One Way Webbing Sling

ஏ ஒரு வழி வலை கவண் is a rated polyester sling bought for one journey: it is fitted to the load, travels with it and is written off against that job instead of being returned to a sling store. This page covers the closed முடிவற்ற வளையம் form — the shape specified for pipe, tube and bundling work, because a loop wraps a cylinder instead of hooking it. நிலையான வரம்பு: 1 டி செய்ய 12 டி, பட்டை அகலம் 25 மிமீ முதல் 300 மிமீ, பாதுகாப்பு காரணி 5:1, 6:1 அல்லது 7:1, வளைய நீளம் 0.5 மீ முதல் 100 மீ, marked to BS EN 1492-1.

What “one way” decides, மற்றும் அது என்ன செய்யாது

The phrase describes the commercial life of the article, not its quality. A one way sling is manufactured, ஆதாரம் ஏற்றப்பட்டது, colour coded and labelled to the same standard as a sling that will be inspected for years; the difference is that it leaves the store once and does not come back.

Three practical consequences follow. It is சுமையுடன் வழங்கப்பட்டது, so it becomes a line on the packing list rather than an item in a sling register. It is inspected once, பிரச்சினையின் கட்டத்தில், while a fault can still be replaced from the same consignment. And its print is its whole record: வேலை சுமை வரம்பு, நீளம், factor and batch are the only traceability the band will ever carry, so the marking has to survive a lorry, a container and a loading bay — not just the production line.

What it does not change is the engineering. A narrow band or a lower factor chosen because “it is only going one way” is not a saving; இது லிப்டில் இருந்து எடுக்கப்பட்ட மதிப்பிடப்படாத விளிம்பு ஆகும். The figure that applies is the figure printed on the band, for the arrangement actually used. Buyers who need the returnable version of the same loop should read the ஒற்றை அடுக்கு முடிவற்ற தட்டையான கவண் page instead.

Why a closed loop is the right form for pipe, tube and bundles

An endless webbing sling is a band joined to itself. There is no eye to line up against a machined pipe end, no stitching stack at the bearing point and no shackle, hook or thimble anywhere on the article. On round loads that single property does most of the work.

• It cannot mark a coating. Galvanising, fusion bonded epoxy, three layer PE and paint are all damaged by the same things: a steel edge, a sliding hook and point pressure. A woven polyester face addresses all three. Nothing metallic contacts the pipe, and the load never slides against a fitting.
• The choke holds itself. Passed round the pipe and back through the loop, the band tightens as the load rises. On a cylinder the contact line is a full wrap rather than two point contacts, which is why a loop resists slipping along the axis and does not walk towards the pipe end during a pick.
• The load stays centred. Because the band wraps symmetrically, the pick point sits over the centre of gravity of a joint or bundle rather than off one side — the usual cause of a tilted, eccentric lift and of one sling taking more than its share.
• Pressure is spread by width. Thin wall PVC, PE and stainless tube dent under a narrow band. A 100–200 mm face turns a point load into a low pressure band, which is the single most effective protection on a soft or thin walled pipe.
• Nothing to lose and nothing to thread. A band with end fittings can arrive with the fittings gone. A loop is one piece of webbing: it is either there or it is not, and the person re-slinging at the far end needs no rigging plan to use it.

Where a one way webbing sling is used

The loop is chosen where the load is போர்த்தப்பட்டது rather than hooked, and where the surface matters as much as the tonnage. On a joint lifted on its own, one loop goes round the pipe near each end and the two legs meet at the hook; on a bundle, one loop per pick position is choked round the pack. The applications below are the ones this range is most often bought for, and each one puts a different line on the enquiry.

Specifications of the one way webbing sling

The figures below describe the standard build. அகலம் ஒரு இலவச தேர்வு அல்ல: it follows from the working load limit and from the safety factor, so the same tonnage appears at three widths. வளைய நீளம், ஓடு, colour and print are made to the order.

Choosing the size: the figure from the pick, the width from the surface

Two decisions are made separately and in this order. தி வேலை சுமை வரம்பு comes from what one pick has to carry, divided by the mode factor of the hitch — not from the mass of the load as weighed. தி அகலம் then comes from the surface being wrapped: a coated pipe and a painted machine at the same tonnage do not want the same band.

நீளம்: the two conventions, and why the mistake is expensive here

A loop has no ends to measure between, so the trade quotes the same article two ways. The two figures differ by about a factor of two, and on a one trip band the error surfaces at the far end — in front of a customer, மாற்றுவதற்கு இரண்டாவது இசைக்குழு இல்லாமல்.

What the same loop carries in each hitch

The figure on the label describes the vertical arrangement only. All three hitches are rigged without any change to the article, which is why the arrangement has to be stated before the width is fixed.

சோக் என்பது ஒரு வளையத்திற்காக வாங்கப்பட்ட ஏற்பாடு, மேலும் அதுவே செலவாகும் 20 % of the printed figure. ஏ 4.5 t குழாய் மூட்டை ஒரு 5 t loop ஒரு சுமை, not a margin — the answer is the next width up, not a longer band.

Coating and surface compatibility

குறியிடுதல், label and what it has to survive

On a single trip article the print is the record, so the marking is a specification line rather than a detail. Four things belong on the label: வேலை சுமை வரம்பு, the loop length with its convention, பாதுகாப்பு காரணி, and the reference the despatch actually uses — a batch, ஒரு பேக் எண், ஆர்டர் எண் அல்லது உங்கள் சொந்த பகுதி எண். That reference is what ties the band on a quay to the line on a packing list in an office.

• பயணத்திற்குப் பிறகு புரியும், உற்பத்திக்குப் பிறகு அல்ல. Small, low contrast print on a face that enters the choke will not be read at the far end.
• Colour as a second channel. ஒரு பேக் வகைக்கு ஒரு வண்ணம், per customer or per tonnage lets a container of identical bands be sorted at a glance.
• Printed to your string. The label can carry your reference in the exact case and format you send, and the bands can be packed inside a crate, ஒரு ஸ்டில்லேஜில் கட்டப்பட்டது அல்லது ஒரு மூட்டையில் ஒட்டப்பட்டது, ஒரு பேக்கிற்கு பெயரிடப்பட்டது.

The single inspection, and what it looks at

A one trip band is checked once, பிரச்சினையில், while a fault can still be replaced from the same consignment. Look at four things, இந்த வரிசையில்: அது சுமையை சந்திக்கும் இடத்தில் நெசவு (வெட்டுக்கள், சிராய்ப்பு, ஒரு பளபளப்பான அல்லது கிள்ளிய முகம்), லூப் மூடப்படும் இடத்தில் சேரவும், the label — an unreadable figure cannot be matched to the pack it was cut for — and what the band has been lying in. கிரிட், ஸ்வார்ஃப், எண்ணெய் மற்றும் தேங்கி நிற்கும் நீர் தொடர்புக்குள் செல்கிறது, and a clean band is the cheapest protection available.

Protect the band from sharp edges, சூடான மேற்பரப்புகள் மற்றும் ஸ்லீவ் அல்லது ஒரு பேடட் ப்ரொடெக்டருடன் வெல்டிங் ஸ்பேட்டர். மேலே 100 °C, or where sparks are present, polyester is the wrong fibre and an முடிவில்லா சுற்று கவண் with a heat resistant cover is the article to discuss.

One way or returnable: the arithmetic

The commercial case is simple and it is arithmetic, not preference. A one way band costs less per unit than a returnable sling and carries no return freight, ஆய்வுப் பதிவு இல்லை, no repair and no loss write-off — but it has to be counted correctly, because nothing comes back to cover a shortfall. பேக்கிலிருந்து எண்ணுங்கள், தொன்மையிலிருந்து அல்ல: ஒரு பேக்கிற்கு இரண்டு தேர்வுகள் இரண்டு பட்டைகள், a four point lift is four, ninety packs at two picks is 180 இசைக்குழுக்கள். Add two to five per cent for the band cut while the pack is made up, எனவே கப்பல்துறையில் தாமதத்திற்கு பதிலாக ஒரு பற்றாக்குறை ஆர்டரில் ஒரு வரியாக மாறும்.

Where the same slings are used week after week in one yard, a returnable article inspected between lifts is the cheaper order over a year. Where the sling leaves with the load — export packing, one off shipments, work that ends on a customer’s site, or a coated pipe consignment that is re-slung at the far end — the one way loop is the right purchase. Where the whole consignment travels as a netted unit instead of being slung joint by joint, அ சரக்கு தூக்கும் வலை is the article to price against it. The form with eyes at both ends, for loads that are hooked rather than wrapped, மீது உள்ளது செலவழிக்கக்கூடிய ஒரு வழி கவண் பக்கம்; the wider family is on the ஒற்றை பயன்பாட்டு கவண்கள் மற்றும் single use lifting slings endless loop பக்கங்கள்.

What to send with the enquiry

Six lines are enough to quote a made to order band, and they remove every ambiguity that shows up later at the load:

1. The load — pipe diameter and wall, bundle mass, or the finished item.
2. The pick positions — how many, and how far apart.
3. The arrangement — vertical, மூச்சுத்திணறல் அல்லது கூடை, and the angle if basket.
4. The girth at each pick, or the loop length with its convention named.
5. The safety factor your market works to, and the standard to mark to.
6. The reference to print, and the quantity per pack.

அடிக்கடி கேட்கப்படும் கேள்விகள்

What is a one way webbing sling?

A rated polyester webbing sling supplied for a single journey. அது சுமையுடன் பயணிக்கிறது, is inspected once at the point of issue and is not recovered or re-issued. The endless form is a closed loop of flat woven polyester with no eye and no metal fitting, which is why it is the form chosen for pipe, tube and bundles.

Is a one way sling weaker than a reusable one?

இல்லை. நார்ச்சத்து, நெசவு, அகலம், பாதுகாப்பு காரணி, working load limit and marking are specified exactly as for a returnable sling. இந்த வார்த்தை பயணத்தை விவரிக்கிறது, not the grade, so a lower factor or a narrower band is not a saving on a single trip article.

Will a webbing sling scratch galvanised or anti-corrosion pipe?

The band is synthetic fibre and no shackle, hook or thimble touches the load when an endless loop is used, so there is nothing to cut or gouge a zinc, epoxy or polyethylene coating. Width is the protection measure: the wider the band, the lower the pressure at the contact.

How is the length of an endless webbing sling measured?

Two conventions are used and they differ by about a factor of two: மூடிய வளையத்தின் சுற்றளவு, மற்றும் இசைக்குழுவின் நீளம் இணைவதற்கு முன் சமமாக அமைக்கப்பட்டது. Name the convention with the figure, or give the girth of the pipe or bundle the loop must go round.

Can the same loop be used in a choker hitch?

ஆம், and a closed loop is the natural form for a choke on pipe, tube and bundles. திணறிய உருவம் 0.8 of the vertical working load limit, எனவே ஒரு 5 t loop chokes 4 டி. Select the width for the arrangement actually used.

நான் எந்த பாதுகாப்பு காரணியை ஆர்டர் செய்ய வேண்டும், 5:1, 6:1 அல்லது 7:1?

7:1 is the usual European figure for flat woven webbing slings to BS EN 1492-1, 5:1 is the customary North American figure under ASME B30.9, மற்றும் 6:1 அவர்களுக்கு இடையே அமர்ந்திருக்கிறது. வெவ்வேறு காரணிகளில் அதே டன்னேஜ் வேறுபட்ட அகலம் கொண்ட வேறுபட்ட கட்டுரையாகும், எனவே காரணி விசாரணைக்கு உரியது.

Can the band be printed with our own reference?

ஆம். வேலை சுமை வரம்பு, வளைய நீளம், பாதுகாப்பு காரணி, batch and your own pack, order or part number can be printed as produced, in the exact string you send, so a band at the far end can be tied back to a line on the packing list.