DIN standard gate valve

Gate valves consists of three main parts.. body, bonnet, and trim. The body is generally connected to other equipment by means of flanged, screwed or welded connections. The bonnet, which containing the moving parts, is attached to the body, usually with bolts, to permit maintenance. The valve trim consists of the stem, the gate, the disc or wedge and the seat rings.

Disks of a Gate valve

Gate valves are available with different disks or wedges. Ranging of the Gate valves is usually made by the type of wedge used.

The most common were..

• Solid wedge is the most commonly used disk by its simplicity and strength.
  A valve with this type of wedge can be installed in each position and it is suitable for almost all liquids. The solid wedge is a single-piece solid construction, and is practically for turbulent flow.
• Flexible wedge is a one-piece disc with a cut around the perimeter to improve the ability to correct mistakes or changes in the angle between the seats.
  The reduction will vary in size, shape and depth. A shallow, narrow cut gives little flexibility but retains strength.
  A deeper and wider cut, or cast-in recess, leaves little material in the middle, which allows more flexibility, but compromises strength.
• Split wedge is self-adjusting and selfaligning to both seats sides. This wedge type consists of two-piece construction which seats between the tapered seats in the valve body. This type of wedge is suitable for the treatment of non-condensing gases and liquids at normal temperatures, particularly corrosive liquids.
• Stem of a Gate valve

• The stem, which connects the handwheel and disk with each other, is responsible for the proper positioning of the disk. Stems are usually forged, and connected to the disk by threaded or other techniques. To prevent leakage, in the area of the seal, a fine surface finish of the stem is necessary.

  Gate valves are classified as either..

  • Rising Stem
  • Non Rising Stem

  For a valve of the Rising Stem type, the stem will rise above the handwheel if the valve is opened. This happens, because the stem is threaded and mated with the bushing threads of a Yoke. A Yoke is an integral part from a Rising Stem valve and is mounted to the Bonnet.

  For a valve of the non Rising Stem type, there is no upward stem movement if the valve is opened. The stem is threaded into the disk. As the handwheel on the stem is rotated, the disk travels up or down the stem on the threads while the stem remains vertically stationary.

  Below you will find links to detailed (large) images of both stem types.

  Seats of a Gate valve

  Seats for Gate valves are either provided integral with the valve body or in a seat ring type of construction. Seat ring construction provides seats which are either threaded into position or are pressed into position and seal welded to the valve body. The latter form of construction is recommended for higher temperature service.

  Integral seats provide a seat of the same material of construction as the valve body while the pressed-in or threaded-in seats permit variation. Rings with hard facings may be supplied for the application where they are required.

  
  
  

  Advantages and Disadvantages of Gate valves

  Advantages..

  • Good shutoff features
  • Gate valves are bidirectional and therefore they can be used in two directions
  • Pressure loss through the valve is minimal

  Disadvantages..

  • They can not be quickly opened or closed
  • Gate valves are not suitable for regulate or throttle flow
  • They are sensitive to vibration in the open state
  • 
    

  Main Connection Dimensions
  型号 Type		公 称 通 径 DM(mm)		Dimension(mm)
  				L		D		D1		D2		b-f		Z-Φd		H	D0
  Z41W-16 Z541W-16 Z941W-16		15		130		100		65		45		14-2		4-Φ14		185	120
  		20		150		110		75		55		14-2		4-Φ14		200	120
  		25		160		120		85		65		14-2		4-Φ14		225	140
  		32		180		140		100		78		16-2		4-Φ18		275	160
  		40		200		150		110		85		16-3		4-Φ18		295	200
  		50		250		165		125		100		16-3		4-Φ18		350	220
  		65		265		185		145		120		18-3		4-Φ18		370	240
  		80		280		200		160		135		20-3		8-Φ18		390	280
  		100		300		220		180		155		20-3		8-Φ18		435	300
  		125		325		250		210		185		22-3		8-Φ18		520	320
  		150		350		285		240		210		24-3		8-Φ23		610	350
  		200		400		340		295		265		26-3		12-Φ23		785	400
  		250		450		405		355		320		30-3		12-Φ25		930	450
  		300		500		460		410		375		30-4		12-Φ25		1080	500
  		350		550		520		470		435		34-3		16-Φ25		1200	550
  		400		600		580		525		485		36-4		16-Φ30		1400	600
  		450		650		640		585		545		40-4		20-Φ30		1500	650
  		500		700		715		650		608		44-4		20-Φ34		1630	700
  		600		800		840		770		718		48-5		20-Φ41		1830	750
  		700		900		910		840		788		50-5		24-Φ41		1930	800
  		800		1000		1020		950		898		52-5		24-Φ41		2030	850
  		900		1100		1120		1050		998		54-5		28-Φ41		2130	900
  		1000		1200		1255		1070		1110		56-5		28-Φ48		2230	950