D-Pro Check Valves
V33, VP33, VA33, VH36 and VL36 Series
VCH36 Series CNG check valves
Fixed and Adjustable cracking pressure
Pressures up to 3000 psig (206 bar) and 6000 psig (413 bar)

Catalog No V336-7
March 2009

Features
Fixed and adjustable cracking pressure.
Reliable DK-LOK Tube Fitting, NPT and ISO pipe end connections.
Stainless and Brass material construction.

Technical Information
VP33 Series

VA33 Series

VA33A and VP33B

VA33A and VA33B

VH36A and VH36B

VH36C

SS316: 2000 psig (137 bar)SS316 & Brass
Brass: 1500 psig (103 bar) 3000 psi (206 bar)SS316 & Brass
3000 psi (206 bar)

SS316
6000 psi (413 bar)

SS316
5000 psi (344 bar)

V33 Series

VH36 Series

Valve Series
V33A, V33B, V33C and V33D
Maximum Operating
Pressure @21 (70 )SS316 & Brass
3000 psi (206 bar)

V33E and V33F

OperatingTemperature Ratings

FKM O-ring: - 18 F to 400 F (- 28 C to 204 C)
NBR O-ring: - 4 F to 221 F ( -20 C to 105 C)

Cracking Pressure

Refer to spring table of each valve sereis

Cracking, Reseal and Back Pressure @ 70

(21 )Cracking Pressure : Valve poppet is actuated when the pressure difference between the inlet and the outlet reaches the range of cracking pressure.
Reseal Pressure : Valves that have higher cracking pressure can be resealed to bubble-tight by the spring force. The reseal pressure is the pressure at thesame flow direction, but lower than the cracking pressure.
Back Pressure : Valves that have cracking pressure of 5 psig (0.34 bar) and lower may not be able to return to the bubble-tight seal. This may require backpressure to press the seal to form a bubble-tight contact in addition to the spring force.

Class Ratings
Ratings are based on FKM O-rings of SS316 valves and NBR O-rings of Brass valves
Valve Series

V33A, V33B, V33C, V33D,
VA33A, VA33B, VP33A, and VP33B Series

V33E and V33F Series

SS316 VH36A, VH36B, and VH36C Series

Working Pressure, psig (bar)Temperature-18 to 100 F (-28 to 38 C)

SS316

Brass

SS316

Brass

VH36A & VH36B

VH36C

3000 (206)3000 (206)2000 (137)1500 (103)6000 (413)5000 (344)200 F (93 C)

2575 (177)2600 (179)1715 (118)1300 (89)5160 (355)4290 (295)225 F (175 C)

2510 (172)2500 (172)1670 (115)1250 (86)5030 (346)4180 (288)250 F (121 C)

2450 (168)1630 (112)4910 (338)4080 (281)300 F (148 C)

2325 (160)

1545 (106)4660 (321)3875 (267)350 F (176 C)

2255 (155)

1490( 102)4470( 308)

3720 (256)375 F (190 C)

2185( 150)

1450( 99)4375( 301)

3640( 250)

4280( 294)

3560( 245)

400 F (204 C)

Operation
When the valve is not actuated for a period of time, it may require a higher cracking pressure than
the set cracking pressure.
D-Pro check valves prevent reverse flow in circuits. Do not use them as relief valves.
D-Pro check valves are designed to prevent loss of media caused by failed connections and foruni-directional flow control of fluids in chemical processing, power generation, oil and gas industries.

V33 series
Working pressure up to 3000 psig (206 bar)
Model Shown:
V33 Series Check Valves
V33C-D-8T-10-S
V33C-F-6N-EP-1/3-S

Valve Cleaning and Factory Test
Every valve is cleaned, and packed in accordance with Dk Tech cleaning standard DC-01.
Every valve is factory tested for cracking and reseals performance.

THE POWER
OF RELIABILITYDK TECH CORPORATION
www.dklok.com

Check Valves
D-Pro V33 Series Poppet Check Valves
Feature: Working pressure up to 3000 psig (206 bar)

Materials of Construction
Valve Body Materials

Component
1. Body
2. Connector
3. Poppet
4. O-ring*
5. Spring
6. O-ring seal

Material Grade/ASTM
SS316/A276, A479

Brass 360
/B16

FKM, optional EPDM, Kalrez.
SS302/A313
FKM, optional EPDM, Kalrez.

NBR
SS302/A313
NBR

Wetted parts are listed in blue.
*4. O-ring is secured in V33E, V33F series.
Lubrication:lSilicon-based Lubricant for Poppet
lMolybdenum Dry Film Lubricant for SS316 Body Threads

V33 Series Ordering Information and Dimensions
Basic Ordering
Number

V33A-

V33B-

V33C-

V33D-

V33E-

V33F-

Inlet

D-2TM-2NF-2ND-4TD-6MMD-4N4TM-4NF-4ND-6TD-10MM-6NF-6ND-8TD-12MM-8NF-8ND-10TD-12TM-12NF-12ND-16TM-16NF-16N-

End Connections
OutletOrifice
mm (in.)Cv

Dimensions
H-Hex

h-Hex

0.16

1/8 in. Dk-Lok
1/8 in. Male NPT
1/8 in. Female NPT
1/4 in. Dk-Lok
6 mm Dk-Lok
1/4 in. Dk-Lok
1/4 in. Male NPT

4.8(0.19)

1/4 in. Male NPT
1/4 in. Female NPT
3/8 in. Dk-Lok
10 mm Dk-Lok
3/8 in. Male NPT
3/8 in. Female NPT
1/2 in. Dk-Lok
12 mm Dk-Lok
1/2 in. Male NPT
1/2 in. Female NPT
5/8 in. Dk-Lok
3/4 in. Dk-Lok
3/4 in. Male NPT
3/4 in. Female NPT
1 in. Dk-Lok
1 in. Male NPT
1 in. Female NPT

7.1(0.28)

10.0(0.39)

19.05 (3/4)

1.48

22.22 (7/8)

1.7

13.5
(0.53)

2.6

28.58 (1-1/8)

16.0(0.63)

5.2

31.75 (1-1/4)

18.0(0.71)

11.11 (7/16)
14.29 (9/16)
14.00
14.29 (9/16)
17.46 (11/16)
19.00
22.22 (7/8)
22.00
25.40 (1)28.58(1-1/8)
38.1 (1-1/2)-

15.88 (5/8)

0.4734.93 (1-3/8)

8.0mm (inch)L

41.28 (1-5/8)

l55.60 (2.19)
44.40 (1.75)
46.50 (1.83)

25.00 (0.98)-

60.00 (2.36)

25.00 (0.98)

56.40 (2.22)
53.40 (2.10)
56.80 (2.24)-

65.50 (2.58)

27.10 (1.07)

55.50 (2.19)
63.80 (2.51)
80.20 (3.16)
74.40 (2.93)
84.70 (3.33)
91.80 (3.61)
110.70 (4.35)
105.30 (4.15)
103.00 (4.06)
121.10 (4.77)
116.20 (4.57)
111.40 (4.39)

36.20 (1.43)
48.10 (1.89)
67.00 (2.64)
68.40 (2.69)

All dimensions shown are for reference only and subject to change. Dimensions with DK-LOK are in finger-tight position.

Table 1. Spring Cracking, Reseal and Back Pressure @ 70
Spring Nominal
Cracking Pressure Designator(21 )ResealPressures

Cracking Pressure Ranges
Min. Pressure

Max. Pressure

psi
1/3

bar
0.02

psig
0

bar
0

psig
3

bar
0.21

psig
Up to 6

1

0.07

0

0

4

0.28

Up to 5bar
0.41
Back Pressure
0.34
Back Pressure

3

0.21

2

0.14

7

0.48

0.28

Up to 4
Back Pressure

10
25
50
75
100

2

0.69
1.72
3.45
5.17
6.89

7
20
40
60
80

0.48
1.38
2.76
4.14
5.51

Copyright 2001-2009. DK Tech Corporation. All rights reserved.

15
30
60
90
120

1.03
2.07
4.14
6.20
8.27

3
17
35
53
70

0.21
1.17
2.41
3.65
4.82

Check Valves
D-Pro VP33 Series 1-Piece Check Valves
Features:O-ring seal blow-out proof design
One piece body construction.
Working pressure up to 3000 psig (206 bar)

Materials of Construction
Valve Body Materials

Component

Material Grade/ASTM

1. Body
2. Poppet
3. O-ring Holder
4. Locking Screw
5. O-ring
6. Spring
Wetted parts are listed in blue.

SS316/A276, A479

Brass 360
/B16

FKM, optional EPDM, Kalrez
SS302/A313

NBR
SS302/A313

Lubrication:
Silicon-based Lubricant on Poppet
Molybdenum Dry Film Lubricant on SS316 Locking Screw.

VP33 Series Ordering Information and Dimensions
End Connections
Inlet
OutletBasic Ordering
Number

VP33A-VP33B-

M-4NM-4RF-4NF-4RMF-4NFM-4NM-8NF-8NMF-8N-

Cv

1/4 in. Male NPT
1/4 in. ISO Male Tapered
1/4 in. Female NPT
1/4 in. ISO Female Tapered
1/4 in. Male NPT
1/4 in. Female NPT
1/4 in. Female NPT
1/4 in. Male NPT
1/2 in. Male NPT
1/2 in. Female NPT
1/2 in. Male NPT
1/2 in. Male NPT

Dimensions

mm (inch)

LHex.

41 (1.62)

14.28 (9/16)

61 (2.41)
64 (2.54)
44 (1.75)
58 (2.28)
58 (2.28)
94 (3.71)
72 (2.83)

0.35

1.20

19.05 (3/4)

22.22 (7/8)
26.98 (1-1/16)

All dimensions shown are for reference only and subject to change.

Table 2. Spring Cracking, Reseal and Back Pressure @ 70

Psi
1/3

bar
0.02

(21 )

Cracking Pressure Ranges

Spring Nominal
Cracking Pressure Designator
Psig
0

ResealPressures

Max. Pressure

Min. Pressure
bar
0

Psig

bar

3

0.21

Psig

bar

Up to 6

0.41
Back Pressure

Up to 5

0.34

0

0

4

0.28

0.69

7

0.48

15

1.03

3

0.21

1.72

20

1.38

30

2.07

17

1.17

1

0.07

10
25

Back Pressure

VA33 Series Adjustable Check Valves
Features
Working pressure up to 3000 psig (206 bar)
Cracking pressure adjustable from 3 to 600 psig (0.2 to 41.3 bar)

Materials of Construction
Component
1. Body
2. Poppet
3. Insert locking screw
4. Insert
5. Adjustable screw
6. Locking screw
7. Spring
8. O-ring

Valve Body Materials
Material Grade/ASTM

SS316/A276, A479

Brass
360 / B16

SS302/A313
FKM, optional
EPDM, Kalrez

NBR

Wetted parts are listed in blue.
Lubrication:
Silicon-based Lubricant on Poppet
Molybdenum Dry Film Lubricant on SS316 Locking Screw andInsert Locking Screw.

3

Check Valves
VA33 Series Ordering Information and Dimensions
Basic Ordering Number

Table 3. Spring Cracking Pressure Range Desingntor
L

Cv

End Connections

Cracking Pressure Range@21 C (70 F)
psig
Bar

Hex

mm

inch

75.7

2.98

3/4

41.1

1.62

9/16

3 to 50

0.2 to 3.4

3

41.1

1.62

9/16

50 to 150

3.4 to 10.350

150 to 350
65.0
2.56
1/2 in. Male NPT
7/8
1.2
350 to 600
M-8R65.0
2.56
7/8
1/2 in. ISO Male Tappered
All dimensions shown are for reference only and subject to change. Dimensions with DK-LOK are in finger-tight position.

10.3 to 24.1

150

24.1 to 41.3

350

F-4NVA33A-

1/4 in. Female NPT
0.35

M-4N-

1/4 in. Male NPT

M-4R-

1/4 in. ISO Male Tappered

M-8N-

VA33B-

Designator

How to Order
To complete ordering number, add adjustable spring designator to the basic ordering number and then specify valve material designator.
Body material designators: S for SS316, B for Brass. Example: VA33A-F-4N-3-S

How to adjust cracking pressure
Step 1

Step 2Adjustable screw

Adjustable screw
Locking screw

INLET

Allen key

OUTLET

OUTLET

VH36 Series High Pressure Check Valves
VCH36 Series CNG Check Valves

3

5

OUTLET

1. Gently slide the allen key up to adjustable screw position.
2. Adjust cracking pressure.
lTo increase cracking pressure, turn adjustable screw clockwise.
lTo decrease cracking pressure, turn adjustable screw counter-clockwise.

Sllghtly unscrew the locking screw
counter-clockwise.

4

Locking screw

INLET

INLET

Locking screw

1

Step 3

6

7

8

2

9

1. Move out the allen key up to the locking screw position.
2. To lock out the locking screw, turn the allen key clockwise.

Features
High pressure 6000 psig (413 bar)
Seal blow-out proof design with thebonded seal on poppet.

Models Shown:
VH36B-D-8T-5-S
VH36C-F-12N-KZ-5-S

Materials of Construction

10 11

Valve Body Materials

Component

Material Grade/ASTM

1. Body
INLET

4. Poppet with bonded seal
H

h

L1

SS316 /A479, A276

2. Connector
3. Poppet stop

OUTLET

5. Spring
6. Indicator ring*
7. O-ring
8. Backup ringL

Poppet: SS316 /A479, A276
Bonded Seal: FKM, optional EPDMHNBR standard for VCH36 series.
SS302 /A313
SS316 /A276
FKM. HNBR standard for VCH36 series.
PTFE /D1710

9. 10. 11. Dk-Lok Front, BackFerrule and Nut

SS316 /A479, A276

Wetted parts are listed in blue.
*Indicator ring bears the information of spring designator.

11

10

4

1

9

3 7

8

5

2

6

9 10

Table 4. Spring Cracking, Reseal and Back Pressure @ 70
Spring Nominal
Cracking Pressure Ranges
Cracking Pressure
Min. Pressure Max. Pressure
Designator

4

Psi

bar

psig

bar

Psig

bar

1/3

0.02

0

0

3

0.21

1

0.07

0

0

4

0.28

5

0.34

3

0.21

9

0.62

10
25

0.69
1.72

7
20

0.48
1.38

15
30

1.03
2.07

Lubrication:
Silicon-based Lubricant on Poppet
Molybdenum Dry Film Lubricant on SS316 Connector threads

11

(21

ResealPressure
bar
psig
0.41
Up to 6
Back Pressure
0.34
Up to 5Back Pressure
0.14
Up to 2
Back Pressure
0.21
3
1.17
17

)

ECE R110 Check valves
Classification: Class 0
Service Pressure: 200 bar (2900 psig)
Working Pressure: 260 bar (3770 psig)
Temperature: -40 to 105 C (-40 to 221 F)

VCH36 series CNG check valves
VCH36 series high pressure check valve with CNG compatible HNBR O-ring areavailable for CNG application.
End Connections:
Dk-Lok tube port 6 to 25mm OD (1/4 to 1 in. OD)
Pipe Thread 1/4 to 1 in.

Check Valves
VH36 Series Ordering Information and Dimensions
Basic Ordering
Number

VH36AVCH36A-

VH36BVCH36B-

VH36CVCH36C-Cv

End Connections

L

Dimensions

mm (inch)

L1

H

h

Pressure
Ratingpsig (bar)11/16

6000 (413)D-2T-

1/8 in. Dk-Lok

57.7 (2.27)

26.4 (1.04)

7/16

D-4T-

1/4 in. Dk-Lok

61.7 (2.43)

26.4 (1.04)

9/16

D-6M-

6 mm Dk-Lok

61.7 (2.43)

26.4 (1.04)

14

F-4N-

1/4 in. Female NPT

54.1 (2.13)

-

-

M-2N-

1/8 in. Male NPT

45.5 (1.79)

26.4 (1.04)

-

M-4N-

1/4 in. Male NPT

55.1 (2.17)

26.4 (1.04)

-

F-4R-

1/4 in. ISO Female Tapered

57.9 (2.28)

-

-

M-4R-

1/4 in. ISO Male Tapered

55.1 (2.17)

26.4 (1.04)

-

D-6T-

3/8 in. Dk-Lok

69.9 (2.75)

31.2 (1.23)

11/16

1

D-8T-

1/2 in. Dk-Lok

75.2 (2.96)

31.2 (1.23)

7/8

1

D-8M-

8 mm Dk-Lok

68.6 (2.70)

31.2 (1.23)

16

1

D-10M-

10 mm Dk-Lok

71.1 (2.80)

31.2 (1.23)

19

1

D-12M-

12 mm Dk-Lok

75.2 (2.96)

31.2 (1.23)

22

1

F-6N-

3/8 in. Female NPT

64.8 (2.55)

-

-

1

F-8N-

1/2 in. Female NPT

77.0 (3.03)--

1-1/16M-6N-

3/8 in. Male NPT

59.9 (2.36)

31.2 (1.23)

-

1

M-8N-

1/2 in. Male NPT

69.3 (2.73)

31.2 (1.23)

-

1

F-8R-

1/2 in. ISO Female Tapered

83.6 (3.29)--

1-1/16M-8R-

1/2 in. ISO Male Tapered

69.3 (2.73)

1.23 (31.2)-

1

D-12T-

3/4 in. Dk-Lok

89.4 (3.52)

45.2 (1.78)

1-1/8

D-16T-

1 in. Dk-Lok

98.6 (3.88)

45.5 (1.79)

1-1/2

D-22M-

22 mm Dk-Lok

88.4 (3.48)

45.5 (1.79)

32

D-25M-

25 mm Dk-Lok

98.6 (3.88)

45.5 (1.79)

40

F-12N-

3/4 in. Female NPT

82.0 (3.23)

82.0 (3.23)-

F-16N-

1 in. Female NPT

97.3 (3.83)

97.3 (3.83)-

M-12N-

3/4" Male NPT

83.6 (3.29)

45.5 (1.79)-

M-16N-

1 in. Male NPT

93.2 (3.67)

45.7 (1.80)-

F-12R-

3/4 in. ISO Female Tapered

90.2 (3.55)

90.2 (3.55)-

F-16R-

1 in. ISO Female Tapered

97.3 (3.83)

97.3 (3.83)-

M-12R-

3/4 in. ISO Male Tapered

85.1 (3.35)

45.5 (1.79)-

M-16R-

1 in. ISO Male Tapered

93.2 (3.67)

45.7 (1.80)

-

0.67

1.8

4.7

1-5/8

6000 (413)5000 (344)

All dimensions shown are for reference only and subject to change. Dimensions with DK-LOK are in finger-tight position.
CNG valve ordering number: The basic ordering number listed in blue represents VCH36 as well as VH36 series check valves.

Optional Features
Seal Materials
O-ringSeal Material

Designator

NBR

BN

FKM

VT

EPDM

EP

Kalrez*KZ-22 to 599

Temperature Rating- 4 to 221(-20 to 105)-18 to 400(-28 to 204)-49 to 275(-45 to 135)(-20 to 315)

FKM is standard for SS316 valves
NBR is standard for Brass valves*Kalrez: TM Dupont

How to Order
Select valve basic ordering number, applicable seal, spring nominal cracking pressure, and body material.

V33A-D-4TVP33B-F-8NVH36C-D-16T-

1/3-

BNVT-

Seal Material Designator
HNBR: Nil for VCH36 CNG valves
NBR: Nil for Brass Valve
FKM: Nil for SS316 ValveNBR: BNFKM: VTEPDM: EP
Kalrez: KZ

S
1-

EP-

B
3-

Spring Nominal Cracking
Pressure Designator
1/3: 1/3 psi
1: 1 psi
3: 3 psi
10: 10 psi
25: 25 psi

S
Valve Body Material Designator
S: 316 stainless steel
B: Brass

Note:
Select the spring designator from Table 1, 2, 3
and 4 of each valve series.

5Check Valves
Spare Parts for Field Assembly
Spring Kit

Seal Kit

To order spring kit, prefix "9SPR",select check valve series
and spring nominal cracking pressure designator.

To order seal kit, prefix "CVO",select valve series and seal designator.

Examples;
9SPR-V33A-1/3: 1/3 psig spring for V33A series
9SPR-VP33B-1: 1 psig spring for VP33B series
9SPR-VH36A-5: 5 psig spring for VH36A series

Examples;CVO-V33A-BN: NBR O-ring for V33A series
CVO-VP33B-VT: FKM O-ring for VP33B series.
CVO-VH36A-VT: FKM bonded seal for VH36A series
Note: Seal kit for V33E/F series and VH36A/B/C series are suppliedwith the poppet.

VL36 Series Lift Check Valves
Features
Working pressure up to 6000 psig (413 bar)Temperature up to 900 F (482 C)
Metal to metal seat
Operation
Operation of this valve heavily depends on gravity assistance.
Thus mounting horizontally with bonnet nut upward to allow
poppet to operate vertically.
Reverse flow closes the valve, keeping poppet in the orifice.
Forward flow opens the valve, lifting the poppet
Materials of Construction
Lift check valve is primarily for use in liquid systems.
Component
If a slight amount of leakage can be tolerated it can
1 Bodybe used with heavy gases.
2 Bonnet Nut
Reverse flow Cv less than 0.1% of forward Cv.

Grade/ASTM Specification
SS316/A276 or A479
SS316/A276 or A479
TYPE630/A564
SS316/A276 or A479

3 Bonnet
4 PoppetComplete Ordering Number and Dimensions
Complete
Ordering Number

End
Connection

Orificemm inchCv

Dimensions mm (in.)
L
H
H1

Pressure-Temperature Ratings
Hex

D4T-S
1/4 in. DK-LOK
61.0 (2.40)
D6M-S
6 mm DK-LOK
9.9
37.3
7/8
4.0
0.156 0.30
50.8 (2.00)
F2N-S
1/8 in. Female NPT
VL36A(.39)(1.47)
F4N-S
1/4 in. Female NPT
46.0 (1.81)
SW4T-S
1/4 in. tube socket weld
71.9(2.83)
D6T-S
3/8 in. DK-LOK
F4N-S
1/4 in. Female NPT
12.7
47.0
1 1/4
VL36B6.4
0.250 0.64
57.2 (2.25)
SW6T-S
3/8 in. Tube Socket Weld(.50)
(1.85)
SW8T-S
1/2 in. Tube Socket Weld
D8T-S
1/2 in. DK-LOK
99.6 (3.92)
D12T-S
3/4 in. DK-LOK
15.7
62.0
1 1/2
VL36C11.1 0.437 2.20
F6N-S
3/8 in. Female NPT
79.2(3.12)(.62)(2.44)
F8N-S
1/2 in. Female NPT
79.5 (3.13)
SW8T-S
1/2 in. Tube Socket Weld
All dimensions shown are for reference only and subject to change. Dimensions with DK-LOK are in finger-tight position.

ASME Class
Material Group
Material Name
Tem p.
F ( C)-65 to 100(-53 to 37)
200 (93)300 (148)
400 (204)500 (260)600 (315)
700 (371)
800 (426)
900 (482)

2500
2.2
SS316
Working Pressure
psig (bar)6000 (413)5160 (355)4660 (321)4280 (294)3980 (274)3760 (259)3600 (248)3460 (238)3280 (225)

How to order: Select complete ordering number. i.e., VL36A-D-4T-S.

Safe Valve Selection
The selection of a valve for any application or system design must be considered to ensure safe performance.
Valve function, valve rating, material compatibility, proper installation, operation and maintenance remain the sole responsibillty of the system designer and the user. Dk Tech accepts no liability for any improper selection, installation, operation or
maintenance.
DK TECH Trademarks
THE POWER
OF RELIABILITYDK TECH CORPORATION
www.dklok.com

Mailing Address
826, Naesam-Ri, Juchon-Myeon, Gimhae-City,
Gyeong Nam, Korea 621-841

DK TECH contact information
Tel. (82) 55-338-0114
Fax (82) 55-338-6745
E-mail: sales@dklok.com

For Dk-Lok
International
USA customers
Tel. (82) 55-338-0031/2
Fax (82) 55-338-6746
E-mail: dklok@dklok.com