Units that have support posts are checked for horizontalness and secured with foundation bolts, after which the unit is connected with pipelines, a control check of shaft alignment, installation of power cables, electrical equipment and automation devices is carried out. The installation ends with individual tests without load and under load.
The installation of the evaporator begins in disassembled form: tank, panels, collectors, mixers, liquid separator. The tank is checked for leaks, the panels are checked for verticality, and the collectors for horizontality. A test run of the mixer is done. Then a liquid separator is mounted on a separate platform. The outside of the tank is thermally insulated, and the assembled evaporator is individually tested.
Installation of batteries and air coolers
Air cooler(a/o)
To fasten suspended ceilings during the construction process, metal embedded parts are provided between the covering or floor slabs. But since the location of the air coolers may not coincide with the embedded parts, a special metal structure is additionally provided.
The installation ends with individual tests of the fan, which include running in the fan and, if necessary, checking the strength and density of the pipe space. Pedestal units can be installed either on foundation supports, or when placed on mezzanines on metal supports. Installation includes installation in the design position, alignment, fastening, supplying the cold water pipelines, laying the drainage pipeline, and connecting the electrical cables.
Battery
Can be ceiling or wall. For fastening ceiling batteries, embedded parts are used. The batteries are made up of sections and can be collector or coil. I test for density and strength with the entire system.
Installation of aggregated equipment
Before installation, the readiness of the premises, foundations, completeness and condition of equipment, availability technical documentation. The units can be located either in one room, the engine room, or dispersed throughout utility rooms. In the latter case, there should be no more than 0.35 kg per 1 m 3 of room (for example, R22). The room must be equipped with a ventilation system. It is prohibited to install units on staircase landings, under stairs, in corridors, in lobbies, in foyers.
In the engine room the following must be observed:
1. The width of the main passage is at least 1.2 m;
2. There is at least 1 m between protruding parts of equipment;
3. The distance between the unit and the wall is at least 0.8 m.
Panels with fittings are placed on the wall near the unit.
The pipelines are laid with a slope to ensure oil return to the compressor crankcase. The thermostatic valves are installed with the capillary tube facing up.
Compressor-condensing units come from the factory filled with cold water, so they are turned off before testing the system for density and strength.
Pipeline installation
When laying pipelines in the wall, a sleeve is installed with a diameter of 100-200 mm larger than the diameter of the pipelines.
Depending on the environment and operating conditions, pipelines are divided into: A-highly toxic; B-fire and explosion hazard; V-everyone else.
Depending on the categories, pipelines are subject to different requirements in relation to: assortment, fittings, type of connection, weld quality control, testing conditions. Eg. For ammonia, seamless steel pipes, which are connected to shaped sections and to each other by welding, and to equipment and fittings using flange connections (tenon-groove, protrusion-valley). For freon chemicals used copper pipes, which conn. with each other using soldering, and with equipment and fittings using connections. nipple-fitting-union nut.
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When laying water pipelines in the ground, they are not allowed to intersect with electrical cables. Pipelines are manufactured on the basis wiring diagrams and drawings, as well as specifications of pipes, supports, hangers. The drawings contain the dimensions and material of pipes and fittings, fragments of connections to equipment, installation locations for supports and hangers. The pipeline route is broken in the room, i.e. Marks are made on the walls corresponding to the axes of the pipelines; along these axes, the installation locations of fastening units, fittings, and compensators are marked. Brackets and embedded parts for fastening are installed and filled with concrete. Before installing pipelines, all equipment must be installed, since installation of pipelines begins with the equipment. The assembly units are lifted onto fixed supports and secured at several points. Then the assembly is connected to the equipment nozzle, verified and pre-fixed. Then a straight section is attached to the assembly by tack welding. The assembled section is checked for straightness and the assembly joints are welded. In conclusion, a control check is carried out and the pipeline section is connected. are finally fixed. After installation, the pipelines are purged compressed air(water-water) and are tested for density and strength.
Air duct installation
In order to unify the location of air ducts relative to building structures, the recommended mounting positions:
Parallelism a 1 = a 2
Distance to walls (columns)
X=100 at =(100-400)mm
X=200 at =(400-800)mm
X=400 at 800 mm
The minimum permissible distance from the axis of the air ducts to outer surface must be at least 300 mm + half. Options for laying several air ducts relative to the horizontal axis are possible.
Distance to the outer wall (from the axes of the air ducts)
-minimum permissible distance from the axes of the air ducts to the ceiling surface
When air ducts pass through building construction detachable connections air ducts should be placed at a distance of at least 100 mm from the surface of these structures. Fastening of air ducts is carried out at a distance of no more than 4 meters relative to each other, with a diameter or size of the larger side of the duct less than 400 mm, and no more than 3 meters with large diameters (horizontal non-insulated on wafer connections), at a distance of no more than 6 m with a diameter of up to 2000 mm (non-insulated horizontal metal air ducts with flange connections)
Connection methods air ducts:
Flange connection;
Telescopic connection;
1,2 – parts to be riveted; 3 – rivet body; 4 – rod head; 5 – stress concentrator; 6 – emphasis; 7 – collet; 8 – rod. Collet 7 pulls rod 8 to the left. The stop 6 presses the rivet 3 to the riveted parts 1,2. The head of the rod 4 flares the rivet 3 with inside and with a certain force, rod 8 tears it off.
Bandage connection;
1-bandage
2-gasket
3-connection air ducts
Operation and service of SCV
After the completed installation of systems is handed over to the customer, their operation begins. Operation of the VCS is the constant use of the system during its normal operation in order to create and maintain specified conditions in the objects being serviced. During operation, the system is turned on, maintenance is carried out, the required documentation is completed, operating parameters are recorded in logs, as well as comments on the work. Ensuring uninterrupted and efficient work SCVs carry out operation services in accordance with the operating instructions. They are on. includes: maintenance periods, preventive examination, repairs, delivery times for spare parts, instructions and materials. SCRs are also used by system diagrams, acts for short-term work, acts for deviation from the project, technological passports for equipment. Before putting into operation SCRs, they are tested and adjusted. Tests incl. individual tests of installed equipment, pneumatic tests of heating and cooling subsystems, as well as air duct systems. The test results are documented in a corresponding document. The purpose of the work on setting up SCR yavl. Achievement and stable maintenance given parameters at the most economical operating mode of all systems. During commissioning, the operating parameters of the system are set in accordance with design and standard indicators. During system maintenance, the technical condition of all equipment, the placement and serviceability of control devices and instrumentation are checked. Based on the results of the inspection, a defective statement is drawn up. If the installed equipment corresponds to the project, then all systems are tested and adjusted as follows. sequences: - adjustment of all functional blocks of the central control system to bring it to the design parameters; - aerodynamic adjustment of the system to the design air flow rates along the branches; - testing and adjustment of heat and cold sources, pumping station; - adjustment of fan coil systems, air coolers and central air heaters; - measurement and verification of air parameters in the room with standard ones.
In order to increase the safety of operation of the refrigeration unit, it is recommended that condensers, linear receivers and oil separators (devices high pressure) With big amount refrigerant should be placed outside the engine room.
This equipment, as well as receivers for storing refrigerant reserves, must be surrounded by a metal barrier with a lockable entrance. Receivers must be protected by a canopy from sun rays and precipitation. Apparatuses and vessels installed indoors can be located in the compressor workshop or special room equipment room, if it has a separate exit to the outside. Passage between smooth wall and the device must be at least 0.8 m, but it is allowed to install devices near walls without passages. The distance between the protruding parts of the devices must be at least 1.0 m, and if this passage is the main one - 1.5 m.
When mounting vessels and apparatus on brackets or cantilever beams, the latter must be embedded in the main wall to a depth of at least 250 mm.
Installation of devices on columns using clamps is allowed. It is prohibited to punch holes in columns to secure equipment.
For installation of devices and further maintenance of condensers and circulation receivers, metal platforms with fencing and stairs are installed. If the length of the platform is more than 6 m, there should be two stairs.
Platforms and stairs must have handrails and edges. The height of the handrails is 1 m, the edge is at least 0.15 m. The distance between the handrail posts is no more than 2 m.
Tests of apparatus, vessels and pipeline systems for strength and density are carried out upon completion installation work and within the time limits provided for by the “Rules for the Design and safe operation ammonia refrigeration units».
Horizontal cylindrical devices. Shell-and-tube evaporators, horizontal shell-and-tube condensers and horizontal receivers are installed on concrete foundations in the form of separate pedestals strictly horizontally with a permissible slope of 0.5 mm per 1 m linear length towards the oil sump.
The devices rest on antiseptic wooden beams at least 200 mm wide with a recess in the shape of the body (Fig. 10 and 11) and are attached to the foundation with steel belts with rubber gaskets.
Low-temperature devices are installed on beams with a thickness no less than the thickness of the thermal insulation, and under
placed with belts wooden blocks 50-100 mm long and height equal to the thickness of the insulation, at a distance of 250-300 mm from each other around the circumference (Fig. 11).
To clean condenser and evaporator pipes from contamination, the distance between their end caps and walls should be 0.8 m on one side and 1.5-2.0 m on the other. When installing devices in a room to replace pipes of condensers and evaporators, a “false window” is installed (in the wall opposite the cover of the device). To do this, an opening is left in the building's masonry, which is filled thermal insulation material, sewed up with boards and plastered. When repairing devices, the “false window” is opened and restored upon completion of the repair. Upon completion of work on placing the devices, automation and control devices, shut-off valves, safety valves.
The cavity of the apparatus for the refrigerant is purged with compressed air, and strength and density tests are carried out with the covers removed. When installing a condenser-receiver unit, a horizontal shell-and-tube condenser is installed on the platform above the linear receiver. The size of the site must ensure all-round maintenance of the device.
Vertical shell and tube condensers. The devices are installed outdoors on a massive foundation with a pit for draining water. When making the foundation, the bolts for securing the lower flange of the apparatus are placed in concrete. The capacitor is installed crane for packs of linings and wedges. By tamping wedges, the apparatus is positioned strictly vertically using plumb lines located in two mutually perpendicular planes. In order to prevent the plumb lines from swinging by the wind, their weights are lowered into a container with water or oil. Vertical arrangement apparatus is caused by the helical flow of water through its tubes. Even with a slight tilt of the device, water will not normally wash the surface of the pipes. Upon completion of the alignment of the apparatus, the linings and wedges are welded into bags and the foundation is poured.
Evaporative condensers. They are supplied assembled for installation and installed on a platform whose dimensions allow for all-round maintenance of these devices. ‘The height of the platform is taken into account the placement of linear receivers under it. For ease of maintenance, the platform is equipped with a ladder, and if the fans are located at the top, it is additionally installed between the platform and the upper plane of the device.
After installing the evaporative condenser, connect it to circulation pump and pipelines.
The most widely used are evaporative condensers of the TVKA and Evako types produced by VNR. The drop-repellent layer of these devices is made of plastic, so welding and other work with open flames should be prohibited in the area where the devices are installed. Fan motors are grounded. When installing the device on a hill (for example, on the roof of a building), lightning protection must be used.
Panel evaporators. They are supplied as separate units and are assembled during installation work.
The evaporator tank is tested for leaks by pouring water and installed on concrete slab 300-400 mm thick (Fig. 12), the height of the underground part of which is 100-150 mm. Antiseptic wooden beams or railway sleepers and thermal insulation are laid between the foundation and the tank. Panel sections are installed in the tank strictly horizontally, level. Side surfaces The tank is insulated and plastered, and the mixer is adjusted.
Chamber devices. Wall and ceiling batteries are assembled from standardized sections (Fig. 13) at the installation site.
For ammonia batteries, sections of pipes with a diameter of 38X2.5 mm are used, for coolant - with a diameter of 38X3 mm. The pipes are finned with spirally wound fins made of 1X45 mm steel tape with fin spacing of 20 and 30 mm. The characteristics of the sections are presented in table. 6.
Total length of battery hoses in pumping schemes should not exceed 100-200 m. The battery is installed in the chamber using embedded parts fixed in the ceiling during the construction of the building (Fig. 14).
Battery hoses are placed strictly horizontally and level.
Ceiling air coolers are supplied assembled for installation. The supporting structures of the devices (channels) are connected to the channels of the embedded parts. The horizontal installation of the devices is checked using the hydrostatic level.
Batteries and air coolers are lifted to the installation site by forklifts or other lifting devices. The permissible slope of the hoses should not exceed 0.5 mm per 1 m linear length.
To remove melt water during defrosting, they are installed drain pipes, on which heating elements of the ENGL-180 type are fixed. The heating element is a glass fiber tape, which is based on metal heating cores made of an alloy with high resistivity. Heating elements are wound onto the pipeline in a spiral or laid linearly, secured to the pipeline with glass tape (for example, tape LES-0.2X20). On the vertical section of the drain pipeline, heaters are installed only in a spiral manner. When laying linearly, the heaters are secured to the pipeline with glass tape in increments of no more than 0.5 m. After the heaters are secured, the pipeline is insulated with non-flammable insulation and sheathed with a protective metal sheath. In places where the heater has significant bends (for example, on flanges), an aluminum tape with a thickness of 0.2-1.0 mm and a width of 40-80 mm should be placed under it to avoid local overheating.
Upon completion of installation, all devices are tested for strength and density.
In the evaporator, the process of transition of the refrigerant from the liquid phase state to the gaseous state occurs with the same pressure; the pressure inside the evaporator is the same everywhere. During the process of transition of a substance from liquid to gaseous (its boiling away) in the evaporator, the evaporator absorbs heat, unlike the condenser, which releases heat to the environment. That. through two heat exchangers, the process of heat exchange occurs between two substances: the cooled substance, which is located around the evaporator and the outside air, which is located around the condenser.
Liquid freon flow diagram
Solenoid valve - shuts off or opens the flow of refrigerant to the evaporator, is always either completely open or completely closed (may not be present in the system)
Thermostatic expansion valve (TEV) is a precise device that regulates the flow of refrigerant into the evaporator depending on the intensity of the refrigerant boiling in the evaporator. It prevents liquid refrigerant from entering the compressor.
Liquid freon enters the expansion valve, the refrigerant is throttled through the membrane in the expansion valve (freon is sprayed) and begins to boil due to the pressure drop, the droplets gradually turn into gas throughout the entire section of the evaporator pipeline. Starting from the throttling device of the expansion valve, the pressure remains constant. Freon continues to boil and in a certain section of the evaporator it completely turns into gas and then, passing through the evaporator, the gas begins to be heated by the air that is in the chamber.
If, for example, the boiling point of freon is -10 °C, the temperature in the chamber is +2 °C, freon, having turned into gas in the evaporator, begins to heat up and at the exit from the evaporator its temperature should be equal to -3, -4 °C, thus Δt ( the difference between the boiling point of the refrigerant and the gas temperature at the evaporator outlet) should be = 7-8, this is the normal operation of the system. For a given Δt, we will know that at the exit from the evaporator there will be no particles of unboiled freon (there should not be any); if boiling occurs in the pipe, then not all the power is used to cool the substance. The pipe is thermally insulated so that the freon does not heat up to the temperature environment, because The refrigerant gas cools the compressor stator. If liquid freon still gets into the pipe, it means that the dose supplied to the system is too large, or the evaporator is weak (short).
If Δt is less than 7, then the evaporator is filled with freon, it does not have time to boil away and the system does not work correctly, the compressor is also filled with liquid freon and fails. Overheating on a larger side is not as dangerous as overheating on a smaller side; at Δt ˃ 7, overheating of the compressor stator may occur, but a slight excess of overheating may not be felt by the compressor and is preferable during operation.
With the help of fans located in the air cooler, cold is removed from the evaporator. If this did not happen, then the tubes would become covered with ice and at the same time the refrigerant would reach its saturation temperature, at which it stops boiling, and then, even regardless of the pressure drop, liquid freon would enter the evaporator without evaporating, flooding the compressor.
In the case when the consumption of the vapor phase of liquefied gas exceeds the rate of natural evaporation in the container, it is necessary to use evaporators, which, due to electrical heating, accelerate the process of evaporation of the liquid phase into the vapor phase and guarantee the supply of gas to the consumer in the calculated volume.
The purpose of the LPG evaporator is the transformation of the liquid phase of liquefied hydrocarbon gases (LPG) into a vapor phase, which occurs through the use of electrically heated evaporators. Evaporation units can be equipped with one, two, three or more electric evaporators.
Installation of evaporators allows the operation of one evaporator or several in parallel. Thus, the productivity of the installation may vary depending on the number of evaporators operating simultaneously.
When the evaporation unit is turned on, the automation heats the evaporation unit to 55C. The solenoid valve at the liquid phase inlet to the evaporation unit will be closed until the temperature reaches these parameters. The level control sensor in the shut-off valve (if there is a level gauge in the shut-off valve) monitors the level and closes the inlet valve when overfilled.
The evaporator begins to heat up. When 55°C is reached, the inlet magnetic valve will open. The liquefied gas enters the heated pipe register and evaporates. At this time, the evaporator continues to heat up, and when the core temperature reaches 70-75°C, the heating coil will be turned off.
The evaporation process continues. The evaporator core gradually cools down, and when the temperature drops to 65°C, the heating coil will be turned on again. The cycle repeats.
The evaporation unit can be equipped with one or two regulatory groups to duplicate the reduction system, as well as the vapor phase bypass line, bypassing the evaporation unit for using the steam phase of natural evaporation in gas holders.
Pressure regulators are used to set the desired pressure at the outlet of the evaporation unit to the consumer.
1. Compact design, light weight;
2. Economical and safe operation;
3. Big thermal power;
4. Long service life;
5. Stable operation at low temperatures;
6. Duplicated control system for the exit of the liquid phase from the evaporator (mechanical and electronic);
7. Anti-icing of filter and solenoid valve (PP-TEC only)
Package Included:
Double thermostat for gas temperature control,
- liquid level control sensors,
- solenoid valves at the liquid phase inlet
- set of safety fittings,
- thermometers,
- Ball Valves for emptying and deaeration,
- built-in liquid phase gas separator,
- inlet/outlet fittings,
- terminal boxes for connecting power supply,
- electrical control panel.
When designing an evaporation plant, three elements must always be taken into account:
1. Ensure the specified performance,
2. Create the necessary protection against hypothermia and overheating of the evaporator core.
3. Correctly calculate the geometry of the location of the coolant to the gas conductor in the evaporator
The performance of the evaporator depends not only on the amount of power supply voltage consumed from the network. An important factor is the geometry of the location.
Correctly calculated location ensures effective use heat transfer mirrors and, as a result, an increase in the efficiency of the evaporator.
In the evaporators “PP-TEC “Innovative Fluessiggas Technik” (Germany), through correct calculations, the company’s engineers achieved an increase in this coefficient to 98%.
Evaporative installations of the company “PP-TEC “Innovative Fluessiggas Technik” (Germany) lose only two percent of heat. The remaining amount is used to evaporate the gas.
Almost all European and American manufacturers of evaporation equipment completely erroneously interpret the concept of “redundant protection” (a condition for the implementation of duplication of protection functions against overheating and overcooling).
The concept of “redundant protection” implies the implementation of “safety net” of individual working units and units or entire equipment, through the use of duplicated elements from different manufacturers and with different principles of operation. Only in this case can the possibility of equipment failure be minimized.
Many manufacturers try to implement this function (while protecting against hypothermia and the ingress of the liquid fraction of LPG to the consumer) by installing two magnetic valves connected in series from the same manufacturer on the input supply line. Or use two connected in series temperature sensor turning on/opening valves.
Imagine the situation. One solenoid valve is stuck open. How can you determine that the valve has failed? NO WAY! The installation will continue to operate, having lost the opportunity to ensure safe operation in time during overcooling in the event of failure of the second valve.
In PP-TEC evaporators this function was implemented in a completely different way.
In evaporation installations, the company “PP-TEC “Innovative Fluessiggas Technik” (Germany) uses an algorithm for the combined operation of three elements of protection against hypothermia:
1. Electronic device
2. Magnetic valve
3. Mechanical shut-off valve in the shut-off valve.
All three elements have absolutely different principle actions, which allows us to speak with confidence about the impossibility of a situation in which non-evaporated gas in liquid form enters the consumer pipeline.
In the evaporation installations of the company “PP-TEC “Innovative Fluessiggas Technik” (Germany), the same thing was implemented when protecting the evaporator from overheating. The elements involve both electronics and mechanics.
The company “PP-TEC “Innovative Fluessiggas Technik” (Germany) was the first in the world to implement the function of integrating a liquid cut-off valve into the cavity of the evaporator itself with the possibility of constant heating of the cut-off valve.
No evaporation technology manufacturer uses this proprietary function. Using a heated cutter, evaporation units “PP-TEC “Innovative Fluessiggas Technik” (Germany) were able to evaporate heavy components of LPG.
Many manufacturers, copying from each other, install a cut-off valve at the outlet in front of the regulators. The mercaptans, sulfur and heavy gases contained in the gas, which have a very high density, entering a cold pipeline, condense and are deposited on the walls of the pipes, cut-off valve and regulators, which significantly reduces the service life of the equipment.
In PP-TEC “Innovative Fluessiggas Technik” (Germany) evaporators, heavy sediments in a molten state are kept in a separator until they are removed through a discharge ball valve in the evaporation unit.
By cutting off mercaptans, the company “PP-TEC “Innovative Fluessiggas Technik” (Germany) was able to achieve a significant increase in the service life of installations and regulatory groups. This means taking care of operating costs that do not require constant replacement of regulator membranes, or their complete expensive replacement, leading to downtime of the evaporation unit.
And the implemented function of heating the solenoid valve and filter at the inlet to the evaporation unit prevents water from accumulating in them and, if frozen in the solenoid valves, causing damage when activated. Or limit the entry of the liquid phase into the evaporation unit.
Evaporation units from the German company “PP-TEC “Innovative Fluessiggas Technik” (Germany) provide reliable and stable operation over many years of operation.
