Description
A quartz sleeve or sheath protects another component by forming a transparent or heat-resistant barrier between that component and the process environment. UV lamp sleeves protect the lamp while allowing ultraviolet output through the tube wall; thermocouple and probe sheaths isolate a sensor from hot, corrosive or contamination-sensitive media.
The key purchasing specification is therefore the component being protected together with the finished OD, length, end condition and seal interface. The sleeve or sheath is sized around the lamp, probe, O-ring, fitting or existing equipment geometry rather than selected only from a generic quartz tube list.
Dimensions
| Use Case | OD | Length | End |
|---|---|---|---|
| UV Lamp Sleeve — Typical | 20 – 30 mm; common examples include 22, 24.5 and 25 mm | 300 – 1700 mm; equipment-specific lengths are common | Open or domed closed end |
| Thermocouple / Probe Protection Tube | Probe OD plus required running clearance | Matched to probe insertion length and fitting position | Normally closed at process end, open at insertion end |
End Configuration
| End Type | Use |
|---|---|
| Open Both Ends | Flow-through or through-access protection where the lamp or protected component must remain accessible from both sides |
| Domed / Closed One End | Submersible or insertion protection where the process-side end must remain isolated from water, gas or other media |
| Fire-Polished | Rounded, heat-finished tube end used where a smoother edge is preferred after cutting |
| Saw-Cut / Ground | Square end for controlled length and fitting engagement |
| Flared / Beaded | Formed end used to locate the sleeve, retain a seal or match existing equipment hardware |
UV Lamp Sleeve Use
- Creates a physical barrier between a germicidal UV lamp and water, air flow, handling or process exposure.
- Clear fused quartz is selected where UV-C transmission through the sleeve wall is required.
- Typical sleeve systems use O-ring seals matched to the sleeve OD; common equipment sizes include approximately 23, 24, 25 and 30 mm, but the installed hardware controls the actual seal specification.
- Open-ended and domed-end versions can be produced to match the lamp chamber design.
- Type 214-equivalent clear fused quartz is a common material basis for general UV sleeve service.
Thermocouple / Probe Protection Use
- Provides a barrier between the process medium and the temperature-sensing element or measurement probe.
- Closed process end reduces direct exposure of the sensor to corrosive vapors, liquids, contamination or furnace atmosphere.
- Open insertion end allows installation and removal of the probe while the quartz sheath remains part of the equipment interface.
- ID is selected from probe OD plus the required running clearance, with allowance for thermal movement and the actual fitting arrangement.
- Insertion length, closed-end geometry and seal position are specified together to ensure the sensing tip sits at the intended process location.
Material
Clear fused quartz is the standard choice for UV lamp sleeves because the tube wall must transmit the required ultraviolet wavelength. High-temperature probe and thermocouple sheaths can use clear fused quartz or another appropriate quartz grade according to process temperature, contamination requirement and optical need.
Where UV, VUV, IR or hydroxyl content is critical, material grade should be selected from the relevant fused quartz material specification rather than inferred from sleeve dimensions alone.
What to Specify
| Parameter | Quotation Input |
|---|---|
| Protected Component | UV lamp, thermocouple, probe or other insert; include model or sample dimensions when available |
| Tube Geometry | OD, ID or wall thickness, overall finished length |
| End Configuration | Open both ends, closed / domed end, fire-polished, ground, flared or beaded |
| Seal Interface | O-ring size, fitting ID, shoulder position or existing housing dimensions |
| Insertion Geometry | Required insertion depth, sensing-tip position and any straight clearance length |
| Material Requirement | Clear fused quartz, UV grade, low-OH grade or other specified material |
| Operating Condition | Temperature, process medium and UV wavelength where relevant |
FAQ
What’s the difference between a sleeve and a sheath?
The construction can be very similar, but the names normally follow the protected component. “Sleeve” is commonly used for UV lamp protection tubes, while “sheath” or “protection tube” is common for thermocouples and probes. Either can be open-ended or closed at one end depending on the equipment design.
Can you match a replacement sleeve to my existing UV system without a part number?
Yes. OD, finished length, end type and seal position are the most useful starting dimensions. A sample, equipment model or photo of the installed sleeve and O-ring arrangement reduces the risk of matching only the nominal lamp size.
Does the sleeve reduce UV output significantly?
Any additional wall introduces some transmission loss. With the correct fused quartz grade and a clean sleeve surface, UV-C transmission can remain high, but the actual output through the installed sleeve depends on wavelength, wall thickness, quartz grade, fouling and lamp condition.