Valves are essential components in various systems that require pressure and flow regulation. Among the many valve series available, the V63 and V66 series are noteworthy for their technical specifications and features.
The V63 series is suitable for applications that require a lower pressure range. Its maximum working pressure is 300 psig @ 68°F, and its cracking pressure range is 10 to 225 psig. This series is ideal for applications that involve gas or liquid handling in industries such as oil and gas, petrochemicals, and pharmaceuticals.

On the other hand, the V66 series has a higher maximum working pressure of 6,000 psig @ 68°F and a wider cracking pressure range of 220 to 6,000 psig. This series is suitable for high-pressure applications in industries such as aerospace, defense, and nuclear power.

Both valve series are equipped with a relief valve that bypasses system fluid to prevent excess pressure from damaging sensitive instruments or gauges in the system. Moreover, the cracking pressure of the valve is only sensitive to inlet pressure and not affected by outlet pressure.
To adjust the cracking pressure of the valve, the user can turn the adjusting cap clockwise to increase pressure and counterclockwise to decrease it. The valve is factory-tested for cracking and reseal performance, and the user is responsible for setting a specific cracking pressure for the valve supplied.
The material of construction for the valve includes a polypropylene cap plug, ASTM A276/A479 Type 316 adjusting cap and locking nut, stainless steel 302 spring, and an ASTM A182 F316 body. The valve is also available in different seal materials, including FKM (Viton), Buna N, and Ethylene Propylene (EPDM), with varying temperature ratings.
In the aerospace industry, the V66 series valves are used for pressure regulation in pneumatic systems, fuel systems, and hydraulic systems of aircraft. The V63 series valves are used in gas and liquid handling applications in the pharmaceutical industry to regulate flow and pressure in drug production.
In the oil and gas industry, the V63 series valves are used in pipeline systems to regulate pressure and flow of natural gas or crude oil. The V66 series valves are used in oil rigs and refineries to control the flow of oil or gas and regulate pressure in high-pressure systems.
V66 Series Spring Designators | |||
Spring Designator | Cracking Pressure | Color Code | Bar (Range) |
RVS-A | 220 to 350 | WHITE | 15.1 to 24 |
RVS-B | 350 to 750 | BLUE | 24 to 51.6 |
RVS-C | 750 to 1500 | CLEAR | 51.6 to 103 |
RVS-D | 1500 to 2250 | BLACK | 103 to 155 |
RVS-E | 2250 to 3000 | GREEN | 155 to 206 |
RVS-F | 3000 to 4000 | YELLOW | 206 to 275 |
RVS-G | 4000 to 5000 | BROWN | 275 to 344 |
RVS-H | 5000 to 6000 | ORANGE | 344 to 413 |


In conclusion, the V63 and V66 series valves offer reliable and efficient pressure and flow regulation in various applications. Their technical specifications and features make them suitable for different pressure ranges, and their material of construction and seal options provide flexibility for various operating conditions. However, proper selection, installation, operation, and maintenance of the valve remain crucial for safe and efficient system performance.
You can download the V63 and V66 PDF here.
For more information about DK-Lok fittings in the oil industry view this post or you can find out about their whole catalog by viewing this post.
If you’re interested in purchasing the V63 or V66 series valves for your application, look no further than Michigan Valve and Fitting. We offer a wide range of valves, fittings, and instrumentation products to meet your needs. Our experienced team can help you select the right valve for your application and provide expert installation and maintenance services to ensure optimal performance. Contact us today to learn more and request a quote for the V63 or V66 series valves.