V61 Series

Rev. 01-01
Aug. 2023

Relief Valves

V61 Series Vent Relief valves

Rev.01-01
Aug.2023

Working Pressure up to 400 psig (28 bar)
Features• Precise cracking pressure with high reliability.
• Keeping the sealing to 95~98% of Set Pressure at least.

• Reliable Reseal performance.
• Tamper proof design.

Design and applocation

V61 Series Vent relief valves is designed to vent out the excess pressure from the line automatically to keep the required line pressure safely when the line pressure is exceededover the limitation unusually. This valves can be used in the case that the working fluid is
not harmful when vented out. The level of cracking pressure should be set by adjusting
the force of the spring in the valve before this valve is installed in the system.

Installation and Operation

This valve should be positioned perpendicularly to the direction of fluid flow in the line
and that position should be considered and the vented fluid should be not directedto the personnel operating and the parts that has any influences on that. The line systemshould be run to check the performance of the valve after the personnel operating
move to the safty zone. Because this valve is opened automatically when the excess of
the required line pressure.

Materials of construction
Component

SS316

Body

Valve Body Material

ASTM A276 / A479 TYPE 316

Stem

Quad-Ring

ASTM A276 / A479 TYPE 316

ASTM B16 / Brass 360

STAINLESS STEEL 302

STAINLESS STEEL 302

STAINLESS STEELSTAINLESS STEEL

FKM

SpringSpring retainer

ASTM A276 / A479 TYPE 316

Lock nut

Brass

ASTM B16 / Brass 360(Nickel plated)· Lubricants listed in blue.

NBR

ASTM B16 / Brass 360

Ordering Number and Table of Dimensions
Basic Ordering No.

Pipe Size NPT

Orifice mm(inch)

1/4” Male NPT

6.98 (0.275)

V61-M-2N

1/8” Male NPT

V61-M-6N

3/8” Male NPT

V61-M--4N
V61-M-8N

V61-M-12N

V61-M-16N

1/2” Male NPT

3/4” Male NPT” Male NPTADimension mm(inch)

4.74 (0.187)

24.6 (0.97)

8.76 (0.345)

31.5 (1.24)

10.41 (0.41)

14.47 (0.57)

19.94 (0.785)

30.48 (1.2)

44.5 (1.75)

57.15 (2.25)

79.25 (3.12)Hex.

12.7(1/2)

15.87 (5/8)

19.05 (3/4)
25.4 (1.0)

28.57 (1-1/8)
38.1 (1-1/2)

Technical Data

1. Set Pressure Range : 0.5 to 150 psig
(0.03 to 10.4 bar)
2. Temperature Range : -65° to 400°F(-54°C to 204°C)(differ from material selection)

1

Material
FKM

NBR

EPDM

All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

Designator

Temperature RatingV-20 to 400°F (-28°C to 204°C)

EP-65 to 300°F (-54°C to 148°C)

N-40 to 250°F (-40°C to 121°C)

www.dklok.com

Technical Data

Cracking & Reseal Tolerance
Cracking

Cracking Pressure

Tolerance

2 to 150 psig (0.14 to 10.3 bar)± 5%

below 2 psig (0.14 bar)

± 10%

Cracking Pressure

ResealTolerance

2 ~ 10 psig (0.14 to 1.7 bar)

80% of Cracking

10 ~ 150 psig (0.7 to 10.3 bar)

92% of Cracking

JIG Reference <picture.1>

According to system line’s requested pressure,
Turn the locknut(with JIG as picture.1)as picture and set thecracking pressure.
* Ordering Jig Part No. : V61 - JIG

Spring Cracking Pressure Range Designator and Flow Data
Designator
1

5

10

Cracking Pressure Range@ 20°C (70°F), psig (bar)Standard Cracking Pressure(The Middle Point Cracking)psig (bar)

1/8"

1/4"

2.6 to 7.5 (0.18 to 0.51)

5(0.34)

0.57

0.62

0.5 to 2.5 (0.03 to 0.17)

20

50

100

150

1.6 (0.11)

7.6 to 15 (0.52 to 1.03)

11.5 (0.79)

36 to 75 (2.48 to 5.17)

56 (3.86)

16 to 35 (1.1 to 2.41)

0.13

0.92

26 (1.79)

76 to 125 (5.24 to 8.61)

1.50

4.33

100 (6.89)

126 to 150 (8.68 to 10.4)

8.33

138 (9.5)

10.17

0.13

1.15

2.05

8.58

33.52

38.17

Flow Data for Size, SCFM
3/8"

1/2"

3/4"

1"

0.97

1.83

1.37

2.92

0.20

1.80

2.50

0.83

1.23

2.50

1.58

3.67

3.75

9.17

24.30

17.50

19.00

66.67

57.50

21.67

62.08

34.67

-

1.90

5.17

9.17

76.67

91.67

Factory Test

Every valve is factory tested for standard set cracking and performance.

How to Order

Select valve basic ordering number, applicable seal, spring nominal cracking pressure, and body material.
V61 -

NIL-

KZ-

1-

EP-

Seal Material Designator

FKM : Nil for SS316 ValveNBR : Nil for Brass ValveFKM : VNBR : NS

Spring Nominal Cracking Pressure Designator

EPDM : EP“Note : Select the spring designtor
1 ,5, 10, 20, 50, 100, 150”

www.dklok.com

S : SS316
B : Brass

B

Valve Body Material Designator

All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

2

V63-V66 Series
Relief Valves

Rev. 01-01
Aug. 2023

Relief Valves

V63 & V66 Series Relief Valves

V63 Series for working pressure 300 psig (20.6 bar)Rev.01-01
Aug.2023

Technical Data

V63 Series Technical Data

• Maximum working pressure : 300 psig @ 68°F (20.6 bar @ 20°C)• Cracking pressure range : 10 to 225 psig (0.68 to 15.5 bar)

Table 1. V63 Series Spring Designator
SpringDesignator

psig

RVS-L

Cracking Pressure

10 to 225

Color
Code

bar

0.68 to 15.5

• Orifice : 4.8 mm (0.19 in.)RED

V63/66 Series Temperature Rating
Seal Material

V66 Series for working pressure 6,000 psig (413 bar)Temperature Rating, °C ( °F)

V63 Series

V66 Series

FKM (Viton)-12 ~ -135 (10.4 ~ 275)

-4 ~ 121 (24.8 ~ 250)

Ethylene Propylene(EPDM)-40 ~ 148 (-40 ~ 298)

-1 ~ 121 (30.2 ~ 250)

Buna N-23 ~ 148 (-9.4 ~ 298)

V66 Series Technical Data

-17 ~ 121 (1.4 ~ 250)

• Maximum working pressure : 6,000 psig @ 68°F (413 bar @ 20°C)• Orifice size : 3.4 mm (0.13 in.)• Cracking pressure range : 50 to 6,000 psig (3.4 to 413 bar)

Table 2. V66 Series Spring Designators
RVS-A

RVS-B
RVS-C

V63 Series Flow RateRVS-D

Cracking Pressure

psig

50 to 350

350 to 750

750 to 1500

1500 to 2250

bar

3.4 to 24

24 to 51.6

51.6 to 103
103 to 155

Color
Code

SpringDesignator

BLUE

RVS-F

WHITE
CLEAR

BLACK

155 to 206

RVS-G

4000 to 5000

275 to 344

RVS-H

Every valve is factory tested for cracking and reseal performance.
All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

bar

2250 to 3000

Factory Test

1

Cracking Pressure

psig

RVS-E

V66 Series Flow Rate

SpringDesignator

www.dklok.com

3000 to 4000

5000 to 6000

Color
Code

GREEN

206 to 275

YELLOW

344 to 413

ORANGE

BROWNHow To Adjust Valve Cracking Pressure

Operation

The valve user shall set a specific cracking pressure of the valve
supplied.

1. To increase the cracking pressure of the valve, turn the adjusting cap
clockwise to compress the spring.
2. To reduce the cracking pressure, turn counterclockwise.
3. Start the pump with the spring relaxed (eight threads showing
with the Locking Nut at bottom), with the discharging port open,
check the gauge pressure as you turn the adjusting cap clockwise toincrease the pressure to the desired operating range.
4. If the system has more than one outlet, set the valve pressure with
one outlet open, and then check again with all outlets open to makesure that the set pressure is within the desired operating range.
5. Set the Locking Nut and the wire to maintain the set cracking pressure.

• Install the valve between the pump outlet as close as possible, and any shutoff
device in the discharge line. The preferable mounting position is verticalwith the adjusting cap at the top.
• D-Pro relief valve bypasses the system fluid to prevent instrument or sensitivegauge in the system from excess pressure.
• When the inlet pressure overcomes the set spring pressure on the poppet,
the poppet lifts off the valve seat, allowing flow to bypass and thereby
balance the system pressure.
• If the valve has not been actuated for a period of time, it may initially crack
above the set cracking pressure.
• Cracking pressure is only sensitive to inlet pressure, and is not affected byoutlet pressure.
• Cv reduction : Valve flow may be reduced by the restriction of pipe andtubing connected.

Material of Construction

Cap Plug

Polypropylene

Adjusting Cap

ASTM A276 / A479 Type 316

SpringStainless Steel 302

Locking Nut
BonnetASTM A276 / A479 Type 316

Stem & O-ring seal

Standard Viton, optional EPDM and Buna N

PoppetBody

Ordering information and Dimensions
Basic Ordering Number

Inlet

D-4T-

End Connections
1/4 DK-Lok

D-6M-

6 mm DK-Lok

D-8T-

1/2 DK-Lok

D-8M-

V63andV66-

D-12M-

MD-8N8T-

MD-8N12MMF-4N-

Orificemm(in.)

Outlet

12 mm DK-Lok

12 mm DK-Lok

1/4 Male NPT

1/4 Female NPT

MF-4R-

1/4 Male ISO 7/1

1/4 Female ISO 7/1

MF-6R-

3/8 Male ISO 7/1

3/8 Female ISO 7/1

MF-8R-

1/2 Male ISO 7/1

1/2 Female ISO

MF-6NMF-8N-

V63 :
4.8 (0.19)
V66 :
3.4 (0.13)

1/2 DK-Lok

1/2 Male NPT
3/8 Male NPT

3/8 Female NPT

1/2 Male NPT

Dimensions mm (in.)

100 (3.93)

8 mm DK-Lok
1/2 Male NPT

H

1/2 Female NPT

ASTM A182 F316

105 (4.13)

BL

37 (1.45)

39 (1.53)

44 (1.73)

42 (1.65)

38 (1.49)

98 (3.85)

36 (1.41)

94 (3.70)

32 (1.25)

98 (3.85)

36 (1.41)

40 (1.57)

42 (1.65)
30 (1.18)
35 (1.37)
38 (1.49)

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

How to order

Please select the desired valve basic ordering number, the applicableseal, spring designator and CE certified option from the table below.
Example : V66-D-4T-BN

Seat Designator

Nil : Standard Viton
BN : Buna N
EP : EPDM-B-CE

Spring Designator

Refer to Table 1,
Table 2 for spring
designator

CE certified

CE : Valve to
2014/68/EU

Safe Valve Selection

Model Shown :V66-MF-4N-A

Factory pressure set valve

To order, specify the set pressure on the valve ordering number.
Example : V66-D-4T-60BAR or V66-D-4T-870PSI

Valve without spring installed

To order, do not specify spring designator on the ordering number.
Example : V66-D-4T
Note : The valve with no spring installed is supplied with the label
stated “NO SPRING INSTALLED” on the adjusting cap.

Spring for field assembly

To order, select an applicable spring from the spring designator table1 & 2. Spring kit includes spring, sticker and wire. Example : RVS-A

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 responsibility of the system designer
and the user. DK-Lok accepts no liability for any improper selection, installation, operation or maintenance.
www.dklok.com

All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

2

V64 Series

Rev. 02-01
Jan. 2024

V64 Series

Rev.02-01
Jan.2024

PED Certified Relief Valves

Relief Valves

Features• Wide Media Applications :Air, Gases, CNG, and Liquid relief applications.
• High Performance Soft Seat :Provides Repetitive & Reliable Bubble-tight Seal.
• Orifice: 0.404 in. (10.26 mm)• Working Pressure: 6,000 psi (413 bar)
• Cracking Pressure Range:
15 to 5,500 psig (1.03 to 379 bar)
Valves are supplied with protective painted surface.

Table 1. Materials of ConstructionNo.
1

Seat Frame

4

Cap O-Ring

5
6
7
8

9

10

17

18

Working Pressure

FKM (Viton)*

HNBR

EPDM

NBR inner ring bonded to carbon steel outer ring

Adjustable Screw

Stainless Steel

SpringAISI 1086 or Equivalent

ASTM A479/A276 Type316
ASTM A479/A276 Type316

Seat O-Ring

FKM (see Table 2 for optional O-rings)

Body O-Ring

FKM (see Table 2 for optional O-rings)

Name Plate

Stainless SteelInsert Holder

ASTM A479/A276 Type316

Lead Seal Wire

12-1

Seat Cap

Stainless SteelStainless Steel

Optional PCTFE Type (only spring spec. No.9~11)

ASTM A476/A276 Type316

Seat

Cracking Pressure Range

PCTFE

Orifice-15 (-26)-25 (-31)-70 (-56)

Orifice Area

0.128 in.2 (82.58 mm2)0.404 in. (10.26 mm)

Temp. Rating °F (°C)

Max.

Stainless SteelASTM A479/A276 Type316

Seat Cap

15 to 5,500 psig (1.03 to 379 bar)Min.

Stainless SteelCarbon Steel with Cr Plated

Spring Keeper

Rivet Bolt

Table 2. Elastomer O-ring Technical Information

Stainless SteelCarbon Steel· Wetted parts are listed in blue.

6,000 psig (413 bar)Component

Bonded Seal

19

14-1

Stainless Steel

RubberCarbon SteelSeat Support

16

ASTM A351 CF3M

ASTM A479/A276 Type316

Carbon Steel

Flat Washer

13
15

ASTM A216 Gr. WCB

ASTM A105 or Equivalent

Jam Nut

Disc

14

Stainless SteelStandard O-ring Type

Cap

11

12

Valve Body Materials

Carbon Steel

Body

2

3

V64 Series Technical Data

Component

Recommended Media

400 (204)

Hydrocarbons, H2S, Mineral Oil/Grease, Silicone Oil/Grease, Fuels, Chlorinated Hydrocarbons.

250 (121)

Glycols, Organic Acids, Inorganic Acids, Hydraulic Fluids, Solvents.

325 (162)

Hydrocarbons, CO2, Dilute Acids, Water and Steam Less than 300 ℉.

* In case of CNG service, FKM of special compound is applied and temperature service is applicable to -40℉ (-40℃).

Operation

When the inlet pressure overcomes the spring set pressure, it causes the valve to open, releasing flow to bypass and thereby balance the pressure.

Factory Test

Every valve is factory tested for cracking and reseal performance.

Certifications

CertificatesPED 97/23/EC(Pressure Equipment Directive)

Module B

Module D

CSEL (China Special Equipment License)1

All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

www.dklok.com

Cerificate No.

HSBI-10-11-045

HSBI-10-11-046

TSF700E53-2023

Table 3. Flow Rate

Ordering Number and Dimensions

Flow rate measured by overpressure of 110% or 3 psig.
Media

Air

0.045862.306

Temp.

60 °F

60 °F

70 °F

1

Kd Factor 0.838

Kd Factor 0.838

15 (1.03)

64

80

SCFM

20 (1.3)

74

30 (2.0)94

25 (1.7)441

39

250 (17.2)

570

711

50

32

45

846

894

55

1117

63

500 (34.4)

1111

1387

71

700 (48.2)

1543

1927

84

1327

1657

1976

77

2467

2192

95

2737

100

1500 (103)

3274

4088

122

2000 (137)

4355

5438

141

3815

4763

5437

3000 (206)4500 (310)5500 (379)

8682

10840

10845

13541

173

200

12191

11927

Table 4. Basic Ordering Number and Dimensions

158

8139

9763

5000 (344)

132

6789

6519

4000 (275)

212

224

14892

235

Dimensions in. (mm)Outlet

H

H1

H2

L

L1

D

D1

1 in. Female NPT

9.25
(235)

3.07
(78.0)

1.64(41.8)

3.32(84.50)1.87(47.5)

2.00(51.0)

2.36(60.0)

1/2 in. Female NPT
3/4 in. Male NPT

22

576

678

2500 (172)

MF16N-

16

306

462

1750 (120)

MF12N16N-

17

353

1000 (68.9)

1/2 in. Male NPT

117

150 (10.3)

245

900 (62.0)

3/4 in. Female NPT

14

171

600 (41.3)

F12N16N-

13

93

137

400 (27.5)

MF8N16N-

GPM

50 (3.4)

300 (20.6)

V64-

K Factor 0.62

SCFM
105

200 (13.7)

F8N16N-184

100 (6.8)

End Connections

0.6

FactorSet Pressure psig (bar)

Inlet

Water

0.0764

SG

Basic Ordering
NumberGas

Density

1 in. Male NPT

Ordering Information

Select the desired valve basic ordering number in the table 4, applicable O-Ring designator, Spring designator, and Valve body material in the table below.
O-Ring Material Designators

Applicable to components
number of 14, and 16
in the table 1.
• Nil: Standard FKM O-Ring• HBN: HNBR
• EP: EPDM

Seat Material Designators

Valve Body Material
Designators

Spring Set Pressure Designators Unit: psig

• 1 : 15-35(Brown)• 2 : 36-70(Light Blue)• 3 : 71-200(Yellow)• 4 : 201- 350(Light Green)• 5 : 351-750(Red)• 5 : 351-750(Red)• 6 : 751 - 1300(Orange)• 7 : 1301 - 1800(Silver)• 8 : 1801 - 2800(Black)• 9 : 2801 - 3700(Dark Brown)• 10 : 3701 - 5500(Gray)• 11 : 5800 (Gold)• C: Carbon Steel• S: Stainless Steel• Nil: Standard O-Ring Type, • PC: PCTFE Type(only spring spec. No.9~11)

Example of a complete Ordering Number.
V64-F12N16N-EP-8-C
V64-MF16N-PC-10-C
Factory Set Valve

To order, specify the set pressure
on the valve ordering number.
i.e., V64-F8N16N-1200-C

Safe Valve Selection

The selection of a valve for any application or system design must be considered to ensure safe performance.
Valves function, valve rating, material compatibility, proper installation, operation and maintenance remain the sole responsibilityof the system designer and the user. DK-Lok accepts no liability for any improper selection, installation, operation or maintenance.

www.dklok.com

All dimensions are in millimeters unless otherwise specified and only for reference subject to change.

2