The present invention relates to a secondary
counter flow barrel type
heat exchanger, which comprises an outer
barrel body with the upper part connected with a hot air inlet, a hot air outlet, a
tap water inlet and a
tap water outlet respectively. The hot air outlet is communicated with the inner cavity of an outer
barrel body; an inner barrel body is arranged in the outer barrel body, the upper end of the inner barrel body is connected with the
tap water outlet, and the tap water outlet is communicated with the inner cavity of the inner barrel body; the hot air inlet is connected with a heating
pipe, the heating
pipe is inserted into the inner barrel body and penetrates form the bottom part of the inner barrel body and is communicated with the inner cavity of the outer barrel body. The periphery of the inner barrel body is coiled with a screwy tap water heat absorbing
pipe, the head end of the tap water heat absorbing pipe is connected with the tap water inlet, and the
tail end is connected with the bottom part of the inner barrel body and is communicated with the inner cavity of the inner barrel body, and the present invention forms a secondary
counter flow heat exchanging structure. The present invention saves the heat absorbing
copper pipe in the original patent, thereby the cost is low, the volume is small, the space is small, the installation is easy and the acid cleaning is convenient. The
water temperature can reach more than 38 DEG C, and is incessant. The materials are chosen stainless steel and a red
copper pipe, and the service life is as long as 10 years.