Replacing something
The part number on the failed sensor contains everything needed to identify a correct replacement. Send it to us, or photograph what is left of the label.
Melt pressure instrumentation
Specify it once.
Specify it right.
Melt pressure transducers and transmitters for plastics extrusion, compounding and moulding — including direct replacements for the sensors already on your line.
350ΩWheatstone bridge
538°CMax, NaK fill
30,000psi full scale
InconelDiaphragm, standard
Where to start
Where to start
Specifying something new
Work from your process conditions instead. The configurator takes melt temperature and working pressure and returns a complete, quotable specification.
Where to start
Not sure yet
Tell us the machine, the polymer and what you are trying to measure. We will come back with a specification rather than a catalogue.
Build your sensor
Choose fill, configuration, range and materials. Watch the drawing update as you go, then send the finished specification straight to us.
Configurator
Build your sensor
Options that do not apply to your selection switch off automatically. When the drawing looks right, send it to us or save the sheet.
The range
Transducers & transmitters
Every sensor here works the same way. Pressure deflects a diaphragm at the tip; a fluid-filled capillary carries that deflection to a 350Ω Wheatstone bridge in a cooler housing. What separates the families is the fluid, the geometry and the metal at the tip.
Mercury fill
Standard
The industry reference. Best temperature stability in the range.
- Max temp 400°C / 750°F
- Error 0.5% FS
- Zero shift 15 psi/100°F
- Sanitary use No
Mercury-free fill
Mercury-free
Same envelope, same rating, no mercury in the process area.
- Max temp 400°C / 750°F
- Error 0.5% FS
- Zero shift 18 psi/100°F
- Sanitary use Check spec
NaK fill
High temperature
Sodium-potassium fill. For engineering polymers and sanitary work.
- Max temp 538°C / 1000°F
- Error 1.0% FS
- Zero shift 15 psi/100°F
- Sanitary use Yes
Oil fill
FDA oil
Diathermic oil for lower-temperature food and medical processes.
- Max temp 350°C / 650°F
- Error 0.5% FS
- Sanitary use Yes, FDA
Geometry
Narrow space
No rigid stem. A thin bare capillary threads through congested die and adapter areas before meeting the armoured section.
- Capillary 0.06 in dia.
- Fills Hg / Hg-free / NaK
Geometry
Compact
Shortened body where axial clearance behind the mounting point is the constraint.
- Stem 3.5 in
- Ranges 1,000–30,000 psi
| Common specification — all families | |
|---|---|
| Sensing element | 350 Ω Wheatstone bridge, four active arms |
| Output | 3.33 mV/V standard; 2.5 and 2.0 mV/V available |
| Excitation | 7–12 V, 10 V recommended |
| Shunt calibration | Internal, 80% of full scale |
| Pressure ranges | 0–300 psi to 0–30,000 psi |
| Repeatability | ±0.2% |
| Overload | 2× full scale |
| Max housing temperature | 120°C / 250°F |
| Zero shift, electronics | 1% per 100°F |
| Diaphragm | Inconel standard; coatings and alloys available |
| Process thread | 1/2"-20 UNF standard; M18×1.5, M14×1.5, M10×1.0 |
| Mounting torque | 150–500 in-lb |
| Connector | 6-pin bayonet standard; 6-pin screw, 8-pin screw, 5-pin, flying lead |
| Ingress protection | IP65 available |
| Certification | CE |
| Warranty | 1 year against manufacturing defects |
Inconel is standard, not an upgrade. Sensors in this class are often
supplied with 17-4 PH stainless at the tip, with anything better charged as an option. The tip
is where these sensors fail, so that is where the material belongs.
Configure one
Pick a family and the configurator will fill in the rest.
Replacements
Tell us what failed
Melt pressure sensors are usually replaced under time pressure, which is exactly when specification mistakes happen. The number on the old unit carries everything needed — range, stem, flex, output, connector and thread — provided someone reads it properly.
DyniscoGefranGentran
TerwinISIGP50
Decode a competitor model number
Type the number from the sensor label. We decode it, you check every line, and we generate the matching Meltman part number.
Step one
Send the number
Email the part number from the sensor label. If the label is unreadable, photograph what survives of it.
Step two
Or work backwards
No number at all? Tell us the machine make and model and where the sensor is mounted, and we will identify it from that.
Step three
We confirm the fit
You get a specification, a price and a lead time. Direct replacements need no wiring change and no modification to the mounting bore.
Some sensors carry two valid part numbers — a manufacturer's own code and a code
mirroring the competitor part it was built to replace. Send whichever one you have.
Send us a part number
One line is enough. We will read it and come back to you.
Reference
Technical
The three tables engineers actually ask for. Anything beyond this, email us and we will answer it properly.
Choosing a fill
Start with temperature — it removes options absolutely. Then apply the sanitary question. Whatever survives both is your answer.
| Fill | Max diaphragm temp | Error | Zero shift | Food / medical / pharma |
|---|---|---|---|---|
| Mercury | 400°C / 750°F | 0.5% FS | 15 psi/100°F | No |
| Mercury-free | 400°C / 750°F | 0.5% FS | 18 psi/100°F | Check requirement |
| NaK | 538°C / 1000°F | 1.0% FS | 15 psi/100°F | Yes |
| FDA oil | 350°C / 650°F | 0.5% FS | — | Yes, FDA |
Choosing a diaphragm
Two failure modes, two different answers. Abrasion thins the diaphragm until it ruptures — answer with a hard coating. Corrosion attacks the metal chemically and can perforate a diaphragm showing no wear at all — answer by changing the base alloy, because a coating with a pinhole is no protection.
| Material | Specify for |
|---|---|
| Inconel — standard | General purpose. Good abrasion and corrosion resistance at temperature. |
| Inconel 718 tip + threads | Where the thread as well as the tip sees melt. |
| Hastelloy C-276 tip + threads | Corrosive melts below 600°F — PVC, halogenated and fluoropolymers. |
| Titanium nitride (TiN) | Abrasive melts — glass-filled and mineral-filled compounds. |
| Titanium aluminium nitride (TiAlN) | Abrasive melts at higher temperature. |
| Chromium nitride (CrN) | Alternative hard coating for abrasive service. |
Reading a specification code
The code produced by the configurator is built as follows.
| Segment | Example | Meaning |
|---|---|---|
| Prefix | MM | Meltman |
| Fill | P | P mercury · F mercury-free · K NaK · O oil |
| Body style | 2 | 1 rigid · 2 stem+flex · 3 stem+flex+temp · 4 narrow · 5 compact |
| Range | 5M | M = psi ×1,000 · C = psi ×100 |
| Geometry | 6/18 | Stem inches / flex inches |
| Electrical & tip | S1S | Connector · output · diaphragm |
| Suffixes | M18 .25 IP65 | Thread, accuracy upgrade, ingress protection |
Meltman codes describe the build. When you order a replacement for another brand,
quote that brand's number as well — we will match both.
Cables & accessories
Accessories
Everything that goes around the sensor. More melt pressure sensors are pulled from service for cable, connector and mounting-bore faults than for anything actually wrong with the sensor, so this is not a category to treat as an afterthought.
01 — Cables
Sensor cables
Built to the connector on your sensor, in the jacket the environment demands. Standard lengths of 12, 25 and 50 ft; other lengths made to order.
- PVC jacket 105°C
- PTFE jacket 200°C
- PTFE + 304 SS braid Abrasion
- PTFE + 304 SS armour Crush
02 — Connectors
Connectors & backshells
Cable-end and box-end connectors for every sensor termination we supply, so a damaged connector does not mean a new cable.
- 6-pin bayonet Standard
- 6-pin screw ·
- 8-pin screw ·
- 5-pin, 4-pin DIN ·
03 — Thermocouple
Thermocouple extensions
For combined pressure and temperature sensors. Type J and Type K, with female and fork terminations to suit the controller already in the panel.
- PVC 105°C
- Fibreglass + SS braid 450°C
- Lengths 12, 25 ft
04 — Hole preparation
Drill, cut & clean kits
A bore full of degraded polymer will falsify a reading no matter how good the sensor is. Cutting kits form the seat and thread; cleaning kits recover a bore between sensor changes.
- 1/2-20 UNF Cut · Clean
- M18 × 1.5 Cut · Clean
- 5/8-11 UNC Cut · Clean
- 3/4-16 UNF Cut · Clean
05 — Tip spacers
Tip spacers
The diaphragm should finish flush with the bore wall. Proud and it takes abrasive impact; recessed and polymer stagnates in front of it. Spacers set the depth exactly.
- 0.025 in ·
- 0.032 / 0.045 in ·
- 0.063 / 0.090 in ·
06 — Mounting
Plugs, adaptors & brackets
Plug an open bore the moment a sensor comes out. Adaptors let a metric machine take an imperial sensor without re-machining. Brackets support every flex-stem build.
- Hole plugs Slot · 3" · 6"
- Thread adaptors M18 → 1/2-20
- Mounting brackets All flex builds
Choosing a cable
Melt pressure signals are millivolt-level and unforgiving of a poor connection. Match the jacket to what the cable will actually sit next to, not to the ambient air temperature of the room.
| Jacket | Rating | Specify when |
|---|---|---|
| PVC | 105°C | Routed away from the barrel, no mechanical exposure. The default for most panel runs. |
| PTFE | 200°C | Cable runs close to heated zones, or where oils and solvents are present. |
| PTFE + 304 SS braid | 200°C | Abrasion from adjacent moving parts, or where the cable is handled often. |
| PTFE + 304 SS armour | 200°C | Crush risk — cable trays, walkways, anywhere a foot or a trolley can find it. |
Order the spacer with the sensor. Tip spacers are the cheapest component in a
melt pressure installation and the one most often left out. A sensor set a few thousandths too deep
will read low, drift, and eventually be returned as faulty when nothing is wrong with it.
Tell us what you need
Give us the sensor part number and we will supply the matching cable, connector and mounting hardware without you having to work out which is which.
Downloads
Catalogue & tools
The full product catalogue, plus the two tools that do the same job faster — one builds a specification from your process conditions, the other reads a competitor part number and returns the Meltman equivalent.
Catalogue
Melt Pressure Products — Edition 01
Every fill, every body type, the complete order code with worked examples, diaphragm selection, accessories and the technical notes that keep a sensor reading true. Six pages, no filler.
Tool
Build a specification
Choose fill, body, range and materials. The drawing updates as you go, and the finished specification prints to a one-page sheet you can forward internally or send to us.
Open the configurator
Tool
Decode a competitor part
Type the number from a Dynisco or Gefran sensor. We decode it, you correct anything that is wrong, and it returns the matching Meltman part number.
Open the decoder
By post
Request a printed copy
Prefer paper on the desk next to the machine? Tell us where to send it and how many you need.
Request printed copiesIn preparation
- Accessories & cables catalogue Next edition
- Mounting hole drawings, by thread size Next edition
- Wiring diagrams — 6-pin bayonet, screw, 8-pin Next edition
- Full competitor cross-reference tables In progress
Need something that isn't here?
Datasheets, certificates, drawings for a specific configuration — ask and we will send it.
Contact
Talk to us
Every enquiry is read by someone who understands the products. If something in a request does not add up, we will say so before you order rather than after.
Meltman
Focal Point Phase V
Ludhiana, Punjab
India