Find Meriam Instruments online at Thermometer Central. Meriam, a Scott Fetzer company, is a trusted leader in measurement and calibration solutions. Joseph Meriam began manufacturing U-Type Manometers in his garage. The need for durable, accurate pressure measuring instruments in the industrial revolution was driving the growth of the company. Meriam manufactures reliable and accurate measurement instrumentation including mechanical and electronic pressure indicators, analog and digital pressure transmitters, primary flow elements, handheld pressure, temperature and loop calibrators, handheld HART communicators, process indicators and complete flow systems.