Roto-Disc, Inc. continues to innovate our industrial valve selections for every industry we serve, including ones that require high-pressure and vacuum environments. Our complete guide discusses Roto-Flate® inflatable seal spherical valves and whether they can work for your industrial processes.
Overview of Roto-Disc
Roto-Disc, Inc. designs and manufactures custom valves for industrial processes that handle dry and slurry material. From spherical valves and airlocks to clean-flow diverters, our products benefit hundreds of global industries. Talk to us if your facility processes food, pharmaceuticals, minerals, agricultural products, or chemicals.
We have a wide range of options to improve your current industrial processes. Our team can custom-make valves that withstand abrasive and demanding material in harsh chemical environments, a wide range of temperatures, and more.
Roto-Disc valves save money by decreasing direct maintenance costs and reducing or eliminating downtime. You’ll optimize production time, which adds up over weeks and months to larger labor savings.
We have been in business for more than 40 years and have thousands of successful installations. All products are designed and manufactured in the United States.
What Is the Roto-Flate® Inflatable Seal Spherical Valve?
The Roto-Flate® inflatable seal spherical valve features a bubble-tight sealing system ideal for high-pressure and vacuum environments. The positive seal prevents leakage of liquids, gasses, or dry material into or out of the valve. Your process runs more efficiently because compressors or vacuum pumps won’t be overloaded with the sealing system of this industrial valve.
Other benefits of the Roto-Flate® inflatable seal spherical valve
- The seal is maintained even when the process fluctuates between pressure and vacuum
- No sliding contact against the seal as the valve rotates
- Seal is bidirectional
- Full open port
- Long, low-maintenance service life
Mechanics of Operation
For an inflated seat, compressed air enters the inflatable seal assembly and inflates the seal against the dome. With a deflated seat, compressed air is released, causing the seal to relax and allowing the dome to rotate.
The mechanics are smooth and simple. Bubble-tight sealing makes a more tightly controlled environment, which means compressors or vacuum pumps don’t have to work as hard, extending the life of the valve.
Typical Installation
You’ll see this valve as a lock-hopper valve attached to a gasifier where two Roto-Flate® valves are placed in series. They are opened and closed independently so pressure or vacuum is contained above or below the assembly.
One Signal for Open and Closing
Roto-Flate® valves utilize an automated sequence controller (ASC) that allows the valve to be controlled with just one signal to open and one to close. This unique device, developed exclusively by Roto-Disc®, Inc., makes controlling the Roto-Flate® as easy as any quarter-turn valve. Yet, it still provides the high performance of a two-stage sealing system.
Our customized valve installation offers simplicity, sturdiness, and longevity.
Applications for Roto-Flate® Inflatable Seal Spherical Valves
Applications that require a valve to seal against both high pressure and vacuum are notoriously difficult to engineer since the variations in pressure force the sealing elements away from each other while one of the two conditions is present. These are applications that benefit most from the Roto-Flate® inflatable seal spherical valve.
Because the seal is dynamic, slight movement of the internal components are compensated for with the elastic bladder and the bubble-tight seal is maintained. If you need a valve that can seal against both pressure and vacuum in the same service, our inflatable seal spherical valves can help.
Bulk Material Handling
Roto-Flate® valves are ideal for both dense-phase and dilute-phase. These are some of the most demanding, dry-material valve applications and are the original reason why the inflatable seal valve was developed. It remains the industry standard for long-lasting, dependable service high-pressure shut-off and sealing with abrasive material is required.
Pharmaceutical
Roto-Flate valves are used on the inlet and discharge of vacuum dryers, reactors and centrifuges to help prevent cross-contamination and maintain purity in the production of pharmaceutical ingredients, including Active Pharmaceutical Ingredients (APIs).
Chemical Processing
Pressure vessel discharge, pump-line shut-off, and material isolation are also common Roto-Flate applications because it can handle corrosive or hazardous chemicals safely, while ensuring bubble-tight containment and operational safety.
Mining and Minerals
Even Gravity shut-off of abrasive materials is common for the Roto-Flate. This is because there is no sliding contact between the opening & closing members which reduces abrasive wear. Other installations in these industries include lock-hopper systems and high-pressure transfer lines, both of which require a durable design that resists abrasion, provides tight seals and operates reliably.
Energy and Power Generation
Handling materials in biomass plants, coal-fired systems, or gasification units with our valves are some of the most common uses because it can manage abrasive and corrosive materials while maintaining airtight sealing in pressurized systems.
Industrial Manufacturing
Isolation of processes in high-pressure or vacuum systems, including dryers and mixers, can reliably seal your production lines to enhance safety, reduce downtime, and increase efficiency in manufacturing processes.
Benefits of Roto-Flate® Inflatable Seal Spherical Valves
See these main benefits that set the Roto-Flate® apart from the competition:
Bubble-Tight Against Full Vacuum and Pressure Up to 150PSIG
- Heavy-duty construction
- Bidirectional sealing
- No sliding contact between the dome and the seal
- Full-open port
- Long, low-maintenance service life
Pressures and Temperatures
- Bubble-tight against full vacuum and pressure up to 150psig
- Seal pressure 5-15psi greater than system pressure
- Temperatures up to 475°F, depending on seal material and system pressures. Water cooling is available for higher temperatures
- Hot water and steam heating, jacketing, and heat-tracing packages available for thermal regulation of valve body and/or dome
Typical Applications
- Pneumatic Conveying
- Tank & Pressure Vessel Discharge
- Vacuum Dryer Inlet & Discharge
- Pump-line Shut-off
- Gravity Shut-Off of Abrasives
- Reactor Fill and Discharge
- Lock-Hopper Valves
Roto-Flate® Inflatable Seal Spherical Valves vs. Similar Valves
If your industrial processes use knife-gate valves, butterfly valves, or ball valves, our Roto-Flate® design can improve your processes with distinct advantages.
Roto-Flate® Inflatable Seal Spherical Valves vs. Knife-Gate Valves
Knife-gate valves will have more wear and tear due to their sliding motion. Plus, our inflatable seal spherical valves reduce material buildup, which is inherent in the design of a knife-gate valve. Our bi-directional seal achieves better performance with reverse flow versus knife-gate valves with a unidirectional seal. A knife-gate valve with an inflatable seal has more complex activation systems, which can lead to more breakdowns versus the Roto-Flate® with the automated sequence controllers.
Roto-Flate® Inflatable Seal Spherical Valves vs. Butterfly Valves
Butterfly valves give you a seal that can degrade faster over time compared to our tighter inflatable seal. This is principally because the vane (disk) and the seal are directly exposed to material flow which will reduce the seal’s effectiveness over time, often quickly. The central disc of a butterfly valve can also restrict the flow of materials, which doesn’t happen with a Roto-Flate® inflatable seal spherical valve because there’s nothing in the flow-stream when it is open.
Roto-Flate® Inflatable Seal Spherical Valves vs. Ball Valves
Traditional ball valves rely on static seals, which can wear faster than a Roto-Flate® valve. A ball valve rotates against the seal during every cycle, causing more wear over time versus Roto-Flate®.
Furthermore, ball valves are prone to material buildup inside the cavity around the ball, which can cause poor valve performance. Our inflatable seal spherical valve eliminates this type of problem.
Materials of Construction of Roto-Flate® Inflatable Seal Spherical Valves
Valve sizes range from 3 to 24 inches.
Body, Dome, and Retaining Plates
- Stainless Steel (304, 316, Duplex)
- Hastelloy-C
- Inconel
- Monel
- Carbon Steel (4140, WCB, A36)
- Other alloys, upon request
Seal Material
- EPDM
- Heat-Stable Silicon
- Viton®- A/B/GF
- Viton Extreme ETP
- Buna-Nitrile
- Neoprene
- Some materials are available in white.
Coatings and Hardfacings
- Electroless Nickel
- Stellite
- Hard Chrome
- Thin-Dense Chrome
- Tungsten Carbide
- Teflon®/PFA
- Others
Case Study With Roto-Flate® Inflatable Seal Spherical Valves
Reference our case study from a satisfied customer who uses Roto-Flate® inflatable seal spherical valves for high-temperature hazardous waste removal and recovery. The customer processes scrap glass contaminated with mercury while using a continuously fed calciner.
Deep vacuum is produced at temperatures that exceed 500° Fahrenheit using indirect heat to vaporize the mercury off the glass and shunt it to a recovery system.
The Problem
Scrap, broken glass is both abrasive and angular, which causes harsh wear on both feed and discharge valves. Valves must be extremely tight because mercury losses can cause hazardous material leaks.
Rotary star feeders were a part of this process. Even with a typical clearance of .003 to .006 inches, a great deal of leakage could occur. Add in the abrasive glass, and the clearance could get bigger as the valve wears down.
Rotary vanes, metal-seated butterfly valves, ball valves, knife gates, and slide gates were considered as replacements. But they did not meet the customer’s requirements.
The Solution
Roto-Flate® valves were installed, and the dome was sealed against the inverted, unexposed surface of the elastomer. Material falls away from the seal by gravity before the seal is inflated against the dome surface.
Our seal material is thick and tough. The upper valve is opened to allow material to fill the intermediate chamber before it is closed, and the lower valve opens to charge the contaminated product into the processor.
The main problem we solved came from the 500°F temperatures. We took two steps to solve this issue. First, seals for the discharge valves were made of silicon rubber, which has a temperature limit of 400°F. Second, these valves were water-cooled using specially bored shafts to circulate 50°F water around the body, coils, and heat-transfer cement.
Contact Roto-Disc for Inflatable Seal Valves
Does your industrial operation need inflatable seal valves? Contact us today to see if our team can help solve your production line problems. We’re happy to help in any way we can.
