Heated Sample Line (JCH)

JCH is the gas-sampling hose from our electrically heated range, the line we supply for sample systems that must not drop below dew point between the probe and the analyzer. The catalog places it in flue-gas pretreatment equipment, online monitoring equipment, IR and UV sampling analyzers and laboratory test equipment. Maximum heat resistance is up to 230 °C (446 °F), higher temperatures are custom on request, and the catalog prints three bores: 3/16", 1/4" and 5/16".

• Max heat resistance230 °C / 446 °F, higher on request
• Pressure classlow pressure, per-size table below
• Inner tubeB, TB, T or X build, 3/16"–5/16"
• Supply110 / 220 / 380 Vac, 12 Vdc
• SensorJ, K, Ni120, PT100, PT1000

Overview

The sample-line calls I get are almost never about a burst hose. They are about a reading that drifts, an analyzer that alarms on flow after a few weeks, or a line that looks fine on the bench and then kinks behind the cabinet once it is installed. In every case the sample was not held at temperature the whole way, or the line took a bend it was not built for.

Condensate is the first suspect. Flue gas carries water vapour, and once any section of the line falls below the dew point the water drops out. It wets the sample, it dissolves what is in the gas, and downstream of that you get a wet filter, a wet pump and a reading you cannot trust. Multi-component analyzers make it worse: sulphur oxides and ammonia in the same sample form salts that set hard in a cold spot. A heated line is the answer only if the heat reaches the wall evenly along the whole run, including the last half metre into the analyzer.

That is what the braided heating layer is for. The heating elements are braided uniformly around the hose rather than wound as a single strand, which keeps the temperature difference along the inner wall small. A single-strand winding leaves a warm side and a cool side; on a narrow bore sample line, the cool side is where condensation starts. The insulation is a high-insulation-efficiency material chosen with surface temperature in mind, so the outer surface stays where you can route it near a cabinet wall.

The second part is mechanical. Sample lines on skids and portable units are coiled and uncoiled, tied to a probe with a clamp and run through a cable carrier. The catalog describes this build as bend- and kink-resistant with stable insulation, and the strand braid and the strain-relief boot at the end are what make that true in service: the boot takes the side load so the hose does not fold at the fitting.

Where it is the wrong choice: this is a three-bore, low-pressure sample line. If you need a larger bore for high flow, or a hose feeding a hot-melt melter or a pressurised extrusion port, look at the hot-melt, extruder or special-industry heated hose instead.

Specifications

All values as printed in the Jingcheng 2025 electrically heated hose catalog.

Size and pressure table

All values as printed in the Jingcheng 2025 electrically heated hose catalog.

Full catalog: Heated hose catalog (PDF, 4.9 MB)

Materials and construction

• Inner tube: specified on the order form by model-code letter – B stainless corrugated tube, TB PTFE hose with stainless braid, T PTFE hose, X special material. For a gas sample the gas composition and the moisture it carries decide the tube; tell us what is in the sample and at what temperature it leaves the probe.
• Heating layer: heating elements braided uniformly around the hose, which keeps the temperature difference along the inner wall small instead of leaving a hot stripe down one side.
• Sensor: a temperature sensor in the assembly, matched to your controller. Type J or K, Ni120, PT100 or PT1000, agreed on the drawing.
• Insulation and cover: high-insulation-efficiency material, selected with surface temperature in mind, under the black braided outer cover shown in the photo.
• End fittings: a hose-end fitting at each end behind a black strain-relief boot, thread standard and size specified per end. The electrical lead exits at one end, as in the photo.

Temperature and pressure notes

230 °C (446 °F) is the maximum heat resistance of the series; the catalog marks higher temperatures as custom, on request. The useful number for a sample line is not the maximum, it is the dew point of your gas at the pressure in the line. Set the controller above that with a margin, and pick the sensor position so the controller reads the section closest to the analyzer, not the probe end where the sample is hottest.

Pressure is given per size in the table above: working pressure 203 bar at 3/16", 173 bar at 1/4" and 158 bar at 5/16", with burst pressure printed on the same row. A sample line normally runs at a few bar at most, so the table is usually a large margin rather than a limit. What actually limits these lines in service is the bend: 30 mm minimum bend radius for 3/16" and 1/4", 40 mm for 5/16", while the assembled hose as a whole is rated to a 0.2 m minimum bend radius. Treat the assembly figure as the rule for routing and the per-size figure as what the inner hose can take.

Keep the ambient inside −40 to +55 °C (−40 to 131 °F) at 85 % relative humidity or less, and keep the surroundings free of gases that corrode metal or damage insulation, of conductive media and of severe mould; anything outside that is a custom build. Do not twist the hose laterally during or after installation – a twisted sample line pulls itself into a tighter bend when it warms up.

Applications

The catalog application is gas sampling, and the four settings it names are the ones we quote most:

• Flue-gas pretreatment equipment – the heated run from the probe to the cooler, filter or pump skid
• Online monitoring equipment – CEMS and process analyzers that need the sample held above dew point right up to the cell
• IR and UV sampling analyzers – short heated runs into the measuring cell, where a cold spot shows up as drift
• Laboratory test equipment – bench and pilot rigs where the line is handled and re-routed between tests

It is a low-pressure sample line. For a high-pressure connection or a melter feed line, use the heated high-pressure builds instead.

Options and related builds

• The long version: our article on the heated sample line for gas analyzers covers construction, sensor placement and how to specify one. This page is the product and its numbers; that one is the how and why.
• Before you specify: the heated hose specification checklist lists the inputs we need for a quotation, in the order we ask for them.
• Same family, different job: the hot-melt adhesive hose is the heated low-pressure build for adhesive machines, on the same bore table with larger sizes.
• High pressure instead: for extruders and line-marking machines, the extruder heated hose is rated up to 35 MPa at 250 °C.
• Other heated builds: browse the Heated Low Pressure Hose and Heated High Pressure Hose families.

How to order

A JCH part number carries the main choices, so the fastest way to order is to quote one. The catalog example is JCH-200-16-B-3X220-P2-8-N:

1. 200 – working temperature in °C. 200 means 200 °C.
2. 16 – inner tube bore in mm. 16 means Φ16 mm.
3. Inner tube letter – B is a stainless corrugated tube, TB is PTFE hose with stainless braid, T is a PTFE hose, X is a special material.
4. Supply – 220 means 220 V, 3X220 means three-phase four-wire 220 V.
5. Sensor code – P2 is PT100 two-wire, P3 is PT100 three-wire, K is type K, J is type J, W is no sensor, T is a special sensor.
6. Pressure – working pressure in MPa. 8 means 8 MPa.

The three catalog bores are 3/16" (Φ7.6 mm), 1/4" (Φ9 mm) and 5/16" (Φ11 mm); quote the size you need rather than the sample code above. If you do not have a part number, send these instead:

1. Bore and length, with the number of pieces, and the distance from probe or take-off point to the analyzer inlet.
2. What is in the sample: the gas, the water vapour it carries, and any acid gas, ammonia or solvent.
3. The dew point, the setpoint you run, and the highest ambient the line passes through.
4. Pressure in the line and the pump or regulator downstream.
5. Supply voltage and the controller or analyzer cabinet the line plugs into.
6. Sensor type and wiring, if the cabinet dictates it, plus the pin table if one exists.
7. End fittings at each end: thread standard, size, angle, with a photo or part number if you have one.
8. The route – fixed tray, cable carrier, portable coil – and the tightest bend on it.

If a drawing exists, send it. We propose the specification against it, you confirm it with the quotation, and production follows the confirmed specification.

Frequently asked questions

What is a heated sample line?

An electrically heated, insulated hose that carries a gas sample from where it is taken to the analyzer without letting it cool to its dew point. It is a heated inner hose, a braided heating layer over it, insulation, a braided outer cover, a strain-relief boot and fitting at each end, and an electrical lead at one end.

What temperature does it run at?

Maximum heat resistance is up to 230 °C (446 °F), with higher temperatures custom on request. Order the setpoint your sample needs, which is set by the dew point of the gas, not by the maximum of the hose.

Which bore do I need?

The catalog prints three: 3/16", 1/4" and 5/16". The choice is usually driven by the flow the analyzer needs and the response time you can accept – a smaller bore reaches the analyzer faster but passes less gas, so the pump and the filter decide. Send the analyzer's sample flow and we will match the bore to it.

Will it kink on a moving or portable run?

The catalog describes the build as bend- and kink-resistant with stable insulation, and the strain-relief boot at each end protects the hose where it leaves the fitting. It is still a hose with a minimum bend radius: route the run so no point goes tighter than the assembly limit of 0.2 m, and support the coil end rather than letting it hang on the boot.

Can I use my existing controller?

Yes, if we know its sensor input and output type before the build. The catalog lists type J and type K thermocouples, Ni120, PT100 and PT1000 sensors, with PID control and SSR or thyristor output. Send the controller model or a photo of its label and the wiring is matched to it.

Is the line supplied with the fittings?

Yes. Both ends are specified separately on the order – US, British or metric threads, or another type – and made to order, so the line arrives ready to connect to your probe stand and your analyzer cabinet rather than needing adapters on site.

Source: Jingcheng 2025 electrically heated hose catalog, p.7 gas-sampling hose and p.4 order form and model code, and our published business policies.