Knowledge HUB

Worm Drive Clamp Family

1. How to select a hose clamp?

Selection of clamp based on-
TYPE: Based on your application Light duty, Medium Duty and Heavy duty
SIZE: Hose clamp size refers to the clamping diameter range, depending upon minimum and maximum achievable diameter. To determine the dimensions needed, install the hose on the spigot with bead (which expands over the hose), now measure the maximum diameter of the hose, then select a clamp that accommodates the mean diameter in about the centre of its range. Ideally clamp should be used up to 25% on either side of mean clamp diameter i.e., if the clamp size is 50-70mm (20mm range, mean diameter- 60mm) the ideal clamping range should be 55-65mm only.
MATERIAL GRADE: Based on the operating environment conditions & material corrosion resistance clamp material grade should be selected.

CodeMaterialCorrosion Resistance Min. (hrs)

2. Difference between Perforated & Serrated clamps & application basis selection of clamp.

The basic difference between Perforated and Serrated clamps is, Perforated clamps have pierced teeth on the band of the clamp which engages with the screw, whereas in case of Serrated clamps, the teeth on band are formed which engages with the screw to provide the necessary clamping force.

In case of perforated clamps there is a possibility of hose biting on a soft hoses due to pierced teeth. To avoid this liner can be orovided to protect soft hose in the specific application. Application torque in perforated clamps would be higher than serrated clamps.

In serrated clamps hose biting issue doesn’t arise due to rolled edges of the threads and smooth underside. Also, the serrated clamp’s residual torque is higher by almost 30% to 50% than perforated clamp.

Note: Perforated clamps confirms SAE J1508 American standard, while Serrated clamps confirms to DIN 3017 German standard.

3. Why is the use of Hose clamp not suggested
on close diameter?

The bottom radius of the clamp housing is adjusted to mean clamp diameter, so if the clamp is tightened on the close diameter there are enhanced possibilities of joint leakage. Also, if the clamp is tightened on the close diameter there will be a long band protruding out of the clamp which may hinder the operator while maintenance tasks & assembling / dismantling time is also wasted.

4.Difference between Heavy Duty &
conventional clamp

The heavy-duty worm drive clamp has more precise & firm engagement of screw & Band achieved by the use of Split housing construction. Split construction of housing provides better torque retention abilities to the clamp. Rigid split construction allows the clamp to withstand higher application torque.

T-Bolt Clamp Family

1. How constant tension spring loaded T-bolt clamps differ from T-bolt clamps

The Constant Tension T-Bolt clamps are equipped with the mechanism to provide constant radial load on the hose circumference at extreme cold weather conditions. This is required as joint diameter contracts at extreme cold weather .In case of standard T-Bolt clamp, tensioning mechanism is not available for automatic diameter compensation. This clamp is used in applications with no considerable temperature changes.

2. Do spring loaded T-bolt clamps works on both hot & cold temperatures?

When the joint temperature is above normal temperature the joint is going to expand & so the hose diameter & clamp diameter, hence there is no need to adjust the clamping diameter. In extreme cold climate the joint contracts but as thermal coefficient of expansion & contraction of rubber is lower than metal the interference between hose & pipe reduces. In such condition clamp is expected to adjust. This adjustment is possible in Spring Loaded T-Bolt clamps. So spring loaded T-Bolt clamps are very useful in extreme cold weather.

3. How heavy duty T-Bolt clamps differ from conventional T-Bolt clamp

The heavy-duty clamps are designed to provide high tensile strength, durability and reliability for tough and demanding applications. The heavy-duty clamps have thicker band as compared to standard T-Bolt clamps. Application torque values are also high in heavy duty T bolt clamps against regular T bolt clamps.


1. How to install No Hub Coupling?

No-hub couplings are used to join cast iron pipes having same or different diameter that does not have the traditional Hub and Spigot. They are normally installed with a calibrated torque wrench set at 6.77 Nm (1½” – 10”) or 9.03 Nm (12” & 15”). To install the coupling on cast iron pipes, follow the below procedure;
1) Install the Neoprene sealing sleeve on one end of the pipe or fitting.
2) Place the stainless-steel shield over the other end to be joined.
3) Insert both ends into the sealing sleeve until they fix against the moulded centre stop, inside the sleeve.
4) Centre the shield over the sealing sleeve and tighten as directed below.

2. What is the difference between shielded coupling and unshielded coupling?

The shielded coupling is manufactured with a neoprene gasket, stainless steel heavy duty clamps and a corrugated shield. The shielded coupling is encased in a metal structure (corrugated shield) allowing it to be protected from the deflection and constant movement of underground infrastructure layers. Shielded couplings are typically used for underground applications, but can be used above ground. Unshielded couplings are made of similar material and composition as a shielded coupling, but do not include corrugated shield and heavy-duty clamps. While they do create a leak-proof seal, unshielded couplings are not recommended to be used in underground applications where shear forces and heavy earth loads are common.

Customized clamps

1. Selection & designing (Required parameters & conditions to be considered)

To meet specific application requirement, we need to develop the part as per customized specification. To design & develop the same following parameters are need to be considered;

  • Operating pressure, vibrations & temp cycles
  • Operating environment
  • Application torque
  • Hose & spigot geometry
  • Bead geometry
  • Hose compression ratio
  • Type of charge to be handled
  • Application industry-Automotive/food/etc.

VTB Family

1. What is the working principle of V Band Clamp?

V-Band clamp’s method of operation is based on principle of inclined plan (Wedging action). When the closure bolt is tightened, this exerts radial force on the V-profile segments. The two halves of the flange are pressed axially together by means of the V-Petal wedging action (see diagram below). The radial force that is exerted is converted into considerably higher axial force.