QUESTION: I’m having an air-lock problem. Our treatment plant has a discharge station where we hook up to a 4-inch female camlock and unload. They meter our loads by the gallon while unloading. Out of all the haulers in the area, my truck is the only one having an air-lock issue when discharging. This morning my truck only got about 15 gallons off and then locked, but when the staff crack a ball valve the air lock lets go and I’m fine. If they don’t do that I’m stuck! So if I come in after hours I’m really stuck.
If I came in tomorrow there might not be any issues at all. It seems to be a hit and miss.
My truck has a 2-inch ball valve on top of the tank to release the air, but I seem to have a lot of air in the discharge hose when I open the valve (after hooking to the discharge station). If I flick one of the cam ears off at the building, air will escape and get the flow going the odd time, but most of the time it doesn’t work. Any tips or ideas?
ANSWER: An air lock is a gas trapped in the high point of a liquid-filled pipe system such as the one you describe. Inside the system, the gas – being lighter than the liquid – rises to the highest point and restricts the flow of liquid.
I’m not sure what gas you have forming, but it can be as simple as oxygen. It rises to its highest point and stops your flow. If you have ever suctioned water from a swimming pool, and your suction starts the water flowing but it soon stops, it is because an air bubble has been created inside the system and it’s strong enough to block the liquid from flowing. Even though your point of suction is lower than the pool, the water will not flow. The key is to prevent creation of the air bubble. If the bubble forms, you need a place for it to vent itself. Basically, it’s time to “burp” the line.
The solution is to install an air-release valve somewhere in the line. Since you most likely are dealing with flexible hose for discharging, installing a release valve on the fitting closest to the discharge hose is the answer.
The other thing you might watch for are the materials in the tank. Since you are the only one with this air-lock problem, perhaps you are building up a different kind of gas than your fellow pumpers who have no problem. You also might check to see how their discharge hoses are set up. It seems if everybody is pumping in the same way, others should have a similar problem. See how they are discharging and you might find a simple answer.
My suggestion is adding an air-relief valve on the fitting of the discharge hose. Be careful not to pop the clutch when starting the pump.
QUESTION: I have a driver who is continually shearing the key in the keyway on the power take-off (PTO). He says he does nothing wrong and claims it’s just bad luck. What can I tell him that might be more factual than mere bad luck?
ANSWER: Tell him to go easy on the clutch when he starts the pump. If he is popping the clutch rather than easing off it, you will get a sheared key on the PTO and it will not work. It is a time consuming and somewhat costly fix.
More and more pumpers are transitioning to automatic transmissions because fewer and fewer people are learning how to drive with a standard transmission. This eliminates the problems caused by lack of finesse on the clutch while starting the PTO.
A final word on transmissions this month: Make sure the truck you buy has a PTO provision. This allows the manufacturer to hook up the PTO with little problem. If the truck does not have the PTO provision, there is no way to rebuild that transmission to hook up the PTO. You will require a separate engine-driven pump.
