pressure fluid is pumped down the power fluid tube 40 through a plurality of ports 66 in the fishing neck 68 which is threaded into the top portion of the carrier housing 58 as indicated at 70 the fishing neck 68 also serves to secure the nozzle 72 onto its shoulder 74 on the carrier 58 this seating shoulder determines the spacing of the nozzle 72 above the top of the mixing tube 56 as well as providing a pressure seal the mixing tube 56 is located and secured in place by interference or press fit in the upper areas 78 and the lower areas 80 of the carrier 58 and by chemical adhesive means in between the press fitted areas the location of the carrier 58 is determined by the shoulder 82 which contacts a matching machined shoulder in the upper seating bore 64 this shoulder provides a positive mechanical fluid seal additional sealing is provided by one or more o rings at 76 a further function of the shoulder 82 besides the aforementioned locating and sealing functions is that its greater diameter prevents the o ring seals 83 immediately below it from contacting the walls of the power fluid tubing when the pump is traveling to or from the surface during pumping or retrieval likewise the shoulder 92 functions primarily to protect the o ring seals 94 from.