1. Manpower requirements
 
Only the persons who have studied this manual, trained in safe methods and techniques of work are allowed to work independently on the equipment.

The person serving the apparatus for butt welding of plastic pipes required to:
- comply with the requirements of this manual;
- comply with the instructions for electrical safety;
- comply with the requirements for maintenance of equipment;
- stop the equipment when detection of equipment, appliances, tools malfunctions and other defects or hazards in the workplace, it is permitted to proceed with the work only after the removal of all deficiencies.

The employee must comply with labor safety to ensure protection from exposure to hazardous and harmful factors related to the nature of work, namely:

- effects of electric current;
- thermal burns (the presence of the hot parts of equipment with the temperature upto 250 ° C); 
- mechanical factors (the presence of the rotating parts of the equipment, defective tool and device).

                                                                                         

 2.General safety requirements
 
2.1. Before work commencement.
 
Before work commencement it should be checked:

 - integrity of the insulation of power supply wires;
- integrity of the hydraulic hoses;
- the level of oil in the hydraulic tank;
- the level of oil in the gearbox of facing machine;
- properly connected electrical equipment (voltage network and connections of phases);
- connect earthing of apparatus.


Before work commencement, you must check the workplace, it must be uniformly illuminated (no glare), not to be cluttered with extraneous items.
Power, electrical and hydraulic units of welding machine must be securely closed. 
In case of lifting (removing) device use in order to remove the heating element and facing machine from the welding zone please make sure the brake mechanism is in good working order and the slings used are in good condition.
 
2.2. During the work.

Keep the workplace by unauthorized persons.
Avoid spills and drips of oil from the hydraulic system of the apparatus.
Do not lean against aggregates of working equipment.
Not to store and place foreign objects on equipment units.
Doors of electric cabinet, body of hydraulic station, remote control of lifting device must be closed with a key or screw up during work. 
Do not operate when a failure of any components and units.
Do not use power tools in wet weather.

To monitor the serviceability of isolation and to prevent mechanical damage to the cable for safety purposes. Avoid contact of current-carrying cable with hot surfaces, sharp and moving objects.

During breaks disconnect power tool. Do not make the connection to the electric power in the absence of a special safety plug and socket connection.
To use only certified extension cords and wires with cross section oriented on the power consumption of the unit or device when operating the equipment.
In a sudden stop of the power tool it should be turned off by the switch.
At the slightest sensation of current flow immediately to turn off the power tool.
When removing or installing parts and assemblies on the equipment, to use tools and devices for executing this type of work. 
Do not start work with defective earthing, low oil level (below the first division of the probe), a weak stretch of facing machine drive.
Works on defatting the heater to produce only by disconnecting the voltage before starting of the welding works on a fully cooled to ambient temperature heater. 

Do not install the operating temperature of the heating element of more than 250 ° C. 
Run the lifting device with working slings and brake. Do not use untested and unmarked slings. 
Do not exceed the capacity of lifting device and slings. 
Do not leave raised unit in a suspended condition, and also to stay under the raised load. 
Do not move the heating element by the control temperature block. 
Do not carry facing machine by motor-reducer.
Do not use the facing machine with the oil temperature over 80 ° C.

2.3. Upon completion of work.

Fix up the workplace.
Tools, accessories and lubricants shall be removed to the places intended for them.
Protect quick couplers by special caps. Quick couplers should be cleaned of dirt and soil before each new connection.
 

                                                                                          3. Operation manual
 
3.1. Requirements for service personnel.

Staff serving apparatus for butt welding of polymer pipes should be trained in the techniques and methods of safe working on electrical installations. Prejob training as per the approved standard training programs should be conducted for service personnel.
 
3.2. Preparation for welding.

Set apparatus’s centralizer on a horizontal plane at the point of welding.
 
Apparatus and weld zone should be protected from the effects of natural factors (fog, rain, dew, wind, low ambient temperature) which may affect the conditions of welding. When the air temperature in the welding zone is below +5 ° C, the ends of pipes to be welded should be pre-heated with warm dry air.
Connect centralizer and hydraulic station by joining of quick couplers. Make the connection of hydraulic station, heating element and facing machine to the mains, keeping phasing and the desired voltage. Before you begin, make sure that the temperature of the heating element has reached a set value. The temperature of the heating element for welding of pipes made of polyethylene ПЭ 80 equals 210 ± 10 ° C, during welding of pipes made of polyethylene ПЭ 100 equals 220 ± 10 ° C.
 
3.2.1. Fixing the pipes in the clamps of welding machine to be done with available removable inserts. Bushes under flange are fixed in base plate with the help of mounting element.
Changing the diameter of welded pipes is achieved by removing - the installation of replacement inserts on clamps, the inserts are fixed with bolts.
Smaller segment of the pipe is fixed in the movable clamps when welding, otherwise possibly moving of the welding apparatus in a horizontal plane relative to the welded segment of pipeline.

3.2.2. Install welded sections in clamps of apparatus’s centralizer and tighten the nuts of clamping bolts. Pipe roughness can be compensated by clamping or release of clamping bolts nuts.

3.2.3. Smooth rotation of the pressure regulator clockwise to increase the pressure in the hydraulic cylinders of the apparatus, at the beginning of the movement of mobile clamps to determine the pressure-load, in the future value of the standby pressure will be necessary for the proper selection of welding parameters. Reduce welded surface to test the strength of pipes fixation with a pressure equal to the amount of clamping pressure idling plus pressure melting ends (see table). Welded surfaces to be placed and centered in such a way as to shift the outer edges of the blanks, as per the outside perimeter is not more than 10% of wall thickness of welded pipes (see Figure 1).

 

Figure 1. Tolerances for offset and gap of welded surfaces

3.2.4. Separate the pipes ends, insert facing machine between the pipes ends, fix it to the guide shafts of centralizer. Gently raising the pressure in the cylinders, bring together the ends of welded pipes and turn on facing machine. Facing shall be carried out at the pressure not exceeding 12 bar. To continue with facing until the inextricable chips on both ends of the pipes not thicker than 0.2 mm occur. After the occurrence of this chip, to prevent the appearance of burrs on the pipes ends, the pressure should be reset to zero and turn off facing machine. Separate the pipes ends inspect the ends on the lack of raw places. Perform re-facing in case of necessity. After facing phase the facing machine to be removed and the formed chips to be disposed without touching treated surfaces. 

Bring together faced surfaces and check the gap between the ends, the permissible gap shall not be more than 0, 5 mm (see Figure 1). In case the conditions of parallelism of the ends and alignment of pipes are not met it is necessary to compensate the offset and repeat the process of facing. After the facing process on the prepared surface the entering of dirt, dust, water, grease, etc is unacceptable. Conduct facing immediately before welding. 

3.1. Welding. 

3.1.1. When bringing together of the ends with a pressure regulator set both the pressure equal to the amount of pressure-load and pressure of ends flashing off. Separate welded surface and insert the heating element. Make clamping of the ends to the heating element with a pressure equal to the sum of standby pressure and pressure of ends flashing off. Due to contacting of ends with the working surface of the heating element the flashing off the ends of welded pipes take place. Flashing off process is conducted until the formation of a uniform bead around the perimeter of the welded surfaces occurs. 

3.1.2. After the formation of uniform bead around the perimeter of the welded surfaces, to turn down the pressure of clamping ends to the surface of the heating element to the pressure of heating ends. Preheating of ends is produced during the time of heating. 

3.1.3. After heating the ends separate welded surfaces and remove the heating element. Technological pause is designed for removal of heating element from the welding zone and is calculated from the moment of blanks separation for removal of the heater until the contact of blanks’ ends.

To prevent oxidation of the blanks ends and formation on the surface of the solid crust of the melt, the period of technological pause should be minimal and not exceed the values shown in the table. 

3.1.4. To avoid shrinkage cavities the setting of weld is carried out after clamping the blanks. Setting of the weld is carried out by a uniform rise of pressure to the pressure welding corresponding to the pressure of cooling during the time of pressure raise. After completion of weld setting the cooling of joint is carried out. 

Time of pressure raise, cooling time and pressure of cooling are shown in the table. Accelerate the process of cooling of the weld by blowing the air or swilling is strictly prohibited. After cooling, turn down the pressure up to 0, loosen the nut of clamping bolts, open the clamps of centralizer and remove welded pipe. Relocate the unit for welding of the next weld connection.