Las Vegas -- New this year to the National Hardware Show was the Pitch Tank, where inventors got two minutes to demonstrate their new products to a panel of three experts for some criticism and advice. But there was no Simon Cowell skewering the amateurs in the glass-walled booth near the Inventor’s Spotlight section. Kevin Harrington of ABC’s Shark Tank and chairman of TVGoods, along with two other product development specialists and marketers, offered mostly positive feedback to a cavalcade of hopeful candidates.