Dryer with air recirculation/heat exchange subassembly

Patent metadata

Field	Value
Publication number	US-9695544-B2
Application number	US-201213437501-A
Country	US
Kind code	B2
Filing date	Apr 2, 2012
Priority date	Apr 2, 2012
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

A laundry dryer is provided with a modular air recirculation subassembly fitted beneath a rotatable drum of the dryer. The subassembly has an air recirculation passage provided between an air supply passage and an air exhaust passage of the dryer. The air recirculation subassembly further has a flow directing flap at the juncture of the air inlet passage and the air recirculation passage to direct the recirculation air flow toward a heater and away from an inlet end of the air supply passage. The air recirculation subassembly may include a filter positioned across the air recirculation passage upstream of the heater, which filter is removable through the air exhaust passage. The subassembly may further include a heat exchanger to transfer heat from the warmer air exiting the exhaust passage to the cooler air entering the air supply passage, and a recirculation air flow regulating flap.

First claim

The invention claimed is:

1. A subassembly for a dryer with a heating tube, a process air fan, and a drum, the subassembly comprising:
an air inlet passage configured to join with an inlet of the heating tube of the dryer;
an air exhaust passage configured to join with an outlet of the process air fan of the dryer;
an air recirculation passage provided between the air inlet passage and the air exhaust passage;
a flow directing flap provided at a junction of the air recirculation passage and the air inlet passage, serving to direct a recirculation air flow toward the heating tube and away from an inlet end of the air inlet passage, wherein the flow directing flap comprises a band portion and a visor-like flap portion connected to said band portion; and
a flow regulating flap provided at a junction of the air exhaust passage and the air recirculation passage;
wherein, the subassembly is configured to fit beneath the drum of the dryer in interconnection with the inlet of the heating tube and the outlet of the process air fan.

2. The subassembly of claim 1 , further comprising a heat exchanger providing thermal communication between the air inlet passage and the air exhaust passage.

3. The subassembly of claim 1 , wherein a minimum cross-section of the air exhaust passage is larger than a minimum cross-section of the air recirculation passage.

4. The subassembly of claim 1 , wherein the visor-like flap portion comprises a convex surface on a first side and a concave surface on an opposite side.

5. A laundry dryer comprising:
a drying chamber;
an air inlet passage provided upstream of the drying chamber for supplying air to the drying chamber;
an air exhaust passage provided downstream of the drying chamber for exhausting heated air and water vapor from the drying chamber;
a heater positioned along the air inlet passage for heating air passing through the air inlet passage;
a process air fan downstream of the drying chamber and upstream of the air exhaust passage;
an air recirculation passage fluidly connecting the air exhaust passage and the air inlet passage;
a flow directing flap provided adjacent a junction of the air recirculation passage and the air inlet passage, serving to direct a recirculation air flow toward the heater and away from an inlet end of the air inlet passage, wherein the flow directing flap comprises a band portion and a visor-like flap portion connected to said band portion; and
a flow regulating flap provided immediately adjacent a junction of the air exhaust passage and the air recirculation passage, serving to regulate an amount of air flow into the air recirculation passage.

6. The laundry dryer of claim 5 , further comprising a heat exchanger providing thermal communication between the air inlet passage and the air exhaust passage.

7. The laundry dryer of claim 5 , wherein a minimum cross-section of the air exhaust passage is larger than a minimum cross-section of the air recirculation passage.

8. The laundry dryer of claim 5 , wherein the air inlet passage, the air exhaust passage, the air recirculation passage, the flow directing flap, and the flow regulating flap are collectively configured to mix recirculated air with fresh air upstream of the heater in a ratio of recirculated air to fresh air no greater than 1.2:1.

9. The laundry dryer of claim 5 , wherein the visor-like flap portion comprises a convex surface on a first side serving to direct inlet air toward said heater, and a concave surface on an opposite side serving to guide recirculation air past said air recirculation passage and toward said heater.

10. A modular recirculation air flow unit for an exhaust-type laundry dryer comprising:
an air inlet duct configured to join with an inlet of a heater of a laundry dryer;
an air exhaust duct configured to join with an outlet of a process air fan of the laundry dryer;
an air recirculation duct provided between the air inlet duct and the air exhaust duct; and
a heat exchanger providing thermal communication between the air inlet duct and the air exhaust duct;
wherein, said unit has a maximum depth dimension of no greater than approximately 31″ (787 mm), a maximum width dimension of no greater than approximately 27″ (686 mm), and a maximum height dimension of no greater than approximately 20″ (508 mm);
wherein, in an installation orientation of the unit in the laundry dryer, the air recirculation duct extends upwardly at a non-right angle from its point of connection to the air exhaust duct to its point of connection to the air inlet duct;
wherein, in an installation orientation of the unit in the laundry dryer, the air inlet duct extends upwardly at an angle from its point of connection to the heat exchanger to its point of connection at the heater; and
wherein a connecting part of the heater is arranged at a greater height than the air inlet duct and the air exhaust duct with respect to a bottom floor of the laundry dryer.

11. A modular recirculation airflow unit according to claim 10 , wherein said maximum depth dimension is no greater than approximately 27.5″ (700 mm), the maximum width dimension is no greater than approximately 24″ (600 mm), and the maximum height dimension is no greater than approximately 16″ (400 mm).

12. A modular recirculation airflow unit according to claim 10 , wherein said maximum depth dimension is approximately 20″ (500 mm), the maximum width dimension is approximately 20″ (500 mm), and the maximum height dimension is approximately 14″ (350 mm).

13. An exhaust-type laundry dryer including a rotatable drum and a modular recirculation air flow unit fitted beneath the drum, said air flow unit comprising:
an air inlet duct configured to join with an inlet of a heater of the laundry dryer;
an air exhaust duct configured to join with an outlet of a process air fan of the laundry dryer;
an air recirculation duct provided between the air inlet duct and the air exhaust duct; and
a heat exchanger providing thermal communication between the air inlet duct and the air exhaust duct;
wherein, in an installation orientation of the unit, the air recirculation duct extends upwardly from its point of connection to the exhaust duct to its point of connection to the air inlet duct;
wherein, in an installation orientation of the modular unit, the air inlet duct extends upwardly at a non-right angle from its point of connection to the heat exchanger to its point of connection at the heater; and
wherein a connecting part of the heater is arranged at a greater height than the air inlet duct and the air exhaust duct with respect to a bottom floor of the dryer.

14. A laundry dryer according to claim 13 , wherein a flow regulating flap is situated at the point of connection of the air recirculation duct to the air inlet duct.

15. A laundry dryer according to claim 14 , wherein a flow regulating flap is situated at the point of connection of the air recirculation duct to the air exhaust duct.

16. A laundry dryer according to claim 13 , wherein a flow regulating flap is situated at the point of connection of the air recirculation duct to the air exhaust duct.

17. A laundry dryer according to claim 13 , wherein, in said installation orientation of the unit, the air inlet duct extends upwardly from its point of connection with said heat exchanger to its point of connection with said air recirculation duct.

Assignees

• Cavarretta Francesco
• Vignocchi Massimiliano
• Ugel Maurizio
• Bison Alberto
• Electrolux Home Products Corp Nv

Inventors

• Cavarretta Francesco
• Vignocchi Massimiliano
• Ugel Maurizio
• Bison Alberto

Classifications

• D06F58/20 Primary

  General details of domestic laundry dryers  (D06F59/00 takes precedence) · CPC title

• D06F58/02 Primary

  having dryer drums rotating about a horizontal axis · CPC title