Figure 1: Modulating butterfly valve (left) and modulating ball valve (right)
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A modulating valve is a control valve that can be fully open, fully closed, or in-between open and closed allowing a partial flow. They are often automated with an actuator in combination with the valve. Common valve types are: globe valve, disc valve, and quarter-turn valves (butterfly valve or ball valve). To accomplish modulation, the actuator uses a feedback system to give feedback on the valve&#;s position to the operator. Modulation of the valve position regulates the flow rate, which is often used to control secondary parameters such as temperature, level, or concentration. Figure 1 shows the example of a modulating butterfly and ball valve.
Certain electrical valve actuators are capable of carrying out modulating control, which is often referred to as a DPS (digital positioning system). It is able to accurately position the valve anywhere between the fully open and fully closed position (i.e. between 0° to 90°). This is necessary for applications that require a variation in flow rate. Typically, modulation is achieved using a control loop system and a positioning circuit board (PCB) placed in the actuator.
It works by comparing the input position (desired position) to the physical position of the output shaft (actual position). The output shaft&#;s location is fed back to the PCB board by a potentiometer that is driven by the output shaft. The PCB board then compares the two positions, and if there is a difference it considers this an &#;error&#;. To correct the error, the control unit will operate the valve until it reaches the desired position (within a tolerance). The control signals are typically either 0-10 V DC or 4-20 mA. A 0 V DC or 4 mA signal completely closes the valve while a 10Vdc or 20mA would completely open it. Any signal between these would cause a corresponding partially opened or closed position. An example would be a 6mA signal that would result in a 12° turn.
An example of an application that requires modulation is in HVAC systems. If the desired input temperature is different than the actual temperature, the actuator will open or close the valve more to increase/reduce the flow of the conditioned air.
Butterfly valves provide good flow control in general. The addition of a modulating actuator to these valves allows the valve to control the flow with even finer precision. The modulating actuator is attached to the valve via the stem which in turn dictates the rotation of the disc at the desired angle (between 0° to 90°).
Figure 2: Modulating butterfly valve
Ball valves are generally not used for flow control applications. Therefore, adding on a modulating actuator allows ball valves to be used for such applications. However, it may require some modifications to be effectively used for flow control. The modifications may include using of V-port ball or inserting a trim disc for optimizing flow. Ball valves with actuators are often used in vacuum applications.
Figure 3: Modulating ball valve
Modulating valves are used in a wide variety of applications because they offer many advantages over a simple on/off control. Some advantages are:
There are also a few disadvantages of using a modulation valve such as:
Modulating valves are commonly used in fluid applications. Some applications using modulating valves are:
A modulating valve automatically controls the amount of flow in the system. It uses control signals to accurately position the valve at any point between fully open and fully closed (i.e. between 0° to 90°).
A modulating gas valve is used to control the temperature fluctuation by regulating the gas flow. It is commonly found in residential furnaces. The PCB board in the modulating gas valve monitors the gas input and the temperature control device (thermostat). When more heat is needed, the gas input going to the burner is increased. When less heat is required, the gas input is reduced. Thus, the desired temperature is maintained.
A modulating control valve precisely controls the process parameters like pressure, temperature, level, flow rate, etc. and adjusts the input/output positions to receive the optimal result.
A modulator valve is found in automatic transmissions to shift gears depending upon the load on the engine. Its vacuum line is attached to the intake which measures the amount of vacuum in the system. When the gas pedal is pushed, the throttle plate opens and the vacuum is released. This will cause the modulator valve to downshift the transmission. When the pedal is released to accelerate, the throttle plate closes and the vacuum is increased. This will cause the modulator valve to upshift the transmission.
A 2-way modulating valve controls the amount of flow from the input to the output from 0-100%.
A modulating actuator is what makes the modulating control valve possible. It is able to open the valve at any position between 0-100% open/closed.
Control Valves Modulation Vs On-Off
The US economic recovery faces significant risks in . You want your business to be as competitive as possible in this rapidly-changing environment. You can&#;t afford unnecessary downtime or inefficiencies.
Using the right control valves helps you optimize your flow control system. Is it time for a new on-off or modulation control valve?
Learn more about the difference between an on-off valve and a modulating control valve. You&#;ll see what these types of valves can do for you.
On-off and modulating valves give you different levels of control over your fluid control system. Each type of valve has different applications.
An on-off valve is either open or closed. It allows unrestricted flow or prevents the flow entirely. On-off valves are also called stop, shutoff, or isolation valves.
Uses for on-off valves include:
An on-off valve can be a backup for a modulating valve.
A modulating control valve gives you precise control over the flow rate in your system.
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The valve actuator allows the right flow rate by using feedback and control signals to open and close the valve. The digital positioning system compares the physical position of the shaft to the desired position. If the valve isn&#;t in the correct position, the control unit will open or close the valve to reach the right position.
Modulating control valves let you position the valve anywhere between fully open and fully closed, which is typically between 0º and 90º. Regulating the flow rate lets you control other system variables like temperature, liquid level, or concentration.
Modulating valves are ideal for applications that need a high level of precision, such as:
A modulating valve can be more energy-efficient than a frequent on-off action.
Automating the actuator for an on-off or modulating control valve gives you several benefits. Automation can increase safety and give you better output control. Electric, pneumatic, hydraulic, or electro-hydraulic energy can power a valve&#;s control system.
An electric actuator converts electrical energy into torque to open or close the valve. They operate using either a motor or a solenoid.
Electric actuators give you extremely precise control. They have a shorter cycle time than pneumatic actuators, and they&#;re more energy efficient.
A pneumatic actuator converts air pressure into valve motion. Pressure from an external air or gas source operates a piston in a cylinder that opens or closes the valve.
Pneumatic actuators require very little maintenance because of their simple design. They&#;re safe and reliable. They&#;re a good choice for many types of hazardous locations.
A hydraulic actuator works using pressurized liquid. Most hydraulic actuators use a piston to convert fluid pressure into mechanical force. The valve stem transmits the motion of the piston to open or close the valve.
Hydraulic actuators can create a large amount of force. They have very stable positioning. They&#;re durable and give you a high level of precision.
An electro-hydraulic actuator combines features of electric and hydraulic actuators. It&#;s a self-contained actuator that doesn&#;t need a separate hydraulic system.
Electrical power energizes a motor that runs a hydraulic pump. The pressurized fluid works the mechanism to open and close the valve.
Electro-hydraulic actuators are fast, very precise, and cleaner than standard hydraulic actuators.
Choosing the right type of valve for your application depends on many factors. Some valves are well-suited for on-off service, while others are better for modulating control.
Ball valves and plug valves are two types of valves that work best in on-off applications. Butterfly valves and globe valves are good options when you need a modulating control valve.
A ball valve is a type of quarter-turn valve. A rotary ball with a bore rotates 90º from off to on.
Ball valves are best-suited for on-off applications. They have a long service life. They provide reliable sealing even after a long period without use.
Specialized ball valves can give you modulation control, but they&#;re less precise than other types of modulation valves.
A plug valve is similar to a ball valve. Instead of a ball rotating to open and close the valve, plug valves have a rotating cone. This conical shape helps plug valves seal exceptionally tightly.
Plug valves are a reliable shutoff option for applications involving hard or corrosive mediums, mud, slurries, or sewage.
A butterfly valve is another type of quarter-turn valve. It has a disk that rotates 90º to open and close the valve.
Butterfly valves can serve in on-off or modulating applications. A butterfly valve is fully closed with the disk perpendicular to the flow direction. Partial rotation allows for a throttled or proportional flow.
Butterfly valves are available in very large sizes. They can handle slurries and liquids with a high percentage of solids. These features make high-performance butterfly valves increasingly popular.
Globe valves are linear movement valves. They have sphere-shaped bodies divided into two chambers with a hole that lets fluid pass between them. The up or down motion of the stem raises and lowers a small plug to open and close the valve.
Globe valves can give you modulation control and on-off service. They&#;re available in three body designs with different advantages. For example, an angle pattern design can handle applications with a pulsating flow.
On-off and modulating control valves serve equally important but different functions in your fluid control system. Finding the right valve for your application is critical for the safety and efficiency of your operations.
Anything Flows specializes in flow control solutions. We&#;ll help you find the right control valves to meet your requirements. You can count on our expedited logistics to deliver what you need when you need it.
Contact us today and let&#;s start designing your flow control solution.
Figure 1: Modulating butterfly valve (left) and modulating ball valve (right)
A modulating valve is a control valve that can be fully open, fully closed, or in-between open and closed allowing a partial flow. They are often automated with an actuator in combination with the valve. Common valve types are: globe valve, disc valve, and quarter-turn valves (butterfly valve or ball valve). To accomplish modulation, the actuator uses a feedback system to give feedback on the valve&#;s position to the operator. Modulation of the valve position regulates the flow rate, which is often used to control secondary parameters such as temperature, level, or concentration. Figure 1 shows the example of a modulating butterfly and ball valve.
Certain electrical valve actuators are capable of carrying out modulating control, which is often referred to as a DPS (digital positioning system). It is able to accurately position the valve anywhere between the fully open and fully closed position (i.e. between 0° to 90°). This is necessary for applications that require a variation in flow rate. Typically, modulation is achieved using a control loop system and a positioning circuit board (PCB) placed in the actuator.
It works by comparing the input position (desired position) to the physical position of the output shaft (actual position). The output shaft&#;s location is fed back to the PCB board by a potentiometer that is driven by the output shaft. The PCB board then compares the two positions, and if there is a difference it considers this an &#;error&#;. To correct the error, the control unit will operate the valve until it reaches the desired position (within a tolerance). The control signals are typically either 0-10 V DC or 4-20 mA. A 0 V DC or 4 mA signal completely closes the valve while a 10Vdc or 20mA would completely open it. Any signal between these would cause a corresponding partially opened or closed position. An example would be a 6mA signal that would result in a 12° turn.
An example of an application that requires modulation is in HVAC systems. If the desired input temperature is different than the actual temperature, the actuator will open or close the valve more to increase/reduce the flow of the conditioned air.
Butterfly valves provide good flow control in general. The addition of a modulating actuator to these valves allows the valve to control the flow with even finer precision. The modulating actuator is attached to the valve via the stem which in turn dictates the rotation of the disc at the desired angle (between 0° to 90°).
Figure 2: Modulating butterfly valve
Ball valves are generally not used for flow control applications. Therefore, adding on a modulating actuator allows ball valves to be used for such applications. However, it may require some modifications to be effectively used for flow control. The modifications may include using of V-port ball or inserting a trim disc for optimizing flow. Ball valves with actuators are often used in vacuum applications.
Figure 3: Modulating ball valve
Modulating valves are used in a wide variety of applications because they offer many advantages over a simple on/off control. Some advantages are:
There are also a few disadvantages of using a modulation valve such as:
Modulating valves are commonly used in fluid applications. Some applications using modulating valvesmodulating valves are:
A modulating valve automatically controls the amount of flow in the system. It uses control signals to accurately position the valve at any point between fully open and fully closed (i.e. between 0° to 90°).
A modulating gas valve is used to control the temperature fluctuation by regulating the gas flow. It is commonly found in residential furnaces. The PCB board in the modulating gas valve monitors the gas input and the temperature control device (thermostat). When more heat is needed, the gas input going to the burner is increased. When less heat is required, the gas input is reduced. Thus, the desired temperature is maintained.
A modulating control valve precisely controls the process parameters like pressure, temperature, level, flow rate, etc. and adjusts the input/output positions to receive the optimal result.
A modulator valve is found in automatic transmissions to shift gears depending upon the load on the engine. Its vacuum line is attached to the intake which measures the amount of vacuum in the system. When the gas pedal is pushed, the throttle plate opens and the vacuum is released. This will cause the modulator valve to downshift the transmission. When the pedal is released to accelerate, the throttle plate closes and the vacuum is increased. This will cause the modulator valve to upshift the transmission.
A 2-way modulating valve controls the amount of flow from the input to the output from 0-100%.
A modulating actuator is what makes the modulating control valve possible. It is able to open the valve at any position between 0-100% open/closed.
Control Valves Modulation Vs On-Off
The US economic recovery faces significant risks in . You want your business to be as competitive as possible in this rapidly-changing environment. You can&#;t afford unnecessary downtime or inefficiencies.
Using the right control valves helps you optimize your flow control system. Is it time for a new on-off or modulation control valve?
Learn more about the difference between an on-off valve and a modulating control valve. You&#;ll see what these types of valves can do for you.
On-off and modulating valves give you different levels of control over your fluid control system. Each type of valve has different applications.
An on-off valve is either open or closed. It allows unrestricted flow or prevents the flow entirely. On-off valves are also called stop, shutoff, or isolation valves.
Uses for on-off valves include:
An on-off valve can be a backup for a modulating valve.
A modulating control valve gives you precise control over the flow rate in your system.
The valve actuator allows the right flow rate by using feedback and control signals to open and close the valve. The digital positioning system compares the physical position of the shaft to the desired position. If the valve isn&#;t in the correct position, the control unit will open or close the valve to reach the right position.
Modulating control valves let you position the valve anywhere between fully open and fully closed, which is typically between 0º and 90º. Regulating the flow rate lets you control other system variables like temperature, liquid level, or concentration.
Modulating valves are ideal for applications that need a high level of precision, such as:
A modulating valve can be more energy-efficient than a frequent on-off action.
Automating the actuator for an on-off or modulating control valve gives you several benefits. Automation can increase safety and give you better output control. Electric, pneumatic, hydraulic, or electro-hydraulic energy can power a valve&#;s control system.
An electric actuator converts electrical energy into torque to open or close the valve. They operate using either a motor or a solenoid.
Electric actuators give you extremely precise control. They have a shorter cycle time than pneumatic actuators, and they&#;re more energy efficient.
A pneumatic actuator converts air pressure into valve motion. Pressure from an external air or gas source operates a piston in a cylinder that opens or closes the valve.
Pneumatic actuators require very little maintenance because of their simple design. They&#;re safe and reliable. They&#;re a good choice for many types of hazardous locations.
A hydraulic actuator works using pressurized liquid. Most hydraulic actuators use a piston to convert fluid pressure into mechanical force. The valve stem transmits the motion of the piston to open or close the valve.
Hydraulic actuators can create a large amount of force. They have very stable positioning. They&#;re durable and give you a high level of precision.
An electro-hydraulic actuator combines features of electric and hydraulic actuators. It&#;s a self-contained actuator that doesn&#;t need a separate hydraulic system.
Electrical power energizes a motor that runs a hydraulic pump. The pressurized fluid works the mechanism to open and close the valve.
Electro-hydraulic actuators are fast, very precise, and cleaner than standard hydraulic actuators.
Choosing the right type of valve for your application depends on many factors. Some valves are well-suited for on-off service, while others are better for modulating control.
Ball valves and plug valves are two types of valves that work best in on-off applications. Butterfly valves and globe valves are good options when you need a modulating control valve.
A ball valve is a type of quarter-turn valve. A rotary ball with a bore rotates 90º from off to on.
Ball valves are best-suited for on-off applications. They have a long service life. They provide reliable sealing even after a long period without use.
Specialized ball valves can give you modulation control, but they&#;re less precise than other types of modulation valves.
A plug valve is similar to a ball valve. Instead of a ball rotating to open and close the valve, plug valves have a rotating cone. This conical shape helps plug valves seal exceptionally tightly.
Plug valves are a reliable shutoff option for applications involving hard or corrosive mediums, mud, slurries, or sewage.
A butterfly valve is another type of quarter-turn valve. It has a disk that rotates 90º to open and close the valve.
Butterfly valves can serve in on-off or modulating applications. A butterfly valve is fully closed with the disk perpendicular to the flow direction. Partial rotation allows for a throttled or proportional flow.
Butterfly valves are available in very large sizes. They can handle slurries and liquids with a high percentage of solids. These features make high-performance butterfly valves increasingly popular.
Globe valves are linear movement valves. They have sphere-shaped bodies divided into two chambers with a hole that lets fluid pass between them. The up or down motion of the stem raises and lowers a small plug to open and close the valve.
Globe valves can give you modulation control and on-off service. They&#;re available in three body designs with different advantages. For example, an angle pattern design can handle applications with a pulsating flow.
On-off and modulating control valves serve equally important but different functions in your fluid control system. Finding the right valve for your application is critical for the safety and efficiency of your operations.
Anything Flows specializes in flow control solutions. We&#;ll help you find the right control valves to meet your requirements. You can count on our expedited logistics to deliver what you need when you need it.
Contact us today and let&#;s start designing your flow control solution.