Reducing Railcar Risks: Why Two Valves Are Better Than One

By OPW | Feb 16, 2021

When it comes to reducing the risk of railcar hazardous product releases, it’s good to remember that two valves are better than one.

Recognizing this, Midland Manufacturing, Inc. has combined its A-719-ML model Top-Transfer Angle Valve and A-190 Check Valve to create the A-719-ML/A-190 Dual Valve System, which provides additional defense against leaks of toxic inhalation hazard (TIH) commodities, such as chlorine, anhydrous ammonia and ethylene oxide.

When paired together, the A-719-ML/A-190 Dual Valve System helps to provide protection against the release of railcar contents in the event of a roll-over accident. Should a railcar roll-over accident occur, the angle valve is designed to shear off, and the check valve becomes the primary seal, halting product flow.

The Dual Valve System is also easy to install, with the check valve fitted through the top of the cover plate, allowing it to be serviced or replaced without removing the cover plate or cutting the valve. The Dual Valve System can be installed on 18-inch or larger cover plates.

The A-719-ML Angle Valve features adjustable spring-loaded packing and a three-bolt Monel® outlet flange, along with a Monel bonnet and valve body. The valve stem and body insert are both constructed of Hastelloy C, with the O-ring and seal fashioned from Viton® and PTFE, respectively. The elevated seat design of the valve permits self-draining, designed to help prevent accidental release or product entrapment. The spring-loaded valve stem packing provides constant load on the packing rings, which when combined with replaceable threaded side and top ports, enables quick in-service maintenance and repair with no need to remove the valve.

The A-190 Check Valve provides reliable, high flow rates with high sensitivity to flow disturbance, a combination that helps enable safer operation and faster unloading times when handling hazardous materials. Like the A-719-ML, the A-190 has a Hastelloy C body and stem, along with a Viton O-ring and PTFE seal, with the spring constructed of Inconel®. All of these components are non-galling, and Midland’s exclusive solid steel retaining bar prevents the ball from dropping out of the bottom of the valve. And should the valve “check,” a pressure bypass enables rapid reopening to reset it.

The combined capabilities of the A-719-ML/A-190 Dual Valve System have allowed it to meet the guidelines of the Chlorine Institute’s Pamphlet 68, which governs the use of “Dual Valve Systems for Bulk Chlorine Transport.” Specifically, Pamphlet 68 spells out performance and selection criteria that should be utilized when identifying and deploying dual valve systems that can be used in bulk chlorine transport. These criteria are in line with the performance standards set forth by the U.S. Department of Transportation and Transport Canada.

 

OPW Products

Finding the right solution for our customers is a mission without boundaries.

A strong global presence, coupled with extensive engineering, research and testing capabilities, enables OPW to create a steady flow of new products while, at the same time, helping enhance the performance of existing products.

View Our Products

 

Delivering the Best Quality Loading Arms

OPW offers premium-grade top and bottom loading arms, swivel joints, sight flow indicators, quick and dry disconnect couplers and safety breakaways for use in railcar rack systems and platforms, bulk plant and liquid terminals applications.

Engineered Systems Homepage

 

Safe and Efficient Fueling Transportation

OPW creates components and systems for use on tank trucks, tankers and rail tank cars to provide for the safe and efficient loading, transport, transfer, handling and unloading of petroleum-based fuels, chemicals and dry bulk cargo hazardous bulk products around the world.

Civacon Homepage Midland Homepage

 

Revolutionizing Fueling Operations Worldwide

OPW offers solutions for conventional, vapor recovery, DEF, Ethanol, Biodiesel, CNG, LPG and Hydrogen fueling, as well as a complete portfolio of solutions for above ground storage tanks.

Retail Fueling Homepage

 
 

Helping to Make Car Wash Operators Successful

PDQ has provided the car wash industry with cutting-edge technological advances in car wash equipment and car wash systems, including the first contouring arch and the Virtual Treadle.

PDQ Homepage Belanger Homepage

 

Delivering the Best Quality Loading Arms

OPW offers premium-grade top and bottom loading arms, swivel joints, sight flow indicators, quick and dry disconnect couplers and safety breakaways for use in railcar rack systems and platforms, bulk plant and liquid terminals applications.

Fluid Transfer Group Europe Homepage

 

Safe and Efficient Fueling Transportation

OPW creates components and systems for use on tank trucks, tankers and rail tank cars to provide for the safe and efficient loading, transport, transfer, handling and unloading of petroleum-based fuels, chemicals and dry bulk cargo hazardous bulk products around the world.

Fluid Transfer Group Europe Homepage

 

Revolutionizing Fueling Operations Worldwide

OPW offers solutions for conventional, vapor recovery, DEF, Ethanol, Biodiesel, CNG, LPG and Hydrogen fueling, as well as a complete portfolio of solutions for above ground storage tanks.

Retail Fueling Homepage