Safety

As machines have become more automated, many manual tasks have been eliminated as well as the hazards associated with human/machine interaction.

However, many of these interactions still occur on a regular basis giving a false sense of security. Manual loading, material change over, tooling adjustments and jam clearing require safety system in place to provide safe employee access to the machine before any of these tasks are performed.

We are pleased to present high performance tools to assist with these safety situations. Ross Controls offers fluid power safety valves with the options of either internal or external monitoring. In all safety rated devices (PLc, PLd, PLe) some form of redundancy and comparison of performance is applied.

What does that mean exactly?

Internal monitoring is when the valve self-checks its performance and if it determines a failed shift or issue of diminished performance has occurred. If so, it returns the valve to a predetermined safe condition and takes itself out of future operation until reset.
This is a less complex solution, often found in smaller / less complex machines and requires a safety relay only in the output portion of the electrical controls to the valve.

External monitoring is when a safety controller or safety PLC monitors the shifting of the valve internals and makes a determination whether to fault and stop operation, or to continue. This is more complex as the decision making has to be wired to and programmed in the external device. External monitoring often becomes advantageous in larger machines where multiple safety functions are required.

Ross offers safety pneumatic valves with either internal and external monitoring options where competitors only offer external monitoring. The following examples are all 3^rd party certified PLe.

How are these safety valves applied?

Safe Exhaust (Dump) 3/2 Normally Closed

• DM2, safety valve (internal monitored). Although it can also be utilized in more complex safety circuits.
• RSe, safety valve 3/2 (external monitored)

Safe Return Home 5/2 where air is at port 4 in the safe, at rest, condition

• CM26, safety valve (internal monitoring)
• RSe, safety valve (external monitoring)

Control reliable cylinder return valves can result in increased safety and savings. Typical safety designs look to remove the air to a machine or zone. If there is a single actuator hazard it can be controlled with a safety actuator return control valve to position the actuator in the safe position when de-energized, providing point of use safety control. Typical applications are machines with two hand control systems or that use presence sensing devices for manual loading. This provides not only safety but offers savings in air consumption by simply returning the actuator to the safe position and eliminates any downtime due to refilling the system.

Safe Pressure Select

• RSe, safety valve PLC (external monitoring)

The RSe 5/2 Series valve can be applied in a dual pressure application which requires safe, reduced or limited pressure, and a higher operational pressure. This would allow users to use safe as the default pressure when required (human machine interaction) and would fi to the higher pressure when selected for normal / auto operation.

An example of this might be that safe, limited pressure, is used when an operator is loading parts into a machine but reverts back to the higher pressure when the operator is out of the loading area. This reduces the potential of serious injury by limiting the pressure and reducing force.

This correlates to reduced torque mode in an electric servo or collaborative robot.

Safe control and load holding

• CC4 safety valve 5/3 closed center (external monitoring)

Safe Cylinder stop valves result in increased safety and savings while eliminating unwanted down time and movement. If there is a single actuator hazard where stopping is the preferred safety solution the ROSS CC4 can provide the safety and actuator control in a single control reliable valve. This valve is a poppet valve and has greatly reduced or non-existent leak in the center closed position as compared to a spool valve. This valve is a safety rated valve that replaces the concept of PO checks for load holding. (Cylinder sealing performance may still impact actuator motion.)

Machines with two hand control systems, or that use presence sensing devices for manual loading or unloading, are typical applications as well processes where losing position can result in unwanted scrap of material or increased employee machine interaction.

Now you know that Ross offers more!

While competitors only offer one technological solution, Ross offers multiple. Ross Controls remains one of the industry’s strongest leaders in pneumatic safety valves and Donald Engineering is a proud distributor.

If you are in need of a Ross safety pneumatic valve for your application, contact your Donald Engineering Technical Salesman today!

Bringing in solutions from ROSS Controls and Continental Hydraulics, Donald Engineering applies Category b-4, Performance Level c-e components to control your stored energy sources. Control Reliable safety isn't just a matter of electrical control. Alternate energy sources, such as gravity, compressed air, and hydraulic pressure from accumulators or pump systems must also be dealt with to ensure maximum safety.

If a solenoid sticks, spring breaks, or contact welds itself shut, do you know how your energy source is going to be controlled and whether or not you can safely enter the machine environment?

Let the safety professionals from Donald Engineering help you with a risk assessment and its documentation, allowing you to move forward confidently knowing you've applied the appropriate equipment and understand the best-known safety practices.

All too often, it is believed that controlling a machine's electrical power supply will mitigate the risk of accident or failure and render the machine safe.

However, when it comes to machine safety, electrons are just one of many forces and factors that need to be considered. Energy from compressed air, hydraulic pressure, and gravity are often overlooked. Donald Engineering offers not only the components to build a safety system, but the skills and expertise to apply them correctly as well. From risk assessment and risk mitigation, to control reliable containment of energy, we'll help you to properly design a safety system that protects your employees and your investment in order to ensure a lower total cost of ownership.