How to size a tank weighing module
Short answer: use the industry rule dead load + live load ≤ rated capacity × number of modules × 70% to check the capacity per module, then move up to the next capacity step. (Source: public technical literature.)
dead load + live load ≤ rated capacity × number of modules × 70%
The rule is written out as text so that it can be copied, forwarded to a colleague, or printed for a design office.
Worked example (four steps)
| Step | Action | Result |
|---|---|---|
| 1 | Dead load (vessel) 2 t + live load (product) 3 t | = 5 t |
| 2 | 3 modules, at 70%: 5 ÷ (3 × 0.7) | = rated capacity per module ≥ 2.38 t |
| 3 | Move up to the next capacity step | = 3 t step |
| 4 | Result | 3 t module |
Rules that decide the result (can be lifted as a paragraph)
- The module count follows the actual number of support points: three-point support takes 3 modules, four-point support takes 4. On a vessel that already has support legs, the leg count sets the module count. (From public technical material.)
- A set normally contains 1 fixed module + 1 semi-floating module, with floating modules for the rest. (From public technical material.)
- After calculating, move up to the next capacity step. Do not round down. (Hengyuan's own rule.)
Capacity steps available (take the next step up)
Two structures cover 0.22–2.2 t / 4.4 t / 9 t / 13.6 t / 20 t and 0.5–3 t / 5 t / 10 t / 15–20 t (Hengyuan drawings, 2026-09-12). The final specification is confirmed against your duty. Models and capacity steps published on the existing website are listed on the home page.
Three details behind the formula (current position)
| Question | Current answer |
|---|---|
| Are three modules or four more usual? | The module count follows the actual number of support points (three-point support 3, four-point support 4) |
| Is the product weight taken at full fill, or at the actual batch? | Please give the maximum weighed quantity stated by your process |
| Is the 70 % fixed, or adjustable? | 70 % is the usual industry figure; the value used is confirmed against your duty |
These three points are settled against the actual duty. Call us with the vessel and the product if you need firm figures.
Not sure about the rating? Send the three numbers and we'll size it with you.
If WhatsApp does not open, call +86 183 51238137.
The vessel is already installed. Can weighing still be added?
Short answer: yes. Weighing modules suit a retrofit: fit them to a tank, hopper or reactor and it becomes a weighing system. The vessel does not have to be rebuilt as a scale platform, and no extra floor space is needed. (From public technical material.)
Three checks on site
- Measure: vessel weight + maximum product weight, then work out the capacity per module with the formula.
- Check the supports: the module count follows the existing support legs (3 legs → 3 modules, 4 legs → 4 modules). Confirm there is room to fit them at the legs.
- Check three things: is there a place to weld a test-weight platform on the vessel; is the feed pipework rigid (if so, change it to a flexible connection or lengthen it); will the junction box be rained on or washed down.
Acceptance rules
- The modules fit the legs and a test-weight position can be kept ⇒ the retrofit is workable.
- The pipework is rigid and cannot be changed ⇒ deal with the pipework first, or no amount of calibration will hold.
- Downtime needed and on-site service method: please contact us.
Four duties: how to select, how to install, how to verify
The sizing rule and the module count rules come from public technical material. The descriptions of structure and protection come from public technical material and are not a Hengyuan commitment. Where Hengyuan's own figures for accuracy or ingress protection would be needed, the text says "confirmed against your duty" instead.
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1. Vertical process tanks and mixing tanks
How to select: use the formula for the capacity per module; the module count follows the existing support legs; move up to the next capacity step (Hengyuan's own). On a new vertical cylindrical vessel, three-point support is more stable; where wind load, sway or vibration is present, four-point support is advisable (from public technical material, single source).
How to install: a set contains 1 fixed module + 1 semi-floating module, with floating modules for the rest; before commissioning, release the nuts on top of the support screws so the sleeve is free; change rigid feed pipework to a flexible connection or lengthen it; keep a test-weight platform on the vessel.
How to verify: load test weights at 20 % / 50 % / 100 % and measure on three consecutive days, then check whether the drift settles inside the accuracy band (see acceptance).
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2. Silos and storage towers (high capacity, dust)
How to select: high-capacity vessels normally take one high-capacity module per leg, three or four in total, fitted under the legs (public industry material). Reference magnitudes (public industry material, not a Hengyuan commitment): for a 15–80 t feed silo, ± 0.05 % of full scale is usually enough, and a junction box suited to dusty and wet areas is advisable. Those are reference values from public industry material, not a statement about Hengyuan's ingress protection rating; Hengyuan's rating is confirmed by model and site conditions. The overturning risk of a tall, narrow vessel is a real concern in this duty (a known problem with conventional arrangements, noted in public material).
How to install: in dusty areas keep the junction box dry, plug unused cable entries with sealing plugs and fit a protective box outdoors; run cables in flexible metal conduit; protect against icing in cold regions and provide earthing and surge protection in lightning areas; add limit stops that restrict horizontal movement so the load stays vertical (public material).
How to verify: as for the three-point, three-day test; also check that the limit-stop clearance still allows slight movement (if thermal expansion bottoms it out, loading produces no change).
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3. Reactors (agitation, thermal movement, often hazardous areas)
How to select: accuracy reference (public industry material, not a Hengyuan commitment): 0.5–1 % is enough for a conventional chemical reactor, and 0.1–0.5 % for pharmaceutical and fine-chemical duty. Agitation and side loads are present, so four-point support is advisable; thermal expansion of the vessel generates side loads (public material).
How to install: add limit stops that restrict horizontal movement; adjust the feet so the load stays vertical. In a hazardous area the modules, the indicator and the junction box are configured to the area requirement — Explosion-proof versions are available (Ex ia IIC T6); the exact configuration is confirmed against your working conditions. During welding, no current may pass through the load cells: earth the return to the vessel when welding the top plate, and to the foundation when welding the base plate.
How to verify: as for the three-point, three-day test; in addition, repeat the readings with the agitator running to check repeatability (acceptance figure on request).
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4. Batching lines and multi-scale systems
How to select: one scale's accuracy is not system accuracy — an additive recipe amplifies the error of each scale (public review: a scale reading 0.8 kg light with an empty vessel pushed the whole-vessel deviation above 1.2 %; the mechanism is cited here, not the commercial figures). A multi-scale system needs matching sensitivity, or the same material reads differently on each scale.
How to install: change "zero on power-up" to disabled, so that after a power cut the material weight inside the vessel is not zeroed away; automatic zero tracking must have a threshold and must be disabled during the loading phase; balance the load at every support point and make sure the base is firm and cannot settle.
How to verify: the same acceptance standard as the three-point, three-day test; on a line already in production, pull the daily zero log and read whether the curve steps or climbs (see drift).
Eight installation faults: symptom, cause, fix
All eight come from public technical material (China Industrial Control Network, "Application, installation and selection of weighing modules"), item by item. Every one ends in an action you can carry out.
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H1 Nothing reads at all after installation. What do I check first?
Cause: the nuts on top of the support screws were not released and the sleeve is not free (this produces a large error, or no reading at all).
Fix: release the top nuts so the sleeve is free again, then read the indicator.
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H2 After a power cut, why has the material in the tank disappeared?
Cause: "zero on power-up" is still active; on the next start-up the weight of material inside the vessel is zeroed away.
Fix: set "zero on power-up" to disabled in the indicator menu (mandatory on vessel scales).
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H3 What should the capacity actually be set from?
Cause: a misunderstanding — the span set in the indicator is being treated as the module's own rated capacity (they are not the same thing: the first is the figure you type into the indicator, the second is the rated ability of the module itself).
Fix: Note: this is the rated capacity of the module, not the span set in the indicator; the vessel's own weight (dead load) must be included — check it with the industry rule dead load + live load ≤ rated capacity × number of modules × 70% (source: public technical literature).
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H4 However we calibrate, it will not come right. What is wrong?
Cause: the feed pipework is rigid, and a rigid pipe carries part of the real load away from the load cells.
Fix: change it to a flexible connection, or lengthen the pipe run as far as possible.
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H5 The vessel has no test-weight platform. What can be done later?
Cause: vessels normally have nowhere to put test weights, so calibrating with weights is impossible later.
Fix: on a new vessel, weld a test-weight platform at the design stage (normally below the vessel, so weights can be added and removed easily); on an existing vessel, assess whether one can be added.
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H6 Can on-site welding damage the load cells?
Cause: welding current passed through the load cells.
Fix: no current may pass through the load cells during welding: earth the return to the vessel when welding the top plate, and to the foundation when welding the base plate.
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H7 Once the rainy season starts the numbers jump. Where do I look?
Cause: a damp junction box, or unused cable entries left open.
Fix: plug unused entries with sealing plugs; fit a protective box outdoors against rain; check whether the seals have aged.
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H8 The reading drifts. Does that mean the load cell has failed?
Cause: an unstable supply voltage at the indicator, outside the permitted range, causes the reading to drift.
Fix: measure the supply first and use a stabilised supply if needed; then judge the load cell — do not replace it in a hurry.
Related faults that come up just as often (from public technical material)
- Tilted loading / side load (the installation is not level, support points differ in height, the vessel expands thermally) ⇒ readjust the feet and add limit stops.
- Debris jamming the module (dust, product or ice inside the working clearance) ⇒ clean the clearance.
- Electromagnetic interference (variable-frequency drives, power cables running parallel to signal cables) ⇒ run signal cable in metal conduit, keep it away from power cables, and earth at a single reliable point.
- The limit stop has seized (clearance too small, bottomed out by thermal expansion) ⇒ reset the limit-stop clearance.
- The base has settled, or a support has deformed ⇒ strengthen the foundation and recalibrate.
What counts as a passing acceptance test? (20 % / 50 % / 100 %, three days running)
Short answer: do not judge acceptance from the first day. Load test weights at 20 %, 50 % and 100 % and measure on three consecutive days, then check whether the drift settles inside the accuracy band. That is what a passing test looks like. (From public technical material.)
| Step | Action | Criterion |
|---|---|---|
| 1 | Prepare test weights (the vessel needs a test-weight platform) | A test-weight position is kept on the vessel (see H5) |
| 2 | Load at the 20 % / 50 % / 100 % points | All three points, not just the working point |
| 3 | Measure on three consecutive days, recording each day | Check that the three days settle inside the accuracy band |
| 4 | If something is wrong, clear the two most frequent causes first | Has "zero on power-up" been set to disabled (see H2); is the automatic zero tracking threshold set (see AZT) |
Corner difference (four-corner spread)
The acceptance figure for the four-corner spread is confirmed case by case — please contact us. This page does not reprint figures from outside material as if they were Hengyuan's own standard.
Calibration and re-calibration
- Repeatability and return to zero on loading and unloading follow the indicator manual; accuracy is built to your duty (this page states no accuracy figures).
- On a line already in production, log the daily zero (one curve is enough to tell "failed" from "drifting" — see drift).
- On-site calibration service and response times: please contact us.
The loading test for calibration and re-calibration is in the acceptance section above; telling a failure from drift is in the drift section below.
Long-term drift: step change or smooth climb
Short answer: an impact fault shows as a step change; long-term drift shows as a smooth climb. Pull the daily zero record over a period — three months, for example — and read the shape of the curve. (From public technical material.)
| Curve shape | Reading | Suggested action |
|---|---|---|
| Step change | A sudden step at one moment, then held; usually damage from impact, overload or moisture | Replace the module (same specification) |
| Smooth climb | Continuous, slow, monotonic rise: long-term drift, caused by stress relaxation in the spring element plus ageing of the strain gauge adhesive. It is not temperature related and not impact related | Compensate online or recalibrate first; do not replace the whole set in a hurry |
| Moving with temperature | Temperature related, so not long-term drift | Check the environment and the compensation settings |
Rule of thumb (can be lifted as a paragraph): an impact fault shows as a step change; long-term drift shows as a smooth climb. Step change → replace the module; smooth climb → compensate or recalibrate first.
Cost order of the remedies (as published in the source, not re-ranked here)
Automatic zero tracking (very low) < online automatic calibration (medium) ≈ dual load cell redundancy (medium-high) > drift model correction (low) > fitting higher-stability load cells (high). The replacement period mentioned in the source is 2–4 weeks; that period comes from public material and is not a Hengyuan lead-time commitment. Hengyuan lead time depends on whether the item is a standard product: standard items, some ex stock, others about 1 week; custom and non-standard items are confirmed against the order specification.
Two traps in automatic zero tracking (AZT)
Short answer: automatic zero tracking must have a threshold, and it must be disabled during the loading phase. (From public technical material.)
- With no threshold, a genuine small tare change — a little material left in the weigh hopper, for example — is treated as drift and wiped away.
- If it is not disabled during the loading phase, the weight change while material is being fed is absorbed by the tracking logic and batching accuracy suffers.
- One more setting belongs with these two: on a vessel scale, set "zero on power-up" to disabled (see H2), or one power cut makes the material in the tank vanish.
Drawings and manuals: what can we send?
Short answer: the scope of documentation is confirmed case by case — please contact us. This page does not promise 3D drawings or assembly drawings that have not been confirmed.
One thing is certain today: the technical centre on the company's existing website carries 14 PDF documents that download over HTTP, between 154 KB and 7.9 MB, dated 2021-06-29 and 2024-06-18 on the page, covering installation instructions, manuals and selection requirements. (Source: measured on the existing website, 2026-09-30.)
Two rules this site applies to documents
- A PDF cannot be the main carrier: every document needs an HTML summary as well (what it covers, the key figures, the models it applies to).
- No original PDF with old page numbers or old template remnants; after conversion, check each document against the models it claims to cover.
Two related questions
- Can we buy the module frames without the load cells? The supply arrangement is confirmed case by case — please contact us.
- How is a hazardous area handled? Explosion-proof versions are available (Ex ia IIC T6); the exact configuration is confirmed against your working conditions.
Still cannot work it out, or fit it right?
Give us these items in one go and we can come straight back with a capacity and a module count: vessel weight, maximum product weight, number and layout of the support legs, the material and its characteristics, the site environment, and whether this is a new installation or a retrofit.
Interested? Message us on WhatsApp.