US 3646701 A
A portable thermal insecticide fogger including an internal combustion engine for generating hot exhaust gases that discharge from an outlet, a supply of liquid insecticide, and a diaphragm pump operated off the changing pressures of the internal combustion engine for pumping the liquid insecticide to a location upstream of the outlet for admixture and common discharge with the exhaust gases.
Description (OCR text may contain errors)
United States Patent [151 3,646,70 1
Plfaffenbach 1 Mar. 7, 1972  PORTABLE THERMAL FOGGER 3,533,387 10/1970 Kaneko ..4l7/380 X 1,408,208 2/1922 Jones ..417/380  Invent mmnbach 3,382,603 5/1968 066116.... ..43/129  Assignee: McGraw-Edison Company, Elgin,111. 3,205,176 9/1965 Tenney... 252/359 A 2,980,032 4/1961 Scheneider ...417/380 X  May 1970 3,145,659 8/1964 Svendsen ..417/3s0  App]. No.: 34,054
Primary ExaminerAldrich F. Medbery 52 US. (:1. ..43/129, 252/359 A, 417/380  Int. Cl. ..A0lm 19/00 [58 min ofSearch ..43/129; 239/1298, 138; ABSTRACT 417/380 381; 251/359 A A portable thermal insecticide fogger including an internal combustion engine for generating hot exhaust gases that  References cued discharge from an outlet, a supply of liquid insecticide, and a UNITED STATES PATENTS diaphragm pump operated off the changing pressures of the internal combustion engine for pumping the liquid insecticide bevey et to a location upstream of the outlet for admixture and com- Duff 6! a1..." mon the exhaust gases 2,611,992 9/1952 Loy et a1 3,045,605 7/1962 Nutten et al. ..4l7/380 6 Claims, 2 Drawing Figures PATENTEDMAR 7 I972 FIG] | NSECTHCI DE TANK v I I l NV E NTO Q- Aefl/ue pFAFFE/VBA 0/4 ATT'Y PORTABLE THERMAL FOGGER It is common to utilize the hot exhaust gases discharged from an internal combustion engine as a vaporizing medium for fogging liquid insecticides. The liquid insecticide is metered to and mixed with the exhaust gases, and discharged as a fog therewith. In large wheeled vehicle-type units, either an insecticide pump or gravity feed of the insecticide is possible to move the liquid insecticide from the storage tank to the admixture location. However, smaller hand held units are more compact and lightweight, so that only slight tilting of the unit is permitted before the gravity feed head is changed or even starved, and elaborate pumping and metering means prove impractical. Since the quality of fog depends on variables including the exhaust temperature and volume and the insecticide volume and type, some reliable metering means is needed to establish and hold the desired combination of insecticide and exhaust.
The main object of this invention is to provide in a thermal fogger having an internal combustion engine generating hot exhaust gases an improved insecticide pumping andmetering arrangement including a diaphragm pump operated off pressure impulses of the internal combustion engine.
This object and others will be fully appreciated after reviewing the following disclosure including the accompanying drawing, wherein:
FIG. 1 shows in an elevational view an overall arrangement of a portable fogger made in accordance with the subject invention;
FIG. 2 is a schematic type diagram showing the principle components including the internal combustion engine, the diaphragm pump powered thereby, and the working connections of each.
The fogger shown has a frame 12 supporting a small twocycle internal combustion engine 14, and a carrying handle 16. The engine exhaust manifold 18 is connected to an outlet mixing tube 20. A fuel tank 22 is connected via line 23 to the engine 14, and an insecticide tank 24 is connected via line 26, pump 28, line 30 and outlet control valve 32 to the mixing tube as at 36. Preferably the exhaust manifold includes a venturi 38 and the insecticide inlet 36 is immediately downstream of the venturi throat. The pump 28 is connected by line 40 to the air-fuel inlet connection 44 of the engine. A trigger control 46 is suitably connected to butterfly inlet control 48 of the engine and to the insecticide control valve 32 for common actuation. In thisregard, at the idle condition of the engine where butterfly 48 is substantially closed, the insecticide valve 32 is completely closed; and each is progressively opened upon actuation of the trigger until both are fully opened.
The engine crank rotates about axis 52 to move the rod connection 54 along a circular path 55, and the engine piston 58 reciprocates in the cylinder 60. The engine is shown in its power stroke where chamber 62 is filled with hot gases and expanding and where the size of the crankcase chamber 64 is reducing. A check mechanism 66 is located over the fuel-air intake 68 from the fuel line 23 so that the pressure in the crankcase chamber 64 then increases. Upon the piston 58 passing exhaust port 70 the hot exhaust gases escape through manifold 18 for discharge from the outlet tube 20, and the intake port 72 is also uncovered to admit the compressed fuel and air mixture in the crankcase chamber into the chamber 62. Upon the crank rod connection 54 passing the full stroke line 74 and the piston direction reversing, the crankcase chamber 64 is expanding to open the check 66 and draw fuel and air mixture into the crankcase chamber. A carburetor (not shown) between the fuel tank 22 and butterfly 48 provides proper air-fuel mixture. When the piston 58 passes the particular ports 70 and 72 the gas and fuel mixture in the chamber 62 is trapped and compressed, and ultimately ignited by spark plug 76.
The pump 28 is formed by two housing elements 80 and 81 secured together and having appropriate hollow cavities complementing one another with some being separated by or having therein a flexible element acting as a diaphragm or check.
Specifically, housing has inlet bore 84 which leads to an opening 85 at the face of the housing, while adjacent thereto a second opening 86 is provided which leads by means of passage 87 to an enlarged chamber 88 open to the face of the housing and further by passage 89 to an opening 90 at the face of the housing. An outlet opening 91 is provided in face of the housing 80 and is connected to the insecticide line 30 as noted above. The housing 81 has a cavity 92 which overlies and connects the openings 85 and 86 of the housing 80, a cavity 94 which overlies and connects the openings 90 and 91 in the housing80, and a cavity 96 opposite to the cavity 88 in the housing 80. The line 40 from the engine inlet is connected to this cavity 96. A thin flexible diaphragm element 98 is extended across and completely separates the chambers 88 and 96 from one another. Moreover, the flexible element is supported between the housings as at 99 and 100 to move asa check valve from a closed position against the adjacent opening to an open position separated from the opening. The flexi ble check valve 99 normally overlies and closes the inlet opening 85 whereas check valve 100 normally overlies and closes the outlet opening 90.
The normal operation of the engine provides pressure variation in the crankcase 64 and connected intake line 44, which pressure is communicated by the line 40 to the chamber 96 to flex the diaphragm element 98. in this regard and as illustrated, the crankcase chamber is superatmospheric and causes chamber 96 to increase and chamber 88 to decrease in size. Because the check 99 closes the port 85, any liquid in the chamber 88 is forced through passage 89 to open check 100, across the connecting chamber 94 and opening 91 to the pump outlet. When the piston 58 reverses direction and during the engine compression stroke, the crankcase chamber 64 goes to a sub atmospheric pressure to collapse the diaphragm element 98 towards the housing 81. Upon the volume of chamber SS-thus increasing, the check 100 closes and insecti-' cide is drawn from the tank 24 past the check element 99 into the chamber 88. The diaphragm pump being powered by gas pressures only cannot be destroyed even when the valve 32 is closed, while on the other hand provides insecticide flow proportionately as the engine output increases. Preferably, the valve 32 further has an adjustment means so that it can be adjusted to suit the fog consistency desired.
What is claimed is:
l. A thermal fogger comprising an internal combustion engine having an exhaust manifold and having a pressure line that experiences varying pressures during each cycle of the engine, an outlet tube including a venturi restriction therein, means connecting the exhaust manifold to the outlet tube for exhaust flow through the venturi restriction, a diaphragm pump having an inlet and an outlet and having a pressure connection for powering the pump, an insecticide tank, connecting means between the insecticide tank and the diaphragm pump inlet and between the diaphragm pump outlet and the outlet tube at a location immediately downstream of the venturi restriction, and means connecting the engine pressure line with the diaphragm pump pressure connection, whereby operation of the internal combustion engine pressure powers the diaphragm pump for forcing insecticide to the outlet tube for heating admixture with the exhaust downstream of the venturi restriction and for common discharge from the outlet tube.
2. A thermal fogger according to claim 1, wherein the internal combustion engine is a two-cycle engine having an intake manifold that experiences varying pressures during each cycle of the engine, and wherein the pressure line is connected to the intake manifold.
3. A thermal fogger according to claim 1, wherein the internal combustion engine has an output throttle control including a trigger mechanism, wherein a control valve is in the connecting means, and wherein linkage means responsive to the trigger mechanism also opens the control valve as the. throttle control is opened such as to increase the output of the engine.
mal fogger is portable and has a carrying handle.
6. A thermal fogger according to claim 3, wherein the connecting means control valve has a manual adjustment means 5 to achieve a desired insecticide flow at full output conditions.