Why is the LPD Better?
Speed of Drying
Typically the vacuum dryer will dry materials in one-sixth the time of a desiccant dryer. If your desiccant dryer drying time is 4 hours, the vacuum dryer will do the job in 40 minutes. The result is time-savings of 3 hours and 20 minutes every time you start up a dryer. This not only represents reduced energy cost (see below), but could also represent 3 hours and 20 minutes of additional production time.
Side-by-side testing of the vacuum dryer and a desiccant dryer shows reduced energy consumption of 70 – 80%. The key to the reduced energy consumption is that the vacuum dryer does not rely on desiccant. Desiccant, once saturated, must be regenerated by a heating and cooling process so it will again be able to absorb moisture. All energy required to regenerate desiccant is lost to ambient.
Since desiccant degrades over time it must be replaced on a regular basis. This expense is avoided with a vacuum dryer. In addition the need to monitor the condition of desiccant is eliminated.
Low Material Stress
Long drying times at elevated temperatures can cause thermal, chemical and physical material degradation. Materials if exposed to prolonged elevated temperature during drying run the risk of degradation including discoloration and/or IV drop which leads to reduced physical properties of the end product. The reduced drying time required with the vacuum dryer dramatically reduces the risk of material degradation. Since the vacuum dryer first heats up the material, then applies vacuum to accomplish drying the heating cycle is only 20 to 30 minutes.
On-The-Fly Material Change
Additional savings can be achieved with the vacuum dryer in the form of on-the-fly material changes. Since the vacuum dryer dries in batches a material or color change can be accomplished on-the-fly. This means no downtime related to clean-out of the drying hopper during a material change. Every time you have a material change with a desiccant dryer the dryer must be shutdown and the drying hopper cleaned. This is normally a time-consuming, labor-intensive process. The vacuum dryer will automatically notify the operator when it’s time to conduct an on-the-fly material change. No interruption of the drying process occurs during the on-the-fly material change.
The LPD Dryer Microprocessor Controller
The LPD controller is very simple to use. The dryer may be operated by simply setting the proper temperature and cycle time on the thumbwheels located to the right. The display will indicate temperature and elapsed cycle time or, alternatively, temperature and vacuum level. If a problem occurs during operation an alarm strobe and horn will be activated and the nature of the problem will be indicated on the display. The controller monitors numerous alarm conditions to ensure proper performance. Comparable to a dew point monitor, vacuum level is always monitored to ensure proper vacuum level is maintained.
As an aid to monitoring dryer performance and documenting operation a printer port is provided on the controller. A printed output of dryer operation may be obtained for each drying cycle.
The controller can be easily removed for service or replacement. If you have a controller problem a complete new control panel may be installed in minutes.
How the LPD Dryer Works:
Filling: In the first stage the canister is filled with material using a specially designed dispense valve to ensure the canister can never overfill. Mounted above the dryer is a surge hopper for material resin which ensures the canister can be filled in the minimum amount of time necessary.
Heating: As the canister is being filled the heating process also begins. Temperature settings are made easily by simply dialing in the required temperature on the thumbwheels of the controller.
Due to the relatively small volume of the canisters when compared to traditional large drying hoppers the material can come up to the required temperature rapidly. Once the canister has been heated for the time set it will then index automatically to the next stage.
Changing Materials on the LPD Dryer
Canister Removal and Cleaning:
Each canister is easily removed from the central carousel by releasing two latches.
Once the canister is removed and emptied all material contact surfaces can be readily accessed for quick and simple cleaning. By turning the canister upside down operators can access the screen by rotating the retaining plate and then both the plate and the screen are removed for complete cleaning.
Surge Hopper Removal and Cleaning:
Material Take-off Pan Cleaning:
|LPD 30||LPD 100 (LPD 12)||LPD 200||LPD 1000|
|Standard version max.||350ºF||180ºC||350ºF||180ºC||350ºF||180ºC|
|Throughput||30 lb/h||15 kg/h||100 lb/h||50 kg/h||200 lb/h||90 kg/h|
|Canister volume||0.32 cu ft||9||1.1 cu ft||30||2 cu ft||57|
|Empty weight||550 lb||250 kg||730 lb||250 kg||950 lb||430 kg|
|Packing weight||620 lb||280 kg||800 lb||360 kg||1010 lb||480 kg|
|Packing dim. (LxWxH)||40″x35″x75″||100x90x190 cm||40″x35″x85″||100x90x190 cm||40″x35″x85″||100x90x190 cm|
|Total Power Supply||460V/3Ph/60Hz||400V/3Ph/50Hz||460V/3Ph/60Hz||400V/3Ph/50Hz||460V/3Ph/60Hz||400V/3Ph/50Hz|
|3.47 kW/16 A||3.47 kW/16 A||6.96 kW/20 A||6.96 kW/20 A||7.7 kW/30 A||7.7 kW/20 A|
|Compressed air requirement||70-90 psi||6 – 8 bar||70-90 psi||6 – 8 bar||70-90 psi||6 – 8 bar|
|Compressed usage||0.4 cfm||0.7 m3/h||2 cfm||3.4 m3/h||2.4 cfm||4 m3/h|
* US voltage: 480, Europe / Asia voltage: 400
|Material||Final Moisture % *||Cycle Time (Min.)**||Drying Temperature***|
|PET (Molding Grade)||0.010||30-35||150||300|
|PET (Preform, Ext.)||0.005||30-35||150||300|
Please note the following: