Quick Exhaust Valves: Types, Features and Advantages
Quick exhaust valves are most often used to achieve better speed control of air cylinders in pneumatic systems. They’re durable, reliable and easy to use, making them a versatile solution for applications in various industries.
What is a Quick Exhaust Valve?
It’s a pneumatic valve designed to release compressed air in a controlled environment. Quick exhaust valves are known for their responsiveness and longevity in high-pressure pneumatic automation systems.
They’re typically positioned at or near air cylinders and downstream of the corresponding control valves. Compressed air from the control valve moves through the quick exhaust to the cylinder, extending or retracting the piston rod. When the control valve shifts and starts to exhaust, the quick exhaust valve senses the upstream pressure drop and shifts instantaneously to open an exhausting flow path near the air cylinder. Designers can control the air cylinder cycling speed at the quick exhaust valve’s exhaust port, achieving greater speeds and improving control of slower speeds.
Quick Exhaust Valve Features
Quick exhaust valves have a simple design. This three-port valve is easy to install and maintains functional integrity in difficult environments and high-pressure applications. The straightforward design is simple and reliable, and maintenance is uncomplicated.
Quick exhaust valves provide an efficient path for air to escape a system, reducing the wear and tear on the control valve and air cylinder.
Other features include:
- Extremely high flow capacity
- Simple, reliable design, including body, cap and molded rubber shuttle
- High-speed cycling
- Direct inline mounting
Advantages of Quick Exhaust Valves
Fast actuation: Quick exhaust valves can vent media from the cylinder quickly once the incoming pressure has surpassed the load resistance, improving system efficiency.
Enhanced productivity: Rapid actuation allows quick exhaust valves to complete more cycles. Creating a direct exhaust path also enhances system efficiency by reducing back pressure.
Compact design: Despite their small size, these valves can easily reroute exhaust air into the atmosphere. They also feature a simple design, eliminating the need for complex components and reducing operating costs.
Durability: Using a quick exhaust valve can prevent pressure and heat buildup that can wear on seals and cylinders.
Disadvantages of Quick Exhaust Valves
Slow retraction: Regular exposure to contaminants and debris can clog a quick exhaust valve, causing a retraction malfunction. Installing a filter can reduce the risk of that issue.
Noise: Exhaust ports can emit noise during operation, especially at high flow rates. Wear on internal components, lodged debris and air leaks can contribute to sound emission.
Air leaks: Any structural or seal damage can result in air leaks in your valve. It’s also important to check connection points around the valve body to ensure they’re tightly secured.
Maintenance: Quick exhaust valves are typically exposed to high pressure, which can strain the hardware over time. It’s essential to conduct regular maintenance to watch for signs of damage and prevent system failure.
When to Use a Quick Exhaust Valve
They’re ideal for pneumatic systems that need air cylinder consistency. Quick exhaust valves excel in applications that demand fast responses, precision pressure control and efficiency.
Consider using quick exhaust valves if your system requires:
Rapid air cylinder extension and/or retraction: Quick exhaust valves provide a greater exhaust capacity at the cylinder port, which is beneficial for double-actuating pneumatic cylinders.
Controlled cylinder piston rod travel: Restrict flow at the exhaust port to achieve smooth, controlled piston rod movement.
Extend air cylinder life: Short-circuiting the exhaust of the cylinder port allows lubricated air from the control valve to migrate toward the cylinder with each cycle, extending the life of the piston and rod seals.
Reduce directional control cost: In remote control applications, you can use a quick exhaust valve with air cylinders to create a smaller, more cost-effective control valve.
Quick exhaust valves are commonly used in:
- Manufacturing equipment
- Emergency stop systems
- Pneumatic tools and machinery
- Injection and ejection systems
- Robotic automation
Other Uses
Shuttle valves: This type of pneumatic valve supplies air pressure from alternative sources. Shuttle valves respond to the higher pressure source and move the air through the valve body to an output port.
Check valves: A check valve allows compressed air to flow in one direction and prevents reverse flow. It will only open if there’s a forward flow of compressed air.
TAC Miniature Quick Exhaust Valve
Humphrey offers a miniature Quick Exhaust Valve from our TAC product line.
The 10-32 UNF ported design specifications include:
- Media: Air or inert gas
- Number of ports: 3
- Operation: Pressurized differential
- Flow coefficient: 13 Cv
- Pressure range: 3-125 psi
Humphrey “Super Quick Exhaust Valves”
Humphrey’s super quick exhaust valves are renowned for their rugged construction and durability, outperforming competitive “sheet stock” diaphragm types. This valve is available in six sizes and provides versatility and consistency in a variety of operations.
Specifications include:
- Media: Air or inert gas
- Sizes: Six pipe sizes from 1/8 NPT to 3/4 NPT
- Exhaust capacity (at 100 psi): 63 ~ 395 SCFM
- Pressure range: 1-150 psi
Quick Exhaust Valves from Humphrey Products
Humphrey’s expert sales representatives will work with you to determine your project specifications and recommend the right valve to get the job done. Contact us to learn more about our products and get a quote.