Miyawaki REH20-M Direct Acting For Steam

Manufacturer: MIYAWAKI Inc.
Model: REH20-M

Features

Self-acting pressure reducing valve for steam

This valve reduces the steam supply pressure to a defined outlet pressure and keeps it steady, even under downstream fluctuations . The valves needs no seperate energy source.

Operating features of direct acting pressure reducing valves

Pressure changes on the downstream side are detected in the detection chamber, and the degree of opening of the valve is directly adjusted to keep the pressure on the downstream side at set pressure.

Wide range of pressure reduction

Due to carfefully selected springs an outstanding reduction ratio of 25:1 is achieved.

Diaphram free design

The valve operates with an O-ring sealing and a piston design. Due to this design, no daiphragm and no external sensing line is required.

Superb durability

Highly durable and carefully selected components, a 360° free rotating, conical plug and the lack of a sensitive diaphragm ensure outstanding lifetime of this valve.

Options available

– additional pressure gauges
– tailored connections for special applications
– softsealing for leakage class VI

Typical applications

Perfect for all applications with medium to high steam flow or high reduction. In particuliar power plants, chemical and petrochemical process applications, ships, food and beverage plants, and other similar installations of of compact steam equipment.

 

Dimensions/Weight

Size (DN)

Dimensions (mm) Kvs Value
L H h
15 210 410 82 1,8
20 230 66 3,2
25 230 66 5,0
32 260 81 7,9
40 260 83 13,0
50 300 586 100 20,0
65 340 615 113 34,0
80 380 733 140 51,0
100 430 762 154 80,0

Specifications

Body Material

Cast steel
G17CrMo 5-5
(1.7357)

Body design conditions
PN63 PN100
Max. design pressure (MPa)           PMA 6,3 10,0
Max. design temperature (℃)        TMA 530 530
Max. operating pressure (MPa)     PMO 5,7 8,4
Max. operating temperature (℃)  TMO 530 530
Pressure – Temperature rating
PN Temperture ℃
-10・・・+50 100 150 200 250 300 350 400 450 500 550
Pressure MPa
PN63 6,3 6,3 6,3 6,3 6,2 5,7 5,3 5,0 4,8 3,8 2,2
PN100 10,0 10,0 10,0 10,0 9,8 9,1 8,4 8,0 7,6 6,1 3,5
Secondary pressure ranges

Secondary pressure range

DN15-DN40 DN50 DN65 DN80 DN100 DN125-DN200
MPa Spring number per size
0,05-0,1 9 28 27 38 37 On request
0,1-0,16 8 27 26 37 36
0,16-0,25 7 26 25 36 35
0,25-0,4 6 25 24 35 34
0,4-0,63 5 24 23 34 33
0,63-1,0 4 23 22 33 32
1,0-1,6 3 22 21 32 32

Secondary pressure ranges higher than 1,6 MPa and lower than 0,05 MPa on request available.

Capacity Chart

Tables of calculation for steam
RE20 (REH20, REC20)
RE20L (REH20L, REC20L)

How to select the size of a PRV correctly?

Check the operating data:

  • Inlet pressure p₁
  • Requested downstream pressure p₂
  • Requested steam flow

Check the requested steam flow in the capacity chart on page 15. Select the necessary size of the PRV. Table 1 shows the maximum available steam flow in kg/h at a given inlet pressure, if the ratio between the requested downstream pressure p₂ and the inlet pressure p₁ is lower than 0.577 (critical flow). Pay attention that the steam pressure is shown as bar_abs!

If the ratio between the downstream pressure p₂ and the inlet pressure p₁ is larger than 0.577 (non-critical flow), the available steam flow amount on the downstream side will be reduced. To get the maximum available downstream flow amount, the maximum steam flow from Table 1 must be multiplied with the calculation factor A. To get the Factor A see the Diagram 1.

Check if the requested steam flow matches the downstream side using Table 2 (page 16) for flows under 40 m/s. Choose the size based on barg pressure. If downstream piping is 1–2 sizes larger than the PRV inlet, you’re good. If the size difference is over 2, increase the PRV size. Keep the difference within 2 sizes!

Example of calculation

Operating data:

  • p₁ = 9 barg = 10 bar_abs
    p₂ = 6 barg = 7 bar_abs
    Steam flow G = 1,100 kg/h
  • Search for the necessary size of the PRV in accordance with p₁.

  • Table 1 shows 1,312 kg/h for size DN40 (1½”).
  • bar_abs = 0.7 (i.e., larger than 0.577)
  • Factor A acc. to Diagram 1 = 0.96
  • Max. available steam flow G = 1,312 kg/h × 0.96 = 1,259 kg/h.

Steam flow in accordance with Table 2 at 6 barg = 1,720 kg/h for DN65.

Conclusion:
The PRV with an inlet size of DN40 and increase of the pipe size to DN65 at the downstream side will be suitable for a flow amount of 1,100 kg/h at the given pressures.

Capacity Chart
The Table 1 shows the maximum available steam flow amount of the pressure reducing valve at a given inlet pressure, if the ratio between the downstream pressure p₂ and the inlet pressure p₁ is lower than 0.577 (critical flow). Pay attention that the inlet steam pressure p₁ is shown as bar_abs.

Table 1

P1 Steam Flow per DN in kg/h
(bar abs) 15 20 25 32 40 50 65 80 100 125 150 200
1,1 21 38 59 94 154 238 405 607 952 1.545 2.14 3.81
1,2 23 41 64 101 167 257 437 655 1.028 1.67 2.313 4.112
1,3 25 44 70 110 181 279 474 711 1.116 1.813 2.511 4.464
1,4 27 48 75 119 195 300 510 765 1.2 1.951 2.702 4.803
1,5 29 51 80 127 208 320 545 818 1.283 2.085 2.887 5.133
1,6 30 54 85 135 222 342 581 871 1.366 2.22 3.074 5.466
1,7 32 58 91 143 236 363 617 926 1.452 2.36 3.267 5.808
1,8 34 61 95 151 248 382 649 973 1.526 2.48 3.434 6.105
1,9 36 64 101 159 262 402 684 1.026 1.61 2.616 3.622 6.438
2,0 38 68 106 167 275 424 720 1.081 1.695 2.755 3.814 6.781
2,2 42 74 116 184 302 465 790 1.185 1.859 3.021 4.183 7.437
2,4 45 81 126 200 329 506 860 1.289 2.022 3.286 4.55 8.09
2,6 49 87 136 215 354 545 926 1.389 2.179 3.541 4.903 8.717
2,8 52 92 144 227 373 575 977 1.465 2.298 3.735 5.171 9.194
3,0 56 101 157 248 409 629 1.069 1.603 2.514 4.086 5.657 10.058
3,5 65 116 182 287 472 727 1.236 1.854 2.908 4.726 6.543 11.632
4,0 75 133 207 328 539 830 1.411 2.116 3.319 5.394 7.468 13.277
4,5 84 149 232 367 604 929 1.58 2.369 3.717 6.04 8.367 14.867
5,0 93 165 258 408 671 1.032 1.755 2.632 4.129 6.709 9.29 16.515
5,5 99 176 274 433 714 1.097 1.865 2.798 4.389 7.132 9.875 17.555
6,0 111 197 308 486 800 1.23 2.092 3.138 4.922 7.998 11.074 19.686
6,5 119 213 332 525 864 1.329 2.259 3.388 5.315 8.637 11.959 21.261
7,0 129 229 358 565 930 1.431 2.433 3.649 5.724 9.302 12.879 22.896
7,5 138 245 382 604 994 1.529 2.599 3.899 6.116 9.939 13.761 24.464
8,0 146 260 407 643 1.058 1.628 2.767 4.15 6.51 10.579 14.648 26.042
8,5 155 277 432 683 1.124 1.729 2.94 4.409 6.917 11.24 15.563 27.667
9,0 164 292 456 720 1.185 1.823 3.098 4.648 7.29 11.847 16.403 29.162
9,5 173 307 480 759 1.249 1.921 3.266 4.899 7.684 12.487 17.289 30.736
10,0 182 323 505 798 1.312 2.019 3.433 5.149 8.077 13.125 18.173 32.307
10,5 191 339 530 837 1.378 2.12 3.604 5.406 8.48 13.78 19.08 33.92
11,0 200 355 555 877 1.443 2.22 3.774 5.661 8.88 14.43 19.98 35.52
12,0 218 387 605 956 1.573 2.42 4.115 6.172 9.682 15.733 21.784 38.726
13,0 235 417 652 1.03 1.695 2.608 4.434 6.651 10.433 16.953 23.474 41.731
14,0 252 449 701 1.108 1.822 2.804 4.766 7.15 11.215 18.225 25.234 44.861
15,0 270 481 751 1.187 1.954 3.006 5.11 7.665 12.023 19.538 27.052 48.093
16,0 288 513 801 1.266 2.083 3.204 5.447 8.17 12.816 20.826 28.836 51.264
17,0 306 545 850 1.343 2.21 3.4 5.78 8.671 13.601 22.101 30.602 54.403
18,0 324 575 899 1.42 2.336 3.595 6.111 9.166 14.378 23.365 32.351 57.514
19,0 342 607 949 1.499 2.466 3.795 6.451 9.676 15.178 24.665 34.151 60.714
20,0 357 635 993 1.568 2.581 3.971 6.75 10.126 15.883 25.81 35.737 63.533
21,0 376 669 1.046 1.653 2.719 4.184 7.112 10.669 16.735 27.195 37.654 66.941
23,0 413 735 1.148 1.814 2.985 4.592 7.807 11.71 18.369 29.849 41.33 73.475
25,0 449 798 1.247 1.969 3.241 4.986 8.476 12.714 19.944 32.409 44.874 79.776
27,0 484 861 1.346 2.126 3.498 5.382 9.149 13.724 21.528 34.983 48.438 86.112
29,0 520 924 1.444 2.282 3.755 5.777 9.82 14.73 23.106 37.548 51.989 92.426
30,0 538 957 1.496 2.363 3.889 5.983 10.17 15.256 23.93 38.887 53.843 95.722
33,0 590 1.05 1.64 2.592 4.265 6.561 11.153 16.73 26.243 42.645 59.047 104.973
Kvs 1,8 3,2 5,0 7,9 13 20 34 51 80 130 180 320

REH20-M

Capacity Chart
The Table 2 shows the maximum available downstream steam flow amount of the pressure reducing valve at the requested downstream pressure p₂. Pay attention that the steam pressure p₂ is shown as barg.

Table 2

P2 Steam Flow per DN in kg/h
p2 (barg) 15 20 25 32 40 50 65 80 100 125 150 200
0,1 16 29 45 73 115 179 303 460 715 1120 1610 2870
0,2 18 31 48 79 124 194 328 498 775 1215 1750 3110
0,3 19 34 52 85 134 209 353 535 835 1310 1880 3350
0,4 20 36 56 92 144 224 380 575 895 1405 2020 3590
0,5 22 39 60 99 154 239 405 615 955 1500 2170 3820
0,6 22 41 64 105 163 254 430 650 1015 1590 2290 4060
0,7 24 43 68 110 173 269 455 690 1075 1680 2420 4300
0,8 26 46 72 116 182 284 480 725 1135 1770 2550 4540
0,9 27 48 75 122 191 299 505 765 1195 1660 2680 4780
1,0 28 50 78 128 200 314 530 800 1250 1950 2820 5020
1,2 31 55 86 140 219 343 580 880 1360 2140 3080 5500
1,4 34 60 93 152 238 377 625 950 1480 2320 3350 5950
1,6 36 65 100 164 257 401 675 1025 1600 2500 3600 6420
1,8 39 69 107 176 275 430 725 1100 1720 2680 3850 6890
2,0 42 74 115 188 294 460 775 1180 1840 2870 4125 7360
2,5 48 84 132 217 338 530 890 1355 2120 3300 4750 8450
3,0 54 96 150 246 385 600 1010 1540 2400 3750 5400 9650
3,5 60 108 168 275 430 670 1130 1720 2680 4200 6050 10700
4,0 67 119 185 305 475 740 1250 1900 2960 4650 6650 11800
4,5 73 130 202 335 520 810 1370 2080 3240 5075 7300 13050
5,0 79 141 220 365 565 880 1490 2250 3520 5500 7900 14100
5,5 85 152 237 395 605 950 1600 2430 3800 5925 8500 15150
6,0 92 163 254 420 655 1020 1720 2610 4080 6350 9125 16300
6,5 98 174 271 445 695 1085 1840 2790 4360 6775 9750 17400
7,0 104 185 288 475 740 1160 1960 2970 4640 7200 10375 18500
7,5 110 196 305 500 785 1220 2070 3140 4900 7650 11000 19600
8,0 117 207 323 530 830 1290 2180 3320 5180 8100 11625 20700
8,5 123 218 341 560 875 1365 2300 3500 5450 8550 12250 21800
9,0 129 229 358 585 915 1430 2410 3670 5720 8975 12875 22900
9,5 135 240 375 615 960 1500 2530 3840 6000 9400 13500 24000
10,0 141 252 392 645 1000 1570 2650 4020 6270 9825 14125 25100
11,0 154 273 427 700 1090 1710 2880 4380 6800 10700 15300 27300
12,0 166 294 461 750 1180 1840 3100 4730 7300 11550 16500 29400
13,0 178 316 495 810 1270 1980 3340 5080 7850 12400 17750 31600
14,0 190 338 530 870 1355 2120 3570 5400 8400 13200 19000 33800
15,0 202 360 565 925 1440 2250 3800 5750 8950 14100 20300 36000
16,0 215 382 600 980 1530 2390 4030 6100 9550 15000 21600 38200
17,0 227 404 630 1020 1620 2530 4270 6450 10100 15900 22800 40400
18,0 240 427 665 1090 1710 2670 4500 6800 10650 16750 24000 42600
19,0 252 450 700 1145 1790 2800 4740 7150 11200 17600 25200 44800
20,0 263 473 730 1200 1870 2930 4950 7500 11750 18400 26500 47000
22,0 288 510 800 1310 2050 3200 5400 8200 12800 20000 28800 51000
24,0 312 555 870 1420 2220 3470 5850 8900 13900 21700 31200 55200
26,0 337 600 940 1530 2400 3750 6300 9600 15000 23400 33700 60400
28,0 362 645 1010 1650 2580 4020 6800 10300 16100 25100 36200 64600
30,0 387 690 1080 1770 2750 4300 7250 11000 17200 26900 38700 68800
32,0 413 735 1150 1890 2950 4600 7750 11800 18300 28800 41300 73500

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