Drying and gas or vapor contact with solids – Apparatus – With indicating or testing means
Reexamination Certificate
2003-05-12
2004-02-24
Bennett, Henry (Department: 3743)
Drying and gas or vapor contact with solids
Apparatus
With indicating or testing means
C034S497000, C034S089000, C034S108000, C034S595000
Reexamination Certificate
active
06694638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to the field of tools and devices used for maintenance and repair services of residential and commercial dryers. More particularly, the present invention relates to the field of tools and devices used for quickly and easily determining the source of malfunction of residential and commercial dryers.
2. Description of the Prior Art
A typical problem causing malfunction of residential and commercial dryers is the clogging of the hot air vent pipe or hose connected to the dryer. Ordinarily the vent pipe provides an exhaust conduit for the hot air and moisture generated from the dryer when the dryer is operating. However, lint, small items (such as women's stocking) and other debris from the dryer operation often accumulate inside the vent pipe which causes the vent pipe to be clogged. In addition, kinked pipe or hose also block the exhaustion of the hot air and moisture from the dryer. As a result, the performance efficiency of the dryer may be significantly reduced. In worst cases, the dryer will malfunction and the clogged vent pipe or conduit will become a fire hazard.
When a dryer becomes less efficient or malfunction, the user often calls for maintenance or repair service which can be very expensive. Often times the service personnel is not sure whether the problem is from the dryer itself or from other sources such as the vent pipe or conduit connected to the dryer, and has to make a laborious effort to find out exactly what is wrong. Unfortunately many standard warranties that come with the new dryers only cover services performed directly on the dryers and do not cover the services for checking up the vent systems. In such event the consumer user has to pay for the services for checking up the vent systems which can be quite expensive.
It is therefore desirable to have a new testing device which can provide a quick and easy check-up of the vent pipe or conduit connected to a dryer to determine whether it is clogged, before laborious effort is undertaken to examine and repair the dryer.
SUMMARY OF THE INVENTION
The present invention is a dryer vent check strip for quick and easy checking of whether a vent pipe or conduit connected to a residential or commercial dryer is clogged, kinked or broken. It can also be used to check the dryer as well.
It is an object of the present invention to provide an inexpensive, portable and disposable device that can be used to quickly and easily check a residential or commercial dryer and/or the vent system of the dryer.
When a dryer functions normally, it heats air going into the dryer drum. This warm dry air picks up moisture from the clothes and blows it out the vent pipe or hose. The temperature inside the dryer may be approximately in the range of 120 to 170 degrees Fahrenheit (° F.). For example, the dryer temperature for cotton clothes may be approximately 155° F. and for permanent press 135° F. If the vent is unblock and permits hot moist air to be exhausted at the outside or distal end of the vent pipe or hose, then the dryer can function normally to dry the clothes inside. In this case the temperature at the distal end of the vent pipe or hose will be very close to that inside the dryer.
If the vent is blocked because of a kinked or broken vent or a build up of lint, the dryer can not move the moist air away from the drum and the dryer can not get the clothes dry. In this case the temperature at the distal end of the vent pipe or hose will be substantially lower than that inside the dryer.
The present invention provides a dryer vent check device in the form of a flexible thin strip that has a temperature sensitive area.
The temperature sensitive area of the present invention dryer vent check strip is pre-treated with a material such as a chemical ink that changes its color under a particular temperature.
When used, one vent check strip is placed inside the dryer and another vent check strip is placed at the outer or distal end of the dryer vent pipe or hose. As the dryer is turned on and allowed to operate for a while, if the dryer itself functions normally, the temperature sensitive area of the inside vent check strip will change to a known color to indicate that the temperature inside the dryer has reached to a certain degree, i.e., 140° F. Meanwhile, if the temperature sensitive area of the outside vent check strip changes to a similar color, it means that the temperature of the hot exhaust air is about the same as the temperate inside the dryer, indicating that the vent system is unclogged. However, if the dryer vent system is clogged, the temperature sensitive area of the outside vent check strip will not change to the similar color as the temperature of the exhaust air is much lower than that inside the dryer due to the clogging of the vent system. In this way, the user or technician can quickly identify the problem and perform the appropriate repair service.
Described generally, the present invention is a device for checking the condition of a vent pipe connected to a dryer and th dryer itself by checking temperature. The vent check device is a generally elongated thin strip made of a flexible material. It has a pre-treated temperature sensitive area that changes its color at a threshold temperature within a working temperature range of the dryer when the dryer functions normally. The vent check strip can be placed inside the vent pipe at a location adjacent to an outer end of the vent pipe. After the dryer is turned on to perform its normal drying function for a period of time until it reaches its working temperature range, the vent check strip can be retrieved for examination.
The present invention has many advantages. It provides a quick way to determine whether a dryer malfunction is caused by a clogged vent system. It is light weight, flexible, portable and inexpensive. It is also very easy to use.
REFERENCES:
patent: 5860224 (1999-01-01), Larson
Krioukov Oleg
Krioukova Zoya
Bennett Henry
Chen Tony D.
Nguyen Camtu
Rozsa Thomas I.
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