pneumatic diaphragm double seat control valve
technical parameter
product model: zman, zjhn
nominal diameter: dn25~300mm
pressure range: pn1.6~6.4mpa
temperature range: -40℃~ 450℃
flange size: gb/t9113.2-2000
body form: double-seat straight-through
valve material: wcbzg230-450, zg1cr18ni9ti
spool material: 1cr18ni9ti (304) or stellite alloy surfacing
sealing packing: v-type ptfe (f4), flexible graphite, stainless steel bellows
product overview
the dynamic diaphragm double-seat control valve is composed of a multi-spring pneumatic diaphragm actuator and a straight-through double-guided double-seat valve. it has the characteristics of compact structure, light weight, sensitive action, small pressure drop loss, large valve capacity and accurate flow characteristics. compressed air drives the valve stem and valve core to control and adjust the flow medium, which can realize the automatic adjustment and control of the fluid medium in the process pipeline. widely used in petroleum, chemical, pharmaceutical, metallurgy, power station and other industrial control fields, mainly controlling gas, liquid, steam and other media.
structural features
1. pneumatic film actuator is used to configure the positioner to achieve precise adjustment and control of the process parameters of the fluid medium;
2. positive action of the actuator: air-closed-normally open type (the valve position moves downward when the signal pressure increases), "type b";
3. actuator reaction: air open type - normally closed type (when the signal pressure increases, the valve position moves upward), "k type";
4. double-seat plunger valve core is suitable for medium with large pressure difference, large flow and not very clean and occasions where leakage requirements are not strict.
the main technical parameters
| nominal diameter (dn) | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | |
| seat diameter (dn) | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | |
| rated flow coefficient (kv) | straight line | 12.5 | 19.5 | 30.5 | 48.4 | 76 | 125 | 195 | 305 | 484 | 760 | 1000 | 1600 |
| equal percentage | 11 | 17,6 | 27.5 | 44 | 69 | 110 | 176 | 275 | 440 | 690 | 900 | 1300 | |
| allowable differential pressure (mpa) | ≤ nominal pressure | ||||||||||||
| nominal pressure (mpa) | 1.6、2.5、4.0、6.4、10.0 | ||||||||||||
| rated stroke (mm) | 16 | 25 | 40 | 60 | 100 | ||||||||
| equipped with actuator model | zha/b-22 | zha/b-23 | zha/b-34 | zha/b-45 | zha/b-56 | ||||||||
| bonnet form | standard type (-17～ 250℃), high temperature type ( 250～ 450℃), low temperature type (-40～-196℃), bellows seal type (-40～ 350℃) | ||||||||||||
| gland form | bolt compression | ||||||||||||
| seal packing | v-type ptfe packing, v-type flexible graphite packing | ||||||||||||
| spool form | double seat plunger guided spool | ||||||||||||
| flow characteristics | linearity, equal percentage | ||||||||||||
actuator technical parameters
| configure actuator class | zha/b multi-spring diaphragm actuator | ||||
| actuator model | zha/b-22 | zha/b-23 | zha/b-34 | zha/b-45 | zha/b-56 |
| effective area(cm2) | 350 | 350 | 560 | 900 | 1400 |
| stroke(mm) | 10、16 | 24 | 40 | 40、60 | 100 |
| spring range (kpa) | 20～100 (standard), 20-60, 60-100, 40-200, 80-240 | ||||
| diaphragm material | nitrile rubber with nylon cloth, ethylene propylene rubber with nylon cloth | ||||
| air supply pressure | 140～400kpa | ||||
| air supply interface | rc1/4" | ||||
| ambient temperature | -30～ 70℃ | ||||
| accessories available | positioner, air filter pressure reducer, position retaining valve, travel switch, valve position transmitter, hand wheel mechanism, etc. | ||||
| form of action | air-to-close (b)—valve open (fo) when gas is lost; air-to-open (k)—valve to be closed when gas is lost (fc) | ||||
material of main parts
| 1 | base | wcb | 304 | 316 | 316l |
| 2 | body | wcb | 304 | 316 | 316l |
| 3 | spool | 304 | 304 | 316 | 316l |
| 4 | seat | 304 | 304 | 316 | 316l |
| 5 | copper sets | brass | |||
| 6 | guide sleeve | 304 | 304 | 316 | 316l |
| 7 | gasket | ptfe\graphite gasket | ptfe\graphite gasket | ptfe\graphite gasket | ptfe\graphite gasket |
| 8 | bonnet | wcb | 304 | 316 | 316l |
| 9 | stem | 304 | 304 | 316 | 316l |
| 10 | packing | ptfe/graphite | ptfe/graphite | ptfe/graphite | ptfe/graphite |
| 11 | packing gland | wcb | 304 | 316 | 316l |
| 12 | bolt | 25 | 0cr18ni9ti | 1cr18ni9ti | 1cr18ni9ti |
main performance indicators
| project | without locator | with locator | ||
| basic error % | ±5.0 | ±1.0 | ||
| return difference % | 3.0 | 1.0 | ||
| dead zone% | 3.0 | 0.4 | ||
| always point deviation % | open air | starting | ±2.5 | ±1.0 |
| starting | ±5.0 | ±1.0 | ||
| air pass | starting | ±5.0 | ±1.0 | |
| end | ±2.5 | ±1.0 | ||
| rated stroke deviation% | ≤2.5 | |||
| leakage l/h | 0.01%×valve rated capacity | |||
| adjustable range r | 30：1 | |||
main connection size
nominal diameter dn(mm) | 25 | 32 | 40 | 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | |
| l | pn16/25 | 185 | 200 | 220 | 250 | 275 | 300 | 350 | 410 | 450 | 550 | 670 | 770 |
| pn40 | 190 | 210 | 230 | 255 | 285 | 310 | 355 | 425 | 460 | 560 | 740 | 805 | |
| pn64 | 200 | 210 | 235 | 265 | 295 | 320 | 370 | 440 | 475 | 570 | 750 | 820 | |
| h | pn16/25 | 117 | 120 | 139 | 144 | 188 | 208 | 220 | 268 | 278 | 320 | 441 | 503 |
| pn40 | 124 | 128 | 145 | 150 | 195 | 220 | 230 | 280 | 290 | 335 | 465 | 528 | |
| pn64 | 130 | 135 | 155 | 170 | 205 | 240 | 255 | 295 | 310 | 360 | 480 | 550 | |
| h1 | 165 | 185 | 185 | 205 | 245 | 255 | 270 | 335 | 365 | 430 | 560 | 680 | |
| h2 | 298 | 298 | 298 | 298 | 380 | 380 | 380 | 510 | 510 | 510 | 650 | 650 | |
| h3 | 177 | 177 | 177 | 177 | 182 | 182 | 182 | 182 | 182 | 218 | 218 | 218 | |
| l1 | 280 | 280 | 280 | 280 | 350 | 350 | 350 | 475 | 475 | 475 | 560 | 560 | |
| a | 282 | 282 | 282 | 282 | 360 | 360 | 360 | 470 | 470 | 470 | 580 | 580 | |
| d | 220 | 220 | 220 | 220 | 270 | 270 | 270 | 320 | 320 | 320 | 400 | 400 | |