Boiler level differential pressure transmitter

I think this is a balance valve; it cannot be opened when in use, as opening it would result in the loss of differential pressure.

It needs to be opened. Once opened, it can effectively direct the condensate formed by vapor condensation to the positive-pressure side; it functions as a valve for online drainage on the low-pressure side.

It needs to be opened. Once opened, it can effectively direct the condensate formed by vapor condensation to the positive-pressure side; it functions as a valve for online drainage on the low-pressure side.

This post was last edited by mutianly on 2021-1-25 at 11:44. I don’t know what’s in the attachment. If the liquid level gauge tube is filled with condensate, this valve cannot be opened. For the boiler differential pressure level, when the valve is open, fluid will gradually accumulate in this section. The pressure measured under positive pressure is not the water pressure across the entire range; rather, it is the measurement pressure obtained under negative pressure (which is higher than the pressure at the positive pressure measurement port). In the negative-pressure type, this pressure can be removed.

This is a balance valve; it needs to be closed during operation

It is not a single-chamber equilibrium vessel; it is a condenser. The balance valve is closed when in use.

It cannot be opened; if opened, the gauge will indicate a low level. The idea of opening up the condensate drain is incorrect; this measurement method requires condensate on the negative pressure side in order for migration to occur.

. This pipeline is called a buffer tube, or it may also be referred to as a compensation tube. The valve should be open during operation. Actually, whether this tube (buffer tube) is installed or not makes little difference. Theoretically, its purpose is to reduce the impact of fluctuations in the liquid level inside the container (fluctuations in pressure or pressure difference) on the transmitter, acting as a buffer; when the valve of the buffer tube is opened, it serves as a connecting duct for the container. The internal liquid level is the same as the liquid level inside the container (in reality, there is a slight difference in the liquid level height due to differences in temperature and density). This is also why, under normal conditions, whether the valve is opened or not has no impact on the measurements ； When the liquid level in the container changes rapidly, the change in the height of the liquid column in the connecting tube occurs at a slower pace compared to the change in the container, which results in the pressure difference detected by the transmitter also changing more slowly, thus providing a certain buffering effect ； If the buffer tube is relatively thick, the buffering effect will be more noticeable ； In the case of lever-type (torque-balanced) differential pressure transmitters, if the input changes too rapidly, it may cause the overload protection mechanism of the lever mechanism to malfunction, leading to changes in the transmitter’s characteristics. The vast majority of transmitters these days don’t have this problem at all, so whether or not to use a buffer tube is not very important ； This pipeline is added only by designers whose knowledge is severely outdated, or when using ancient installation manuals. .