An Overview and Benefits of Rupture Detection in Double Diaphragm Pumps

What is a double diaphragm pump and rupture detection in detail?

A double diaphragm pump consists of two flexible diaphragms that moves back and forth, drawing fluid into the pumps and pushing it out. Rupture detection system in a double diaphragm pump monitors the condition of the pump's diaphragm to prevent cross-contamination of the process fluid and the pump's hydraulic system. In most cases, the redundant diaphragm is a diaphragm in contact with the process fluid.

How is a ruptured diaphragm detected in a double diaphragm pump?

During normal operation, the pressure between the two diaphragms is much lower than the process pressure. If either diaphragm fails, the system senses the process pressure from either fluid while the redundant diaphragm continues to create a seal between the two fluids. When pressure is encountered, the rupture detection system indicates the pressure change on a gauge (see Figure 1) or can activate the pressure switch (see Figure 2) to stop the pump or sound an alarm. Additional options for connecting a pressure transmitter are available.

Figure 1

Figure 2

Types of Rupture Detection:

Conductivity Rupture Detection

The fluid between two diaphragms, usually referred to as the intermediate fluid, is selected to have conductive properties that differ primarily from the hydraulic fluid and, if possible, from the process fluid.

Conductivity probe (see Figure 3) is inserted through the walls of the intermediate ring into the intermediate fluid. Thus, when either the process or hydraulic diaphragm ruptures, a change in intermediate fluid conductivity is sensed.

Most applications feature a process liquid that is highly conductive. The most common intermediate fluid is vegetable oil.

The main component of the conductivity rupture detection system is the sensor, or conductivity probe. The sensor may be connected to either the user’s system, or to a conductivity actuated on/off relay supplied by Milton Roy. The relay can be wired in various ways to sound an alarm, stop the pump, or trigger other mechanisms in response to a diaphragm rupture.

Figure 3

What are the primary benefits of having a diaphragm pump with integrated rupture detection?

Rupture detection system senses the pressure change between the two diaphragms and prevents cross-contamination of the process fluid and the pump's hydraulic system.

It helps the user know if the diaphragm is failing and when maintenance is required.

Having the rupture detection system issue a warning before total failure helps to prevent the fluid from leaking outside.

Rupture detection systems are also essential to the hydraulic efficiency of a pump, as any connection could potentially be an additional point of hydraulic loss. It allows manufacturers to create a more efficient pump and that directly influences the performance of the pump.

What are the applications for rupture detection systems?

Rupture detection systems add additional security and are ideal for critical dosing applications where toxic, aggressive or environmentally hazardous chemicals are used, or where pumps are remotely mounted and not routinely observed in operation. Below are types of applications rupture directions systems are used in.

Visual Indication- A pressure gauge is routinely monitored for indication of unusual pressure. This does not apply to conductivity type double diaphragm

Switch Closure- Either the relay in the conductivity sensor, or the contact in the pressure switch can be used in

• Sound alarm
• Shut down the pump
• Start up a standby pump
• Shut down the entire process