Deltaba flow meter installation and maintenance

Installation requirements of Deltaba flowmeter:

1. For type I sensors, the detection rod has been welded to a section of pipe. When installing, the sensor must be in the direction of fluid flow. The inner diameter of the process pipeline is required to be consistent with the inner diameter of the sensor, or at least the angle between the axis of the sensor and the axis of the pipeline is as close to zero as possible within the required length of the upstream straight pipe section.

Other types of sensors insert their detection rods into the process pipeline. When installing, in addition to the total pressure hole facing the flow velocity direction, the sensor detection rod must be perpendicular to the axis of the process pipeline, and its position angle pressure deviation is allowed. The

angle between the center of the total pressure hole of the sensor and the axis of the pipeline should be less than 7°.

The sensor detection rod is inserted to the bottom along the diameter direction of the pipeline, and its angle deviation is less than 7°.

The vertical pipeline sensor can be installed at any position along the 360° circumference of the pipeline on the horizontal plane of the pipeline. The high and low pressure lead pipes should be in the same plane, as shown in Figure 6 (a); when measuring liquids, it should be installed tilted downward; when measuring gas vapor, it should be installed tilted upward

2. Straight pipe section

Since the sensor is based on the velocity area method, the approximate integral theory is used to describe it with more points. The distribution equation is established under the condition of fully developed velocity distribution. Therefore, in order to obtain an ideal distribution, a certain length of straight pipe section must be provided before and after the sensor. No. Average velocity pipe flow sensor installation position Upstream side A Downstream side B With rectifier Without rectifier Same plane Different plane.

1. There is a 90° elbow or tee 6D 7D 9D 3D;
2. There are two 90° elbows in the same plane 8D 9D 14D 3D;
3. There are two 90° elbows in different planes 9D 19D 24D 4D;
4. The pipe diameter changes (contraction or expansion) 8D 8D 8D 3D;
5. Partially opened gate valve, ball valve or other throttle valve 8D 8D 8D 3D.

Note: (1) "D" in the table is the inner diameter of the pipe. (2) In the case of insufficient pipe section, the upstream should account for 70% of the total length of the pipe and the downstream should account for 30%. At this time, a stable indication can still be given, but the accuracy is reduced. The device for clamping the sensor should ensure no leakage, looseness or displacement.

Maintenance of Deltaba flowmeter:

The sensor of Deltaba flowmeter should be cleaned regularly during the overhaul of process pipeline. There are many ways to clean it, such as using air source to blow away the accumulated dirt in the detection tube; using kerosene and soft wire brush to clean it to keep all pressure holes unobstructed. Possible causes of failure and elimination methods: No. Cause of failure phenomenon Elimination method.

1. No differential pressure signal output: The high and low pressure valves are not opened, open the high and low pressure valves.
2. The high and low pressure balance valves are not tightened: Tighten the balance valve
3. The differential pressure signal output is too small: There is a leak in the pressure guide system; carefully find and eliminate the leak.
4. The secondary meter range is improperly selected: reduce the upper limit value of the differential pressure transmitter
5. The differential pressure signal output is too large: The secondary meter range is improperly selected, increase the upper limit value of the differential pressure transmitter, the back pressure hole is blocked, clean the average velocity tube, and eliminate the blockage.