Not every hose is the same – hose applications in the plastics industry
Hoses in the plastics industry tend to be rather inconspicuous and their importance easily underestimated. However, observant visitors to a plastics processing factory are often surprised at the hugely diverse applications in which hoses are used. Choosing the right hose or hose system is vital because any application is only as good as its hose. NORRES, the Gelsenkirchen based hose manufacturer, offers a broad range spanning all hose applications and supports its customers efficiently in the search for the perfect hose.
Plastics extrusion and injection moulding are a good example that is found almost ubiquitously – many different hoses are used to transport plastic pellets and powders in virtually every manufacturing step, from the arrival of the raw materials at the plant through production to shipping.
Careful selection of the hose systems is essential, as the failure of just one hose can paralyse an entire application. And in a modern production facility, the failure of an application can quickly result in economic damage in the region of several thousand euros. The right hose system is also a key element of efforts to reduce energy costs. Given that it is not unusual for each production line to have around two hundred interfaces along a conventional transport path from the silo to the extruder, and that leakage can occur at any of these points if the hoses are assembled incorrectly, it is not difficult to imagine the potential energy saving that is facilitated by the use of suitable hose systems. However, let's take one step at a time. We'll start with the arrival of the raw materials.
Arrival
Example: A plastics manufacturer receives deliveries of plastic pellets several times a week in silo vehicles. The pellets are conveyed into the silos through hoses. The experts at NORRES recommend choosing the AIRDUC® 356 reinforced hose for this purpose, clamped in the CONNECT Safety Clamp System 230 – a system for thick-walled polyurethane spiral hoses that are used to load and unload silo vehicles. This system enables polyurethane hoses, which are much lighter and more flexible, to take the place of rubber hoses, which are heaver, less flexible and far less resistant to abrasion. Once the plastic pellets have been loaded into the appropriate silos, various transport processes can begin.
Preparation for production
Next, the pellets are supplied to the piping. The AIRDUC® 355 and AIRDUC® 356, clamped in the CONNECT Safety Clamp System 231, are excellently suited here.
Pellet drying
The plastic pellets are pumped through the piping into the drying equipment. Here, too, hoses play an important role – they control the air supply and heat the pellets.
NORRES offers a good alternative to NEO or SIL hoses, namely HT-PUR. These hoses are particularly heat-resistant and they age comparatively slowly, even if the temperature reaches 150°C. The fact that the material shows a 40 percent improvement in mechanical stability and very high resistance to abrasion during heat exposure is an immense advantage.
Transport and distribution
The pellets exit the dryer and are fed through the downstream piping via more hoses. The transparent version of the AIRDUC® 355 hose system is recommended for this step. It allows the process to be observed, so that any errors in production are detected before it is too late. The pellets are subsequently transported onward through the piping to the hose stations.
The hose stations are where other hoses distribute the product to the various production stations and processes – for instance to the dosing equipment, the suction conveyors on the extruders or the injection moulding machines.
Packaging process
Hoses are also needed to pack the finished products: they help extrude and blister foils, suck away packaging waste and add small parts to the packages.
Since May 2009, explosion protection measures in Germany have been governed by TRBS 2153 – which also applies to the transport of plastic pellets, for example, if large amounts of dust are produced as a result of the conveying process or the plastic is transported in powder form. Compliance with TRBS 2153 is nearly always stipulated if the plastic is delivered in silo vehicles, because its sheer volume is assumed to inevitably lead to high dust levels.
General statements contained in TRBS 2153 (formerly BGR 132):
A new section describing the pneumatic transport of combustible bulk materials has been incorporated. This section refers to the situation where a potentially explosive atmosphere exists inside the hose. In such cases, the hose wall should be made of material that is either conductive or capable of electrostatic discharge.
TRBS 2153 is not a directive but a technical rule. It is a legislative text.
TRBS 2153 is an ownership based rule, in other words responsibility for ensuring compliance with this technical rule lies primarily with the owner.
Hoses in the Plastics Industry
Not every hose is the same – hose applications in the plastics industry
Hoses in the plastics industry tend to be rather inconspicuous and their importance easily underestimated. However, observant visitors to a plastics processing factory are often surprised at the hugely diverse applications in which hoses are used. Choosing the right hose or hose system is vital because any application is only as good as its hose. NORRES, the Gelsenkirchen based hose manufacturer, offers a broad range spanning all hose applications and supports its customers efficiently in the search for the perfect hose.
Plastics extrusion and injection moulding are a good example that is found almost ubiquitously – many different hoses are used to transport plastic pellets and powders in virtually every manufacturing step, from the arrival of the raw materials at the plant through production to shipping.
Careful selection of the hose systems is essential, as the failure of just one hose can paralyse an entire application. And in a modern production facility, the failure of an application can quickly result in economic damage in the region of several thousand euros. The right hose system is also a key element of efforts to reduce energy costs. Given that it is not unusual for each production line to have around two hundred interfaces along a conventional transport path from the silo to the extruder, and that leakage can occur at any of these points if the hoses are assembled incorrectly, it is not difficult to imagine the potential energy saving that is facilitated by the use of suitable hose systems. However, let's take one step at a time. We'll start with the arrival of the raw materials.
Arrival
Example: A plastics manufacturer receives deliveries of plastic pellets several times a week in silo vehicles. The pellets are conveyed into the silos through hoses. The experts at NORRES recommend choosing the AIRDUC® 356 reinforced hose for this purpose, clamped in the CONNECT Safety Clamp System 230 – a system for thick-walled polyurethane spiral hoses that are used to load and unload silo vehicles. This system enables polyurethane hoses, which are much lighter and more flexible, to take the place of rubber hoses, which are heaver, less flexible and far less resistant to abrasion. Once the plastic pellets have been loaded into the appropriate silos, various transport processes can begin.
Preparation for production
Next, the pellets are supplied to the piping. The AIRDUC® 355 and AIRDUC® 356, clamped in the CONNECT Safety Clamp System 231, are excellently suited here.
Pellet drying
The plastic pellets are pumped through the piping into the drying equipment. Here, too, hoses play an important role – they control the air supply and heat the pellets.
NORRES offers a good alternative to NEO or SIL hoses, namely HT-PUR. These hoses are particularly heat-resistant and they age comparatively slowly, even if the temperature reaches 150°C. The fact that the material shows a 40 percent improvement in mechanical stability and very high resistance to abrasion during heat exposure is an immense advantage.
Transport and distribution
The pellets exit the dryer and are fed through the downstream piping via more hoses. The transparent version of the AIRDUC® 355 hose system is recommended for this step. It allows the process to be observed, so that any errors in production are detected before it is too late. The pellets are subsequently transported onward through the piping to the hose stations.
The hose stations are where other hoses distribute the product to the various production stations and processes – for instance to the dosing equipment, the suction conveyors on the extruders or the injection moulding machines.
Packaging process
Hoses are also needed to pack the finished products: they help extrude and blister foils, suck away packaging waste and add small parts to the packages.
Since May 2009, explosion protection measures in Germany have been governed by TRBS 2153 – which also applies to the transport of plastic pellets, for example, if large amounts of dust are produced as a result of the conveying process or the plastic is transported in powder form. Compliance with TRBS 2153 is nearly always stipulated if the plastic is delivered in silo vehicles, because its sheer volume is assumed to inevitably lead to high dust levels.
General statements contained in TRBS 2153 (formerly BGR 132):
A new section describing the pneumatic transport of combustible bulk materials has been incorporated. This section refers to the situation where a potentially explosive atmosphere exists inside the hose. In such cases, the hose wall should be made of material that is either conductive or capable of electrostatic discharge.
TRBS 2153 is not a directive but a technical rule. It is a legislative text.
TRBS 2153 is an ownership based rule, in other words responsibility for ensuring compliance with this technical rule lies primarily with the owner.
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Photo 1: CONNECT 231
Photo 2: AIRDUC® 356 clamped in the CONNECT Safety Clamp System 230
Attachments
norres_1_connect_231 (GIF)
2_norres_airduc® pur 356 mhf-as verstärkt eingeb (JPG)
norres_logo (GIF)
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