Dew point control of insulating glass
Issuing time:2019-07-17 16:18
Insulating glass is widely used as building energy - saving material because of its good heat insulation and sound insulation. At the same time, the quality requirement of insulating glass is higher and higher. It is understood that the biggest quality problem of insulating glass is the condensation of air layer in use. Therefore, controlling the dew point of insulating glass is the key to control the quality of insulating glass.
In the process of using insulating glass, when the ambient temperature drops to the dew point in the dry air layer, the surface of the dry air layer will produce dew or frost. The dewing or frosting on the inner surface of glass will affect the properties of insulating glass. If air layer above 40 ℃ below zero no condensation, hollow glass in use process will not appear the phenomenon of condensation air layer.
1. Cause analysis of dew point rise
The dew point of insulating glass refers to the temperature when the air humidity in the air layer reaches the saturation state. Below that temperature, water vapor in the air layer condenses into liquid water. The higher the content of water, the higher the dew point temperature of the air. When the temperature of the inner surface of the glass is lower than the dew point of the air in the air layer, the moisture in the air will form dew or frost on the inner surface of the glass. Dew point rise of insulating glass is caused by external moisture entering the air layer and not being absorbed by the desiccant. There are three reasons that may lead to dewpoint rise:
(1) There are bubbles in the sealant memory, causing air moisture to enter.
(2) Water vapor diffuses into the air layer through the polymer.
(3) The desiccant has a low effective adsorption capacity.
2. Insulating glass dew point control measures
(1) strictly control the humidity of the production environment
Production environment mainly affects the desiccant adsorption capacity and residual adsorption capacity.
(2) reduce the diffusion of water through the polymer
It mainly depends on the selection of sealant with low permeability coefficient and the determination of reasonableseal thickness to reduce the temperature difference between inside and outsideof insulating glass (that is, to control the production within a certain temperature range without making the temperature range too large).
(3) reduce production process time
Reduce the contact time between the desiccant and the atmosphere as far as possible and reduce the loss of the adsorption capacity so that the desiccant has a higher adsorption capacity.
(4) select appropriate aluminum profiles
The air gap of the fine hole should be small to reduce the water absorption of the molecular sieve in the process of operation.
(5) choose the right desiccant
To choose a higher adsorption rate and lasting desiccant.
It is believed that the quality of insulating glass can be obviously controlled through material selection, processing and environment control.