Share optimized solutions, professional valve knowledge and industry news

What is CV of Control Valves?

Control valve CV refers to the flow coefficient of the valve. It applies to the factor of the head drop (Δh) or pressure drop (ΔP) over a valve with the flow rate Q.
Table of Contents
    Add a header to begin generating the table of contents

    Control valve CV refers to the flow coefficient of the valve. It applies to the factor of the head drop (Δh) or pressure drop (ΔP) over a valve with the flow rate Q.

    Calculating Control Valve CV

    When Sizing (calculating which size valve is needed for your application ) a control valve specialist needs to calculate the flow coefficient. A few key concepts that we need to clarify before we start with the math are pressure drop, flow rate, and their relationships.

    Pressure drop: There will always be a pressure drop from the upstream flow to the downstream flow over a control valve, this is not caused by the valve alone but also by the system demand. To determine the pressure drop

    you must subtract the outlet pressure (P2) from the inlet pressure (P1). This is a key element needed for the control valve sizing.

    The relation between flow rate and pressure drop is an easy concept. The higher the flow rate through the valve ( restriction in process line) the greater the pressure drop.

    The definition of Cv is the number of GPM (Gallons per minute ) that will pass through the control valve with a pressure drop of 1psi.

    Control valve Cv refers to the flow coefficient of the valve. It applies to the factor of the head drop (Δh) or pressure drop (ΔP) over a valve with the flow rate Q. The formula will differ depending on the product the valve regulates, such as liquid, gas, or steam. The following article also gives a thorough explanation of the calculation of the flow coefficient:

    Flow Control Loop

    Also, the Cv varies across control valves because each valve lets the flow pass through differently. The difference in Cv relates to the type of valve and its opening position. When you need to do valve sizing for your application, you need the Cv to select the right valve.
    Some vendors have standardized the flow coefficient (Kv). They created this standard using reference conditions, such as water at a specific temperature, flow rate, and drop pressure units. Keep in mind also that the Kv uses metric units and the Cv imperial units. Here’s the formula if you need it:

    Kv = 0.865 · Cv

    Kv is the flow coefficient in metric units. It is defined as the flow rate in cubic meters per hour [m3/h] of water at a temperature of 16 degrees Celsius with a pressure drop across the valve of 1 bar.

    Cv = 1,156 · Kv

    Cv is the flow coefficient in imperial units. It is defined as the flow rate in US Gallons per minute [gpm] of water at a temperature of 60℉ with a pressure drop across the valve of 1 psi.

    Percent Cv
    Percent Cv

    In Conclusion

    Cv is just one of the technical terms for control valves, and if you are interested in more sizing processes for control valves, you can refer to our download page to see more calculations and sizing methods of control valves. All are free to download.

    Contact Us

    With expertise in valves and rich experience in the oil&gas, chemical industry, textile mills, power plants, and sugar mills. THINKTANK has become the premier manufacturer of next-generation precision control valves.

    With a customer base that includes over 42 of the world’s leading engineering&contractors and international valve brands, THINKTANK Valves offers cost-effective valves that help our customers achieve automated process control without paying high prices.

    solenoid valve in control valve

    What is SOV(solenoid valve) in Control Valve 

    Solenoid valves are often used in applications where a control valve is required to be actuated quickly to a fault position under certain conditions. It is generally designed to be in the air supply line and is an important accessory to the air control system.

    Read More
    diesel generators

    Fusible Link Valves For Diesel Generators

    The fusing link valve for the diesel generator set includes the valve body and actuator, and the valve body and actuator are fixed by a fixed bracket/yoke. The actuator of the fused valve includes the shaft, fusible link, manual/gear operator, actuator protection cover, limit switch, etc.

    Read More
    sluice gate valve

    Sluice Gate Valve 101

    The sluice gate valves are real end-of-line valves designed to hold back water with minimal leakage in applications such as drains, sump tanks, and distribution boxes.

    Read More
    condensate recovery system

    Condensate Return System

    Condensate has a large amount of heat, generally accounting for about 20-30% of the total heat of steam, and for some equipment, it can be as high as 40%.  Therefore, if high-temperature condensate can be recycled as boiler make-up water or used for secondary flash steam, it not only saves industrial water but also saves a large amount of fuel.

    Read More
    three way control valves

    Water Mixing

    Water mixing is the mixing of water at different temperatures, and the resulting mixing temperature varies at different hot and cold flows

    Read More
    uni directional knife gate valve manufacturer

    Knife Gate Valve 101

    Knife gate valves are primarily made for isolation and on-off services in systems with high suspended particle contents. Knife gate valves are particularly useful for managing viscous, corrosive, and abrasive media in addition to the slurry.

    Read More
    Joy Preview

    A good partner is a lasting and effective investment

    Focused on Control Valves & Self-Operated Pressure Regulators For Over 10 Years

    Grow Your Business is Our Top Priority. Contact Now You Will Get More Than You Expect.

    Joy Preview


    Just leave your name, email, and simple message or requirements, We will contact you within 1 hour.

    WhatsApp: +86 185 1656 9221

    Skype ID: sowell85

    Wechat ID: +86 189 5813 8289