Polycold Cryochiller
Appendices
Installation and Operation Manual
Appendix E: Water Vapor Cryotrapping
Brooks Automation
214072 Revision B
12-9
The average cryosurface temperature is a convenient number to use when there is a temperature gra-
dient between the coil inlet and coil outlet temperatures. The average cryosurface temperature is simply
the average of the coil inlet and coil outlet temperatures. In non-cryopumping applications, such as
those used for heat removal, it is the coil outlet temperature that is most important.
Table 12-1: Cryosurface Temperature needed for desire Water Vapor Partial Pressure
Desired Water
Vapor Partial
Pressure
Cryosurface Temperature Needed, °C
torr
mbar
98%
95%
90%
80%
60%
20%
0%
5.0E+00 6.7E+00 -40.8
-32.3
-25.4
-18.2
-10.5
-2.3
1.0
2.0E+00 2.7E+00 -48.7
-40.8
-34.4
-27.7
-20.6
-13.0
-9.7
1.0E+00
1.3E+00
-54.3
-46.8
-40.8
-34.4
-27.7
-20.6
-17.3
5.0E-01
6.7E-01
-59.7
-52.6
-46.8
-40.8
-34.4
-27.7
-24.5
2.0E-01
2.7E-01
-66.4
-59.7
-54.3
-48.7
-42.8
-36.5
-33.4
1.0E-01
1.3E-01
-71.2
-64.8
-59.7
-54.3
-48.7
-42.8
-39.7
5.0E-02
6.7E-02
-75.8
-69.7
-64.8
-59.7
-54.3
-48.7
-45.6
2.0E-02
2.7E-02
-81.5
-75.8
-71.2
-66.4
-61.4
-56.1
-53.1
1.0E-02
1.3E-02
-85.6
-80.1
-75.8
-71.2
-66.4
-61.4
-58.4
5.0E-03
6.7E-03
-89.6
-84.3
-80.1
-75.8
-71.2
-66.4
-63.5
2.0E-03
2.7E-03
-94.6
-89.6
-85.6
-81.5
-77.2
-72.7
-69.9
1.0E-03
1.3E-03
-98.2
-93.4
-89.6
-85.6
-81.5
-77.2
-74.4
5.0E-04
6.7E-04
-101.6
-97.0
-93.4
-89.6
-85.6
-81.5
-78.8
2.0E-04
2.7E-04
-106.0
-101.6
-98.2
-94.6
-90.8
-86.9
-84.3
1.0E-04
1.3E-04
-109.1
-104.9
-101.6
-98.2
-94.6
-90.8
-88.2
5.0E-05
6.7E-05
-112.2
-108.1
-104.9
-101.6
-98.2
-94.6
-92.0
2.0E-05
2.7E-05
-116.0
-112.2
-109.1
-106.0
-102.7
-99.3
-96.8
1.0E-05
1.3E-05
-118.8
-115.1
-112.2
-109.1
-106.0
-102.7
-100.3
5.0E-06
6.7E-06
-121.5
-117.9
-115.1
-112.2
-109.1
-106.0
-103.6
2.0E-06
2.7E-06
-125.0
-121.5
-118.8
-116.0
-113.1
-110.1
-107.8
1.0E-06
1.3E-06
-127.5
-124.1
-121.5
-118.8
-116.0
-113.1
-110.8
5.0E-07
6.7E-07
-129.9
-126.7
-124.1
-121.5
-118.8
-116.0
-113.8
2.0E-07
2.7E-07
-132.9
-129.9
-127.5
-125.0
-122.4
-119.7
-117.5
1.0E-07
1.3E-07
-135.2
-132.2
-129.9
-127.5
-125.0
-122.4
-120.2
5.0E-08
6.7E-08
-137.3
-134.5
-132.2
-129.9
-127.5
-125.0
-122.8
2.0E-08
2.7E-08
-140.1
-137.3
-135.2
-132.9
-130.6
-128.2
-126.2
1.0E-08
1.3E-08
-142.1
-139.5
-137.3
-135.2
-132.9
-130.6
-128.6
5.0E-09
6.7E-09
-144.1
-141.5
-139.5
-137.3
-135.2
-132.9
-131.0
2.0E-09
2.7E-09
-146.6
-144.1
-142.1
-140.1
-138.0
-135.9
-133.9
1.0E-09
1.3E-09
-148.4
-146.0
-144.1
-142.1
-140.1
-138.0
-136.1
