The body is the largest part of the valve. The body can Gate valves be connected to the process piping in three ways: flanges, threaded, or welding. The seating consists of two fixed surfaces or rings inside the body of the valve that the gate closes against to stop flow. The seating area falls into two categories: replaceable or fixed.
§2.3 Gate Valves
The typical gate valve consists of a gate, body, seating area, stem, bonnet, packing, stuffing box, packing gland, and hand wheel. The gates are sized to fit the inside diameter of a pipe.
Rising Stem and Nonrising Stem Q6
1.
Rising（RS，升杆式，即明杆）: the hand wheel （ ，升杆式， 明杆） countclockwise →open →stem (in the center of the hand wheel) rises. Look at →tell Nonrising （NRS，非升杆式，即暗杆） :a collar ，非升杆式， 暗杆） cannot look at →can not tell. Maintenance (HW)
Brass 黄铜
line 7
黄铜是铜与锌的合金。最简单的黄铜是铜—— 黄铜是铜与锌的合金。最简单的黄铜是铜—— 锌二元合金，称为简单黄铜或普通黄铜。 锌二元合金，称为简单黄铜或普通黄铜。改变黄 铜中锌的含量可以得到不同机械性能的黄铜。 铜中锌的含量可以得到不同机械性能的黄铜。黄 铜中锌的含量越高，其强度也较高，塑性稍低。 铜中锌的含量越高，其强度也较高，塑性稍低。 工业中采用的黄铜含锌量不超过45%， 工业中采用的黄铜含锌量不超过45%，含锌量再 高将会产生脆性，使合金性能变坏。 高将会产生脆性，使合金性能变坏。 Cast iron 铸铁（生铁） line 9 铸铁（生铁） cast steel
Common Gates: P26, Fig.2.3-2 Fig.2.3Key terms
spring line2 P26, Para4/this part 1. Solid wedge 整体楔形闸板→ should never 整体楔形闸板 闸板→ be overtightened； overtightened； 2. Solid split gate整体开口闸板→ high T； gate整体开口闸板→ 整体开口闸板 T； 3. Parallel discs平行闸板 →the higher the P, discs平行 平行闸板 the more tightly the disc fits into the seat.
Classification of Valves:
Process operators classify valves by:
Flow-control element Gate valve Globe valve Needle valve Plug valve function Cut-off valve Adjusting valve Check valve Three-way valve Safety valve Connecting manner Flange connection Threaded connection Clamp connection Welding connection Operating condition Hand-operating valve Electric-operated valve Pneumatic-operated valve
§2.4 Globe valves
Globe valves must be installed properly to work well. If the valves is installed backward it will tend to wear unevenly and push the flow-control element down.
Chapter 2 Valve
After study this chapter, the student will be able to: Explain the purpose of valves in industrial manufacturing. Identify the basic components of a gate valve. Identify the basic components of a globe valve. Explain the operation and design of a ball valve. Identify the basic components of a check valve. Describe the design and operation of a butterfly valve. Describe the design and operation of a plug valve. Describe the design and operation of a diaphragm valve. Describe the design and operation of a relief valve and safety valve. Describe the design and operation of a automatic valves.
Bridgewall Markings: some useful information specific to the valve.
§2.3 Gate Valves
Characteristics: most common tape;
A device that places a movable metal gate in the path of a process flow. Key terms diameter erosion inch line 6, P24 line 2, P25 line 9,P24
Characteristics:
Valves─are designed to withstand pressure, temperature, and flow and can be found in homes and industry across the world.
Para 2: The types of valves The common valves found in the manufacturing environment are:
3. Body → largest part. 4. Hand wheel → is attached to the valve stem; Turn clockwise → closes; Turn counterclockwise →opened.
Gate Valve Materials
corrosive= erosion line 3,P27 Bronze 青铜 （ line 6, P27） ） 青铜原指铜锡合金，因颜色呈青灰色， 青铜原指铜锡合金，因颜色呈青灰色， 铜锡合金 故称为青铜；但工业上都习惯称含铝、 故称为青铜；但工业上都习惯称含铝、硅、 锰等的铜基合金为青铜， 铅、铍、锰等的铜基合金为青铜，所以青铜 实际上包括有锡青铜、铝青铜、铍青铜等。 实际上包括有锡青铜、铝青铜、铍青铜等。 青铜也可分为压力加工青铜( 青铜也可分为压力加工青铜(以青铜加工产品 的形式供应)和铸造青铜两类。 的形式供应)和铸造青铜两类。
§2.2 Valve Applications and Theory of Operation
Para 1: valves’ importance (2nd sent.) Primary purpose：（P23，line 3） P23， 3）
Valve─ a device to direct and control the fluids by starting, stopping, and throttling (restricting) flow to make processing possible.
When the hand wheel is turned, it transmits rotational energy to the stem, causing it to rise to open or lower to close. The bonnet provides a housing for the gate or disc when it is lifted out of the process flow. It is attached to the body permanently by welding or temporarily by threading or bolts. The stem is a long, slender shaft attached to the gate, bushing, or wheel.
Yoke 机架 Bonnet 机罩
Very little restriction occurs when it is in the open position.
Size: from 0.125” to several feet. Path: from “wide open” to “completely shut”. Should not be used to throttle flow. The gate can be wedge shaped or may consist of parallel discs. The gate is placed directly in the path of a process flow when it is shut and is lifted completely out of the way when open.