The design of the dye dosing systems depends on dye sorts used on particular paper machines. It depends whether the solutions are made of powder products or whether ready-made liquid dyes are dosed and dissolved by ratio before applying.

If dyes are prepared from powder products (for example FeOx slurries – iron oxide colour pigments for decor paper manufacture) the products are purchased either in 20 kg sacks or450-650-1000kg “Big-Bags”. The systems are similar in both cases. 

The plant consists of a hopper able to contain hundred kgs of product (depending on a specific weight) – then either a 430 liter 3 hopper or a 1 to 2 m silo is used. A device for “Big-Bag” packaging is either delivered with a lifting tower or an existing proper lifting device is utilised. The powder material is furnished into the hopper and from there transported into a dissolving tank by means of worm conveyor in a defined mode. The conveyor drive is controlled by means of frequency converter to achieve high dosing accuracy.
The quantity of the product furnished into the tank is measured by means of strain gauge installed in the dissolving tank legs.

The covered tank contains a high performance dispersing agitator of a performance designed as per the dissolved material and the final concentration. The agitator work element is a Z-disc.

The agitator is driven directly. Its electric motor is driven by means off requency converter.Thus, the system variability concerning the usage mode is enhanced. The dissolving tank components are a water measuring system, a high-pressure wall and an agitator shower system, a material furnish air filtration and measuring & control (M&C) elements (such as level and temperature sensors). The solution is pumped either by a diaphragm pump driven by pressure air (of a high capacity and a long lifespan) or by a screw (Mohno) pump (with or without a performance control) or by a centrifugal pump. The solution is pumped into a storage tank of a volume designed from the given conditions

The storage tank volumes are in a very wide 3 range from 3 to 100 m . They are equipped with agitators to achieve homogeneity of the solutions or slurries. They are equipped with level sensors and emergency limit level sensors.

The design of the dosing stations depends on the required capacity in the range of tens up to thousands of litres per hour. The pumps are either an electrically driven diaphragm type or a screw type, always controlled by means of frequency converters. The solution or slurry throughput is measured by means of inductive flowmeter or mass flowmeter for higher demands. The dosing station is designed with regards to the performance and it contains either one or more pumps with needed fittings and M&C elements. Usually it is designed as a compact unit connected to the inlet and outlet pipelines by means of standard flanges. The connection to the power and signal cabling systems is designed with regards to the conditions on site.

Concentrator boxes as well as switchboards can be used or the M&C elements are connected directly to the mill control system in the main electric distribution cabinet.

Material:

• Plastics (PP, PE) or AISI 304/316 stainless steel depending on the used product

The tanks are either delivered fully assembled (standing on legs and fixed to concrete foundations by means of anchor bolts) or they are welded on site – in such case the
tank bottom is concrete grouted.

The systems for purchased liquid raw materials include proper pumps to enable a liquid dye delivery into proper 3 storage tanks (volume 3 to 100 m ) from 1 000 kg IBC containers. Usually diaphragm pumps driven by pressure air or screw (Mohno) pumps or centrifugal pumps are used; the choice depends on the raw material properties.
The storage tanks are equipped with agitators to enable a permanent slurry or solution homogeneity. The dosing station is designed in the very same way as described above.

The plants preparing and dosing FeOx slurries are similar to those used for china clay, PCC, GCC, TiO and others. 2 They differ only in their performances used for particular applications

The machinery design and safety comply with the EU and EAC industrial standards.

Biocide storing and dosing systems sare always designed t oprovide maximum operation safety referring to the product nature. Biocides are presumably purchased in 1 000 kg IBC containers or alternatively in 200 kg drums.

If the IBC containers are used the “mother daughter” configuration of two vertically positioned IBCs (one above another) can be possibly utilised. The bottom work container volume is 1 200 liters to contain the entire volume of the top standard 1 000 kg IBC.Both containers are placed in a steel frame.The top container from where the agent flows to the bottom work container by gravity is put into the frame by means of crane or forklift.The bottom work container is equipped with a limit level sensor or an analogue 4 to 20 mA level sensors providing the paper machine (PM) control system with the container level status signal.

Biocides are dosed by precise electric diaphragm dosing pumps with built-in processors. The number of the pumps is derived from the number of the dosage points to be served, usually 3 to 6 pumps. Given that only especially trained personnel is allowed to operate them, the dosing pumps are installed in a locked glassed-in case. They are remotely controlled by means of the PM control system and the dosing diagram is set on the basis of the biocide sort and on the grade of the microbial pollution. Then the pumps work intermittently or continuously.

The suction system is connected to flushing water advantageously utilised for servicing pumps or another dosage station part. For the output system between the pump and the dosage point either special resistant plastic hosepipes with protective sheaths or stainless pipes are used depending on the particular conditions. The only required electric installation works are plugging the dosing pumps in main socket outlets and connecting the pump control signal cables

The station is put in a sump preventing a biocide leakage in case of purchased biocide packaging damage or leak. In the installation places there are always safety showers with drinking water for eye flushing and body showers used in case of hitting other body parts or pieces of clothing

Defoaming agent storing and dosing systems

Defoamers are presumably purchased in 1 000 kg IBC containers or alternatively in 200 kg drums. If the IBC containers are used the “mother-daughter“ configuration of two vertically positioned IBCs (one above another) can be possibly utilised. The bottom work container volume is 1 200 liters to contain the entire volume of the top standard 1 000 kg IBC.

Both containers are placed in a steel frame.The top container from where the defoamer flows to the bottom work container by gravity is put into the frame by means of crane or forklift. The bottom work container is equipped with a limit level sensor or an analogue 4 to 20 mA level sensors providing the paper machine (PM) control system with the container level status signal.

Defoamers are dosed by precise electric diaphragm dosing pumps or screw (Mohno) pumps. The number of the pumps is derived from the number of the dosage points to be served, usually 1 to 3 pumps (e.g. white water for top and bottom ply, cooking starch etc.).

The suction system is connected to flushing water advantageously utilised for servicing pumps or another dosage station part. Either plastic hosepipes or stainless pipes are used depending on the particular conditions of the output system between the pump and the dosage point

The pump performance is controlled by means of frequency converters. Pumps are protected by pressure sensors and the dosed quantities are measured by inductive flow meters. It is recommended to advantageously dissolve products before applying using pure filtrate or fresh water. Water flow is measured also by means of inductive flowmeters and the dosage is set on a constant throughput with a hand wheel valve.

The dosage station electric installation is designed as a small electric switchboard or a concentrator box. The station is designed as a compact unit installed in an assembly frame. Thus the installation and putting the station into operation are significantly simplified.

The machinery design and safety comply with the EU and EAC industrial standards.

The plants enable to prepare filler and pigment slurries in required concentrations, to store them in storage tanks and to dose them into the process in set quantities. In papermaking the issue is preparing slurries of china clay, micro ground limestone (GCC), precipitated calcium carbonate (PCC), talc, bentonite, titanium dioxide and others.

Concept

• Slurry preparation intermittent mode
• The preparation mode depends on packaging paper sacks, 1 000 kg “BigBags” or large capacity silos
• Furnish is weighed by means of strain gauge sensors
• The slurry outlet concentration is controlled by means of the control system as a ratio of furnished raw material quantity and measured water volume
• Slurry storage tank with a slow running agitator and measuring & control (M&C) elements
• Dosing pump performance controlled by means of frequency converter with an inductive flowmeter
• Electric switchboard with a control system

Raw material dosage mode

• If 1000 kg “Big-Bags” are purchased “Big-Bag” stations are delivered optionally with lifting devices on the customers’ request
• If paper sacks are purchased, furnish is manually poured into a hopper
• The hopper with a worm conveyor and M&C elements
• The conveyor with a controlled drive furnishes raw material into a dispersing tank in quantities weighed by the strain gauge
• Water volumes poured into the dispersing tank are controlled by means of an inductive flowmeter or strain gauges

Slurry storage tank

• Slow running agitator
• The volume depends on a paper machine 3 output(2 – 150 m
• M&C elements (level sensors, a limit level sensor preventing a tank overflow
• Depending on the tank size accessories are delivered (service platforms, safety elements like handrails, ladder self closing gates etc.)
• Dispersing plant 3D model with two “Big-Bag” towers

Slurry dosage mode

• Screw (Mohno) pump performance controlled by means of frequency converter
• On-line dilution circuit setting a required slurry work concentration is delivered on demand; the circuit is controlled by means of the paper machine control system
• The flushing water circuit is installed for automated pipeline cleaning
• The slurry dose is controlled by means of the system controlling the slurry throughput and alternatively also a dilution water ratio depending on the PM performance
• The calculated slurry furnish quantity depends on paper dry matter as per the customer’s request and the PM performance

If raw material slurry is purchased directly from the supplier, the pigment dosage is designed as the dosing station described above (a set of a storage tank, a pump, an on-line dilution circuit with automatic fittings and a control system).

The machinery design and safety comply with the EU and EAC industrial standards.

Rope threading system is used for utomatic paper web threading through the threading ropes from the press part via drying section onto the reel of the paper machine.

Design

It consists of a set of pulleys, rope stretchers and if necessary a rope drive. Auxilliary chutes and air pipes with nozzles can be used as other equipment to be placed in transfer points. A two-rope system is applied normally, but for heavier paper grades a three-rope system can be used. Because of different speeds in different parts of PM, the rope threading system is divided into several sections. Into the sections, where the paper web transfer is more complicated, the tail shooter with the cutter and with air or vacuum transporter is installed.

Rope pulleys

Pulleys dimensions (diameter, width, groove depth) depend on the machine speed and the basis weight.

Leading pulleys

The pulleys are used to form rope threading wedges (lower depth of a groove) in transfer points.

Guiding pulleys

The pulleys are used for guiding threading ropes in the machine (higher depth of a groove) and are manufactured in a single or double modification.

Ropes drive is used when the threading ropes do not pass through the drying cylinders or when the web contact is not sufficient for the rope dragging which might cause slips. The speed of the electric motor is controlled by a frequency converter and is derived from the speed of a closest suitable roll. The drive is provided with a safety cover.

Main parts

• pneumatic rope stretching
• set of pulleys with holders

Material

• standard design is common steel, eventually stainless steel according to customer’s request

Accessories

• threading rope drive
• tail cutter
• tail shooter
• air conveyor

Scope of delivery

• complete machine according to the main parts description
• accessories optional, upon customer’s request

Rope threading system is used for utomatic paper web threading through the threading ropes from the press part via drying section onto the reel of the paper machine.

Design

It consists of a set of pulleys, rope stretchers and if necessary a rope drive. Auxilliary chutes and air pipes with nozzles can be used as other equipment to be placed in transfer points. A two-rope system is applied normally, but for heavier paper grades a three-rope system can be used. Because of different speeds in different parts of PM, the rope threading system is divided into several sections. Into the sections, where the paper web transfer is more complicated, the tail shooter with the cutter and with air or vacuum transporter is installed.

Rope pulleys

Pulleys dimensions (diameter, width, groove depth) depend on the machine speed and the basis weight.

Leading pulleys

The pulleys are used to form rope threading wedges (lower depth of a groove) in transfer points.

Guiding pulleys

The pulleys are used for guiding threading ropes in the machine (higher depth of a groove) and are manufactured in a single or double modification.

Ropes drive is used when the threading ropes do not pass through the drying cylinders or when the web contact is not sufficient for the rope dragging which might cause slips. The speed of the electric motor is controlled by a frequency converter and is derived from the speed of a closest suitable roll. The drive is provided with a safety cover.

Main parts

• Pneumatic rope stretching
• Set of pulleys with holders

Material

• Standard design is common steel, eventually stainless steel according to customer’s request

Accessories

• Threading rope drive
• Tail cutter
• Tail shooter
• Air conveyor

Scope of delivery

• Complete machine according to the main parts description
• Accessories optional, upon customer’s request

Rope stretching system is designed for stretching the threading ropes individually. Its size depends on an overall rope length of a threading circle.

Vertical mechanical rope stretching is done by a system of weights. The system allows rope stretching by a doubled stroke (L=2 x STROKE). Offered only upon customer’s request.

Rope stretching system is done by pneumatic cylinders controlled by a pneumatic control board. The system allows rope stretching by a quadruple stroke of pneumatic cylinders (L = 4 x STROKE). Maximum rope stretching stroke (pulleys in end positions) is signalled by magnetic position sensors.

Rope stretching system is done by pneumatic cylinders controlled by a pneumatic control board. The system allows rope stretching by a quadruple stroke of pneumatic cylinders (L = 4 x STROKE). Maximum rope stretching stroke (pulleys in end positions) is signalled by magnetic position sensors.

Advantages of the pneumatic rope stretching

Continuous and simple adjustment of the required stroke of the threading ropes and a possibility of a stroke release when the paper is threaded. A fully automatic equipment.

Machine design and work safety are in compliance with the EU and EAC standards.

Driyng part is the longest part of the PM. Its main purpose is to ensure the necessary drying capacity to reach the set PM performance. Maximal width drying part is 7,500 mm.

The drying parts types (the drying fabrics arrangement criteria):

Classical (conventional) design

• drying cylinders (∅ 1,250, ∅ 1,500, ∅ 1,800 mm)in two parallel rows with an upper and lower fabrics guiding.

Slalom fabric design

• drying cylinders (∅ 1,250, ∅ 1,500, ∅ 1,800 mm)in two parallel rows with one fabric guiding only or a single-row where the lower row is formed by guide rolls (non-heated, with grooves or bores) with complementary stabilization boxes. The main goal of such a setting is a permanent contact between the paper and the drying fabric to prevent breaks. The vacuum cylinders can be connected to the vacuum directly through a shaft on the drive side or form the part of the vacuum together with the stabilization box mounted tightly above this cylinder.

Yankee cylinder design

• the drying cylinder itself (∅ 4,000 mm) with or without fabric

Zero cylinder design

• one drying cylinder of a smaller diameter (∅ 1,000 mm) is installed in the beginning of the drying part with a complementary stabilization box.

Bearing structure types in the drying part

• cast iron stands with steel supports made of welded metal sheets and profiles (preferred solution with new structures)
• steel stands and supports (reconstructions or when complementing the load bearing structure)

Drying, cooling cylinders and guide rolls

• types, design and their location are described in the chapter dedicated to PM rolls. The bedding lubrication can be made as a central oil or grease lubrication. The cooling cylinders are located at the end of drying part and are necessary for decreasing of the temperature of the paper web, what leaves the drying part. The cooling cylinders are connected on the closed colling system.

Elements for a fabric guiding

• guides, stretching, sensors for position monitoring and fabric tension are described in separate chapters for a PM.

Fix and oscillating doctors

• described in an individual chapter for a PM.

Steam and condensation system, recuperation

• • highly efficient multi-grade (type of cascade) drying system based on pressure regulation in cylinders. The process control is done either conventionally through anelectronic regulation or through a computer system.

The steam-and-condensate system together with recuperation and a good closed hood reduces significantly overall production costs in the energy field. Therefore our goal is to install a modern and economical steam-andcondensate system into the drying part, even though it might be economically more challenging; however, from the operational point of view it is more economic and effective. The system installation starts at the steam heads of the drying cylinders where a rotary or stationary (for higher speeds) siphon trap is installed in each drying cylinder.

The main task of the steam-and-condensate system is a suitable setting of a drying curve and its sufficient regulation for the given production assortment. The steam-andcondensate system control is done from an individual or central control system. The waste in the steam-and-condensate system is a condensate that goes back to the boiler house and a waste vapor. The temperature descent can be further used for air heating in recuperation.

Recuperation units use the waste heat from the warm and damp air leaving the drying part hood to heat a fresh air destined for the hood ventilation. The recuperation units are an integral part of modern drying parts either delivered or reconstructed and they are supplied by a subcontractors.

Drying part hood

The task of hood is to lower the thermal radiation from the drying cylinders into the air, to prevent a damp and warm air leak from the drying part into the hall and to lower the amount of air necessary for the vaporized water from the paper outlet by increasing its total moisture content.

Cleaning of drying fabrics

It prevents the fabric contamination which would cause a wrong dewatering and at the same time through a contact between the guide rolls to a web bundling on their surface which would consequently cause a partial or total damage of the fabrics. The cleaning is performed by subcontractors.

Slitter

It enables a guiding tail slitting into the POPE reel in case of a paper breakage. The device is located at the end of the drying part in front of the cooling cylinder. The slitter is supplied subcontractors.

Variations of silent drying cylinders drives

A half-silent drive where the driving force from the drive unit of the adequate section is transferred on the last upper and lower cylinder only by a common plugging gearbox. Other cylinders in the lower and upper row are carried away by individual drying fabrics. „Silent drive” where the drying part is driven through the guide rolls of the drying fabrics. Oother drying cylinder: motor of the drive is located right on the shaft of the guide roll from the service side.

Paper rope threading

The most common version is a double-rope over the whole drying part. We use an automatic threading ropes stretching, i.e. when the paper is threaded, the ropes are stretched only as necessary so that the machine would run continually.

Rolls are the basic functional element of the paper machine. Design of each roll depends on its location in PM and its usage purpose. The rolls are standardly dynamically balanced for the required designed speed. For long slim rolls, we use a method of dynamic roll balancing in more levels.

Some rolls are operating as pressure vessels (with internal overpressure), are designed and tested in compliance with EU standards. If required, the rolls are delivered with corresponding certificates.

List of the rolls produced for the paper industry

• Guide rolls for wire, press and drying wire and paper (made of steel, grinded, with a rubber cover, copper-plated, chrome- plated, plasma-sprayed)
• Deflocculation rolls for headboxes
• Segment rolls for rewinders (made of aluminium alloy)
• Driving rolls with a rubber cover for wire parts
• Forming rolls for a Crescent former
• Press rolls (incl. rolls for JUMBO presses) with blankets and internal cooling system
• Drying cylinders
• Made of cast iron or welded
• Chrome plating included, or with special coatings
• Fix or free rope pulleys included (possibly with rope grooving)
• Size press rolls-incl. covers in accordance with the sizing agent and pressure
• Yankee rolls
• Carrying rolls of a rewinder, plasma spraying included
• Carrying rolls of a reel – made of cast iron or welded carbon or stainless steel)
• Reel spools – incl. covers (polyurethane, rubber)
• Suction rolls, pressure
• Transfer rolls
• Spreading rolls – paper, felt

Rolls types

• With hot-pressed cast ends and with pressed-on steel pins
• With hot-pressed steel pins or pins fixed through freezing
• With bolted ends

Design

The company produces rolls, cylinders and cylindrical bodies in all known design modifications, such as;

• Massive rolls
• Rolls made of weldless thin-walled and thick-walled tubes
• Rolls made of grey cast iron
• Roll-bended
• Cylindrically grinded or crowned

Material

• Depending on customer’s request
• According to the load

Machine design and work safety are in compliance with EU and EAC standards.

Rolls can be delivered with following coatings and covers:

• Rubber or polyurethane cover, teflon cover, copper plating, ceramic cover, hard chrome plating or high-grade steel coating (stainless steel, type 13 % Cr, chrome- nickel steel, chrome-nickel-molybdenum steel, tungsten-carbide etc.) according to special requirements
• We provide rolls with particular coating and covers as blind-bored, grooved or with combined surfaces

Special roll surfaces can be provided also through subdeliveries by reputable and specialized roll manufacturers within the scope of delivery and based upon previous agreement with the customer.

Servicing

For all mentioned rolls (made or by PAPCEL or other manufacturers), we provide repairs, overhauls and replacements of roll pins and also coating of necks, grinding of roll surfaces and also new covers. The service is offered completely, i.e. from dismantling of the roll through its repair. For all rolls, we produce and deliver also the bedding for oil and grease lubrication.

Rolls are delivered for all available paper grades for paper machines with wire table up to 7.500 mm.