First, the density compensation of steam should be scientific and accurate In order to correctly measure the mass flow of steam, the change of steam pressure and temperature must be considered, and the steam density should be compensated by the flow totalizer. The platinum resistance for measuring the steam temperature must be installed in a standard way: the temperature of the platinum thermal resistance is inserted into the center of the pipe, the platinum thermal resistance is installed at the pipe diameter 5 times downstream of the flowmeter, and the pipe position where the platinum thermal resistance is installed is taken to ensure the measurement. The obtained temperature value is accurate. In the measurement of steam pressure, it must be noted that if the pressure of the pressure tube is used, zero point migration must be carried out (because the gravity of the condensate in the pressure tube will cause a certain pressure between the pressure measured by the pressure transmitter and the actual pressure. The difference, which causes the error in the density compensation, can also be corrected in the flow totalizer. The pressure transmitter is installed at 4 times the diameter of the downstream of the steam flow meter. The valve and gasket in front of the pressure transmitter should be well-connected to ensure accurate measurement of steam pressure. If the set pressure and temperature are used for compensation, the set value should be close to the actual value, otherwise the error is very large, and it is generally not recommended.
Correctly setting the operating state of the steam flow meter in the flow totalizer is critical to the correct calculation of steam costs. For the occasions where the steam state is not well defined, it is recommended to use an intelligent flow totalizer, with platinum resistance and pressure transmitter for temperature and pressure compensation, so that the measured mass flow of steam is the most accurate.
Second, the existing vibration and electromagnetic interference should avoid the influence of the design principle of the most widely used vortex flowmeter in steam metering. It is sensitive to mechanical vibration, the measurement result is susceptible to vibration interference, and the front and rear pipe sections of the steam flowmeter should be reliably supported. Design, install vibration buffer components, such as pipeline vibration is inevitable, should use a relatively strong anti-interference ability of the steam flow meter (such as gas ultrasonic flowmeter, intelligent vortex flowmeter, differential pressure flowmeter, etc.). If there is vibration interference at the steam flowmeter, it will affect the vortex flowmeter in use to generate low-frequency pulse signals, and the steam flowmeter will transmit these pulses as flow signals to the flow totalizer to form a cumulative flow. As a result, some vortex steam flowmeters still have a certain amount of value accumulation without using steam for a period of time. This is the reason why “the flow meter is not used without steamâ€. Therefore, if the steam user does not use steam, it should also keep a record of the bottom of the watch with the steam supply unit to prevent the steam flow meter from “running emptyâ€.
Third, the steam flowmeter range ratio reasonable range ratio refers to the ratio of the maximum flow rate and the minimum flow rate that a flow meter can measure within a given accuracy range. The user should select the flow meter according to his actual usage. In theory, the range of the steam flow meter to be selected should completely cover the user's use range. Exceeding the upper and lower flow limits will cause serious misalignment of the steam flow meter. For example, a vortex flowmeter with an actual average flow rate of 5t/h should generally select a vortex flowmeter with a diameter of 150mm, but when the flow rate is reduced to 0.3t/h or exceeds 15t/h, the flowmeter will be severe. Inaccurate measurement.
Fourth, the correct installation of the upstream and downstream straight pipe sections of the steam flowmeter For the traditional vortex flowmeter, the requirements for the straight pipe sections before and after installation are 20 times the pipe diameter and 5 times the pipe diameter (this is the obstacle without the valve in front of the flowmeter). Technical requirements; there are also obstacles to increase the straight pipe section, see the manufacturer's instructions). If the upstream and downstream straight pipe sections are not enough, the steam flow in the pipeline will not fully develop and the flow velocity distribution profile will be distorted. The user can adjust the flow rate distribution of the pipe by installing a flow regulator in front of the steam flow meter or adding a straight pipe section to make the fluid at the steam flow meter fully developed. For some large diameter steam flow meters, it is more important to meet the installation requirements of the upstream and downstream straight pipe sections.
Daily maintenance of excavator hydraulic cylinders
The hydraulic cylinder of an excavator is one of the important hydraulic components responsible for driving and controlling mechanical movements. In order to ensure the normal use of hydraulic cylinders and extend their service life, daily maintenance is necessary.
1. Regularly clean the hydraulic cylinder: During use, the hydraulic cylinder will be attacked by various pollutants, such as dust, sediment, oil stains, etc. These pollutants can affect the working efficiency and lifespan of the hydraulic cylinder. Therefore, it is necessary to regularly clean the hydraulic cylinder.
2. Regular inspection of seals: The seals of hydraulic cylinders are key components to ensure their normal operation. If the seals are damaged or worn, it can lead to oil leakage or unstable operation of the hydraulic cylinder. Therefore, it is necessary to regularly inspect the sealing components of the hydraulic cylinder and replace them in a timely manner if there is any damage or wear.
3. Regular inspection of hydraulic oil: The operation of hydraulic cylinders requires the support of hydraulic oil, so the quality of hydraulic oil has an important impact on the working effect of hydraulic cylinders. Regularly check the quality of hydraulic oil, and replace it promptly if there is contamination or deterioration.
4. Regularly check the hydraulic pipeline: The hydraulic pipeline is the blood vessel of the hydraulic cylinder. If there is oil leakage or damage to the pipeline, it can cause the hydraulic cylinder to not work properly. Therefore, it is necessary to regularly inspect the hydraulic pipelines and promptly repair or replace them if there is any oil leakage or damage.
5. Regularly lubricate the hydraulic cylinder: The piston rod and piston ring of the hydraulic cylinder need to be lubricated to reduce wear and friction. Therefore, it is necessary to regularly apply lubricating oil to ensure the normal operation of the hydraulic cylinder.
In short, the daily maintenance of excavator hydraulic cylinders is very important, which can extend their service life and improve work efficiency. Regular cleaning of hydraulic cylinders, inspection of seals, hydraulic oil, hydraulic pipelines, and lubrication of hydraulic cylinders are required.
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