The low-velocity spray nozzle is utilized to facilitate the application and placement of the cement liner material. The nozzle is supplied by both a 1-inch plaster hose which provides delivery of the mixed cementitious material, and a 3/8 inch air line which provides delivery of compressed air. The material is injected with the compressed air within the body of the nozzle which in effect atomizes the material discharge from the nozzle into a conical shaped spray pattern. The actual discharge of the cementitious material from the nozzle is at a very low velocity, and therefore the nozzle is generally positioned 6-12 inches from the surface during spray application. This low velocity discharge produces little or no “surface rebound” of the cementitious material during application, thus making this material application technique very conducive for applications involving confined space entry parameters (i.e. manholes).
spray-nozzle