valve
Is one of the most common and important processing equipment,
valve
It is an indispensable part of the whole water treatment equipment. It is a control part in the fluid conveying system. It has the functions of cut-off, regulating, diversion, preventing backflow, regulating, shunting or overflow relief. The valve is usually composed of valve body, valve cover, valve seat, opening and closing parts, drive mechanism, seal and fastener, etc. The control function is to rely on the drive mechanism or fluid to drive the opening and closing parts to lift, slide, swing or turn Movement to change the size of the flow channel to achieve.

    Human use of the valve has been nearly 4,000 years of history, and China in ancient times from the salt wells in the brine salt, had used in the bamboo pipe in the plug valve; 1800 BC, the ancient Egyptians in order to prevent the flood of the Nile The construction of large-scale water conservancy, have also used a similar wooden cork to control the distribution of water; these are the prototype of the valve.

    Industrial valves for a large number of applications, from the invention of the steam engine after the beginning of the beginning of the twentieth century cast steel, cast iron, forged steel and forging structure of the valve.

    http://en.luobai.org/content/Valve definition

    In the water treatment industry, the valve is a very common and important one of the processing equipment, the valve is small, but it is an indispensable part of the entire water treatment equipment, fluid transmission system control components, with cut-off , Regulation, diversion, to prevent backflow, regulator, shunt or overflow pressure and other functions.

    The valve is usually composed of valve body, valve cover, valve seat, opening and closing parts, drive mechanism, seal and fastener, etc. The control function is to rely on the drive mechanism or fluid to drive the opening and closing parts to lift, slide, swing or turn Movement to change the size of the flow channel to achieve.

    http://en.luobai.org/content/Valves are widely used and are closely related to people's daily lives, such as faucets for tap water pipes and liquefied petroleum gas stoves.
Pressure reducing valve
Are valves. http://en.luobai.org/content/Valves are also indispensable parts for a variety of mechanical equipment such as internal combustion engines, steam engines, compressors, pumps, pneumatic drives, hydraulic drives, vehicles, ships and aircraft.

    http://en.luobai.org/content/Valve classification

    The valve can be divided into two categories: automatic valve and drive the valve.

    Automatic valves: valves that rely on the ability of the medium (liquid, gas) itself to act on its own. Such as
Check valve
,
Safety valve
,
Regulating valve
,
Traps
,
Pressure reducing valve
Wait.

    Drive valve: with manual, electric, hydraulic, pneumatic to manipulate the action of the valve. Such as
gate
,
Shut-off valve
, Throttle,
Butterfly valve
,
Ball valve
,
Plug the valve
Wait.

    According to the use of functions can be divided into cut-off valve,
Regulating valve
,
Check valve
, Diverter valve,
Safety valve
, Multi-purpose valve six categories.

    (1) truncated class: also known as closed-circuit valve, mainly used to cut off the fluid path, including
Shut-off valve
,
gate
,
Plug the valve
,
Ball valve
,
Butterfly valve
,
Diaphragm valve
, Pinch valve, etc .;

    (2) regulating valve: mainly used to adjust the fluid pressure, flow, etc., including the control valve, throttle, pressure relief valve and float control valve;

    (3) check valve: also known as one-way valve or check valve, check valve is an automatic valve, used to prevent the reverse flow of fluid, water pump off the end of the valve also belong to the check valve;

    (4) diverter valve: for the distribution of fluid flow path, or two-phase fluid separation, including the slide valve, multi-valve,
Traps
And exhaust valve;

    (5) safety valve: mainly used for safety protection, to prevent the boiler, pressure vessel or pipe due to overpressure and damage;

    (6) multi-purpose valve: is a more than one function of the valve, such as cut-off check valve can not only stop the role of the same function.

    According to nominal pressure can be divided into
Vacuum valve
, Low pressure valve, medium pressure valve, high pressure valve, high pressure valve.

    (1)
Vacuum valve
: Refers to the work pressure below the standard atmospheric pressure of the valve.

    (2) low pressure valve: refers to the nominal pressure PN ≤ 1.6Mpa valve.

    (3) medium pressure valve: refers to the nominal pressure PN 2.5Mpa, 4.0Mpa, 6.4Mpa the valve.

    (4) high pressure valve: refers to the nominal pressure PN is 10.0Mpa ~ 80.0Mpa the valve.

    (5) ultra-high pressure valve: refers to the nominal pressure PN ≥ 100.0Mpa the valve.

    According to the working temperature can be divided into ultra-low temperature valve, low temperature valve, room temperature valve, temperature valve, high temperature valve.

    (1) ultra-low temperature valve: for the media operating temperature t <-101 ℃ valve.

    (2) low temperature valve: for the media operating temperature -101 ℃ ≤ t ≤ -29 ℃ valve.

    (3) room temperature valve: for the media operating temperature -29 ℃ (4) temperature valve: for the media operating temperature 120 ℃ ≤ t ≤ 4225 ℃ valve.

    (5) high temperature valve: for the media operating temperature t> 425 ℃ valve.

    According to the nominal diameter can be divided into small diameter valves, small diameter valves, large diameter valves, large diameter valves.

    (1) small diameter valve: nominal diameter DN ≤ 40mm valve.

    (2) in the diameter of the valve: nominal diameter DN 50 ~ 300mm of the valve.

    (3) large diameter valve: nominal valve DN 350 ~ 1200mm valve.

    (4) large diameter valve: nominal diameter DN ≥ 1400mm valve

    According to the drive classification is divided into automatic valve type, power-driven valve and manual valve class.

    (1) automatic valve refers to the valve does not require external force, but rely on the energy of the medium itself to make the valve action. Such as safety valve, pressure reducing valve, trap, check valve, automatic control valve.

    (2) power drive valve: power drive valve can be used to drive a variety of power sources. Divided into electric valves, pneumatic valves, hydraulic valves and so on. Electric valve: Electric driven valve. Pneumatic valves: valves driven by compressed air. A valve driven by liquid pressure such as oil. In addition there are several combinations of the above drive, such as gas - electric valve.

    (3) manual valve: manual valve with hand wheel, handle, lever, sprocket, by the man to manipulate the valve action. When the valve opening and closing torque is large, can be set between the hand wheel and stem gear or worm reducer. When necessary, you can also use the universal joint and drive shaft for long-distance operation.

    Classification by structural features: The structural characteristics of the valve are based on the direction in which the closing member moves relative to the valve seat.

    (1) cut-off: closing parts along the center of the valve seat; such as cut-off valve

    (2) Cocks and Spheres: Closed pieces are plungers or balls, rotating around their centerline; such as plug valves, ball valves

    (3)
Gate
Shaped: closing parts along the vertical seat center movement; such as gate valve,
Gate
Wait

    (4) swivel-shaped: closing parts around the valve seat outside the axis of rotation; such as the swing check valve

    (5) butterfly: the closure of the disc, around the shaft inside the shaft rotation; such as butterfly valve, butterfly check valve

    (6) Slide valve: The closing member slides in the direction perpendicular to the channel.

    According to the valve and pipe connection can be divided into flange connection valve, threaded connection valve, welding connection valve, clamp connection valve, card sets to connect the valve.

    (1) flange connection valve: the valve body with a flange, and the pipeline with a flange connection valve.

    (2) threaded connection valve: the valve body with internal or external thread, and the pipeline with threaded connection valve.

    (3) welding connection valve: the valve body with a welding port, and the pipeline connected with the welding valve.

    (4) Clamp connection valve: the valve body with a folder, and the pipe with a clamp connected to the valve.

    (5) card sets to connect the valve: the use of card sets and pipe connected to the valve.

    Classification of non-metallic materials by valve material, metal material valves, metal body lining valves.

    (1) non-metallic materials valves: such as ceramic valves, glass steel valves, plastic valves.

    (2) metal materials valves: such as copper alloy valves, aluminum alloy valves, lead alloy valves, titanium alloy valves, Monel alloy valves cast iron valves, carbon steel valves, cast steel valves, low alloy steel valves, high alloy steel valves.

    (3) metal body lining valve: the valve body shape for the metal, the internal contact with the main surface of the media are lining, such as lining the lead valve, lined with plastic valves, lining enamel valve.

    According to the direction of the switch can be classified as:

    (1) angular travel including ball valve, butterfly valve, plug valve and other classification;

    (2) straight stroke, including gate valve, globe valve, angle seat valve;

    General classification method

    This classification method is not only the principle, the role and structure by division, is the international and domestic most commonly used classification method. General sub-gate valve, globe valve, throttle valve,
Instrument valve
, Plunger valve,
Diaphragm valve
, Plug valve, ball valve, butterfly valve, check valve, relief valve safety valve, trap, regulating valve, bottom valve, filter, sewage valve.

    The valves may be named individually or in combination according to various classification methods, or may be named according to the structural features or specific uses of the opening and closing parts.

    The basic parameters of the valve are working pressure, operating temperature and caliber. For a large number of valves used in industrial pipelines, commonly used nominal pressure and nominal diameter as the basic parameters. Nominal pressure refers to a material of the valve, at the specified temperature, the maximum allowable working pressure. Nominal diameter refers to the nominal diameter of the valve body and the joint end of the pipe.

    http://en.luobai.org/content/Valve according to its type and use have different requirements, mainly sealed, strength, regulation, circulation, opening and closing performance. In the design and selection of valves, in addition to taking into account the basic parameters and performance, but also consider the performance of the fluid, including the fluid phase (gas, liquid or solid particles), corrosive, viscosity, toxicity, flammable and explosive , Preciousness and radioactivity. (According to China's first valve network)