Cooling system for a blower

Arrangement in a blower including at least an engine and a fan, the fan includes a fan housing enclosing a fan wheel and a fan inlet. The engine and fan are surrounded by a casing provided with an air inlet to let air in to the fan inlet placed inside the casing. The air stream from the air inlet in the housing to the fan inlet cools the engine and components inside the casing before it enters the fan inlet and leaves the blower via a blower tube. The fan housing is provided with an opening (31) placed in the fan housing so that air is allowed to leave the fan in case of blocked air stream in the fan outlet or blower tube.

BACKGROUND OF THE INVENTION

The claimed invention relates to an arrangement in a blower comprising at least an engine and a fan. The fan comprises a fan housing surrounding a fan wheel, a fan inlet and a fan outlet. The engine and fan are surrounded by a casing provided with an air inlet to let air in to the fan inlet placed somewhere inside the casing. The air stream from the air inlet in the casing to the fan inlet cools the engine and components inside the casing before it enters the fan inlet and leaves the blower via a blower tube.

Engine powered blowers are frequently used for different kinds of work outdoor. The number of areas where blowers are used are increasing. In many areas are blowers replacing traditional brooms since a blower is an efficient and time saving tool for cleaning of large areas such as parking places, pavements and lawns.

In order to reduce the sound emitted from the tool does an insulated casing surround the engine and related components in the tool machinery. In order to make the insulating casing effective is the casing provided with as few and small openings as possible. The engine and some of the components inside the casing, however, generates a lot of heat when they are running and it is important that the components inside the casing are cooled in order to prevent tool break down because of overheated and damaged components inside the casing.

The engine rotates a fan comprising a fan housing enclosing a fan wheel and a circular fan outlet placed around the periphery of the fan wheel. The air to the fan enters the casing through an opening in the casing and passes the engine and the components inside the casing that needs cooling on its way to the fan inlet placed inside the casing. The cool air is thereby cooling the engine and components before it enters the fan inlet and then finally leaves the tool via an exit opening in the fan housing and a bower tube connected to the exit opening in the fan housing. The operator maneuvers the blower tube to make the tool perform the intended work.

This solution works satisfying as long as the air is passing through the fan and the blower tube. If the air stream through the blower tube or the fan for some reason is blocked or stopped will no cool air be sucked into the casing and the fan. This means that no cool air will pass the engine and components inside the casing and the cooling of the engine and components is thereby not working as intended. If this happens is it a risk that the engine or someone of the components inside the casing will overheat and cause a break down of the tool.

BRIEF SUMMARY OF THE INVENTION

The claimed invention eliminates the risk that the engine or components inside the casing will overheat in case of blocked or stopped air stream through the fan or blower tube.

The problem is solved by providing the fan housing that encloses the fan wheel and fan outlet with an opening placed somewhere in the fan housing.

If the air stream through the fan or blower tube for some reason is blocked will the pressure inside the fan and blower tube increase since no air leaves the system. The increased pressure inside the fan generates an air stream through the opening in the fan housing. The air stream through the opening reduces the pressure inside the fan housing and makes it possible for cool air to enter the fan inlet so that the cooling of the engine and components inside the casing will be maintained even though the blower tube or fan is blocked.

The opening in the fan housing is placed so that the opening is pointing towards a section of the tool casing where the heated air stream from the opening could be lead out from the casing to avoid that the heated air is circulated inside the casing and increases the temperature inside the casing further. The opening is preferably placed in a position on the fan housing where the pressure inside the fan housing is low during normal running of the blower to minimize the amount of leaking air through the opening during normal running conditions. One preferred position for the opening is close to the periphery of the fan wheel on the side of the fan housing that is facing towards the operator.

DETAILED DESCRIPTION OF THE INVENTION

InFIG. 1is a blower10illustrated. The blower10comprises an insulating casing11surrounding a tool engine20and machinery. The casing11is provided with two straps12and a waist belt13to make it possible for the operator to carry the blower comfortably on the back. A blower tube14with a flexible section18is extending from an exit opening19in the casing11placed on the right side of the blower body. The blower tube14is placed close to the hip of the operator and the end of the blower tube14positioned in front of the operator during use. The operator controls the movement of the blower tube14with a handle15or a handle bar placed on the blower tube14. Some blowers have a handle15provided with a lever to control the speed of the engine20. On the topside of the casing11is a handle16placed to facilitate transports and movements of the blower10when it not is placed on the back of the operator and in the lower section of the blower10is a fuel tank17placed where it is easy for the operator to refill the fuel tank17.

The tool engine20, illustrated inFIG. 2, is powering a fan also placed inside the casing11. The fan comprises a fan housing24enclosing a fan wheel21and a circular fan outlet22placed around the periphery of the fan wheel21. The fan wheel21is placed parallel to the back of the operator and the engine20is placed in axial direction outside the fan wheel21. In the bottom of the casing11is an air inlet26for air to the fan placed (see arrowhead inFIG. 1pointing to the underside of the blower10). The air enters the air inlet in the bottom of the casing11and passes the engine20and other components that need cooling on its way to a fan inlet23placed on the side of the fan wheel21facing away from the operator. The air to the fan is thereby cooling the engine and components inside the casing11before it enters the fan inlet23and leaves the blower10via the blower tube14connected to an outlet pipe25on the fan housing24. The outlet pipe25is placed close to the exit opening19in the casing11.

If the air stream through the fan housing24or blower tube14for some reason is blocked will the cooling of the engine20and related components placed in the air stream to the fan inlet23be lost since no air will pass through the fan housing24and blower tube14.

The claimed invention ensures that the engine20and components inside the casing11will be cooled even though the air stream through the fan housing24or blower tube14is blocked.

The claimed invention is illustrated in the perspective view inFIG. 3. InFIG. 3is one section30of the fan housing24illustrated. The fan housing24is enclosing the fan wheel21and comprises the circular fan outlet22and outlet pipe25. The substantially flat side of the section30of the fan housing24inFIG. 3is placed towards the back of the operator. The section30of the fan housing24is provided with an opening31placed close to the periphery of the fan wheel21.

The opening31is preferably provided with a guiding cover32around at least a part of the opening31so that the air stream generated from the opening31in case of a blocked fan outlet22or blower tube14is lead towards the exit opening19in the casing11where the heated air is allowed to exit the blower casing11. The air stream from the opening31could also be lead through other openings in the tool casing if they are better positioned or for some reason more favorable to use.