In the confectionery industry a variety of pumps are widely used.
In installations for boiling confectionery masses under vacuum, piston and rotary vacuum pumps are used; for pumping liquid and viscous semi-finished products, piston, plunger, gear and rotary are used.
Piston wet-vacuum pumps
These pumps are designed to maintain constant vacuum in coil, spherical and other vacuum devices used for boiling caramel mass, fruit and berry fillings, etc. They are also used in installations for pumping masses to be boiled in batch vacuum apparatuses.
Fig. 13. Schemes of direct-flow mixing capacitors: a - jet capacitor; b - shelf capacitor.
Wet piston vacuum pumps are vertical and horizontal. In the confectionery industry, vertical pumps are the most common.
Usually they are made joint by mixing capacitors, which are designed to create the necessary vacuum in the vacuum chamber by condensing the secondary vapor generated in the apparatus during the boiling process of the product.
Condensers are direct-flow and counter-current, with the supply of cooling water by spraying through small holes in the pipe or feeding it along the shelves (shelf-type condensers).
In fig. 13 shows circuits of two varieties of once-through mixing capacitors.
In the first condenser (Fig. 13, a), secondary steam and air are supplied from the vacuum chamber of the apparatus through the 1 nozzle. At the same time, cold water supplied from the water supply network is sprayed from the 3 pipe located in the center of the 2 condenser body through the side openings; in contact with the secondary steam, water condenses it; a mixture of condensate, air and water is sucked off by a vacuum pump.
In fig. 13, b a direct-flow condenser of the shelf type is shown, in it cold water flows sideways to the upper shelf, from which it then flows downstream into lower shelves, condensing the secondary steam coming from the vacuum chamber; a mixture of condensate, air and water is sucked off by a vacuum pump through the bottom opening.
In the confectionery industry are the most widely used vertical wet-piston vacuum pumps VVN-30.
The single-cylinder vacuum pump (fig. 14) consists of an 1 mixing condenser, a bed, an 12 cylinder with an 11 piston, and a valve and actuator system. The reciprocating movement of the 11 piston is communicated using
Fig. 14. Vertical piston wet-vacuum pump VVN-30.
7 crank mechanism. The pump is driven by an individual 4 motor through an 5 worm gear, V-belt drive and 8 crankshaft. The 8 crankshaft rotates in two 6 bearings, whose housings are mounted on the bottom 13 pillar. An 9 flywheel is mounted on the left side of the shaft.
The 12 cylinder is bolted to the 13 column. A suction port with a bottom 2 valve is connected to the bottom of the cylinder. The pipe is connected by a bend to a shelf-type mixing condenser 1, to which a steam line is connected, coming from the evaporator part of the vacuum apparatus, and a pipe with a control valve for supplying cooling water from the water pipe to the condenser.
An 10 bypass valve is installed on the cylinder piston; at the top of the cylinder there is an 3 top valve.
The vacuum pump operates as follows. When the piston moves upward, a vacuum is created in the lower part of the cylinder. Due to the difference in pressure between the condenser and the lower cavity of the cylinder, the 2 suction valve opens and a mixture of condensate, cooling water and air is sucked from the condenser into the cylinder.
When the piston moves down, the lower 2 valve closes under the pressure of the air-water mixture and the suction mixture moves from the lower cavity of the cylinder to the upper one, penetrating the piston 10 bypass valve opening at the same time into the over-piston space. Then, with the subsequent movement of the piston upward, the upper valve 3 of the cylinder opens and the air-water mixture located in the upper cavity of the cylinder above the piston is pushed through the upper valve 3 and the discharge pipe into the outlet pipe, while the bypass intermediate valve 10 of the piston is closed; at the same time, the next portion of the mixture is sucked in through the lower 2 valve, and the process is repeated.
The manufacturer of VVN-30 vacuum pumps is the Melitopol Compressor Plant. This factory also produces VNK-0,5M vertical piston wet air vacuum pumps with a crosshead mechanism.
Technical characteristics of the vertical piston wet-vacuum pumps
|Serve m3 / h||Until 30||30||Electric motor power, kW||2,8||2,8|
|The diameter of the piston, mm||200||200|
|The piston stroke, mm||200||200||Dimensions, mm|
|The number of double strokes per minute||80||80||length||1292||862|
|Residual pressure in the condenser, kPa||10||10||height||2005||1725|
Rotatsyonnыe mokrovozdushnыe water ring vacuum pumps
The pumps are designed to remove air from the condenser to the mixture and the condensed water vapor and maintain the vacuum in the vacuum purpose vehicles and other facilities.
The pump runs exclusively on clean water, not contaminated with abrasive impurities.
Such pumps are manufactured by the Livensky pump plant of two brands - KVN-8 and KVN-4.
KVN-8 3 pump consists of a housing, a cover 1, the working-rotor disc 2, 4 shaft and support bracket 5.
When the rotor is rotated, mounted on the shaft eccentrically with respect to the pump cover, the air-water mixture supplied through the condenser, entrained by the rotor blades, is discarded to the walls of the cover under the action of centrifugal forces, forming an 3 water ring. A rarefied 1 space is created between the disc hub and the inner surface of the water ring, allowing the air-to-water mixture to be sucked in through a large crescent-shaped cut-out in the pump casing.
With further rotation, the mixture is compressed, which is ejected through the small crescent-shaped cut-out 2 in the housing and the discharge pipe of the pump.
To maintain a gradual volume of the water ring and heat dissipation, it is necessary that water (250 — 300 l / h) continuously circulate through the pump. Before starting the pump must be filled with water.
This minimizes the formation of sugar decomposition products in the syrup, therefore, the syrup and caramel mass are more transparent and stable during storage than when preparing the syrup in dissectors.
However, this station, as shown by operating experience, has several disadvantages, the main of which is that it is impossible to obtain high concentration syrup in it. The ShSK station is inefficient, it can provide only two or three caramel lines with syrup, therefore it is used mainly in small factories. These stations are also used in candy manufacturing.
Fig. 18. Siropovarochnaya station with six section IFLA solvent in water of sugar.
Siropovarochnaya station-1 hinge connected buses to dissolve the sugar in the molasses.
As a result of a comparative evaluation of the work of various syrup stations, it was found that the station, which is based on the principle of dissolving sugar in molasses under pressure with the addition of water in small quantities, has the shortest production cycle and allows to obtain higher quality syrup, which increases the shelf life of caramel.
The station (Fig. 19) consists of a device for preparing granulated sugar and an apparatus for preparing syrup, the latter depending on the station's capacity, consisting of two or more units with an output of 2 or 4 t of syrup per hour each.
The station includes the following equipment: 5 molasses collector, 9 invert syrup collector, two 10 two-plunger pumps for dispensing molasses and invert syrup, sugar hopper with 6 belt dispenser, 5 solvent-mixer with a stirrer and steam jacket, pl 4 pump for delivering a mushy mixture from the mixer to the coil of the cooking column, 3 cooking column (heating part of the unified coil vacuum apparatus), 2 steam separator, 7 collection of syrup, 7 heating tank for water.
The station is equipped with technological control devices and automatic regulators. The station provides light alarm and blocking the operation of technological equipment, an automatic purge system for equipment and pipelines. Electrical equipmentremote control devices and controllers are installed on the management and control panel.
The station can be prepared sugar and syrup, invert sugar, sugar syrups and pure.
After sifting, granulated sugar is fed into the hopper, from which it enters the 6 belt dispenser. The latter continuously doses it into the 5 mixer-solvent. Here, according to the recipe, the corresponding plunger metering pumps 10 through the pipelines are supplied with molasses and invert syrup. Dosing of water to the mixer from the 7 heater is carried out by throttling while controlling the flow rate with a rotameter.
Fig. 19. Siropovarochnaya station-1 hinge connected buses to dissolve the sugar in the molasses.
The temperature of the invert syrup 40 — 50 ° C, the temperature of the molasses supplied to the mixer is stabilized in the 8 collection and maintained within 65 — 70 ° C. In the mixer, all components of the recipe mixture are mixed and heated with steam using a steam jacket to a temperature of 65-70 ° С. 3 — 3,5 mixer filling time min.
The resulting recipe mixture with humidity 17 — 18%, which is a slurry with incompletely dissolved sugar crystals, is fed into the 4 coil cooking column by the 5 plunger pump, where the mixture passes for 1 — 1,5 minutes and the sugar crystals completely dissolve. Excessive heating steam pressure is maintained within 0,45 — 0,55 MPa.
The finished syrup with humidity 12 — 14% passes through a glass filter and an 2 steam separator to the receiving hopper of the finished 7 syrup, from where it is pumped to the places of consumption.
Due to the short production cycle (no more than 5 min) and the peculiarities of the process of dissolving sugar in molasses under pressure, a syrup station allows to obtain a light, transparent syrup of high concentration (88% dry matter) with a low content of reducing substances in caramel mass (up to 14%). When pure sugar syrup is produced with humidity 18 — 20%, the humidity of the prescription mixture is maintained within 24 — 26%; accordingly, the excess pressure of the heating steam decreases to 0,3 — 0,35 MPa.
|Basic specifications siropovarochnoy station hinge connected buses-1|
|Proyzvodytelnost in syrup t / h||2|
|Frequency mixer rotation / min||60|
|Electric motor power, kW||1,7|
|speed, rev / min||930|
|The residence time of the mixture in the mixer, min||3-3,5|
|Coil cooking heater|
|Heating surface, m2||4,2|
|Steam pressure, MPa||0,6|
|The residence time of the mixture in the apparatus, min||1-1,5|
Stations for the preparation of fruit and berry fillings
Earlier boiling of fruit berry fillings used in caramel production was carried out mainly in spherical vacuum devices of periodic action, while boiling and tempering of fillings were carried out separately. Boiling of fillings in batch-type spherical vacuum apparatuses lasts about 40 min, and as a result of prolonged heat exposure to the sugar-fruit mixture, the filling becomes dark, and due to the destruction of pectin, the viscosity of the filling decreases.
Now, for boiling the fillings, coil vacuum devices are used. The duration of boiling of the filling in such devices was reduced to 3 — 4 min, while no burning of the mass to the inner surface of the coil occurs, the filling is light.
Since the amount of evaporated moisture when cooking fillings in 2,5-3 times more than when cooking caramel mass, respectively, increase the volume of the evaporation chamber. Unloading of the finished filling is done periodically, as with boiling caramel mass.
Nachinochnaya station includes equipment to prepare the mixture and nachinochnoy unit for continuous boiling and cooling fillings.
The filling is prepared at the filling station as follows (Fig. 20, a). 1 barrels with sulfitated fruit and berry preparations in the form of mashed potatoes or pulp are fed into the 2 barrel washer. The pulp from the barrels by the 3 barrel lifter is discharged into the 4 desulphurizer-spreader with a screw; here the pulp is mixed and sulfur dioxide is removed from it. Then it enters the 5 collection, from where it is pumped to the 6 wiper with an 7 pump. Here, the mass is rubbed with a rotating drum through a mesh drum and collected in an intermediate 8 tank. From the 8 container, the puree is pumped through the filter to the 9 mixer, where syrup supplied from the syrup station and molasses are added in the required proportion.
The prepared fruit and berry mixture with 45 — 50% moisture is pumped through pipelines through the 2 filter to the 1 collector (fig. 20, b) of the unit for boiling the filling. From the 1 collection, the mixture is pumped by the 3 plunger pump into the coil of the 4 digester, heated by steam with excess pressure up to 0,45 MPa. The mixture passes the coil for approximately 3 minutes. The filling, together with the secondary steam, enters the 5 steam separation cyclone, from which the steam is sucked off by a fan, and the filling flows into the 6 tempering machine. To control the temperature of the boiled filling at the outlet of the cyclone, a thermocylinder of a gauge thermometer is installed.
The temperature of the filling varies within 115 — 118 ° C, which corresponds to its final humidity 17 — 19%.
To introduce the essence provided 7 dispenser.
In a tempering machine, the filling is continuously cooled to 70 — 75 ° C. This machine is also an intermediate tank, which compensates for the possible unevenness of the inflow or consumption of the filling. Due to intensive mixing, the mass in the tempering machine acquires an average temperature close to the temperature
Fig. 20. Driving station for the preparation of fruit and berry fillings:
a - plot for the preparation of the filling mixture; b - unit for continuous boiling and cooling of the filling.
outgoing toppings. Due to the relatively low rate of arrival of hot fillings, it is evenly distributed in the total mass. The cooling process lasts less than 1 min.
In the outlet fitting of the tempering machine, a pressure gauge thermometer cylinder is installed to control the temperature of the outgoing filling.
The finished filling with the 8 plunger pump is pumped into a ring line passing over the filling of 9 fillers of 10 caramel wrapping machines installed in caramel production lines. Excess fillings are discharged along the reverse branch to the tempering machine.
The humidity control of the filling is made according to the readings of the thermometer by changing the steam pressure, and the temperature is controlled by changing the water flow in the jacket of the tempering machine.
Technical characteristics of the vacuum-coil unit
|Productivity, kg / h||to 800|
|Coil heating surface area, m2||7,5|
|Steam pressure, MPa||0,45|
|The average moisture content of incoming mixture%||48|
|Average humidity the cooked stuffing,%||18,5|
|The temperature of the boiled filling, ° C||115|
|boiling time, min||to 3|
|The steam consumption in the 1 kg filling, kg||0,8|
|Chilled filling temperature, ° С||70-75|
|Cooling water temperature, ° С||to 25|
|Water consumption, m3 / h||2|
|Electric motor power, kW||1|
The caramel-forming stations included in each caramel production line include, in addition to a coil-type vacuum apparatus, a piston wet-air vacuum pump with a mixing condenser and a feeding syrup plunger pump.
In fig. 21 is a schematic and calculation diagram of a caramel melting station with the necessary letter designations for the corresponding parameters of the heating steam, syrup, finished caramel mass, secondary steam and condensate; the direction of the heat flux introduced by heating steam and syrup is also seen from the diagram.
Fig. 21. The concept and design scheme karamelevarochnoy station.
Caramel melting stations usually consist of an 1 syrup supply tank, into which the finished syrup is continuously pumped from the factory syrup station, an 2 syrup (food) plunger pump for continuous supply of caramel syrup to the 3 coil of the 4 vacuum chamber and the piston wet air vacuum pump 6 with mixing capacitor 5.
In small confectionery enterprises or in retail shops with a wide range of confectionery products, where universal cooking devices are used, for a more complete use of the device, it is advisable to install it as part of a station, which is usually equipped with an 1 digester (Fig. 22), an 2 filter bath, small-sized gear pump 3 and universal vacuum apparatus 4 type M-184 with integrated rotary wet-air liquid ring vacuum pump 6 and mixing condenser 5.
The mixture components to be boiled in the apparatus are previously dissolved in boiler I, from which they are then pumped for boiling into a universal vacuum apparatus.
Fig. 22. Universal vacuum-cooking station.