Lever type is by the force of the lever and weight. With the need for large capacity, there is a pulse-type pressure relief valve, also known as pilot-operated pressure relief valve, by the main relief valve and auxiliary valve. When the pressure of the medium in the pipeline exceeds the specified pressure value, the auxiliary valve opens first, the medium along the conduit into the main relief valve, and the main relief valve will be opened, so that the increased medium pressure reduction.
Pressure relief valve notes
1. Pressure relief valves can be installed horizontally or vertically, but the installation should pay attention to the direction of the valve body water flow in and out of the direction of the valve body, can not be mistaken. In general, a fire water supply system can only install a pressure relief valve.
2. If the pressure relief valve drain location is farther away, the relief water pipeline is too long (& gt; 20m), the caliber of the relief water pipe should be enlarged than the specifications of the relief valve a gear, in order to prevent the relief of the flow is not smooth back pressure, to ensure that the pressure relief valve valve valve before the pipe network pressure stability.
3. Fire water supply system in the pressure test process, such as the system test pressure is higher than the nominal pressure of the selected relief valve l, should close the pressure relief valve shut-off valve, so as to avoid damage to the relief valve or malfunction.
4. pressure relief valve in the operation process, such as failure, control failure,? Should first check whether the pipe lucid. Then check whether the water filter on the Yan body control pipeline is clogged, whether the main valve and pilot valve membrane rupture, and whether the main valve and guide thick gasket is damaged.
Above we have compared the working principle and structure of different pressure relief valve models. We can know that for the different areas of application, that is to say, leading to the structure of their different models have certain differences. But the basic principle is the same. Therefore, when we buy, we must understand the place you want to apply and the equipment, which is the key.