Patent Application
20150069147
The disclosure relates generally to spray guns operated with air supplied by a high-volume, low pressure (HVLP) turbine blower to spray liquids such as paint.
Various spray guns are known in the art. Some rely on high pressure air flows, typically in the range of 40-50 pounds per square inch, to atomize and discharge liquids. Others rely on high-volume, low pressure (HVLP) air flows, typically under 10 pounds per square inch.
Various HVLP spray guns rely on standard compressors. Others rely on high-volume, low pressure turbine blowers that are often used in association with paint sprayers. Turbine air flow is constant and can be varied by a turbine motor from approximately 2 to 10 PSI. Turbine motors are preferred as they result in a more efficient atomization of liquids and lower wastage of liquid.
Various HVLP turbine spray guns are known in the art. Some rely on fan size adjustment at the rear. Some rely on fan size adjustment at the front air jet. Others rely on fan size adjustment, side-mounted behind the front barrel.
An embodiment of the present disclosure describes an apparatus for spraying liquids for use in association with an HVLP blower and a fluid container. The apparatus has an air inlet port which can be connected to the HVLP blower. Air is divided into two horizontally adjacent channels, a variable channel and an open channel, both in flow communication with the air inlet port and both receiving air from the HVLP blower. A side controller is positioned such that the flow of air through the variable channel can be varied whereas the air flow through the open channel remains constant. The spray head is for mixing air from one or both channels as well as fluid from the fluid container.
More specifically, the open channel feeds air into the centre orifice and the variable channel feeds air into two side orifices such that when air is cut off from the variable channel the output fluid mixture has a substantially circular shape and when air flows through the variable channel the output fluid mixture has a substantially fan shape.
In another embodiment, a rotatable nipple extends from one or more of the spray gun's air channels and a second nipple extends from the fluid container such that the nipples are connected by a tube and some air is diverted from the channels to drive fluid from the container to the spray head.
In an alternate embodiment, the fluid container can be located above the spray gun such that gravity in addition to pressure drives the fluid into the spray head.
In another embodiment, a common trigger controls all air flow from the air inlet port such that fluid mixture only exits the spray gun when the trigger is activated.
The air and liquid may be mixed externally of the spray head.
Further features will be described or will become apparent in the course of the following detailed description.
a is a side view of an embodiment of the spray gun;
b is a cross sectional view of a portion of an embodiment of the spray gun showing the variable channel when air is allowed to flow through;
a is a side view of an embodiment of the spray gun and showing rotation of the side air controller;
b is a cross sectional view of a portion of an embodiment of the spray gun showing the variable channel when air is cut off by the side air controller;
The embodiments will now be described by way of example only, with reference to the accompanying drawings, in which:
A high volume low pressure manual spray gun that operates from a standard HVLP turbine blower is shown in
The spray head 185 has a liquid jet 15 that discharges liquid received from the container and an air jet 10 surrounds the liquid jet 15. The air valve 80 and liquid needle valve 95 are operated with a common trigger 155 in sequence to ensure that paint is not introduced before atomizing air. The air flows within the barrel 165 are directed through passages in the air jet 10 to atomize and spray the discharged liquid.
Trigger 155 is pivotally attached to the barrel with a trigger pin 160 and a retaining ring 150. Trigger 155 is operably connected to air valve 80 and liquid needle valve 95.
Referring to
Referring to
As shown in
As shown in
The rotatable nipple assembly 70 includes a nipple 75, a rotatable portion 205, a small seal 210, a nipple assembly nut 215, a large seal 220 and a retaining ring 225. The rotatable nipple assembly 70 allows the flexible tube 190 (shown in part in
To control the size of the fan pattern by turning a knob requires the pressurized air to pass from a main air channel 170 through to the right air channel or open air channel 175 and left air channel or variable 180 that are separate and distinct. The left air channel 180 airflow is controlled by a side air controller 110. The right air channel 175 is always fully open for constant airflow. These passages reside in the main barrel 165 behind the spray head 185. Airflow through the right air channel 175 is diverted by the air divider 35 through to the air diffuser 20 so that air flows only through the center hole of the air jet 10. Airflow through the left channel is controlled by a rotating side air controller 110 allowing varying levels of airflow through to the spray head 185. The air flow from the left air channel 180 is diverted by the air divider 35 and through the air diffuser 20 so that air flow can only pass through the side holes of the air jet 10.
When air is passed through both air channels the atomized liquid is discharged in a wide ‘fan’ pattern. When air is completely cut off by the side air controller 110 in the left air channel 180, the atomized liquid is discharged in a small round circular pattern. By turning the fan control knob 125 to restrict and vary air volume through the spray head 185, a full incremental range of fan sized patterns can be produced.
Unlike other HVLP turbine spray guns with side mounted fan control, the barrel 165 is split down the middle forming two natural horizontal air channels set side by side. This method allows for both right 175 and left air channels 180 to have a much greater cross sectional area, as compared to spray guns where the channels are an upper and lower channel, resulting in greater airflow through the spray head 185. The left air channel 180 is fitted with a rotating side air controller 110 to reduce or shut off the air flow thereby adjusting the size of the fan of the atomized liquid discharge.
A unique rotatable nipple assembly 70 placed in a unique location at the rear of the barrel 165 supplies pressurizing air to the container through a flexible tube 190 attached to the nipple 75. The flexible tube 190 connects nipple 75, which is part of the rotatable nipple assembly 70, to the other nipple 75 attached to the liquid container 200. A liquid tube 195 extends into the liquid container 200. Pressurized air from flexible tube 190 is connected to the liquid container 200 so that liquid container 200 is pressurized and liquid is forced into the spray gun when the trigger 155 is activated.
Several advantages are achieved over the prior art, particularly HVLP turbine spray guns with side mounted fan pattern control. Placing the two air channels side by side allows for a greater volume of airflow through the spray head 185 reducing back pressure and air turbulence in the gun barrel 165 and through the spray head 185. Placing the two air passages side by side streamlines the linear air flow producing superior atomization. Use of a simpler, shorter side air controller 110 reduces the incidence of jamming and the need for periodic adjustment.
An alternate embodiment is shown in
As used herein, the terms, “comprises” and “comprising” are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms, “comprises” and “comprising” and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components.
As used herein, the term “exemplary” means “serving as an example, instance, or illustration,” and should not be construed as preferred or advantageous over other configurations disclosed herein.
As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.
Unless defined otherwise, all technical and scientific terms used herein are intended to have the same meaning as commonly understood to one of ordinary skill in the art.
