A brief introduction to z40y-300lb U.S. standard gate valves

The opening and closing parts of the gate valve are the gate plate. The movement direction of the gate plate is perpendicular to the direction of the fluid. The gate plate has two sealing surfaces, the most commonly used two sealing surfaces of the gate valve are wedge-shaped and wedge-shaped angles vary with the valve parameters, usually 50

Z40y-300lb us standard gate valve details

The opening and closing parts of the gate valve are the gate plate. The movement direction of the gate plate is perpendicular to the direction of the fluid

American standard gate valve

Valves can only be fully opened and fully closed, not for regulation and throttling. Sealing face has two gate, two of the most commonly used mode gate valve sealing surface form a wedge, the wedge Angle vary with the valve parameters, usually in the form of 50, when the medium temperature is not high for 2 ° 52 '. Wedge gate valve gate plate can be made into a whole body, called rigid gate plate; It can also be made into a slightly deformed gate, called an elastic gate, to improve its technology and make up for the deviation of the sealing surface Angle during processing.

The types of gate valves can be divided into wedge gate valves and wedge gate valves according to the sealing surface configuration. Wedge gate valves can also be divided into single gate type, double gate type and elastic gate type. Parallel gate valves can be divided into single and double gate valves. According to the position of the screw thread of the stem, it can be divided into two types: open stem gate valve and dark stem gate valve.

Gate valve is closed, sealing surface can only rely on medium pressure to seal, that depend on medium pressure, the disc will be to the other side of the valve seat sealing surface pressure to ensure that the seal face seal, this is the seal. Most gate valves are hermetically sealed, that is, when the valve is closed, it must rely on external force to force the gate to the seat to ensure the sealing of the sealing surface.

The gate plate of a gate valve moves in a straight line along with the stem. Generally, there are trapezoid thread on the lifting rod. Through the nuts on the top of the valve and the guide groove on the valve body, the rotary motion is changed into linear motion, that is, the operating torque is changed into operating thrust.

When the valve is opened, the flow channel is completely unblocked when the height of the gate lift is equal to 1:1 of the valve size, but this position cannot be monitored during operation. In practical use, the top of the stem as the mark, that is, the position of the immovable valve, as its full open position. In order to take account of the temperature change, the lock occurs, usually at the opening to the peak position, and then back 1/2 to 1 lap, as the position of the full open valve. Therefore, the full open position of the valve shall be determined by the position of the gate (i.e. > stroke). Stainless steel gate valves, forged steel gate valve, flanged gate valve, flanged ball valve, two type ball valve gate valve, the valve stem nut in ram, the hand wheel rotate to drive the stem, and make the disc, the valve is called rotating lever gate or non-rising stem gate valves.

Advantage 1: gate valves have the following advantages:

The fluid resistance is small, and the sealing surface is less affected by the medium.

It's easier to open and close.

The flow direction of media is not limited, not disturbing the flow, not reducing pressure.

Simple shape, short structure length, good manufacturing technology, wide range of applications.

The disadvantages of gate valves are as follows:

Sealing surface between easy to cause erosion and abrasion, maintenance is difficult.

The appearance size is large, opening needs certain space, opening and closing time is long.

Types of latches

According to the sealing surface configuration, it can be divided into wedge gate valve and traveling gate valve, and wedge gate valve can be divided into single gate type, double gate type and elastic gate type. Parallel gate valves can be divided into single and double gate valves. According to the position of the screw thread of the stem, it can be divided into two types: open stem gate valve and dark stem gate valve.

The installation and maintenance of gate valves shall pay attention to the following matters:

Handwheel, handle and drive mechanism are not allowed to be hoisted, and collision is strictly prohibited.

Double gate gate valves shall be installed vertically (i.e. the stem is in a vertical position and the handwheel is at the top).

Gate valves with bypass valves should open bypass valves before opening (to balance pressure differential at inlet and outlet and reduce opening force).

Gate valves with drive mechanism shall be installed according to the specifications of the product operating instructions.

If valves are frequently switched on and off, lubricate at least once a month.

Structural characteristics of

On the market for a long time to use a common general valve leakage or rusty phenomenon, the company introduced the European high-tech rubber and valve manufacturing technology of elastic seat seal gate valves, overcome the general gate seal bad, rust and other defects, seal gate valves of the elastic base seat using elastic disc produce elastic deformation compensation effect to achieve good sealing effect, this valve has the switch light, reliable sealing, good elastic memory and service life etc. It can be widely used in water supply, sewage, construction, petroleum, chemical industry, food, medicine, light textile, electric power, ship, metallurgy, energy system and other body pipelines as regulating and intercepting devices.

Gate valves feature light weight: the body is made of high grade ductile black cast iron, the weight of which is about 20%~30% less than that of traditional gate valves, easy to install and maintain.

Flat type brake block: traditional gate often wash the tube in the water after the external objects such as stone, wood, cement, iron filings, sundry sedimentation on the bottom of the valve such as the slots, easy to cause cannot close tightly and form slack phenomenon, at the bottom of the seal of the elastic base seat gate valves with water pipe with flat design, not easy to cause debris deposition, make the flow unimpeded.

The overall plastic bags: ram is made of high quality rubber, outsourcing, the whole Europe first-class rubber vulcanization technology make the gate to ensure accurate after vulcanization of geometry size, and rubber and ductile cast gate, then fall off not easily and elastic memory preferred. water

Precision cast valve body: the valve body is precision cast, and the precise geometry allows the sealing of the valve body without any finishing.

Gate valves have the following advantages: 1. The fluid resistance is small, and the sealing surface is less washed and corroded by the medium.

2. It is easier to open and close.

3. The flow direction of the medium is not restricted, and it will not disturb the flow and reduce pressure.

4. Simple shape, short structure, good manufacturing technology and wide application.

Disadvantages of gate valve 1. It is easy to cause erosion and abrasion between sealing surface, and maintenance is difficult.

2. The external dimension is large, which requires a certain space to open and close for a long time.

3. Complex structure.

The type of gate width can be divided into wedge gate valve and wedge gate valve according to the sealing surface configuration. Wedge gate valve can also be divided into single gate type, double gate type and elastic gate type. Parallel gate valves can be divided into single and double gate valves. According to the position of the screw thread of the stem, it can be divided into two types: open stem gate valve and dark stem gate valve.

Installation and use of gate valves

1. Before installation, the valve cavity, sealing surface and other parts shall be inspected, and no dirt or sand particles shall be allowed to attach; 2. Bolts at all connection parts shall be uniformly tightened; 3. The packing part shall be compressed to ensure the sealing of the packing and the flexible opening of the gate; 4. Before installing the valve, the user must check the valve model, connect the size and pay attention to the flow direction of the medium to ensure the consistency with the valve requirements; 5. When installing the valve, the user must reserve the necessary space for valve drive; 6. The wiring of the driving device shall be carried out according to the circuit diagram; 7. Gate valves shall be maintained regularly and shall not collide or squeeze at will to avoid affecting the sealing.

Air tightness test 0.5-0.7

Working temperature

PTFE 150 ℃ or less PPL 300 ℃ or less carbon fiber 350 ℃ or less

Applicable medium

C: water, oil, steam P: nitrate class (the temperature of 200 ℃ or less) R: acetic acid class (temperature of 200 ℃ or less)

Design parameters:

Design and manufacture: GB/ t12237-89

Flange connection: JB/ t79-94, gb9113-2000

Structure length: gb12221-89

Nominal size: DN15~DN150mm

Nominal pressure: PN1.6, 2.5, 4.0MP.

Routine maintenance of gate valves

1. Gate valves with bypass valve should open bypass valve before opening (to balance pressure difference between inlet and outlet and reduce opening force).

2. The gate valve with drive mechanism shall be installed according to the specifications of the product operation manual.

3. If the valve is frequently switched on and off, lubricate at least once a month.