Ventilation System for a Perishable Goods Store

Abstract

The present invention provides a ventilation system for a perishable goods store and a method of operating a ventilation system for a perishable goods store. The system of the present invention may monitor and control the temperature and humidity of the goods within the store and comprises a controller for automatically operating the system, a duct through which air is propelled into the store, pressure control means for controlling the pressure within the duct and a pressure monitoring means for measuring the pressure within the duct. The controller monitors the pressure within the duct and controls the pressure control means ensure the air pressure within the duct is maintained within a defined pressure range. The pressure control means may comprise at least one variable speed fan. The present invention is advantageous in that it optimises the back-pressure within the duct, against which the at least fan must act, thereby providing a more efficient ventilation system.

1 . A ventilation system when used with a perishable goods store comprising:
 a controller for automatically operating the system,   a duct through which air is propelled into the store,   a pressure monitoring means for measuring the air pressure within the duct; and   pressure control means for controlling the pressure within the duct;   wherein when air is propelled through the duct the controller monitors the duct pressure, as measured by the pressure monitoring means, and controls the pressure control means to ensure that the air pressure within the duct is maintained within a defined pressure range.   
     
     
         2 . The system according to  claim 1 , wherein the pressure control means comprises at least one variable speed fan. 
     
     
         3 . The system according to  claim 1 , wherein the pressure control means comprises a plurality of fans. 
     
     
         4 . The system according to  claim 3 , wherein the pressure control means comprises a plurality of fans operated in series. 
     
     
         5 . The system according to  claim 2 , wherein the at least one fan is an axial fan. 
     
     
         6 . The system according to  claim 2 , wherein the at least one fan is a centrifugal fan. 
     
     
         7 . The system according to  claim 2  further comprising a fan housing in which the at least one fan is housed. 
     
     
         8 . The system according to  claim 7 , wherein the fan housing comprises a closeable air inlet that allows air to be drawn into the housing by the at least one fan from the surroundings when air inlet is open and wherein the fan housing may draw air into the housing from within the store when the air inlet is closed. 
     
     
         9 . The system according to  claim 1 , wherein the pressure control means comprises at least one controllable opening from the duct. 
     
     
         10 . The system according to  claim 1 , wherein the pressure monitoring means comprises a pressure sensor positioned about one third of the length of the duct from the at least one fan. 
     
     
         11 . The system according to  claim 1 , further comprising a plurality of air speed sensors positioned within the goods stored within the perishable goods store for monitoring the air speed through the goods. 
     
     
         11 . The system according to  claim 1 , further comprising humidity monitoring means for monitoring the humidity within the store. 
     
     
         12 . The system according to  claim 11 , wherein the humidity monitoring means comprises a humidity sensor positioned within the duct. 
     
     
         13 . The system according to  claim 11 , wherein the humidity monitoring means comprises a plurality of humidity probes positioned within the perishable goods within the store. 
     
     
         14 . The system according to  claim 1 , further comprising humidity monitoring means for monitoring the humidity outside the store. 
     
     
         15 . The system according to  claim 10 , wherein the system is controlled to operate when the humidity within the store is outside of a defined humidity range such that the humidity within the store is corrected to within the defined range. 
     
     
         16 . The system according to  claim 1 , further comprising at least one heater. 
     
     
         17 . The system according to  claim 16 , further comprising temperature monitoring means for monitoring the temperature within the duct. 
     
     
         18 . The system according to  claim 17 , wherein when the system is operated and the temperature within the duct is below a set duct temperature the heater is operated to thereby raise the temperature within the duct. 
     
     
         19 . The system according to  claim 16 , further comprising temperature monitoring means for monitoring the temperature within the store. 
     
     
         20 . The system according to  claim 18 , wherein the temperature monitoring means for monitoring the temperature within the store comprises a plurality of temperature probes positioned within the perishable goods within the store. 
     
     
         21 . The system according to either  claim 19 , wherein the system, including the at least one heater, are controlled to operate and thereby raise the temperature of the air within the store when the temperature within the store is below a defined store temperature. 
     
     
         22 . The system according to  claim 1 , further comprising data storage means for recording data from the monitoring means and for recording when and how the components of the system are operated. 
     
     
         23 . The system according to  claim 1 , further comprising a plurality of exhaust means located around the store for controlling the exhaust of air from the store such that when the system is in use the volume of air being drawn into the store is substantially equal to the volume of air leaving the store. 
     
     
         24 . The system according to  claim 23 , wherein the exhaust means comprise exhaust louvers. 
     
     
         25 . The system according to  claim 23 , wherein the exhaust means are automatically controlled by the controller. 
     
     
         26 . A method of operating a ventilation system of a perishable goods store comprising a duct through which air is propelled into the store, wherein the air pressure within the duct is monitored and pressure control means are used to control the pressure within the duct such that it remains within a defined pressure range. 
     
     
         27 . A The method according to  claim 26 , wherein the air speed through the perishable goods is monitored and when the system is operated it is controlled to provide at least a minimum air speed through the goods.