With the development of China's economy and the improvement of production process requirements, screw chillers have become an important aspect of the cooling demand of most enterprises. Therefore, screw chillers are used in enterprises more and more widely, but the screw that comes with them The maintenance and maintenance of chillers has also become an important aspect of the owners of screw chillers.
(1) Preparation before the start of the screw chiller
The correct commissioning of the screw chiller is an important part of ensuring the normal operation of the refrigeration unit, saving energy and prolonging the service life. For on-site installation of large and medium-sized refrigeration systems, first of all, according to the requirements of the drawings, familiarize yourself with the layout and connection of the entire system, understand the shape and structure of each equipment, as well as the electronic control system and water supply system. To this end, engineers such as refrigeration and hydropower should participate in the commissioning. Users should carefully read the product operation instructions provided by the factory before commissioning, and proceed step by step according to the operation requirements. The operator must undergo special training from the factory to obtain the operation certificate of the unit before the operation can be carried out, so as to avoid fatal damage to the unit caused by wrong operation.
1. Preparation before the test
(1 ) Since the screw type chiller is a medium and large chiller, it needs to be closely coordinated in design, installation and use during commissioning. In order to ensure that the commissioning work is carried out in an orderly manner, it is necessary for the relevant personnel to form a temporary commissioning team to fully conduct the commissioning work.
(2 ) The personnel responsible for commissioning should be fully familiar with the structure and performance of the screw chiller, understand the safety technology of the chiller, clarify the method, steps and technical requirements to be debugged, formulate detailed and specific plans, and make each post The commissioning staff clearly understands their tasks and requirements.
(3 ) Check whether the installation of the screw chiller meets the technical requirements, whether the foundation of the screw chiller meets the requirements, and whether the size, specification and material of the connecting pipeline meet the design requirements.
(4 ) The power supply system of the unit should be fully installed and commissioned.
(5 ) Pass the water test on the cold water and cooling water system separately, flush the dirt of the waterway system, the water pump should work normally, and the circulating water quantity meets the requirements of working conditions.
(6 ) Clean and debug the environmental site to achieve clean, bright and smooth.
(7 ) Prepare the various common tools and special tools required for debugging.
(8 ) Prepare various measuring instruments and meters for pressure, temperature, flow, quality, time, etc. required for commissioning.
(9 ) Prepare the safety protection equipment necessary for commissioning operation.
2 . Screw chiller commissioning
(1 ) Charge of refrigerant. At present, the refrigeration unit is generally filled with refrigerant before leaving the factory. After the installation on site, if no accidental damage is found in the visual inspection, the relevant valve can be opened directly (you should read the manufacturer's instruction manual first, in transit, on the unit). The valve is normally in the off state) for commissioning. If the refrigerant has been leaked or insufficient, first find the leak point and eliminate the leak phenomenon, then add the required grade of refrigerant according to the product manual, pay attention to the refrigerant charge should meet the technical requirements.
(2 ) Some screw-type chillers need to be filled with refrigerant at the user's site. The refrigerant charge and refrigerant grade must be in accordance with regulations. The refrigerant charge is insufficient. Will result in insufficient cooling. Excessive refrigerant charge will not only increase the cost, but also adversely affect the operating energy consumption.
(3 ) Refrigeration system commissioning. After the refrigerant is charged (if the refrigerant needs to be charged), the load can be debugged. In recent years, screw chillers have made great progress in performance and electrical control. Many screw chillers can perform analog operation check on the main electronic control system before the official start-up, that is, the main unit of the unit is not energized, and the control system Power on, and then through the internal settings of the unit, the unit's electronic control system is tested, and the components are running normally. If there is any problem with the electronic control system, it can be resolved in time. After the zui, connect to the host power supply for debugging. During the debugging process, special attention should be paid to the following points:
1 ) Check that the valves in the refrigeration system are in the normal open state, especially the exhaust shut-off valve, and do not close.
2 ) Open the cooling water valve of the condenser and the cold water valve of the evaporator. The flow of cold water and cooling water should meet the requirements of the factory.
3 ) Before starting, pay attention to observe whether the power supply voltage of the unit is normal.
4 ) After the unit is started, check whether the parameters of the unit are normal according to the start-up manual provided by the factory.
5 ) According to the screw chiller operating data record table provided by the factory, record the data of the screw chiller, especially some main parameters must be recorded clearly.
6 ) During the operation of the screw chiller, attention should be paid to whether the upper and lower downloading mechanisms of the compressor are working properly.
Sprinkler irrigation and micro-irrigation automatic control equipment With the development of economy, water resources, energy shortage and labor cost increase, more and more water-saving irrigation systems will adopt automatic control. This article focuses on the advantages and classification of automated irrigation.
The advantages are as follows:
(1) It is possible to truly control the amount of irrigation, irrigation time and irrigation cycle in a timely and appropriate manner, thereby increasing crop yield and significantly improving water utilization.
(2) Saving labor and operating expenses.
(3) The work plan can be arranged conveniently and flexibly, and the management personnel do not have to go to the field at night or other inconvenient time.
(4) Since it can increase the effective working time every day, the initial capital investment in pipelines, pumping stations, etc. can be reduced accordingly.
classification:
First, fully automated irrigation system
The fully automated irrigation system does not require direct human involvement. The pre-programmed control procedures and certain parameters that reflect the water requirements of the crop can automatically open and close the pump for a long time and automatically irrigate in a certain order. The role of the person is simply to adjust the control program and overhaul the control equipment. In this system, in addition to emitters (heads, drip heads, etc.), pipes, fittings, pumps, and motors, it also includes central controllers, automatic valves, sensors (soil moisture sensors, temperature sensors, pressure sensors, water level sensors, and rain sensors). Etc.) and wires.
Second, semi-automatic irrigation system
In the semi-automated irrigation system, no sensors are installed in the field. The irrigation time, irrigation volume and irrigation period are controlled according to pre-programmed procedures, rather than feedback based on crop and soil moisture and meteorological conditions. The degree of automation of such systems is very different. For example, some pump stations implement automatic control, and some pump stations use manual control. Some central controllers are only one timer with simple programming function, and some systems have no central control. The controller, but only some of the sequential switching valves or volume valves are installed on each branch pipe.
Automated irrigation is the trend of the times. In the future water-saving irrigation projects, more and more automated irrigation systems will be applied.
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JIANGSU SKYPLAN GREENHOUSE TECHNOLOGY CO.,LTD , https://www.greenhousehydroponic.com