FAQ

Frequently Asked Questions

 The most important advantage of desiccant air dryers is that they absorb moisture from the air through different kinds of desiccant materials. The dryer delivers very dry air to a vessel holding the plastic resin. By heating up the resin for a period, the moisture residing in the resin will be driven to the surface and taken away by the very dry air. Air dewpoint is typically -40 degrees F or below.  

 Some plastic materials absorb small amounts of water in humid, summer months. Because plastic material is a good insulator, it also does not want to give off the absorbed moisture very easily. If the moisture level in the resin is not removed, it will cause many problems in quality of the part.  Unfortunately, in many cases the flaws do not show up until later in premature part failures. When selecting a dryer, it is important to consider the rate of usage, drying temperature, the time the material is exposed to the recommended temperature, the air flow of the dryer to remove the moisture vapor and the dryness of the air being passed across the material known as dewpoint. 

Pressure dew point is the main difference between refrigerated and desiccant air dryers. Refrigerated air dryers are used in air conditioning systems and other applications. They can give pressure dew points between +35 and +40° F. On the other hand, a desiccant air dryer can attain a pressure dew point much lower – into the negative degrees. Thus, the desiccant air dryer produces very dry air for whisking away any moisture. Resin material suppliers recommend dewpoints below – 40 F and an exposure time of 4 hours or more.

 Normally, desiccant products of closed-loop systems have a life cycle of 3 years. However, the products may be damaged before these times. It depends on the environment in which it operates, and the materials being dried. When the desiccant is contaminated by oils in the resin, effectiveness is reduced and it must be replaced. Desiccant is field replaceable.  

Most equipment manufacturers will size a system to meet your needs but to do a proper job certain information is required. The important information needed is the required pounds per hour, the distance the material must travel, and the number of twist and turns the material must take. Elevation above sea level of the plant location is critical also. With this information a specialist can determine the pump size, horsepower, and line size needed to provide an efficient working system. 

The sizes of the vacuum pump sound enclosures depend on multiple factors. First, how much sound is produced and what is the desired level of control? Second, how many vacuum pumps work in the set-up? Lastly is whether the room where vacuum pumps are placed has enough space to set sound enclosure for each pump.    

 

Frequently Asked Questions

What is an advantage of desiccant air dryers for drying plastic resin? 

 The most important advantage of desiccant air dryers is that they absorb moisture from the air through different kinds of desiccant materials. The dryer delivers very dry air to a vessel holding the plastic resin. By heating up the resin for a period, the moisture residing in the resin will be driven to the surface and taken away by the very dry air. Air dewpoint is typically -40 degrees F or below.  

 What are the keys to drying resin material? 

 Some plastic materials absorb small amounts of water in humid, summer months. Because plastic material is a good insulator, it also does not want to give off the absorbed moisture very easily. If the moisture level in the resin is not removed, it will cause many problems in quality of the part.  Unfortunately, in many cases the flaws do not show up until later in premature part failures. When selecting a dryer, it is important to consider the rate of usage, drying temperature, the time the material is exposed to the recommended temperature, the air flow of the dryer to remove the moisture vapor and the dryness of the air being passed across the material known as dewpoint. 

 What is the difference between refrigerated and desiccant air dryers? 

 Pressure dew point is the main difference between refrigerated and desiccant air dryers.  Refrigerated air dryers are used in air conditioning systems and other applications. They can give pressure dew points between +35 and +40° F. On the other hand, a desiccant air dryer can attain a pressure dew point much lower –  into the negative degrees. Thus, the desiccant air dryer produces very dry air for whisking away any moisture. Resin material suppliers recommend dewpoints below – 40 F and an exposure time of 4 hours or more.  

How long does desiccant material last in a dryer before needing replacement? 

 Normally, desiccant products of closed-loop systems have a life cycle of 3 years. However, the products may be damaged before these times. It depends on the environment in which it operates, and the materials being dried. When the desiccant is contaminated by oils in the resin, effectiveness is reduced and it must be replaced. Desiccant is field replaceable.  

What are the keys in determining a properly sized vacuum pump? 

Most equipment manufacturers will size a system to meet your needs but to do a proper job certain information is required. The important information needed is the required pounds per hour, the distance the material must travel, and the number of twist and turns the material must take. Elevation above sea level of the plant location is critical also. With this information a specialist can determine the pump size, horsepower, and line size needed to provide an efficient working system. 

What size vacuum pump sound enclosures do I need? 

The sizes of the vacuum pump sound enclosures depend on multiple factors. First, how much sound is produced and what is the desired level of control? Second, how many vacuum pumps work in the set-up? Lastly is whether the room where vacuum pumps are placed has enough space to set sound enclosure for each pump.    

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