Maintenance of auger macaroni presses includes the following list of operational measures: preparation of the press for work, start-up and exit to the operating mode, operating rules and safe operation mode. To prepare the press for work it is necessary:
- check for lubrication in all friction parts; fill the gears of the main drive, dosing unit and kneading machine with industrial grade 30 oil to the required level;
- to inject the fittings, lubricate the seating surfaces of the fuses and the other nodes of the press with oil of the Solidol US-2 (L) brand.
- check the condition of the control mechanisms of oil lines and lubrication devices, fencing and control and measuring
- check the operation and reliability of locking mechanisms for the kneading machine.
- stop the water supply to the cooling pressing devices; put in place the pressing augers, after having been lubricated with vegetable oil.
To start and exit the press to the operating mode, you must:
- close the outlet valve of the kneading machine; include the supply of warm water in shirts of the auger chambers
- turn on the drive of the kneader and dosing machines and adjust the flow of flour and water according to a given technology, set the required water temperature.
- fill the dough to the level of the shafts and turn on the drive
- turn on the drive of the vacuum pump and open the valve;
- check the humidity of the dough coming out of the press heads or the collector of the tube, and if necessary, make additional adjustments to the dispenser; do not work when the humidity of the dough is below 29%;
- install in the pressing heads of the matrix (tube), smearing them with vegetable oil;
- enable drives of blower devices and cutting mechanisms;
- after 20 ... 30 min press work in the shirt of the pressing body to supply tap water.
The normal operating mode of the press operation is ensured with the pressure of forming 5,5 ... 7 MPa for the presses LPL-2М; 9 ... 12 MPa for LPS presses with residual pressure in vacuum devices 0,6 ... 0,8 MPa and cooling water outlet temperature
The rules of operation of screw pasta presses provide for the following activities:
- monitoring the normal operation of the press;
- if the parameters deviate from the established norms, it is necessary to determine the cause and immediately eliminate it;
- Observation of molding pressure: if it reaches the upper permissible limit, it is necessary to stop the press and find out the cause (most often this is observed when working with a low humidity test or a cold test, as well as when the matrix channels are clogged); if the residual pressure in the vacuum chamber (vacuum trough) decreases, the filter should be changed;
- monitoring the operation of the dosing unit, the temperature of the water entering the dough, the constant level of the dough in the chambers of the kneading machine, the humidity and the structure of the dough. If the dough does not mix well, has a large-rolled structure, it is necessary to change the angle of rotation of the blades while the press is stopped;
- monitoring of press stops: short press stops should not exceed 30 min; during long stops of the press (for a time longer than 30 minutes and up to 1 days) it is necessary:
set the ratchet handle to zero
remove the dough residues from the chambers and vias of the tube, lubricate the inner surfaces of the chambers with vegetable oil (cleaning and lubrication should be carried out only after turning off the power to the press!);
remove dies, nets, grids and seals, clean them outside of the dough and send them to the sink;
select the dough from the internal cavity of the press heads or tube collectors, and the visible remaining surface of the dough
When the press stops for more than a day, it is necessary to additionally remove the flanges from the press heads or tubes, remove the pressing augers, thoroughly clean all surfaces that are in contact with it from the dough, and lubricate with vegetable oil.
The basic rules for the safe operation of screw presses are as follows:
daily check the serviceability of the mechanisms for blocking the opening of covers and chambers;
during the operation of the press, do not make any repairs, lubrication or cleaning of moving mechanisms, do not remove fences and parts, do not touch moving parts;
the press must be reliably grounded, all electrical appliances and wiring must be in good condition;
Inspection and repair of electric motors, starting equipment and electrical wiring should be carried out only with the power off;
all guards and press covers should always be in place and in good condition;
for maintenance of the press, a platform with railings and a staircase must be in order and kept clean.
During the operation of the press, the current repair must be carried out at least once in the 6 months, overhaul - once in the 3 of the year and constantly conduct the turnaround inspection of the press in accordance with the established schedule.
Basics of technological calculation of pasta press
Productivity screw dosing flour PM (kg / s) is determined by the formula:
where D is the outer diameter of the spiral auger, m; d - diameter of the screw shaft, m; s — screw pitch, m; p - screw rotation frequency, s-1; pH is the bulk density of the flour, kg / m3; f is the fill factor (f = 0,8).
The performance of the water dispenser Pv (l / s) is determined by the formula:
PV = VкnлК
where Vк is the capacity of one pocket (scoop), l; nл - the number of measured doses per second; K - coefficient of filling the pocket with water (K = 0,4 ... 0,5).
Productivity of the kneading machine PТ (kg / s) of any press can be calculated by the formula:
Пт = [(100% - Wт) / (100% - Wn)] (VρтК3/ t)
where Wт is the humidity of dough,% (Wт = 29 - 31%); W and - moisture products,% (W and = 13%); V - kneader capacity, м3; RT - bulk density of the dough, kg / m3 (rt = 700 ... 730 kg / m3); K3 - kneader dough filling ratio (K3 = 0,5); t - the duration of the mixture, s (t = 9 ... 18 s).
The performance of the press is characterized by the amount of dough supplied by the screw to the matrix per unit of time, and the throughput of the matrix.
The actual performance of the injection screw Pф (kg / s) is determined by the formula:
where m is the number of auger visits; R is the number of screws; R2 , R1 - respectively, the outer and inner radii of the screw, m; S - pitch screw screw auger, mm; B1and b2 - the width of the screw blades of the screw in the normal section, respectively, on the inner and outer radii, m; a - angle of the helix of the blade along the average diameter of the screw, hail; n - screw rotation frequency, s »1; р0 - the mass of the test in 1 м3 [р0 = (1,33 - 1,45) 103 kg]; К3 - coefficient of filling the cavity of the auger with dough (for auger dia120 meter mm Kg = 0,25 ... 0,74); Ku - coefficient taking into account the degree of compaction of the dough (Ku = 0,51 ... 0,56); Kn is the coefficient characterizing the dough feed by the screw (Kn = 0,9 ... 1).
The angle and lift the helix of the blade on the average diameter of the screw is calculated by the formula
where Y is the pitch of the helical blade, m; Dr. is the average screw radius, m (App = + Я2) / 2, where Л, and Я2 - internal and
outer radii of the screw, m