The answer currently is 154. The leading brand of sample coolers – Sentry – supplies more than 6,000 per year to customers around the globe.
A sample cooler, also called a heat exchanger, is used to cool a sample from a process stream. It may seem simple, but it is a uniquely designed small tube in a shell heat exchanger. The sample to be cooled flows through the tube side of the cooler, and the cooling fluid, usually water, flows through the shell side. The cooled sample then is taken to a laboratory for analysis or piped to in-line process instrumentation for continuous monitoring of properties such as conductivity, pH or other chemical constituents.
Sample coolers can be used for both cooling and heating of water, steam, gases and hydrocarbons. For example, a volatile hydrocarbon sample can easily exceed temperatures of 500°F (260°C) and need cooling before analysis, while a diesel fuel may need to be heated using a similar heat exchanger before being sent to a diesel generator.
The primary users of sample coolers are power plants, refineries and petrochemical and chemical plants. Other uses for sample coolers include sanitary applications, such as water for injection in the pharmaceutical industry, fuel preheaters for diesel engines, instant hot water heaters and heaters for cleaning solutions such as those used by professional carpet cleaners.
Sample coolers generally range from one to five square feet of heat transfer surface and have different purposes. It’s important that the right sample cooler is used for the right application, considering specific type of fluid, temperature, pressure and flow conditions. Selecting a one-size-fits-all cooler for all samples is uneconomical and can be hazardous to personnel and equipment. It’s safer and more cost-effective to choose a single efficient Sentry sample cooler than multiple competitor coolers that don’t do the job.
There are many models of sample coolers to meet a variety of application conditions:
- Types of fluid
- Flow rates
- Pressure drops
- Liquid or gas phases
- Characteristics of cooling water, such as chlorides, calcium/hardness, or high Total Dissolved Solids (TDS)
Different sample cooler designs offer different tube diameters, materials, wall thicknesses or lengths. The tubing may need to be welded or seamless. Plus, the shell materials can vary. Sentry sample coolers also are designed to meet varying inspection requirements such as Canadian Registration Number (CRN), Pressure Equipment Directive (PED), TÜV, ASME Section VIII, and Material Test Reports (MTRs).
Sentry sample cooler and heat exchanger types include:
Single Helical Tube – This type of cooler is compact, with high efficiency for cooling high temperature and/or high pressure liquid or gas samples. It is the highest efficiency sample cooler commercially available, and can handle temperature ratings to 1100°F at 5000 psig (593°C at 345 bar). It can be made to specification in a wide range of materials and configurations to meet EPRI/ASTM/ASME sampling guidelines, and many models are available with the ASME section VIII code stamp, CE or CRN registrations.
Spiral Tube – Spiral tube heat exchangers provide high efficiency in a small footprint for high pressure applications, such as hot water heating, and processes. This type of sample cooler consists of a dual manifold multi-tube spiral assembly inserted into a shell, where two paths are created for full counterflow heat transfer. This type of sample cooler is up to 40 percent more efficient than a typical shell and tube heat exchanger. Its spring-like design means it can handle pressure ratings at 5000 psi (345 bar) and even up to 10,000 psi (689 bar), and temperature ratings up to 1000°F (540°C). It is compact and lightweight, and highly resistant to thermal and pressure shock.
Dual Tube Coil (DTC) – This design is a helically wound tube-in-tube full counter flow design for a variety of lower flow applications, with a fully drainable inner and outer coil with no dead spots or crevices. It is available in a wide variety of materials and features tri-clamp and electropolished units to meet sanitary requirements.