Patent GB-1307706-A (GB)
Title: Spray nozzles
IPC: F23D11/38
Filed: 1970-03-19
Abstract: 1307706 Spray nozzles F F POLNAUER 19 March 1970 13382/70 Heading B2F '[Also in Division F4] The invention comprises a method of determining the B, D and H parameters for a logarithmic spiral flow spray nozzle where:- B is the minimum width of the swirl chamber inlet opening; D is the diameter of the nozzle outlet orifice, and H is the height of the swirl chamber, so that a nozzle with a pre-determined patternation index can be produced, said method involving operating a plurality of nozzles having different B, D and H parameters at different inlet fluid pressures which produce different actual pressure drops through the corresponding different nozzles, measuring the actual flow rate of each of the nozzles operated at the different pressures to determine the respective nozzle discharge coefficient at the different pressures, measuring the spray cone angles of the different nozzles at the different pressures, and producing from the measurements made the functions f 1 , f 2 , f 3  and f 4  of the following equations:- where:-' #P is the actual pressure drop of the nozzle, Kref is the nozzle discharge coefficient at a reference pressure drop, Cp is a correction factor, 2° ref is the spray cone angle at the reference pressure drop, and C2° is a further correction factor. The Specification discloses methods of designing a nozzle once the functions f 1 -f 4  are determined. The Specification further discloses nozzles having parameter ratios of the parameters B, H and H and also of the parameters L, R and S held within certain limits where:- L is the thickness of the orifice defining means at the orifice; R is the largest internal radius of the swirl chamber and, S is the thickness of a rib formed by the inner wall of the swirl chamber at the swirl chamber inlet. An example of a spray nozzle having a logarithmic spiral flow and for use particularly with burners is shown in Fig. 1 and comprises a housing 1 having located in a bore 6 thereof a swirl chamber body 2 and concentric therewith an orifice plate 3 formed with an outlet orifice 10, the swirl chamber body 2 having an inlet 13 tangential to an inner wall 14 thereof formed as a logarithmic curve. A cap 4 threaded on a body 1 retains the body 2 and plate 3 in place and leakage of the sprayed fluid is prevented by a seal. A further nozzle similar to that shown in Fig. 1 is described with respect to Fig. 7 (not shown). In a further embodiment, Fig. 12, a housing 22 has located in a bore 25 a swirl chamber body 2 and orifice plate 3, the fluid to be sprayed being admitted through a bore 26 via a filter 34. The parts 2 and 3 are held in place by a threaded cap 27 threaded at 23 to the housing 22. The peripheral portion 28 of cap 27 is of circular cross section and has located over it an air shroud 30, longitudinal cut-outs 32 of the shroud mating with channels 31 in cap 27 enabling air to enter the shroud and pass to the outlet region of the nozzle. A lock ring 39a prevents loosening off of the threaded connected 23 and a threaded portion 24 of the housing 22 enables the nozzle to be located in the wall of a combustion chamber or manifold. Further embodiments similar to that shown in Fig. 12 are described with respect to Figs. 15 and 16 (not shown).