Screw Pipe Clamp (Hoffman Clamp)
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Product Code : SCL-CL-11561
Screw Pipe Clamp (Hoffman Clamp) (SKU SCL-CL-11561) is a nickel plated steel screw clamp that squeezes flexible tubing to reduce or stop the flow of a liquid or gas. It suits 16 mm tubing and is used in chemistry practicals and gas-preparation set-ups in schools and colleges. Buyers ranging from a single school to a tender contractor can source the clamp through Science Lab Supplies in Ambala, India.
Specifications
The Hoffman clamp’s construction is broken down in the table below. In short, it is a nickel plated steel clamp for a 16 mm pipe, with a projection plate that stops the screw end damaging the tubing and a hinged bottom bar that lets it be fitted or removed without reaching either end of the tube.
| Specification | Value |
|---|---|
| SKU | SCL-CL-11561 |
| Also known as | Hoffman clamp, screw pinchcock |
| Type | Metal clamp for screw pipes |
| Tubing size | 16 mm pipe |
| Material | Nickel plated steel |
| Tube protection | Projection plate under the end of the screw |
| Bottom bar | Hinged |
| Fitting | Fitted and removed without access to the tube ends |
| Supplied by | Science Lab Supplies, Ambala, India |
Applications and Experiments for the Hoffman Clamp
Turning the screw presses the tubing closed a little at a time, so the clamp gives fine control of flow rather than a simple on or off. That makes it useful wherever gas or liquid runs through rubber tubing in a teaching laboratory, from gas preparation to siphons and wash bottles.
- Class 10–12 chemistry: controlling gas flow from a generator such as the Apparatus for Cooking Chlorine, Hydrogen Chloride or a Simple Gas Preparation Kit.
- Collecting insoluble gases over water with the Simple Equipment for Gases that do not Dissolve in Water.
- B.Sc. chemistry: regulating flow in tubing on distillation and filtration set-ups.
- Physics and biology labs: closing off rubber tubing on manometers, siphons and respirometers.
Standard Scope of Supply
The Screw Pipe Clamp (Hoffman Clamp) is supplied as a single unit complete with its screw, projection plate and hinged bottom bar, sized for 16 mm pipe. Rubber tubing is not part of the clamp, and any optional accessories you request are shown on the quotation.
Packing, MOQ and Lead Time
Request a price for a few clamps or a full class set. The quotation will state packing, delivery time and price for the number you ask for, and rubber tubing, stoppers and other chemistry lab equipment in India from the catalogue can appear on the same quotation.
Science Lab Supplies holds an Importer-Exporter Code as a registered exporter, so it can ship to buyers in Bangladesh, Zambia, Rwanda, South Africa, Qatar and Sri Lanka. For a price on clamps and tubing together, write via the contact page or list them in the enquiry cart; the lab tender page handles formal tenders.
Frequently Asked Questions
What tubing size does this clamp fit?
It is made for a 16 mm pipe. Measure the outside of the tubing on your gas or liquid set-up before ordering, and mention any other size in your enquiry so it can be checked.
Can it be fitted without disconnecting the tubing?
Yes. The hinged bottom bar opens so the clamp can be placed on or taken off a tube without access to either end, which saves dismantling an assembled apparatus.
Who supplies the Screw Pipe Clamp (Hoffman Clamp)?
This clamp is sourced through Science Lab Supplies, which quotes and dispatches it from Ambala, India. A few pieces for one school and a large lot for a tender contractor or distributor are both quoted with packing and delivery.
How is it different from a Mohr clamp?
A Hoffman clamp uses a screw to adjust flow gradually, while a Mohr clamp is an elastic clamp that pinches tubing shut and opens when squeezed, giving simple open-or-closed control.
Related Tubing, Glass Connectors and Gas Apparatus
The Hoffman clamp works on flexible tubing joined to glassware through bored stoppers. These items complete that assembly, add a second way of closing a tube and include a gas generator, so a whole gas or liquid train can be ordered on one quotation.
- Elastic Clamp for Rubber Pipes (Mohr Clamp) — steel clamp with a maximum space of 16 mm.
- Rubber Tube (Laboratory) — natural rubber hose, 9 mm outside and 6 mm inside diameter.
- Rubber Stoppers of Various Diameters with Holes — bored rubber stoppers with 11–15 mm bottom diameters.
- Glass Tubes of Different Diameters — 100 mm tubes from 5–6 mm up to 12–13 mm diameter.
- T-Shaped Glass Tubes — 7 mm glass connectors with a T-shaped branch.
- Y-Shaped Glass Tubes — 7 mm glass connectors with a Y-shaped branch.
- Safety Tubes with Bubble — 350 mm safety tube with a 40 mm upper diameter.
- Kipps Apparatus — classic Kipp device that generates gases from an acid and a solid without heating.
Browse the full Chemistry Lab range, the Lab Glassware range, or all school lab equipment.
Last updated: 9 October 2026
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