Hello pavemanpro, great question. First lets look at spray application. There are a couple pump type sytems that are very reliable. First system is hydraulic, these type of pump systems are common on dual squeegee machines, large truckmounted units that utilize spray bar applications and dual wand applicators with heavy sand loads.. Second, is air diaphram pump system. No differance except Air is more cost effective and easier to maintain than a hydraulic pump system. In your case having a 550 gravity flow, i would suggest putting on a smaller air diaphram pump to spray, i assume small commercial and private driveways are your markets at this time. There are a few companies that sell air pumps and hydraulic pumps. Check with Neal, Sealmaster, or any of the equipment manufacturers that specialize in this. I also feel your sealer supplier also will have valuable info on what you need as well as where to get it! Now, in regards to sealer in your hose. Wet pavement sealer in your hose does not set up under normal working situations. If you completed a job and shut your rig down, the sealer that is in your hose is under minimum pressure, and is air free. this will keep the sealer wet. If air intrusion occurs you will find that it will be very chalky thick. If Sealer is in your tank for very prolonged periods of time, water evaporates from the sealer and will settle out the solids to the bottom. The addition of some water while agitating will loosen and remix the sealer, but it should not harden like a rock. Only if your sealer has not been agitated for a season will it become totaly hard. Thankyou for your question.
