Is there an on-site flow meter similar to a water meter that can provide quantitative measurements?

There are similar flowmeters that can achieve the functions you described, such as electromagnetic flowmeters or mass flowmeters. These flowmeters can operate without being connected to a DCS system, and can be powered by batteries or driven mechanically. There are also various material options available, which can accommodate different properties of liquids such as acids, bases, and oxidizing liquids. Regarding the function of having a set flow rate and automatically shutting off once a certain cumulative flow is reached, this can usually be achieved by installing an electric or pneumatic valve on the flow meter that is connected to a control system such as a PLC. When the flow rate reaches a preset value, the control system commands the valve to close, thereby stopping the feed. For specific product information and technical data, it is recommended to visit the official websites of well-known flowmeter manufacturers such as Rosemount, Emerson, Endress+Hauser, etc., or contact their technical support for detailed product manuals and application guidance. .

A water meter measures the volume of water that passes through it by using the water to drive the impeller to rotate. However, it does not have a function to display instantaneous flow rate; only cumulative flow rate is shown. There are remote water meters that operate on two different principles: one relies on the different resistances of each digit to determine what number it is, while the other uses rotating discs for each digit, with changes in the holes on these discs used to identify the specific number. For each digit, there is a disc divided into ten equal angles, and each angle has 4 holes; these 4 holes form a code – if the holes are blocked, it represents 0, and if they are open, it represents 1. In this way, the 4 holes can be used to represent the numbers from 0 to 9. The first method, which relies on resistance to detect values, has its drawbacks; it uses the value of resistance to determine specific numbers. If the contacts oxidize or rust, it can lead to incorrect readings of the numbers. This is exactly why we had to replace the water meters in our community. Previously, the water meter reading was 285.9 tons; after rounding, it became 286 tons. However, the contact at the units place, which should have been 6, oxidized, causing it to be misread as 0. As a result, the remote display showed 280 tons, leading to an error. There was a problem with the remote water meter in our factory, so an experienced technician upstairs modified the circuit board on his own. Initially, the meter relied on photoelectric sensors to detect numbers, but a voltage-reducing chip was used instead; this chip consumed a lot of power, and as a result, the overall power consumption was high. The meter could function fine when data was transmitted remotely once a day, but problems arose when transmission occurred frequently. It was necessary to switch to a switching power supply with an inductor for voltage reduction. If the microcontroller works, it can be used to modify remote-read water meters. The smallest unit of measurement for such meters is 0.001 tons; by placing a photoelectric sensor on this dial, one full rotation corresponds to 1 kilogram. By knowing how much time it takes for the dial to rotate, it’s possible to calculate the flow rate. Taobao and Pinduoduo offer Hall flow meters and water flow sensors for around ten yuan each; however, they generate pulse signals – for example, 468 pulses correspond to one liter of water. These signals need to be fed into a PLC, where a high-speed counter is used to count the pulses and thereby determine the flow rate. Of course, I understand microcontrollers; it’s possible to use a microcontroller that costs just a few dollars to achieve this. A digital display can be used to show the flow rate, and one pin can be used to detect the voltage level and count it, thereby calculating the instantaneous flow rate. You can also look for turbine flow meters on online stores – those designed for diesel and gasoline use are available readily, and their price ranges from 100 to 400 yuan. Just search online. For example, the 2-inch version made of stainless steel costs 383 yuan, with a minimum flow rate of 40 L/min and a maximum flow rate of 700 L/min