Hose clamps are everywhere. Open your car’s hood and you will probably see at least three different types of automotive hose clamps. Check out the plumbing on a boat or camper and you will see even more types of hose clamps. While these hose clamps are available in a wide array of materials and sizes, you will also notice that these different types of hose clamps are constructed differently and are used in different ways. Here is an overview of four different types of hose clamps and their uses:
Perforated Hose Clamps
One of the most common types of hose clamps is the perforated hose clamp. The perforated hose clamp includes a stainless steel or galvanized steel band with a series of evenly spaced slots cut into it. The band is formed into a circle with the ends held in a sleeve adjacent to a captive screw. The slots mate with the threads of the screw, which acts as an adjuster. As the screw is turned, it acts as a worm gear to expand or contract the circumference of the band.
The hose clamp is placed over a hose with the hose passing through the circle formed by the band. The hose is connected to a nipple with a barb, and the screw is turned. This tightens the band, clamping the hose to the nipple behind the barb. Clamped in this manner, the barb and hose clamp cooperate to hold the hose on the nipple.
Embossed Hose Clamps
Embossed hose clamps are similar in construction to perforated hose clamps but rather than a perforated band, the band is embossed with evenly spaced indentations rather than cut with slots.
The benefit of embossed hose clamps is that hoses made from softer material, such as rubber, can be damaged by perforated hose clamps. Specifically, tightening a perforated hose clamp over a soft hose can force the hose material to be pressed through the slots, damaging the surface of the hose. This does not happen with embossed hose clamps since the embossed indentations do not cut into the hose.
Moreover, the embossed indentations are typically triangular or trapezoidal in shape. This provides a surface that more closely conforms to the shape of the screw threads and allows embossed hose clamps to be tightened and loosened more easily, and with less torque, than perforated hose clamps.
Constant Tension Hose Clamps
One of the purposes of hose clamps is to secure the hose with uniform force all the way around the hose. If the circumferential force is uneven, the hose could work loose or the connection could leak. For most applications, a perforated or embossed hose clamp provides a uniform circumferential force that is sufficient to secure the hose onto the nipple without leaking.
However, in some applications, thermal expansion from hot fluids can cause hoses and nipples to expand and contract. Thermal expansion is a material property that will typically be different for the nipple, hose, and hose clamp since they are typically made of different materials. A constant tension hose clamp is intended to maintain a constant circumferential force on a hose even when thermal expansion causes the hose and nipple to change in size.
Constant tension hose clamps are constructed similarly to perforated hose clamps and embossed hose clamps. However, a spring is disposed around the screw between the screw and the sleeve to impose a force on the sleeve that is translated to the band. As the band expands, the spring force increases; as the band contracts, the spring force decreases. In this manner, the tension in the hose clamp is maintained constant by the spring.
Specialty Hose Clamps
There are also many types of hose clamps that are specifically designed for particular applications. For example, heavy duty hose clamps are formed from thicker or stronger materials to withstand higher forces or greater hose pressures. Another form of specialty hose clamp includes a V-shaped band which can be positioned over the flanges of a flanged connection to hold the flanges together.
Hose clamps come in a variety of types, materials, and sizes. Different hose clamps have different characteristics, as well as benefits and drawbacks. Knowing your application and your needs will help determine which hose clamp is most appropriate for your particular use.
