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Forged steel gate valve: All gate valves processed with forging materials are collectively called forged steel gate valves. The forging materials are A105, F11, F5, 304, 304L, 316, 316L and so on. Forged steel gate valves commonly referred to in China usually refer to small-diameter forged steel gate valves, with a diameter range of DN10~DN50; pressure range: national standard PN16~PN320, American standard: Class150～2500, can be produced by American standard or national standard size, manufacturers are Available from stock. Forged steel gate valves exceeding the DN50 diameter are required to be ordered, and domestic demand is small.
There are many different ways to classify gate valves. The main difference is that the sealing elements used are different in structure. According to the structure of the sealing elements, the gate valves are often divided into several different types, and the common form of zui is parallel gate valves and Tie gate valve; according to the structure of the valve stem, it can also be divided into open gate valve and dark rod gate valve.
Forged steel gate valve is suitable for small diameter pipelines of Class 150～2500, working temperature -29～425°C (carbon steel) or -29～500°C (stainless steel), used to cut off or connect the medium in the pipeline, choose different Material, can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media. More applications on oil pipelines.
Forged steel gate valves are mostly Dalian-type reduced diameter design. Compared with cast steel gate valves of the same diameter, the flow rate is slightly smaller, but the pressure and temperature range are higher than cast steel valves, and the sealing performance is much better than cast steel gate valves. The life is longer and the flow direction of the medium is the same as other gate valves.
Installation points 1, installation position, height, import and export direction must meet the design requirements, the connection should be firm and tight.
2. All kinds of manual valves installed on the insulated pipe, the handles must not be downward.
3, the valve must be visually inspected before installation, the nameplate of the valve should comply with the current national standard "General Valve Mark" GB12220. For valves with a working pressure greater than 1.0 MPa and a shut-off function on the main pipe, the strength and rigorous performance tests shall be carried out before installation, and shall be used after passing the test. In the strength test, the test pressure is 1.5 times the nominal pressure, the duration is not less than 5 min, and the valve casing and the packing should be free of leakage. In the rigorous test, the test pressure is 1.1 times of the nominal pressure; the test pressure shall meet the requirements of GB50243 in the duration of the test, and the leakage of the sealing surface of the ram shall be qualified.
Forged steel gate valve performance standards <br> <br> design specifications: JB / T7746, API602
Structure length: JB/T7746, factory specification socket/thread: JB/T1751/GB7306, ANSIB16.11/B2.1
Test and inspection: JB/T9092, API598
Pressure-temperature: GB/T9131, ANSIB16.34
Product identification: GB/T12220, MSSSP25
Supply specification: JB/T7928
The standards produced by major manufacturers in China are different. For example, the length and production standard of American Standard Gate Valve produced by Shanghai Meidede Valve Manufacturing Co., Ltd. and the former Shanghai Minhang High and Medium Pressure Valve Factory and Shanghai Liangzhong Valve Factory are different. Forged steel gate valves often ignore pressure problems. In the grease injection operation, the grease-loaded regular semi-free float-type steam trap has a peak-to-valley change. The pressure is too low, the seal leaks or the safety valve fails, the pressure is too high, the valve of the grease injection port is blocked, the seal grease is hardened or the seal ring is locked with the valve ball and the valve plate. Usually, when the grease pressure is too low, the injected grease flows into the bottom of the valve chamber, which usually occurs in a small gate valve. On the one hand, the pressure of the grease flow control valve is too high. On the one hand, the grease valve is inspected to check the grease nozzle. If the grease remote control float valve hole is blocked, the spring seal is replaced with a wrench. The other plunger valve is a lipid. To harden, use a cleaning solution, repeatedly soften the failed sealing grease, and inject a new grease to replace it. In addition, the sealing type and sealing material also affect the grease filling pressure. Different sealing forms have different grease filling pressures. Generally, the hard sealing grease pressure is higher than the soft sealing.
The main components <br> <br> ID NO. CStoASTM name American Standard ANSI Carbon steel Stainless steel AStoASTM American Standard SStoASTM ??
PartNameTypeA105TypeF22TypeF304(L)TypeF316(L)??
1 valve body BodyA105A182F22A182F304(L)A182F316(L)
2 seat SeatRingA276420A276304A276F304(L)A276F316(L)
3 gate WedgeA276430 & 410A182F304A182F304 (L) A182F316 (L)
4 stem StemA182F6A182F304A182F304(L)A182F316(L)
5 gasket GasketCorrugatedSS+graphiteSS+PTFE??
6 bonnet BonnetA105A182F22A182F304(L)A182F316(L)
7 bolt BonnetBoltA193B7A193B16A193B8A193B8M
8 pin PinA276420A276F304??
9 packing gland GlandA276410A182F304 (L) A182F316 (L)?
10 live joint screws GlandEyeboltA193B7A193B16A193B8A193B8M
11 packing gland GlandFlangeA105A182F11A182F304(L)A182F316(L)
12 nuts GlandNutA1942HA1944A1948A1948M
13 stem nut StemNutA276420/Cu-Alloy (copper alloy) ???
14 hand wheel lock nut HWLockNutA1942HA1944A1948A1948M
15 nameplate NameplateSS???
16 hand wheel HandwheelA197???
17 padding BearingGasketA473431???
18-filler StemPackingFlexibleGraphitePTFE??
Applicable medium SuitableMedium (water, oil, gas, etc.) WOGetc (acid) HNO3, CH3OOHetc????
Applicable temperature SuitableTemperature-29°C～425°C-29°C～550°C-29°C～180°C???
Forged steel gate size diameter reduced diameter <br> <br> RB3 / 81/23/4111/ 411/22?
NPS full diameter FB?3/81/23/4111/411/22
L150～800Lb797992111120120140178
900Lb7992111120120140178210
1500Lb111111111114120140162210
H(OPEN)150～800Lb158158169197236246283330
900～1500Lb169197197236246283330354
W150～800Lb100100100125160160180200
900～1500Lb100125125160160180200240
WeightsBolted150～800Lb2.12.02.34.35.96.911.115.2
900～1500Lb2.54.34.26.68.812.517.223.5
Welded150～800Lb1.81.72.03.85.16.110.214.2
900～1500Lb2.44.24.06.38.712.117.222
When forging steel valves, pay attention to the water inlet problem in the electric head and its transmission mechanism. Especially the rain that infiltrates during the rainy season. One is to rust the transmission mechanism or the transmission bushing, and the other is to freeze in winter. The torque caused by the operation of the electric valve is too large. Damage to the transmission components may cause the motor to be unloaded or the over-torque protection may not be electrically operated. The drive components are damaged and manual operation is not possible. After the over-torque protection action, the manual operation also fails to switch. For example, forced operation will damage the internal alloy parts.
Both steel and iron are iron-based alloys with carbon as the main additive element. They are collectively referred to as iron-carbon alloys. The cast pig iron is smelted in a molten iron furnace to obtain cast iron (liquid), and the liquid cast iron is cast into a casting. Cast iron is called cast iron. Where is the difference between cast steel and carbon steel. First, steel is classified according to chemical composition (1) carbon steel: a. low carbon steel (C ≤ 0.25%); b. medium carbon steel (C ≤ 0.25 ~ 0.60%); c. high carbon steel (C ≤ 0.60%) ). Steel is classified according to the forming method: (1) forged steel; (2) cast steel; (3) hot rolled steel; (4) cold drawn steel. The gates of all gate valves have two sealing faces, which are determined by the structure of the gates, otherwise they are not called gate valves. The common ram type of Zui is wedge-type ram. The two sealing faces of this ram form a wedge shape. The wedge angle varies with the valve parameters, usually 50, and the temperature of the dielectric gate valve is 2°52' when the temperature is not high. The gate of the wedge gate valve can be made into a whole body, called a rigid ram. It can be expressed as "Z41H" with "1"; it can also be made into a ram that can produce slight deformation to improve its processability and make up for the angle of the sealing surface. The deviation generated in the process, this ram is called the elastic ram, and it is represented by "0" as the Z40H type.
General <br> <br> valve works by sealing surface configuration can be divided into wedge gate-type valve and parallel gate valve, wedge gate-type valve can be divided into: single-gate type, double plate and the resilient brake Plate type; parallel gate type gate valves can be divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve.
<br> <br> sealing surface can only rely on the valve closed when the media pressure to seal, i.e., the medium pressure to ram pressure to the sealing surface on the other side of the valve seat to ensure the sealing of the sealing surface, which is self-sealing. Most of the gate valves are forced to seal, that is, when the valve is closed, the external force is forced to press the gate to the valve seat to ensure the sealing of the sealing surface.
The gate of the gate valve moves linearly with the valve stem, which is called the lift gate valve (also called the open gate valve). Usually there is a trapezoidal thread on the lifting rod, and the rotary motion is changed into a linear motion by the nut at the top end of the valve and the guide groove on the valve body, that is, the operating torque is changed to the operating thrust.
When the valve is opened <br> <br> shutter valve lift height equal to diameter of 1: 1 time, the fluid channel completely, but at run time, this position is not monitored. In actual use, the apex of the valve stem is used as a mark, that is, the position where the valve is opened, as its fully open position. In order to consider the temperature change, the lock phenomenon occurs, usually at the position of the opening to the apex, and then back to 1/2-1 circle as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the shutter (ie stroke).
In some gate valves, the stem nut is arranged on the gate, and the rotation of the hand wheel drives the valve stem to rotate, and the gate is lifted. This valve is called a rotary lever gate valve or a dark rod gate valve.
A, the working principle of the manual gate valve:
Turning the handwheel, through the advancement and retreat of the thread of the handwheel and the stem, lifting or lowering the valve plate connected with the valve stem to achieve the function of opening and closing
The gate valve has the following advantages:
The fluid resistance is small.
Opening and closing is more labor-saving.
The flow direction of the medium is not limited, and it does not disturb the flow and does not reduce the pressure.
The utility model has the advantages of simple shape, short structure length, good manufacturing process and wide application range.
The disadvantages of the gate valve are as follows:
Erosion and abrasion are easily caused between the sealing surfaces, and maintenance is difficult.
The external dimensions are large, and a certain space is required for opening, and the opening and closing time is long.
The structure is more complicated.
Universal valve installation and maintenance <br> <br> by sealing surface configuration can be divided into wedge gate-type valve and parallel gate valve, wedge gate-type valve can be divided into: single-gate type, double plate and the resilient brake Plate type; parallel gate type gate valves can be divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve.
The following matters should be noted for the installation and maintenance of the gate valve:
The handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited.
The double gate valve should be installed vertically (ie the stem is in the vertical position and the handwheel is on the top).
The gate valve with the bypass valve should open the bypass valve before opening (to balance the differential pressure between the inlet and outlet and reduce the opening force).
The gate valve with transmission mechanism is installed according to the product manual.
If the valve is used frequently, it should be lubricated at least once a month.
The general gate valves used in the market for a long time are generally leaking or rusting. The elastic seat sealing gate valves produced by European high-tech rubber and valve manufacturing technology have overcome the defects of poor sealing and rust of general gate valves, and elastic seat sealing gate valves. The use of the elastic ram to produce a slight elastic deformation compensation effect to achieve a good sealing effect, the valve has the advantages of light switch, reliable sealing, good elastic memory and service life. Can be widely used in tap water, sewage, construction, petroleum, chemical, food, pharmaceutical, textile, electric power, shipbuilding, metallurgy, energy systems and other body pipelines as a regulating and intercepting device.
Elastic seat sealing gate valve B, the characteristics of the gate valve:
Light weight: The body is made of high-grade ductile iron, which is about 20%~30% lighter than traditional gate valves, and is easy to install and maintain.
Flat-bottomed gate: Traditional gate valves are often deposited in the groove of the valve bottom due to foreign objects such as stones, wood blocks, cement, iron filings, debris, etc. after the water is washed, which is easy to close and form a leak. The bottom of the elastic seat sealing gate valve adopts the same flat bottom design as the water pipe machine, which is not easy to cause debris accumulation, so that the fluid is unobstructed.
Integral lagging: The ram is made of high-quality rubber for the whole inner and outer rubber. The rubber vulcanization technology of Europe* enables the vulcanized ram to ensure precise geometrical dimensions, and the rubber and spheroidal cast slabs are secure and not easy to fall off. Flexible memory is good.
Precision cast body: The valve body is precision cast, and the precise geometry allows the valve body to be sealed without any finishing.
Advantage closure valve seat <br> <br> a resilient, fluid resistance, small sealing surface by erosion and scour medium.
Second, opening and closing is more labor-saving.
Third, the flow of the medium is not restricted, does not disturb the flow, does not reduce the pressure.
Fourth, durable, easy to use.
5. Simple shape, short structure length, good manufacturing process and wide application range.
Resilient seated gate valve <br> <br> a disadvantage, can lead to erosion and abrasion between the sealing surface, maintenance is difficult.
Second, the external dimensions are large, opening requires a certain amount of space, and the opening and closing time is long.
Third, the structure is more complicated.
The types of gate valves can be divided into wedge gate gate valves and parallel gate gate valves according to the sealing surface configuration. The wedge gate valve can be further divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valves can be divided into single gate type and double gate type. According to the thread position of the valve stem, it can be divided into two types: open gate valve and dark gate valve.
Gate valve analysis and process flow
The opening and closing member of the gate valve is a gate. The direction of movement of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully open and fully closed, and cannot be adjusted and throttled. The direction of the gate of the gate valve is perpendicular to the direction of the fluid. The gate valve can only be fully open and fully closed, and cannot be adjusted and throttled. The gate has two sealing faces. The two sealing faces of the common mode gate valve of Zui form a wedge shape, and the wedge angle varies with the valve parameters. Gate valve drive mode classification: manual gate valve, pneumatic gate valve, electric gate valve. There are many different ways to classify gate valves. The main difference is that the sealing elements used are different in structure. According to the structure of the sealing elements, the gate valves are often divided into several different types, and the common form of zui is parallel gate valves and Tie gate valve; according to the structure of the valve stem, it can also be divided into open gate valve and dark rod gate valve.