Centrifugal Fans maintenance manual www.dcs.fi
Contents 1 Safety... 4 1.1 Explanations... 4 1.2 Basic safety rules... 4 1.3 Noise level... 5 2 General... 6 2.1 Fan types... 6 2.1.1 Use types... 6 2.1.2 Rotational and blow directions... 7 2.1.3 Wing types... 7 2.2 Accessories... 7 2.2.1 Sensors... 8 2.3 The marking of the fan... 8 2.4 Installation... 9 2.4.1 Dimensions, weight and lifting instructions... 9 2.4.2 The beam frame... 9 2.4.3 Concrete base... 10 2.5 Operating conditions... 10 2.6 Storage... 10 3 The introduction of the fan... 11 3.1 Introduction... 11 3.2 Start-up... 11 3.3 Monitoring during the operation... 11 3.3.1 Vibration... 11 3.3.2 Noise... 12 3.3.3 Bearing sound... 13 3.3.4 Vibration dampers... 13 3.3.5 Drive belt... 13 3.3.6 Flexible connectors... 13 3.3.7 Hub seal... 13 4 Maintenance... 13 4.1 Impeller... 14 4.1.1 General... 14 4.1.2 Impeller installation... 14 2
4.1.3 Removing the impeller... 18 4.2 Bearings... 19 4.2.1 General... 19 4.2.2 Lubrication... 20 4.2.3 Lubrication intervals and amount of grease... 21 4.3 Electric motors... 22 4.4 Electrical connections... 22 4.5 Hub seal... 22 4.6 Switch... 23 4.7 V-belts... 23 5 Troubleshooting... 24 6 Maintenance intervals... 25 3
1 Safety 1.1 Explanations The manual contains warnings. They indicate hazards that can cause injury and the likelihood of their occurrence. The warnings are divided according to the severity: DANGER! Warning! and Important! DANGER! Means the accident, which in case of non-compliance with the instructions will result in serious injury Warning! Means that an accident may occur, resulting in serious personal injury if the instructions are not followed Important! Means that an accident may occur, which results in personal injury or property damage Note! Means operational interference or damage due to improper use 1.2 Basic safety rules The use of the machine correctly and in the right circumstances guarantees the safe operation of the fan. The fan should be used only for the purposes for which it is made and the user must follow the general safety precautions. The fan should also be installed in accordance with the instructions. The fan is manufactured in compliance with safety standards, marked with the CE mark and is supplied with a declaration of conformity. Improper use may result in accidents and/or cause damage to the device. o the fan may only be used in its intended conditions o safety devices of the fan must not be removed under any circumstances and do not reach behind the protective covers o precaution of moving parts o the fan may only be maintained by the professional specialized to provide service o the fan must not be used for moving another kind of air or gas than what it is made to move o after maintenance, always check the structures and all the protective covers o the user must have the appropriate protective equipment 4
o after service all bolts and nuts should be checked, as well as their tension o Do not exceed the maximum speed specified for the fan 1.3 Noise level EU Machinery Directive 89/392/EEC requires a one-meter distance from the measured sound pressure and sound power level. Maximum sound pressure is measured at the front of the suction side. The sound power level is defined as the measurement methods BS 848 and VDI 2081. Sound pressure and power levels are indicated on the base of the fan case. 5
2 General This document contains the most common maintenance procedures of the product, instructions for proper use and safety instructions. These instructions are designed to ensure an efficient, correct and safe operation of the fan. Proper maintenance and operation extend the life cycle of the fan. Service documentation must be kept with the product, or in its vicinity, so that it will be easy to find. 2.1 Fan types The fans are classified according to the operating and the impeller type as well as the rotation and air flow direction of the fan. 2.1.1 Use types The impeller is mounted on the motor shaft (use Type-S), which is sometimes also called a direct-driven fan. In the belt driven fan (the use of type-h), engine power is transmitted to the impeller shaft using a V-belt. The motor is attached by the adjustment rails to the stand. In a switch operated fan, (use type-k) the power transmission is performed by the switch connecting the motor and impeller shafts and with the impeller shaft with separate bearings. 6
2.1.2 Rotational and blow directions When determining the blowing direction, the fan is considered from its operating side. The direction is shown in accordance with the drawings with letters indicating the direction of rotation (RD impeller rotates clockwise or LG impeller rotates counter-clockwise) and with numbers that indicate the angle between the air flow direction and the vertical 2.1.3 Wing types direction in degrees. If the main directions indicated in the figure cannot be used, the fan may be produced to set any intermediate direction. The direction and the shape of the impeller blades influence the different characteristics of the fan. These characteristics are the yield of pressure and volume, the efficiency and the volume flow rate. The choice of the wing type also affects the particles moving with the gas entrained. 2.2 Accessories The instructions and documents of the accessories such as sensors, dampers, guide vane controls, vacuum boxes and engine accessories are submitted on a case by case basis. 7
2.2.1 Sensors The validity of the fan warranty requires the connection of the condition monitoring sensors supplied as the accessories of the fan and introduction of surveillance. The "standard" surveillance packet offered for fans as an option, contains at least one rotation monitor, one vibration monitor, two temperature sensors + converters and four 5 m extension cables. Upon the request of the customer, condition monitoring may be larger. Condition monitoring sensors as standard equipment are for the fans with oil lubricated bearings or the engine power of 250 kw and upwards. Oil lubricated bearings are always equipped at least in the impeller end bearing with vibration measurement and both bearings with temperature measurement (oil lubrication sensor packet includes VKV021, two TS229, two TP3237 and three EVC005). Fans equipped with motors of 250 kw and above include as standard accessories in addition to bearings monitoring (vibration and temperature monitoring in both bearings), also vibration and temperature monitor on D-end of the motor. Temperature sensor TS2229 Measurement signal converter Vibration guard Plug connector/cable 5m EVC005 TP3237 VKV021 Rotation monitor The speed monitor is DI6001 [M18] (if necessary, the DI5003 [M30] can also be used). In case of separate bearings (vertical bearing housings) the sensor is most commonly mounted between the bearings and the output gauge is attached to the shaft with a compression fitting. The sensor bracket is bolted to the base and the sensor is mounted so that the clearance between the output gauge is 6 mm (DI5003 5 mm). 2.3 The marking of the fan In each fan is a shield, which is marked with the required information about the fan. The fan has an alphanumeric code that indicates the type of fan. The shield also indicates the year of manufacture, the serial number and the fan performance values. The shield also bears the CE marking. For example, DCKE-40/2-j-k RD90 8
DC Affix which is not relevant (Dust Control) KE K = marking of the series on the fan (M, D, E, H, B, C or D), E =wing type (E, T, S or L) -40 Nominal size of the fan / 2 Narrowing, if you have a narrowed impeller (/2 or /3) -j Included, if the fan has a cooling disc -k Type of use (-k = switch,-s = impeller on the shaft of The motor, -h = belt (not marked in the name)) RD Rotation direction (RD or LG) 90 Blow direction (0-359, 0 is up) W In belt drive motor position (W or Z) 2.4 Installation 2.4.1 Dimensions, weight and lifting instructions Fan-specific assembly drawing includes dimensions, weight data and lifting instructions. Permitted lifting points are marked on the fan. 2.4.2 The beam frame The centrifugal fans are mounted horizontally on vibration dampers. Dampers should be installed only when the fan is at the level of the installation, in order to prevent damage to the dampers in the context of the drop, the Dampers should be able to flex freely. The sag is determined according to the damper type, for example, LV 10/200 will sag under load 7.5-9 mm (75-90% of 10 mm), and deflection should be the same + / - 1 mm between all the dampers. 9
2.4.3 Concrete base If the fan is mounted on a concrete base, it needs case bushings and a levelling partition if the base is not smooth enough. When the installation is clear, the concrete mixture is cast under the mounting flange. When the concrete mixture has dried, the bolts are tightened. 2.5 Operating conditions Operating conditions of a fan are largely determined by the choice of manufacturing material, surface treatment, outfitting and structure of the fan. As a result, the fan may only be used for the specified application/conditions. The fan is to be placed in a warm and dry internal space (5... 40 C), which is free from condensing, unless otherwise agreed with the fan manufacturer. Corrosives, high temperature, solids and external constraints such as air humidity can weaken the parts of the fan. If the operating conditions are different from normal, the fan has to be originally designed for use in these abnormal circumstances. 2.6 Storage Fan and motor must be protected from moisture and dust. Large temperature changes should be avoided. Otherwise, damage can occur to the electric motors, plastic fittings and bearings, painted surfaces or seals. All materials are not weather resistant. Suction and discharge openings must be closed during storage. Prolonged standstill may affect the lubrication properties of grease or oil. Corrosion may also affect the bearings. Certain components, such as bearing seals and V-belts in belt-driven fans can become brittle over time. The fan should be used at least about 10 min monthly. If this is not possible, it is recommended to rotate the impeller by hand. This maintains the operational condition of the bearings. 10
3 The introduction of the fan 3.1 Introduction 3.2 Start-up 1. Check the fan and motor mounts to the frame, anti-vibration mounting to the base, the suction and discharge opening connections to the duct and check the tightness of the bolts. 2. Check the belt guard or the connection guard mounting and clearance (at least 10 mm) in relation to the moving parts. 3. Check that the direction of rotation of the fan (motor) and the direction of the gas flows are in the direction of the arrows on the casing by switching on the fan for a while. 4. Check the fan bearings. If there is reason to suspect that condensation of water has entered the bearings e.g., during storage, the bearing is to be opened, cleaned and re-greased. 5. Check all guards and protective covers. 6. Check that there is nothing inside the fan. When starting cold a fan which carries hot gas, its power consumption is considerably greater than the operating conditions. If power consumption is determined in accordance with the operating conditions, the fan is to be started against the closed damper or regulator. The damper or regulator is gradually opened to the run position along with the increase of the gas temperature. 3.3 Monitoring during the operation In order to avoid the switch and motor load and overheating it is recommended up to four starting times per hour, unless otherwise specified in the documentation. Between start-up times should be at least ten minutes of cooling time. Excess vibration or noise are the signs of a faulty operation, in which case the operation of the fan is not allowed to continue until the fault is cleared and repaired. 3.3.1 Vibration Vibration is a significant factor in terms of performance and life-cycle of the fan, which is why vibration control is very important. Vibration can cause cracks, bearing failures, bolts loosening and noise. Periodic vibration measuring is recommended. Vibration is a great gauge of condition monitoring. The machine's operations can extensively be interpreted on its basis. For critical needs, tough conditions or larger than 50kW fans we recommend continuous vibration monitoring equipment. 11
Vibration can be caused by wear of the impeller, dirt accumulated in the impeller, contact of moving parts with other parts or an imbalance caused by the alignment of the fan. Good tools for vibration measurement are, for instance, the SPM Leonova Infinity or SPM Bearing Checker. Dust Control Systems Oy manufactured impellers are balanced dynamically according to ISO 1940 class Q 6.3. In operating conditions the fan vibration stress value must stay below the value of alarm limit. Once the value of alarm limit is exceeded, the impeller cleaning and bearing checking must be carried out as quickly as possible. If these measures do not help, the impeller must be re-balanced or other vibration removing repair must be performed. It is advisable to discontinue the use of the fan and to contact the manufacturer of the fan if, on use, the vibration stress values exceeds the value of trigger limit. If the reason for vibration is not recognized with certainty and are determined to be harmful, the fan cannot be used when the trigger limit is exceeded. Measurements are performed according to ISO 10816 standard, within the fan operation rotation frequency. The following table applies to fans that are equipped with vibration dampers (flexible platform). Specific instructions are presented in separate annex Sensor limits, or in separately defined fan-specific instructions. Assessment of fan vibration stress values (v r ms ) according to standard ISO 10816. Coupling operated/ Impeller mounted Belt operated on the motor shaft Trigger limit 7.10 11.2 Alarm limit 2.80 4.50 3.3.2 Noise The fan causes noise while operating. Noise levels and the frequency depend largely on the size and structure of the fan. The noise does not always reflect a defect in itself. If excessive fan noise becomes apparent during operation or some extra sound occurs, it may be a sign of a malfunction. In certain circumstances, the clearance between bearings may cause a rattling sound if the bearing temperature rises. 12
Bearing operating temperature is affected by the speed and environmental conditions. The maximum permissible operating temperature depends on the bearing structure, the used lubricant and the length of lubrication intervals. Normally, the greased bearing temperature must not exceed 65 C, measured from bearings housing, and never 110 C, measured from bearing. The rise of temperature may be due to a faulty bearing, lack of lubrication, or too generous amount of lubricant. 3.3.3 Bearing sound The bearings sound can be heard and measured with devices separately manufactured for this purpose. Vibration level measurement and measurement with bearings test devices are the right way to distinguish between the sound caused by the failure of the structure. 3.3.4 Vibration dampers Check that the dampers are in good, working order and evenly loaded. In addition, the dampers must be able to flex freely. 3.3.5 Drive belt Check the amount and tension of belts. Typically, stretched and worn belts vibrate and make a noise. 3.3.6 Flexible connectors Installation instructions and tolerances for the connectors are in the annex. 3.3.7 Hub seal The fan may be provided with a hub seal used for sealing of the impeller hub and the fan casing bushing/joint. If discharged gas leaks from the joint inside the fan, it is advisable to check the sealing operation. 4 Maintenance Service date and the length of the maintenance periods are determined by the maintenance and repair needs. Sufficient spare parts must be available. The attached table of the most common service and maintenance work periods. 13
4.1 Impeller 4.1.1 General If the fan operates with exhaust gas or in dust containing air, or if in the impeller has been formed a deposit or unusual wear, it may cause a balance disorder. This can result in damage to the bearing or impeller failure. Impeller cleaning is carried out with a wire brush or scraper. The loose dirt should be removed from the fan housing before the fan is restarted. For inspection and cleaning of the impeller, in the fan casing is usually an inspection hatch. A worn impeller must be replaced or repaired by welding. After welding, the repair of the impeller is to be balanced again. Measure the vibration level from the frame of the motor and from each of the bearing housing, from three different directions. 4.1.2 Impeller installation Follow the instructions concerning the coupling and belt operated fans. If the fan has a V-grooved hub, its fitting is carried out by tightening against the shaft shoulder and preventing opening of the screws of the locking plate, for example, by welding the screw into the locking plate. 1. Remove cover and clean the impeller and shaft contact surfaces thoroughly. Detailed instructions are in the Annex labelled installing the clamping sleeve (EX- and SKF SHT- sleeve). 14
2. Set the friction joint sleeve in place so that the bolt positions do not exceed the front edge of the hub. 3. Place the impeller into the shaft. Make sure that the friction joint sleeve is still in place in the depth direction. It is recommended to install impeller with fan-specific impeller lift tool (available as accessory, with additional assembly drawing in fan-specific documentation). 15
4. Fit the inlet cone and check whether it fits into the place. Tighten the bolts of the friction joint sleeve according to the tightening instructions. The friction joint sleeve tightening instructions are attached. To achieve the right connection, tightening is to be carried out on all the bolts several times by gradually tightening each bolt in turn, until tightening the last bolt no longer loosens the first tightened bolt and the torque prescribed by instructions has been reached. 5. On the inner surface of the outer rim of the front panel of the fan are adjustment screws for the inlet cone position. 16
6. Attach the inlet cone bolts and tighten them to the desired torque. 17
4.1.3 Removing the impeller EX-41 7. Place heat-resistant silicone (e.g., Super RTV silicone, red 60... 315 C) between the surfaces of the impeller hub plate and the impeller hub and attach the hub plate evenly by tightening the torque. Remove the screws and screw them into the pull-out threads of the outer ring so that the inner ring is released and the sleeve comes off. Remove the screws from the pull-out threads only when the sleeve is removed from the hub. EX-60 Method 1: Remove the screws and screw them into the outer ring pullout threads and release the ring. Method 2: Remove the screws to the pull-out threads of the central flange and release the rear inner ring SKF SHT Detachment instructions in separate annex. V-grooved hub Remove the locking plate and pull the impeller off with a wheel puller. Sometimes, the impeller is so rugged that the damage of the shaft cannot be avoided. A damaged shaft must be replaced. 18
4.2 Bearings 4.2.1 General The bearing types used in the fans produced by Dust Control Systems Oy are generally spherical ball or roller bearings and toroid bearings. They are attached to the shaft with a clamping sleeve. There are two bearings, one of which receives the compression load. This bearing locked to the axial direction must be marked when both bearings are replaced at the same time. In the fans are used mainly two vertical bearing housings (separate bearings), which are SKF manufactured SNL or SONL-bearing housings or ConCentra bearing units. SNL and ConCentra bearing housings are lubricated with grease and SONL bearing housings are lubricated with oil. ConCentra units are designed to facilitate installation and maintenance. ConCentra bearing units are assembled, greased and pre-sealed. ConCentra advantages include easy installation, longer service life, greater reliability and easy maintenance. In DCS fans are used ConCentra SYNT bearing units. ConCentra bearing units are used in small and medium-sized fans. DCS fan bearings are always determined in fan case bases taking into condition the design input data and the fan operating conditions to achieve optimal serviceability and reliability. The bearings must be handled with care and must be protected from dust and moisture. The bearings are therefore kept in the original packaging, which should be opened only upon installation. The rust-preventive agent in the new bearings does not need to be removed, if the bearing has not been contaminated. For cleaning of bearings use a white spirit or a similar detergent. After washing, the bearings are lubricated with oil immediately. The shaft pins, bearing housings, etc., must be thoroughly cleaned and soaked in oil prior to installation. Taper bushing surfaces must be only lightly lubricated. Achieving a suitable interference fit may otherwise be impaired. After installation, oil must also be entered into the bearings, in order to avoid dry running at start-up. After lubrication and the installation of the bearings, a test run is carried out, during which is monitored the temperature rise and operating noise of the bearings. 19
General installation instructions of the separate bearings are in the annex Installing and removing separate bearings. Temperature guard limits are presented in annex Sensor limits. Detailed installation instructions for different bearing and housing types can be found on the manufacturer's website www.skf.com. Dust Control Systems Oy will assist in the acquisition of more detailed instructions. 4.2.2 Lubrication Before maintenance and repair measures, stop the fan from the maintenance switch and make sure e.g., by written notice or with a switch lock that the fan is not started accidentally during maintenance. Ball and roller bearings are usually greased (SNL bearing housings). Oil lubrication is used in special cases, such as when the speed is too high for greasing or if the bearings need cooling (SONL-bearing housings). Grease-lubricated bearing housings are equipped with grease nipples, from which grease is pressed in by a grease gun. If the bearing housings have to be replaced, make sure that the grease nipple place is positioned so that the grease can migrate into the bearing. For the first lubrication of fan-axis grease-bearings, grease type and amount is shown in the main assembly drawing. If the fan is not used for 20
a long period of time, add grease and check the condition of seals visually from time to time. In lubricated bearings there is an external level gauge, from which can be checked the oil level and visually also pollution. In the oil compartment is the so-called quit, which also splash lubricates the upper part of the bearing. The addition of oil is done through the hole in the cover of the bearing housing. At the bottom of the bearing housing has a plug from which the oil is retrieved if necessary. Clean the bearing housing and grease nipples before lubrication, so that no dirt reaches the bearing with grease. Too large amount of grease in the bearing housing can cause a sharp rise in temperature and bearing damage. Different types of oils should not be mixed with each other! Operating conditions are significantly associated with the choice of oil type. The user should pay particular attention to the final selection of the oil suitable for the purpose! On inquiry, the manufacturer will provide detailed instructions on the matter. 4.2.3 Lubrication intervals and amount of grease Lubrication interval depends on the rotational speed (n), the bearing structure and the size (d = bearing bore diameter). With grease-lubricated bearings, re-greasing interval is shown at the type shield (located at the fan base), and in bearing assembly drawing. With oil-lubricated bearings, Fuchs Renolin B15 (ISO VG 46) oil is normally used as first-fill oil. First-fill oil is recommended to be exchanged for the first time already after a few hours of operation, so that the potential impurities in the oil compartment can be removed. Fuchs Renolin B20 (ISO VG 68) or B15 (ISO VG 46) oil is normally used after first-fill oil. However, all fans and working conditions are individuals, so oil-types and oil-change intervals must be examined individually. Contact manufacturer for more info. More about lubrication of bearings and lubrication intervals can be found in the manufacturer's website (www.skf.fi). 21
4.3 Electric motors Start-up and maintenance is done in accordance with the instructions prepared by the manufacturer of the motor. In the protection of the motor, the frequency converter enabled protections such as overload, over-current and stall protection, pump and fan applications, as well as the squared load must be taken into account. For more detailed maintenance and lubrication instructions, see the engine manufacturer's maintenance instructions. Instructions comes along the motor, and can also be found in the web site of the manufacturer of the motor. For the electric motor s re-lubricated bearings, first-lubrication must be performed during commissioning. First-lubrication must be performed according to motor manufacturers instructions. 4.4 Electrical connections Electrical work must only be performed by qualified personnel on machines when switched off, the power supply off and restart disabled. Electrical wiring to the motor must be flexibility so that any moisture does not enter the switch box. In addition, the fan should be equipped with the so-called maintenance switch. In the switching, installation and cable selection must be taken into account the frequency converter manufacturer's and the motor manufacturer's instructions for the approved implementation, which will prevent possible bearing damage. 4.5 Hub seal Normally a Teflon produced booklet type sheet ring seal which is compressed into the rear wall of the casing is used as a hub seal. In more demanding applications a tape box seal can be used wherein the sealing is achieved by graphite tape squeezed into the packing. Over time, the tape box may need to be tightened so that the graphite tape remains sufficiently tight. Clamping nuts should not be tightened all the way, because then the tape will tighten too tightly and create too much heat. The cover part of the box is tightened and at the same time the shaft is rotated by hand until resistance is felt on the shaft. Tightening nuts are locked with the lock thread, so that they do not open during operation. In the Purso air box, gas is conducted into the box to prevent the gas leaking from the inside of the casing from coming out. Different types of slip-ring seals are also possible to use. 22
If the hub seal will have to be adjusted, the cooling disc guard as well as the cooling disc must be removed, so you can access the hub seal. Sealing type is presented in fan-specific main assembly drawing. 4.6 Switch 4.7 V-belts Detailed instructions for installing the switch are attached. Detailed instructions for installing V-belts are attached. 23
5 Troubleshooting Problem Cause Solution Rattle Wear of propeller blade Check/Change Smudging of the propeller blade Loose/Worn bearnings Loose parts Contact of moving parts Alignement errors Worn rattle dampers Instable installation location Twisted shaft Environment caused rattle Improperly installed flexible connector Clean with the steel brush Check/Change Check the mounting of the parts Check the mounting of the parts Realignement Check/replace Check/replace Check/replace Check instllation/installation location Check installation Noise Abrasive parts Check the mounting of the parts Loose parts Improperly installed bearing Excessive/improper lubrication Improperly installed flexible connector Check the mounting of the parts Check installation Check/remove the excessive lubricant Check installation Improper performance Wrong rotation direction Check Damaged flexible connector Improperly installed flexible connector Worn propeller blade Wrong rotation speed Check/repair Check installation Check/replace Check/adjust 24
6 Maintenance intervals Check the condition of the guards Check the condition of the flexible connections Check the condition of the accessories Check the condition of vibration absorbers In case of oil lubrication, check the oli level Make sure that the rattle of the fans has not increased Make sure that the fan does not emit abnormal noises Short explanation of maintenance works. Weekly visual check of all the appropriate parts. Also we recommend check coupling, belt parts and belt tightness, bolt tightness, impeller condition and cleaniness, bearing and motor bearing lubrication in 3 month intervalls. Recommended service intervals are part of the preventive maintenance program, the purpose of which is to prevent the breaking down and to predict failures. Compliance with maintenance intervals gives the customer valuable information about fan service, which can be used as part of the company's own maintenance. 25