| 摘要 |
A self-service, wet-vacuum cleaning machine for carpets, upholstery, and the like, utilizes a hand-held tool attached to both a vacuum hose and a hot water hose. A motor driven pump operates for a metered time to provide hot water under a high pressure in a direction that closes a valve in the hand tool to prevent spraying until it is called for by manually unseating the valve, thus allowing hot water to be sprayed on an area to be cleaned by wet-vacuuming. A spring in the valve housing exerts a force against the valve in a direction to unseat it, but not with sufficient force to do so against the hot water pressure. When the hot water pump is turned off, cold water under line pressure enters the hot-water hose through a T-fitting at a controlled low rate and passes through the valve now opened by the spring. This flow at a low rate prevents freezing in the hot water hose or spray valve.
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