This new year brought new regulations from the worker's comp office where owner-operated firms without staff are subjected to inspections for safe workplace conditions.
A few minor tweaks were needed like installing flashback arrestors on all my air to gas connections (yeah, a useless expense) and the fitting of an electric gas valve meaning propane is only available when my blower is turned on.
However the issue of free hands when using the bombarder came up. They'd prefer I wire two deadman switches in series forcing me to hold two momentary switches, mounted 24" apart, at the same time to activate the bombarder. I've always kept one hand free to adjust the choke or stopcocks but stay away from the leads and tube being pumped.
I understand what they are trying to arrange, a similar setup is used on hydraulic presses to prevent crushing of the worker's hands, but are there any downsides to this setup for bombarding?
Thanks for any input you can offer.
Thank you for the reply. My contactor enclosure is on the side wall next to the manifold and just above that is a double-pole double-throw disconnect switch that feeds the 240v to the contacts. This was a requirement for my electrical inspector for two reasons: to act as an emergency disconnect device (breakers are in the basement) and it's equipped to accept a padlock to keep the circuit open when not in use. Guess this offers the same redundancy as the two contactors in series except that I have to throw the disconnect manually if the contacts ever weld together.
I'll probably wire the deadman switches as requested just to keep the next inspector happy,
Last thing I need is the gas inspector getting refered by the WCB folks. He's forced other shops in the region to replace all the latex and other barb-type connections with brazed-on flare-type fittings that must use approved 3/8" Type 1 threaded propane hose assemblies to carry the pure propane to the mixing valves and the air-gas mix to the fires. Even the handtorches must have a threaded fitting attached to accept the above gas hose. A 15-foot section of approved hose can get a bit heavy after a long day.
I use a 240v contactor powered by a 24v dc transformer. I run the 24v dc power through a big red button momentary switch which powers the contactor you could use 2 buttons. I always keep my left hand in my pocket when bombarding and stand on an thick rubber mat.This way i am never exposed to more than 24v dc power. Can you explain what you used for your propane metering valve this is something I have had concerns about as a potential safety hazard in my shop. I should mention i also have a switch to turn of the 120v power to the 24v transformer should the momentary switch become stuck in the on position.
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The only real downside is it may take a few seconds longer to process a unit. But 24" apart seems a bit excessive.
I also recommend redundant relay/contactors (use 2 instead of 1) wired in series. I have one wired to my dead-man on/off push button (I am not yet required to have 2 buttons) and the other to a separate, normal on/off toggle switch. If you have 2 push buttons you could wire 1 contactor to each button. The reason for this is, points-type contactors that are commonly used with bombarders have been known to weld themselves together in the closed position. If this happens it is impossible to turn off the bombarder by releasing the push button. The only way to turn it off is to run to the panel box and turn the breaker off. With 2 contactors in series, it is extremely unlikely that both would stick closed at the same time. Releasing the 2 push buttons (assuming you have them wired as described above) will immediately turn off the bombarder.
For those who use a foot pedal, please consider the set up mentioned above. Two free hands around an energized bombarder is an accident waiting to happen. If new regulations come to your area, or if they already exist and you are ignoring them, you may have to do it at some point anyway. Better to be safe than sorry.