Installation Precautions for the Source Components of Automatic Instruments in Refrigeration Units

2025-03-11

The source components of automatic instruments refer to the special pipe fittings, outlets, connecting valves and other components set on the measured object for installing and connecting the detecting elements.

I. General Provisions for Installing Source Components

The structure, dimensions, material and installation location of the source components shall comply with the provisions of the design documents.
The source components on the equipment shall be installed simultaneously with the equipment manufacturing, and the source components on the pipeline shall be installed simultaneously with the pipeline prefabrication and installation.
The opening and welding work for installing the source components on the equipment or pipeline must be carried out before the anti-corrosion, lining and pressure test of the equipment or pipeline.
When opening holes on high-pressure, alloy steel, non-ferrous metal equipment and pipelines, the mechanical processing method shall be adopted.
For the source components that are vulnerable to damage, protective measures shall be taken during installation.
When installing source components, holes shall not be opened and welding shall not be carried out on the weld seam and its edge.
When the equipment and pipeline have an insulation layer, the installed source components shall be exposed outside the insulation layer.
The connection between the source valve and the equipment or pipeline should not use a ferrule-type joint.
After the installation of the source components is completed, the pressure test shall be carried out simultaneously with the equipment and pipeline.

II.

Installation Precautions for the Source Components of Automatic Instruments in Refrigeration Units1741623496031

Installation of Temperature Source Components on Pipelines
The installation of temperature source components on pipelines shall meet the following requirements:

When installed perpendicular to the pipeline, the axis of the source component shall be perpendicular to the axis of the pipeline.
When installed at an inclined angle to the pipeline, it is advisable to install it against the flow direction of the material, and the axis of the source component shall intersect with the axis of the pipeline.
When installed at the bend of the pipeline, it is advisable to install it against the flow direction of the material, and the axis of the source component shall coincide with the axis of the process pipeline.
When the source component is installed on the enlarged pipe, the installation method of the enlarged pipe shall comply with the provisions of the design documents.

III.

Installation Precautions for the Source Components of Automatic Instruments in Refrigeration Units1741623496173

Pressure Source Components

The installation location of the pressure source component shall be selected at a position where the flow bundle of the measured material is stable.
When the pressure source component and the temperature source component need to be installed on the same pipeline section, the pressure source component shall be installed on the upstream side of the temperature source component.
The end of the pressure source component shall not exceed the inner wall of the equipment or pipeline.
When detecting the pressure of turbid materials such as dust, solid particles or sediments, on vertical and inclined equipment and pipelines, the source component shall be installed obliquely upward, and on a horizontal pipeline, it is advisable to install it at an acute angle along the flow bundle of the material.
When installing the pressure source component on a horizontal and inclined pipeline, the orientation of the pressure tapping point shall meet the following requirements:

When measuring the gas pressure, it shall be in the upper half of the pipeline.
When measuring the liquid pressure, it shall be within the range of an angle of 0°-45° between the lower half of the pipeline and the horizontal centerline of the pipeline.
When measuring the steam pressure, it shall be in the upper half of the pipeline, as well as within the range of an angle of 0°-45° between the lower half of the pipeline and the horizontal centerline of the pipeline.

IV. Flow Source Components

The minimum length of the straight pipe sections upstream and downstream of the flow source component shall comply with the provisions of the design documents.
Within the specified minimum length range of the straight pipe section, no other source components or detecting elements shall be installed. The inner surface of the straight pipe section shall be clean and free of pits and protrusions.
When installing a thermometer upstream of the throttling element, the distance of the straight pipe section between the thermometer and the throttling element shall comply with the following provisions:

When the diameter of the thermometer pocket or sleeve is less than or equal to 0.03D (D is the inner diameter of the pipeline), it shall not be less than 5D.
When the diameter of the thermometer pocket or sleeve is between 0.03D and 0.13D, it shall not be less than 20D.

When installing a thermometer downstream of the throttling element, the distance of the straight pipe section between the thermometer and the throttling element shall not be less than 5 times the inner diameter of the pipeline.
When the throttling device is installed on a horizontal and inclined pipeline, the orientation of the pressure tapping port shall comply with the following provisions:

When measuring the gas flow, it shall be in the upper half of the pipeline.
When measuring the liquid flow, it shall be within the range of an angle of 0°-45° between the lower half of the pipeline and the horizontal centerline of the pipeline.
When measuring the steam flow, it shall be within the range of an angle of 0°-45° between the upper half of the pipeline and the horizontal centerline of the pipeline.

V. Level Source Components

The installation location of the level source component shall be selected at a position where the level changes sensitively and the detecting element shall not be impacted by the material.
For the internal float level gauge and the float level gauge, when using a guide tube or other guide device, the guide tube or guide device shall be installed vertically, and the liquid flow in the guide tube shall be unobstructed.
The flange stub pipe for installing the float level instrument shall enable the float to move freely within the full range.

VI. Quality Acceptance after the Installation of Source Components
First of all, the structural dimensions, material and installation location of the source components shall comply with the provisions of the design documents. For the source components installed on the equipment or pipeline, check the construction records of the opening and welding work. After the installation of the source components is completed, the pressure test shall be carried out together with the equipment and pipeline.